仲宗根 秀樹

To characterize the outcomes of patients who developed a particular subsequent solid cancer after hematopoietic cell transplantation (HCT), age at cancer diagnosis, survival, and causes of death were compared with the respective primary cancer in the general population, using data from the national HCT registry and population-based cancer registries in Japan. Among 31 867 patients who underwent a first HCT between 1990 and 2013 and had progression-free survival at 1 year, 713 patients developed subsequent solid cancer. The median age at subsequent solid cancer diagnosis was 55 years, which was significantly younger than the 67 years for primary cancer patients in the general population (P < .001). The overall survival probability was 60% at 3 years after diagnosis of subsequent solid cancer and differed according to cancer type. Development of most solid cancers was associated with an increased risk of subsequent mortality after HCT. Subsequent solid cancers accounted for 76% of causes of death. Overall survival probabilities adjusted for age, sex, and year of diagnosis were lower in the HCT population than in the general population for colon, bone/soft tissue, and central nervous system cancers and did not differ statistically for other cancers. In conclusion, most subsequent solid cancers occurred at younger ages than primary cancers, emphasizing the need for cancer screening at younger ages. Subsequent solid cancers showed similar or worse survival compared with primary cancers. Biological and genetic differences between primary and subsequent solid cancers remain to be determined.

The aim of this study was to develop a new composite endpoint that accurately reflects the long-term success of allogeneic hematopoietic stem cell transplantation (allo-HSCT), as the conventional graft-versus-host disease (GVHD)-free, relapse-free survival (GRFS) overestimates the impact of GVHD. First, we validated current GRFS (cGRFS), which recently was proposed as a more accurate endpoint of long-term transplant success. cGRFS was defined as survival without disease relapse/progression or active chronic GVHD at a given time after allo-HSCT, calculated using 2 distinct methods: a linear combination of a Kaplan-Meier estimates approach and a multistate modelling approach. Next, we developed a new composite endpoint, refractory GRFS (rGRFS). rGRFS was calculated similarly to conventional GRFS treating grade III to IV acute GVHD, chronic GVHD requiring systemic treatment, and disease relapse/progression as events, except that GVHD that resolved and did not require systemic treatment at the last evaluation was excluded as an event in rGRFS. The 2 cGRFS curves obtained using 2 different approaches were superimposed and both were superior to that of conventional GRFS, reflecting the proportion of patients with resolved chronic GVHD. Finally, the curves of cGRFS and rGRFS overlapped after the first 2 years of post-transplant follow-up. These results suggest that cGRFS and rGRFS more accurately reflect transplant success than conventional GRFS. Especially, rGRFS can be more easily calculated than cGRFS and analyzed with widely used statistical approaches, whereas cGRFS more accurately represents the burden of GVHD-related morbidity in the first 2 years after transplantation.

The actual heparin concentration of harvested allogeneic bone marrow varies among harvest centers. We monitor the activated partial thromboplastin time (APTT) of the patient during bone marrow infusion and administer prophylactic protamine according to the APTT. We retrospectively reviewed the charts of consecutive patients who underwent bone marrow transplantation without bone marrow processing at our center between April 2007 and March 2016 (n = 94). APTT was monitored during marrow transfusion in 52 patients. We analyzed the relationship between the APTT ratio and several parameters related to heparin administration. As a result, the weight-based heparin administration rate (U/kg/hour) seemed to be more closely related to the APTT ratio (r = .38, P = .005) than to the total amount of heparin. There was no significant correlation between the APTT ratio and renal or liver function. Bleeding complications during and early after infusion were seen in 3 of 52 patients, and included intracranial, nasal, and punctured-skin bleeding. The APTT ratio during transfusion was over 5.88 in the former 2 patients and 2.14 in the latter. All of these patients recovered without sequelae. In conclusion, slow bone marrow infusion is recommended to decrease the weight-based heparin administration rate when the heparin concentration per patient body weight is high.

BACKGROUND: No standard method for measuring renal function has been established in allogeneic hematopoietic cell transplantation (allo-HCT). METHODS: We retrospectively analyzed 80 patients with hematological diseases who underwent allo-HCT at our center. We assessed renal function using creatinine clearance (Ccr), estimated glomerular filtration rate (eGFR) based on creatinine (eGFRcre), eGFR based on cystatin C (eGFRcys), and the average of eGFRcre and eGFRcys (eGFRave). We then evaluated the impact of pre-transplant renal function on the exacerbation of renal function and non-relapse mortality after transplantation. RESULTS: There was a significant correlation between Ccr and eGFRcre, eGFRcys, and eGFRave. eGFRave best predicted the exacerbation of renal function according to the area under the receiver-operating characteristic curve. The cumulative incidence of renal function exacerbation at 1 year was higher in the lower eGFRave group (<90 ml/min/1.73 m2) than in the higher eGFRave group (≥90 ml/min/1.73 m2; 0.85 vs. 0.39, p < 0.001), which was confirmed by a multivariate analysis (HR 2.75, p = 0.001). A lower eGFRave value was a marginally significant factor for non-relapse mortality (HR 3.29, p = 0.076). CONCLUSION: Among the four parameters, eGFRave best predicted the exacerbation of renal function in allo-HCT. Further, the marginal association between low eGFRave and high non-relapse mortality warrants further study in a prospective study in allo-HCT.

Optimal donor selection is critical for successful allogeneic hematopoietic cell transplantation (HCT). Donor sex and parity are well-established risk factors for graft-versus-host disease (GVHD), with male donors typically associated with lower rates of GVHD. Well-matched unrelated donors (URDs) have also been associated with increased risks of GVHD as compared with matched sibling donors. These observations raise the question of whether male URDs would lead to more (or less) favorable transplant outcomes as compared with parous female sibling donors. We used the Center for International Blood and Marrow Transplant Research registry to complete a retrospective cohort study in adults with acute myeloid leukemia, acute lymphoblastic leukemia, or myelodysplastic syndrome, who underwent T-cell replete HCT from these 2 donor types (parous female sibling or male URD) between 2000 and 2012. Primary outcomes included grade 2 to 4 acute GVHD (aGVHD), chronic GVHD (cGVHD), and overall survival. Secondary outcomes included disease-free survival, transplant-related mortality, and relapse. In 2813 recipients, patients receiving male URD transplants (n = 1921) had 1.6 times higher risk of grade 2 to 4 aGVHD (P < .0001). For cGVHD, recipient sex was a significant factor, so donor/recipient pairs were evaluated. Female recipients of male URD grafts had a higher risk of cGVHD than those receiving parous female sibling grafts (relative risk [RR] = 1.43, P < .0001), whereas male recipients had similar rates of cGVHD regardless of donor type (RR = 1.09, P = .23). Donor type did not significantly affect any other end point. We conclude that when available, parous female siblings are preferred over male URDs.

BACKGROUND: Consensus has yet to be reached regarding secondary prophylaxis in allogeneic hematopoietic stem cell transplantation (HSCT) with a complete resolution of invasive aspergillosis (IA) confirmed by chest computed tomography (CT). METHODS: We retrospectively evaluated the feasibility of antifungal prophylaxis with fluconazole in allogeneic HSCT recipients who had previously developed IA which showed complete resolution as confirmed by chest CT before HSCT. Consecutive adult patients who underwent allogeneic HSCT at our institution and who had received fluconazole as systemic antifungal prophylaxis from June 2007 to January 2015 were included. We compared the clinical outcomes between patients with a past history of IA who showed a complete resolution of chest CT abnormalities (n = 13) and those without a previous history of IA (n = 137). RESULTS: The cumulative incidence of proven or probable IA was 8.8% in the group without a past history of IA and 0.0% in the group with a past history of IA (p = .268). The cumulative incidence of proven or probable invasive fungal disease (IFD) within 100 days after allogeneic HSCT was 10.9% in the group without a past history of IA and 15.4% in the group with a past history of IA (p = .647). Fluconazole was switched to anti-mould agents in two-thirds of the patients in each group by day 100 after HSCT. CONCLUSIONS: Fluconazole was confirmed to be an acceptable prophylactic agent early after allogeneic HSCT in appropriately selected patients.

Complete response (CR) after treatment for multiple myeloma is associated with superior progression-free survival (PFS). Multiple myeloma patients were prospectively recruited for induction treatment with bortezomib and dexamethasone (BD) followed by autologous hematopoietic cell transplantation (auto-HCT) between 2010 and 2012. If patients did not achieve CR after auto-HCT, BD consolidation therapy was added to target CR. After the BD induction phase (n = 46), greater than or equal to CR was achieved in 4 patients (8%). After auto-HCT (n = 34), greater than or equal to CR was achieved in 9 patients (20%) and very good partial response (VGPR) was achieved in 11 (24%). Of the 24 patients who received auto-HCT and whose response was less than CR, 21 received BD consolidation therapy for a median of 4 courses. Finally, the maximum response with or without BD consolidation was greater than or equal to CR in 19 (41%), VGPR in 7 (15%), and PR in 6 (13%). Through BD consolidation, CR was achieved in 8 of 11 patients with post-HCT VGPR and in 2 of 12 patients with post-HCT PR. In total, 4 year PFS and overall survival were 43 and 80%, respectively. After adjusting for clinical factors, there was no difference in PFS between CR patients after auto-HCT and BD consolidation, while patients with less than or equal to VGPR after consolidation had a significantly lower PFS. Patients with post-HCT CR showed good PFS, and targeting CR through BD consolidation could improve the CR rate. It would be worthwhile to prospectively compare the efficacy of consolidation only for patients who failed to achieve CR to a universal consolidation strategy.

Delayed platelet recovery (DPR) despite prompt neutrophil engraftment is frequently observed after allogeneic hematopoietic stem cell transplantation (HSCT). However, few studies have evaluated the risk factors and long-term outcome. Therefore, we retrospectively analysed 219 adult patients who underwent their first allogenic HSCT with neutrophil engraftment. Of these 219 patients, 50 (22.8%) had DPR that was defined as relapse-free survival at day 60 after HSCT without primary platelet recovery despite neutrophil engraftment. The results of a multivariate analysis showed that a high-risk underlying disease (odds ratio [OR], 2.38; 95% confidence interval [CI], 1.04-5.48; P = .041) and human leukocyte antigen-mismatched HSCT (OR, 2.63; 95% CI, 1.28-5.43; P = .009) were associated with an increased risk of DPR. In univariate analyses, the occurrence of DPR was significantly associated with inferior overall survival, high nonrelapse mortality, and a low incidence of chronic graft-versus-host disease (GVHD), despite a comparable relapse rate. In multivariate analyses, DPR was associated with inferior overall survival (hazard ratio [HR], 2.00; 95% CI, 1.23-3.27; P = .005) and a low incidence of chronic GVHD (HR, 0.42; 95% CI, 0.22-0.78; P = .002). In conclusion, DPR was a strong predictor of shorter survival but also less frequent chronic GVHD.

Complete response (CR) after treatment for multiple myeloma is associated with superior progression-free survival (PFS). Multiple myeloma patients were prospectively recruited for induction treatment with bortezomib and dexamethasone (BD) followed by autologous hematopoietic cell transplantation (auto-HCT) between 2010 and 2012. If patients did not achieve CR after auto-HCT, BD consolidation therapy was added to target CR. After the BD induction phase (n = 46), greater than or equal to CR was achieved in 4 patients (8%). After auto-HCT (n = 34), greater than or equal to CR was achieved in 9 patients (20%) and very good partial response (VGPR) was achieved in 11 (24%). Of the 24 patients who received auto-HCT and whose response was less than CR, 21 received BD consolidation therapy for a median of 4 courses. Finally, the maximum response with or without BD consolidation was greater than or equal to CR in 19 (41%), VGPR in 7 (15%), and PR in 6 (13%). Through BD consolidation, CR was achieved in 8 of 11 patients with post-HCT VGPR and in 2 of 12 patients with post-HCT PR. In total, 4 year PFS and overall survival were 43 and 80%, respectively. After adjusting for clinical factors, there was no difference in PFS between CR patients after auto-HCT and BD consolidation, while patients with less than or equal to VGPR after consolidation had a significantly lower PFS. Patients with post-HCT CR showed good PFS, and targeting CR through BD consolidation could improve the CR rate. It would be worthwhile to prospectively compare the efficacy of consolidation only for patients who failed to achieve CR to a universal consolidation strategy.

We hypothesized that systemic corticosteroid administration would be safely avoided not only in grade I acute graft-versus-host disease (GVHD) but also in selected patients with grade II acute GVHD limited to the skin (grade IIs GVHD). We retrospectively evaluated risk factors for subsequent GVHD progression, defined as the involvement of other organs or progression to grade III to IV GVHD, in 50 patients with acute GVHD of grade IIs at its onset. Sixteen patients received systemic corticosteroid administration before GVHD progression. The cumulative incidence of GVHD progression at 28 days from the onset of grade IIs GVHD was 24%. Twenty-five patients did not require systemic corticosteroid administration throughout the entire episode of acute GVHD. Systemic corticosteroid administration before GVHD progression did not affect GVHD progression, chronic GVHD, or non-relapse mortality. Early onset (less than 26 days from transplantation) of grade IIs GVHD was identified as the only statistically significant risk factor for GVHD progression (hazard ratio 6.73, 95% confidence interval 1.5-31.1, P = 0.01). In conclusion, avoiding systemic corticosteroid administration for selected patients with grade IIs GVHD before GVHD progression did not compromise the transplantation outcomes. Patients with early-onset grade IIs GVHD were at high risk for GVHD progression.

Although a positive cytotoxic crossmatch (XM) has been reported to predict graft failure, mainly in solid organ transplantations, its significance in allogeneic hematopoietic cell transplantation (HCT) remains to be elucidated. We retrospectively assessed the impact of positive XM on neutrophil engraftment in 41 patients who underwent HCT with an HLA-mismatched related donor. XM was positive in 22 patients. Six of these 22 patients were also positive for anti-HLA antibody, whereas only 1 was positive for donor-specific anti-HLA antibody. The cumulative incidence of engraftment at day +28 was 89.5% in patients with negative XM versus 59.1% in those with positive XM (P = .08). In particular, positive B cell warm XM was significantly associated with a lower probability of engraftment at day +28 (46.7% versus 88.5%; P = .04). In a multivariate analysis, both positive XM and positive B cell warm XM were significantly associated with delayed engraftment (hazard ratio [HR], .46; P = .02 and HR, .41; P = .01, respectively). There was no significant difference in the achievement of engraftment between those with and without detection of anti-HLA antibodies. In conclusion, positive XM might be associated with a delayed neutrophil engraftment after HCT from HLA-mismatched related donors.

We previously reported that the T-cell receptor (TCR) repertoire of human T-cell lymphotropic virus type 1 (HTLV-1) Tax301-309-specific CD8+ cytotoxic T cells (Tax301-309-CTLs) was highly restricted and a particular amino acid sequence motif, the PDR motif, was conserved among HLA-A*24:02-positive (HLA-A*24:02+) adult T-cell leukemia/lymphoma (ATL) patients who had undergone allogeneic hematopoietic cell transplantation (allo-HSCT). Furthermore, we found that donorderived PDR+ CTLs selectively expanded in ATL long-term HSCT survivors with strong CTL activity against HTLV-1. On the other hand, the TCR repertoires in Tax301- 309-CTLs of asymptomatic HTLV-1 carriers (ACs) remain unclear. In this study, we directly identified the DNA sequence of complementarity-determining region 3 (CDR3) of the TCR-β chain of Tax301-309-CTLs at the single-cell level and compared not only the TCR repertoires but also the frequencies and phenotypes of Tax301-309-CTLs between ACs and ATL patients. We did not observe any essential difference in the frequencies of Tax301-309-CTLs between ACs and ATL patients. In the single-cell TCR repertoire analysis of Tax301-309-CTLs, 1,458 Tax301-309-CTLs and 140 clones were identified in this cohort. Tax301-309-CTLs showed highly restricted TCR repertoires with a strongly biased usage of BV7, and PDR, the unique motif in TCR-β CDR3, was exclusively observed in all ACs and ATL patients. However, there was no correlation between PDR+ CTL frequencies and HTLV-1 proviral load (PVL). In conclusion, we have identified, for the first time, a unique amino acid sequence, PDR, as a public TCR-CDR3 motif against Tax in HLA-A*24:02+ HTLV-1-infected individuals. Further investigations are warranted to elucidate the role of the PDR+ CTL response in the progression from carrier state to ATL.

BACKGROUND: We evaluated the clinical significance of repeat blood cultures in persistent and recurrent fever during neutropenia in adult acute myeloid leukaemia (AML) and myelodysplastic syndrome (MDS) patients undergoing intensive chemotherapy. METHODS: We retrospectively reviewed the chemotherapy cycles at our centre between January 2007 and December 2015. Blood cultures obtained within three days after initial febrile neutropenia (FN) were defined as initial blood cultures and those obtained on or after day 4 were defined as repeat blood cultures. RESULTS: Overall, 321 chemotherapy cycles in 89 patients were subjected to review. FN was identified in 276 (86.0%) chemotherapy cycles. In persistent FN (134 episodes), the causative pathogens were detected by repeat blood cultures in seven episodes (5.2%), including only three episodes (2.2%) of new infection. Shaking chills and high body temperature were identified as significant predictors for bloodstream infection (BSI). In recurrent FN (85 episodes), the causative pathogens were detected in seven episodes (8.2%), and all of these were new organisms. The frequency of detecting new pathogens by repeat blood cultures in recurrent FN (7/85) was higher than that in persistent FN (3/134) (p = .0491). A history of recent BSI was identified as a significant predictor for BSI in recurrent FN. CONCLUSIONS: The diagnostic yield of repeat blood cultures for persistent FN was low in intensive chemotherapy for AML and MDS. The frequency of repeat blood cultures for persistent FN could be reduced based on predictors. On the other hand, blood cultures were considered to be essential in cases with recurrent FN.

We previously reported that the T-cell receptor (TCR) repertoire of human T-cell lymphotropic virus type 1 (HTLV-1) Tax301-309-specific CD8+ cytotoxic T cells (Tax301-309-CTLs) was highly restricted and a particular amino acid sequence motif, the PDR motif, was conserved among HLA-A*24:02-positive (HLA-A*24:02+) adult T-cell leukemia/lymphoma (ATL) patients who had undergone allogeneic hematopoietic cell transplantation (allo-HSCT). Furthermore, we found that donor-derived PDR+ CTLs selectively expanded in ATL long-term HSCT survivors with strong CTL activity against HTLV-1. On the other hand, the TCR repertoires in Tax301-309-CTLs of asymptomatic HTLV-1 carriers (ACs) remain unclear. In this study, we directly identified the DNA sequence of complementarity-determining region 3 (CDR3) of the TCR-β chain of Tax301-309-CTLs at the single-cell level and compared not only the TCR repertoires but also the frequencies and phenotypes of Tax301-309-CTLs between ACs and ATL patients. We did not observe any essential difference in the frequencies of Tax301-309-CTLs between ACs and ATL patients. In the single-cell TCR repertoire analysis of Tax301-309-CTLs, 1,458 Tax301-309-CTLs and 140 clones were identified in this cohort. Tax301-309-CTLs showed highly restricted TCR repertoires with a strongly biased usage of BV7, and PDR, the unique motif in TCR-β CDR3, was exclusively observed in all ACs and ATL patients. However, there was no correlation between PDR+ CTL frequencies and HTLV-1 proviral load (PVL). In conclusion, we have identified, for the first time, a unique amino acid sequence, PDR, as a public TCR-CDR3 motif against Tax in HLA-A*24:02+ HTLV-1-infected individuals. Further investigations are warranted to elucidate the role of the PDR+ CTL response in the progression from carrier state to ATL.IMPORTANCE ATL is an aggressive T-cell malignancy caused by HTLV-1 infection. The HTLV-1 regulatory protein Tax aggressively promotes the proliferation of HTLV-1-infected lymphocytes and is also a major target antigen for CD8+ CTLs. In our previous evaluation of Tax301-309-CTLs, we found that a unique amino acid sequence motif, PDR, in CDR3 of the TCR-β chain of Tax301-309-CTLs was conserved among ATL patients after allo-HSCT. Furthermore, the PDR+ Tax301-309-CTL clones selectively expanded and showed strong cytotoxic activities against HTLV-1. On the other hand, it remains unclear how Tax301-309-CTL repertoire exists in ACs. In this study, we comprehensively compared Tax-specific TCR repertoires at the single-cell level between ACs and ATL patients. Tax301-309-CTLs showed highly restricted TCR repertoires with a strongly biased usage of BV7, and PDR, the unique motif in TCR-β CDR3, was conserved in all ACs and ATL patients, regardless of clinical subtype in HTLV-1 infection.

We previously reported that oral low-dose acyclovir (200 mg/day) for the prevention of herpes simplex virus (HSV) infections after allogenic hematopoietic stem cell transplantation (HSCT) is effective without the emergence of acyclovir-resistant HSV infections. However, HSV infections are of significant concern because the number of allogeneic HSCT with T-cell depletion, which is a risk factor of the emergence of drug-resistant HSV infections, has been increasing. We experienced a 25-year-old female who received allogenic HSCT from an unrelated donor with 1-antigen mismatch using anti-thymocyte globulin. Despite acyclovir prophylaxis (200 mg/day), she developed the right palatal ulcer that was positive for HSV-1 specific antigen by fluorescent antibody on day 20 and developed new hypoglossal and tongue ulcers on day 33. Replacement of acyclovir with foscarnet improved her ulcers. We isolated 2 acyclovir-resistant and foscarnet-sensitive strains from the right palatal and hypoglossal ulcers, which had the same frame shift mutation in the thymidine kinase genes. The rate of proliferation of the isolate from the hypoglossal ulcer was faster than that from the right palatal ulcer in the plaque reduction assay. HSV strains that acquired acyclovir-resistant mutations at the right palatal ulcer with larger plaque might spread to the hypoglossal ulcer as the secondary site of infection because of better growth property. Second-line antiviral agents should be considered when we suspect treatment failure of HSV infection, especially in HSCT with T-cell depletion. Further studies are required whether low-dose acyclovir prophylaxis leads to the emergence of virological resistance.

Levofloxacin (LVFX) is widely used for antibacterial prophylaxis during neutropenia. Garenoxacin (GRNX), which has been investigated in Japan, has stronger antibacterial activity than LVFX against gram-positive bacteria; however, no studies have compared the effectiveness of LVFX and GRNX. We retrospectively analyzed 42 patients with acute leukemia and 32 patients who underwent hematopoietic cell transplantation. Thirty-one patients before September 2009 received GRNX, and subsequent 43 patients received LVFX. We compared the cumulative incidences of positive blood and stool cultures. There was no significant difference in the incidence of bacteremia between the GRNX and LVFX groups. However, while gram-negative bacteria were detected in 80% of the patients with bacteremia in the GRNX group, they were detected in only 33% of the patients with bacteremia in the LVFX group. Patients in the GRNX group more frequently experienced positive stool cultures than those in the LVFX group, and this was confirmed by a multivariate analysis. Gram-negative bacteria accounted for 100 and 67% of the stool culture results in the GRNX and LVFX groups, respectively. While both fluoroquinolones may be appropriate antibacterial prophylactic agents for neutropenia patients with hematological malignancies, vigilance for gram-negative bacterial infections should be exercised when GRNX is used as prophylaxis.

OBJECTIVES: To clarify optimal strategies for human leukocyte antigen (HLA)-mismatched haploidentical hematopoietic stem cell transplantation (HSCT). METHODS: Twelve patients who underwent HSCT from a haploidentical related donor using low-dose thymoglobulin were analyzed retrospectively. Thymoglobulin was added to conditioning regimens at 2.5 mg/kg/day for 2 days (days -4 and -3). Prophylaxis against graft-versus-host disease (GVHD) was performed with cyclosporine and methotrexate. RESULTS: The median age of the patients was 33 years. Six patients had previous allogeneic HSCT, and HSCT was performed in non-remission for nine patients. All patients but one, who died due to early infection, achieved neutrophil engraftment at a median of 17 days with complete donor-type chimerism. Acute and chronic GVHD were observed in six and five patients, respectively, but no patients died of GVHD-associated complication. No one developed cytomegalovirus disease, but Epstein-Barr virus-related lymphoproliferative disorder was observed in one patient. Long-term survival in remission without immunosuppressive agents are observed in two patients who underwent HSCT in remission, but the majority of patients who underwent HSCT in non-remission experienced disease progression. CONCLUSION: Haploidentical HSCT could be performed with thymoglobulin at 5 mg/kg, with the balance between GVHD and relapse rate. The dose reduction of thymoglobulin may be considered for advanced hematological malignancy.

BACKGROUND: We examined the clinical characteristics and predictive factors for mortality in coryneform bacteria bloodstream infection in hematological patients. METHODS: We searched for hematological patients who had positive blood cultures for coryneform bacteria at our center between April 2007 and January 2016. Patients with definite bloodstream infections were included. We started species identification in April 2014. RESULTS: Twenty of twenty-eight cases with a positive blood culture for coryneform bacteria were regarded as definite infections. Sixteen and two patients were allogeneic and autologous hematopoietic stem cell transplantation (HSCT) recipients, respectively. Corynebacterium striatum was identified in all nine of the cases tested and one patient was co-infected with Corynebacterium amycolatum. None of the patients died directly due to coryneform bacteria infection. The survival rates at 30, 60 and 180 days were 100%, 73.7% and 51.3%, respectively. Causes of mortality included progression of the underlying disease (n = 6), other infections (n = 4) and HSCT complications (n = 2). Mixed infection (hazard ratio (HR) 5.47, 95% confidence interval (CI) 1.30-23.0), renal impairment (HR 6.31, 95% CI 1.06-37.4) and absence of a central venous (CV) catheter at the onset (HR 6.39, 95% CI 1.04-39.45) were identified as predictive factors for mortality. CONCLUSION: Most of the coryneform bacteria bloodstream infections occurred in HSCT recipients. Contamination seemed to be less common when coryneform bacteria were detected in blood in hematological patients. Although coryneform bacteria bloodstream infection seemed to mostly be manageable, the prognosis was not desirable, particularly in patients with mixed infection, renal impairment and absence of a CV catheter.

Total body irradiation (TBI) has been thought to promote donor cell engraftment in allogeneic hematopoietic cell transplantation (HCT) from alternative donors. However, recent progress in HCT strategies may affect the clinical significance of TBI on neutrophil engraftment. With the use of a Japanese transplant registry database, we analyzed 3933 adult recipients (>15 y.o.) who underwent HCT between 2006 and 2013 from an 8/8 HLA-matched unrelated bone marrow donor (MUD, n = 1367), an HLA-mismatched unrelated bone marrow donor (MMUD, n = 1102), or unrelated cord blood (CBT, n = 1464). Conditioning regimens were divided into five groups: High-TBI-(>8Gy), Low-TBI- (≤8Gy), and no-TBI-myeloablative conditioning (MAC), and Low-TBI- and no-TBI-reduced-intensity conditioning (RIC). In both MUD and MMUD, neutrophil engraftment rate was >90% in each of the five conditioning groups, and TBI was not associated with prompt neutrophil engraftment in multivariate analyses. Conversely, in CBT, TBI regimens had a higher rate of day-30 neutrophil engraftment than no-TBI-regimens: 78% in High-TBI-MAC, 83% in Low-TBI-MAC, and 76% in Low-TBI-RIC versus 65% in No-TBI-MAC, and 68% in No-TBI-RIC (P < .001). Multivariate analyses in CBT demonstrated that TBI-regimens were significantly associated with a higher rate of neutrophil engraftment. Subsequently focusing on CBT patients alone, TBI-regimens were significantly associated with a higher rate of neutrophil engraftment in patients who received CBT with a 4/6 or less HLA allele-match, or who had anti-HLA antibodies. In summary, TBI-regimens had no impact on neutrophil engraftment in the current practice of unrelated bone marrow transplantation. However, in CBT, TBI is still necessary to enhance engraftment.

Graft-versus-host disease-free relapse-free survival, which is defined as the absence of grade III-IV acute graft-versus-host disease, systemically treated chronic graft-versus-host disease, relapse, and death, is a novel, meaningful composite end point for clinical trials. To characterize risk factors and differences in graft-versus-host disease-free relapse-free survival according to a variety of graft sources, we analyzed 23,302 patients with hematologic malignancy that had a first allogeneic transplantation from 2000 through 2013 using the Japanese national transplant registry database. The 1-year graft-versus-host disease-free relapse-free survival rate was 41% in all patients. The rate was higher after bone marrow transplantation than after peripheral blood stem cell transplantation due to the lower risks of III-IV acute and chronic graft-versus-host disease. The rate was highest after HLA-matched sibling bone marrow transplantation. The rate after single cord blood transplantation was comparable to that after HLA-matched unrelated bone marrow transplantation among patients aged 20 years or under, and was comparable or better than other alternative graft sources among patients aged 21 years or over, due to the low risk of chronic graft-versus-host disease. Other factors associated with better graft-versus-host disease-free relapse-free survival include female patients, antithymocyte globulin prophylaxis (for standard-risk disease), recent years of transplantation, sex combinations other than from a female donor to a male patient, the absence of prior autologous transplantation, myeloablative conditioning, negative cytomegalovirus serostatus, and tacrolimus-based prophylaxis. These results provide important information to guide the choice of graft sources and are benchmarks for future graft-versus-host disease prophylaxis studies.

We sought to assess the late mortality risks and causes of death among long-term survivors of allogeneic hematopoietic stem cell transplantation (HCT). The cases of 11,047 relapse-free survivors of a first HCT at least 2 years after HCT were analyzed. Standardized mortality ratios (SMR) were calculated and specific causes of death were compared with those of the Japanese population. Among relapse-free survivors at 2 years, overall survival percentages at 10 and 15 years were 87% and 83%, respectively. The overall risk of mortality was significantly higher compared with that of the general population. The risk of mortality was significantly higher from infection (SMR = 57.0), new hematologic malignancies (SMR = 2.2), other new malignancies (SMR = 3.0), respiratory causes (SMR = 109.3), gastrointestinal causes (SMR = 3.8), liver dysfunction (SMR = 6.1), genitourinary dysfunction (SMR = 17.6), and external or accidental causes (SMR = 2.3). The overall annual mortality rate showed a steep decrease from 2 to 5 years after HCT however, the decrease rate slowed after 10 years but was still higher than that of the general population at 20 years after HCT. SMRs in the earlier period of 2 to 4 years after HCT and 5 years or longer after HCT were 16.1 and 7.4, respectively. Long-term survivors after allogeneic HCT are at higher risk of mortality from various causes other than the underlying disease that led to HCT. Screening and preventive measures should be given a central role in reducing the morbidity and mortality of HCT recipients on long-term follow-up.

We sought to assess the late mortality risks and causes of death among long-term survivors of allogeneic hematopoietic stem cell transplantation (HCT). The cases of 11,047 relapse-free survivors of a first HCT at least 2 years after HCT were analyzed. Standardized mortality ratios (SMR) were calculated and specific causes of death were compared with those of the Japanese population. Among relapse-free survivors at 2 years, overall survival percentages at 10 and 15 years were 87% and 83%, respectively. The overall risk of mortality was significantly higher compared with that of the general population. The risk of mortality was significantly higher from infection (SMR = 57.0), new hematologic malignancies (SMR = 2.2), other new malignancies (SMR = 3.0), respiratory causes (SMR = 109.3), gastrointestinal causes (SMR = 3.8), liver dysfunction (SMR = 6.1), genitourinary dysfunction (SMR = 17.6), and external or accidental causes (SMR = 2.3). The overall annual mortality rate showed a steep decrease from 2 to 5 years after HCT; however, the decrease rate slowed after 10 years but was still higher than that of the general population at 20 years after HCT. SMRs in the earlier period of 2 to 4 years after HCT and 5 years or longer after HCT were 16.1 and 7.4, respectively. Long-term survivors after allogeneic HCT are at higher risk of mortality from various causes other than the underlying disease that led to HCT. Screening and preventive measures should be given a central role in reducing the morbidity and mortality of HCT recipients on long-term follow-up.

Secondary failure of platelet recovery (SFPR), a late decrease in the platelet count after primary platelet recovery that is not due to relapse or graft rejection, occasionally occurs after allogeneic hematopoietic stem cell transplantation (HSCT). The risk factors and impact of SFPR on transplantation outcomes are not well known in the clinical setting. Therefore, we retrospectively evaluated 184 adult patients who underwent their first allogeneic HSCT and achieved primary platelet recovery. The cumulative incidence of SFPR, defined as a decrease in the platelet count to below 20,000/µL for more than 7 days, was 12.2% at 3 years, with a median onset of 81 days (range, 39 to 729) after HSCT. Among patients who developed SFPR (n = 23), 19 (82.6%) showed recovery to a sustained platelet count of more than 20,000/µL without transfusion support, and the median duration of SFPR was 23 days (range, 7 to 1048 days). A multivariate analysis showed that in vivo T cell depletion (hazard ratio [HR], 6.92; 95% confidence interval [CI], 2.31 to 20.7; P < .001), grades II to IV acute graft-versus-host disease (HR, 3.99; 95% CI, 1.52 to 10.5; P = .005), and the use of ganciclovir or valganciclovir (HR, 2.86; 95% CI, 1.05 to 7.77; P = .039) were associated with an increased risk for SFPR. The occurrence of SFPR as a time-dependent covariate was significantly associated with inferior overall survival (HR, 2.29; 95% CI, 1.18 to 4.46; P = .015) in a multivariate analysis. These findings may help to improve the management and treatment strategy for SFPR.

Patients with hematological malignancies show a high prevalence of asymptomatic colonization with Clostridium difficile (CD colonization). Therefore, it is difficult to distinguish CD colonization with diarrhea induced by a conditioning regimen from true Clostridium difficile infection (CDI) in hematopoietic stem cell transplantation (HSCT) recipients. We retrospectively analyzed 308 consecutive patients who underwent a CD toxin A/B enzyme immunoassay test for diarrhea within 100 d after HSCT from November 2007 to May 2014. Thirty patients (9.7%) had positive CD toxin results, and 11 of these had positive results in subsequent tests after an initial negative result. Allogeneic HSCT, total body irradiation, stem cell source, acute leukemia, and the duration of neutropenia were significantly correlated with positive CD toxin results. In a logistic regression model, allogeneic HSCT was identified as a significant risk factor (odds ratio 18.6, p < 0.01). In an analysis limited to within 30 d after the conditioning regimen, the duration of neutropenia was the sole risk factor (odds ratio 10.4, p < 0.01). There were no distinctive clinical features for CDI, including the onset or duration of diarrhea. In conclusion, although CDI may be overdiagnosed in HSCT recipients, it is difficult to clinically distinguish between CDI and CD colonization.

Enzyme-linked immunosorbent assays (ELISAs) have traditionally been used to detect alloantibodies in patient plasma samples post hematopoietic cell transplantation (HCT); however, protein microarrays have the potential to be multiplexed, more sensitive, and higher throughput than ELISAs. Here, we describe the development of a novel and sensitive microarray method for detection of allogeneic antibodies against minor histocompatibility antigens encoded on the Y chromosome, called HY antigens. Six microarray surfaces were tested for their ability to bind recombinant protein and peptide HY antigens. Significant allogeneic immune responses were determined in male patients with female donors by considering normal male donor responses as baseline. HY microarray results were also compared with our previous ELISA results. Our overall goal was to maximize antibody detection for both recombinant protein and peptide epitopes. For detection of HY antigens, the Epoxy (Schott) protein microarray surface was both most sensitive and reliable and has become the standard surface in our microarray platform.

The patient was a 62-year-old woman with CD5(+) diffuse large B-cell lymphoma. Treatment with the R-CHOP regimen (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone) was started. On the eleventh day of the third cycle, headache and low grade fever developed. Her consciousness gradually deteriorated. Seven days after symptom onset, she was brought to the emergency department of our hospital. Cerebrospinal fluid (CSF) analysis revealed a white blood cell count of 25/μl, and a protein level of 188 mg/dl. Antibacterial and antiviral agents were administered based on a diagnosis of acute meningitis. She showed no improvement. We performed another lumbar puncture and intrathecal chemotherapy, a combination of methotrexate and dexamethasone, was administered because we suspected central nervous system involvement of lymphoma. She showed transient improvement. On day 12, we started the R-MPV regimen (rituximab, methotrexate, procarbazine, and vincristine). However, fever and disturbance of consciousness persisted. On day 20, we empirically started anti-tuberculosis treatment. Four days later, tubercle bacilli were confirmed by CSF culture after a 23-day incubation. We ultimately confirmed a diagnosis of tuberculous meningitis. Impaired cellular immunity in lymphoma patients increases the risk of tuberculosis. It is important to consider tuberculous meningitis in the differential diagnosis of a lymphoma patient presenting with meningitis.

Anaplastic lymphoma kinase-positive large B-cell lymphoma (ALK+LBCL) is a rare, aggressive B-cell lymphoma with ALK fusion genes. Histopathologically, the ALK immunohistochemical staining pattern is suggestive of the fusion partner of ALK. Here, we examined an ALK+LBCL case showing a unique diffuse cytoplasmic ALK staining pattern and identified EML4-ALK, which has not previously been reported in ALK+LBCL. Furthermore, to clarify whether the prognosis differs depending on the staining pattern, we reviewed 112 previously reported cases, and analyzed immunohistochemical markers and clinical data stratified by the staining pattern. We found that ALK staining can be classified into a granular cytoplasmic staining (GCS) or a non-GCS patterns. Sixty-four adult cases for which both the ALK staining pattern and survival time were reported were further analyzed for survival trends. The non-GCS pattern was significantly associated with inferior overall survival (P = 0.031). This difference remained significant after adjusting for age and clinical stage (hazard ratio 5.08, 95 % CI 1.88-13.7, P = 0.0013). Given that the ALK immunohistochemical staining pattern is associated with the ALK fusion partner, the present results suggest that the prognosis for ALK+LBCL differs depending on the ALK fusion partner.

OBJECTIVES: The D-index and the L-index, calculated as the area over the neutrophil and lymphocyte curves, respectively, reflect both the intensity and duration of cytopenia. We, retrospectively, investigated the impact of these indexes on pulmonary infection (PI) in induction chemotherapy for acute lymphoblastic leukemia (ALL) and lymphoblastic lymphoma (LBL). METHODS: We included 92 patients (ALL 83, LBL 9) from two institutions. We calculated the D-index and cumulative D-index until the development of PI (c-D-index), which enables real-time risk assessment for infection. We also calculated the L-index (35), defined as the area over the lymphocyte curve during lymphopenia (<700/µl) until day 35 and the cumulative-L-index until the development of PI (c-L-index). RESULTS: Eight patients developed PI on day 20 (median). Two patients were strongly suspected to have bacterial pneumonia, and the others were suspected to have pulmonary fungal infection. The D-index and the L-index (35) in patients with PI were higher than those in patients without PI (7230 ± 4734 vs. 4519 ± 3416, P = 0.041 and 15 458 ± 5243 vs. 8920 ± 5901, P = 0.018), while the c-D-index and the c-L-index were not significantly different. Although the c-L-index did not have predictive value for PI, c-D-index, when treated as a dichotomous variable with a cutoff value of 5589 as determined by a receiver operating characteristic curve analysis, showed a significant difference between two groups (P = 0.045). This association became clearer when we focused on suspected pulmonary fungal infection. DISCUSSION AND CONCLUSION: In induction chemotherapy for ALL/LBL, c-D-index with a cutoff value of 5589 might have predictive value for the development of PI.

Hepatic acute GvHD (aGvHD) is associated with high mortality owing to poor response to immunosuppressive therapy. The pathogenesis of hepatic aGvHD differs from that of other lesions, and specific risk factors related to pre-transplant liver conditions should be determined. We conducted a cohort study by using a Japanese transplant registry database (N=8378). Of these subjects, 1.5% had hepatitis C virus Ab (HCV-Ab) and 9.4% had liver dysfunction (elevated transaminase or bilirubin levels) before hematopoietic cell transplantation (HCT). After HCT, the cumulative incidence of hepatic aGvHD was 6.7%. On multivariate analyses, HCV-Ab positivity (hazard ratio (HR), 1.93; P=0.02) and pre-transplant liver dysfunction (HR, 1.85; P<0.01), as well as advanced HCT risk, unrelated donors, HLA mismatch and cyclosporine as GvHD prophylaxis, were significant risk factors for hepatic aGvHD, whereas hepatitis B virus surface Ag was not. Hepatic aGvHD was a significant risk factor for low overall survival and high transplant-related mortality in all aGvHD grades (P<0.01). This study is the first to show the relationship between pre-transplant liver conditions and hepatic aGvHD. A prospective study is awaited to validate the results of this study and establish a new strategy especially for high-risk patients.

The effects of intensive regimens and the roles of drugs used might differ between T- and B-lineage acute lymphoblastic leukemia (ALL). We performed a literature search for clinical studies published from January 1998 to March 2013. Studies were eligible for inclusion in the analyses if they included more than 80 patients with adult ALL who were treated with a uniform regimen and compared T- and B-lineage ALL. Studies that included only adolescent or elderly patients were excluded. We identified 11 clinical studies, which included a total of 381 and 1366 patients with T- and B-lineage ALL, respectively, and performed meta-analyses using the selected studies. Nine studies included patients with Philadelphia chromosome-positive (Ph+) ALL. A meta-analysis using the random-effect model demonstrated superior survival in patients with T-lineage ALL compared to those with B-lineage ALL (hazard ratio 1.78, 95 % confidence interval 1.50-2.11), though the inclusion of patients with Ph+ ALL in B-lineage ALL must have influenced this result strongly. We performed meta-regression analyses, adjusted according to whether or not patients with Ph+ ALL were included in each study. Use of dexamethasone (Dex), higher dose of methotrexate (MTX), and higher dose of L-asparaginase (L-asp) were associated with a significant trend toward a better outcome in T-lineage ALL. A meta-regression analysis including Dex and the dose of L-asp or MTX together as covariates showed that these factors were independently significant. In conclusion, the use of Dex and high-dose L-asp or MTX may improve the outcome of T-lineage ALL. This hypothesis should be tested in a prospective study including only patients with Ph-negative ALL.

OBJECTIVE: The purpose of this study was to review the high-resolution computed tomography (CT) findings in patients with pulmonary complications after allogeneic hematopoietic stem cell transplantation (HSCT), and to evaluate the relationship between CT findings and clinical outcomes. PATIENTS AND METHODS: We collected the clinical data in 96 consecutive patients who underwent CT scan for pulmonary complications after allogeneic HSCT and analyzed the relationships among these clinical characteristics, CT findings and clinical responses. Radiologists who were blinded to clinical information evaluated the CT findings. RESULTS: In multivariate analyses, the presence of chronic graft-versus-host disease (GVHD) and non-segmental multiple consolidations were significantly associated with a poor response to antimicrobial therapies, and the disease risk was significantly associated with a poor corticosteroid response. In addition, the existence of cavity formation and pleural effusion were significantly associated with a fatal prognosis. Twenty-five patients underwent bronchoscopic examination and 4 of them also underwent transbronchial lung biopsy (TBLB), but diagnostic information was not obtained in 15 patients. There was no significant association between specific CT findings and the diagnosis based on bronchoscopic examination. CONCLUSIONS: No specific CT finding was identified as a predictor for either an antimicrobial response or for a corticosteroid response in this study. The presence of cavity formation and pleural effusion may predict a poor prognosis.

Sex-mismatched hematopoietic cell transplantation is linked to increased graft-versus-host disease and mortality in myeloablative conditioning. Here we evaluated outcomes of 1,041 adult transplant recipients at two centers between 2006 and 2013 and investigated how the effect of sex-mismatching differed in myeloablative, reduced-intensity, and non-myeloablative total lymphoid irradiation with anti-thymocyte globulin conditioning. Among patients who underwent myeloablative conditioning, male recipients with female donors had increased chronic graft-versus-host disease (hazard ratio 1.83, P<0.01), increased non-relapse mortality (hazard ratio 1.84, P=0.022) and inferior overall survival (hazard ratio 1.59, P=0.018). In contrast, among patients who received reduced-intensity conditioning, male recipients with female donors had increased acute graft-versus-host disease (hazard ratio 1.96, P<0.01) but no difference in non-relapse mortality or overall survival. Among the patients who underwent total lymphoid irradiation with anti-thymocyte globulin, male recipients with female donors showed no increase in graft-versus-host disease or non-relapse mortality. Notably, only in the cohort receiving total lymphoid irradiation with anti-thymocyte globulin were male recipients with female donors significantly associated with reduced relapse (hazard ratio 0.64, P<0.01), and allo-antibody responses against H-Y antigens were predictive of reduced relapse. In the cohort given total lymphoid irradiation with anti-thymocyte globulin, the graft-versus-leukemia effect resulted in superior overall survival in recipients of sex-mismatched grafts (HR 0.69, P=0.037). In addition, only in the cohort treated with total lymphoid irradiation with anti-thymocyte globulin were female recipients with male donors associated with reduced relapse (hazard ratio 0.59, P<0.01) and superior survival (hazard ratio 0.61, P=0.014) compared with sex-matched pairs. We conclude that the risks and benefits of sex-mismatched transplants appear to differ according to conditioning strategy and this could affect donor selection.

OBJECTIVES: Limited data are available on the effect of how cyclophosphamide (CY) and total body irradiation (TBI) are administered. We analyzed the effect of the interval from TBI to hematopoietic stem cell transplantation (HSCT) on the outcome of HSCT. METHODS: Adult patients who underwent HSCT using myeloablative conditioning consisting of TBI and CY were retrospectively analyzed. They were divided into three groups according to the duration between the start of TBI and HSCT (Group A: 2-4 days, Group B: 5-8 days, Group C: 9-10 days). RESULTS: Seventy-five adult patients were included. The 3-year overall survival rate was 56, 47, and 77% in Groups A, B, and C, respectively (P = 0.14). Similarly, there was no significant difference among the three groups with respect to progression-free survival (57, 47, and 72%, P = 0.17), relapse rate (32, 37, and 16%, P = 0.29), or non-relapse mortality (8, 14, and 12%, P = 0.81). In addition, we observed no significant difference among the three groups with respect to the incidence of grade II-IV acute graft-versus-host disease (GVHD) (31, 47, and 32%, respectively, P = 0.56) and that of chronic GVHD (23, 23, and 22%, respectively, P = 0.97). DISCUSSION AND CONCLUSION: Although recipient immune system at HSCT might be affected by the timing of TBI, the duration between the start of TBI and HSCT did not influence the outcome of HSCT using myeloablative conditioning with TBI and CY.

Limited data are available on prophylaxis for herpes simplex virus (HSV) and varicella zoster virus (VZV) disease following autologous hematopoietic stem cell transplantation (auto-HCT). We retrospectively reviewed the clinical charts of 105 consecutive patients who underwent their first auto-HCT at our institution between September 2007 and June 2014. Before August 2009, 30 patients received oral acyclovir at 1000 mg/day until engraftment, whereas after September 2009, 69 patients received oral acyclovir at 200 mg/day. After engraftment, acyclovir was continued at 200 mg/day at the discretion of the attending physicians in both groups. The cumulative incidence of HSV disease at 1 year after auto-HCT was 7.7 and 4.5 % in patients who received oral acyclovir at 1000 and 200 mg/day, respectively (P = 0.75). Patients were next divided into three groups according to the timing at which acyclovir prophylaxis was stopped after auto-HCT; at engraftment, between engraftment and 1 year after auto-HCT, and later than 1 year. The cumulative incidence of VZV disease was 25.8, 7.7, and 0.0 % at 1 year, respectively. This study suggests that low-dose acyclovir prophylaxis may be effective for preventing HSV and VZV disease after auto-HCT. Our findings support the recommendation of acyclovir prophylaxis within the first year after auto-HCT.

Allogeneic antibodies against minor histocompatibility antigens encoded on the Y chromosome (HY-Abs) develop after hematopoietic cell transplant (HCT) of male recipients with female donors (F→M). However, the temporal association between HY-Ab development and chronic graft-versus-host disease (cGVHD) has yet to be elucidated. We studied 136 adult F→M HCT patients, with plasma prospectively collected through 3 years posttransplant, and measured immunoglobulin G against 6 H-Y antigens. Multiple HY-Abs were frequently detected beginning at 3 months posttransplant: 78 (57%) of F→M patients were seropositive for at least 1 of the 6 HY-Abs, and 3-month seropositivity for each HY-Ab was associated with a persistent seropositive response throughout the posttransplant follow-up period (P < .001 in each). There were no associations between pretransplant features and 3-month overall HY-Ab development. Detection of multiple HY-Abs at 3 months (represented by HY score) was significantly associated with an increased risk of cGVHD (P < .0001) and nonrelapse mortality (P < .01). Compared to clinical factors alone, the addition of HY score to clinical factors improved the predictive potential of cGVHD (P < .01). Monitoring HY-Ab development thus stratifies cGVHD risk in F→M HCT patients and may support preemptive prophylaxis therapy for cGVHD beginning at 3 months posttransplant.

In Japan, intravenous busulfan (ivBu) is usually given four times per day as an infusion at 0.8 mg/kg over 2 h. However, as this requires a midnight administration, a once-daily infusion of ivBu at 3.2 mg/kg over 3 h has been investigated as a more convenient and safer method. In this study, 20 Japanese patients received once-daily ivBu in conditioning regimens before allogeneic hematopoietic stem cell transplantation (HSCT), and blood samples were obtained just before, and 3, 3.5, 5, 7, 10, and 24 h after the initiation of ivBu infusion. The outcomes of HSCT were evaluated prospectively. The median area under the plasma concentration versus time curve (AUC) of Bu was 5272 μmol × min/L (range 3491–6284 μmol × min/L), and was similar to those in previous once-daily ivBu studies and to the estimated daily AUC in previous 4-times-daily ivBu studies. All of the patients but two, who died early due to infection, achieved neutrophil engraftment at a median of 25 days after transplantation. No patient was diagnosed with veno-occlusive disease according to the criteria established by Jones. No regimen-related toxicity was significantly associated with AUC. In conclusion, once-daily administration of ivBu has a stable pharmacokinetic profile, and was safely performed in Japanese patients.