山本 千裕

TAFRO syndrome, a rare systemic inflammatory disease, can lead to multiorgan failure without appropriate treatment. Although thrombocytopenia is frequently seen in patients with TAFRO syndrome, little is known about its pathogenesis. Moreover, while recent studies have reported the presence of an anterior mediastinal mass in some patients, the pathological status of this remains unclear. Here, we report a case of fatal bleeding in a patient with TAFRO syndrome accompanied by an anterior mediastinal mass. A 55-year-old female was transferred to our hospital with a 2-week history of fever, epistaxis, and dyspnea. Laboratory tests revealed severe thrombocytopenia, computed tomography (CT) showed pleural effusions, and bone marrow biopsy revealed reticulin myelofibrosis. We suspected TAFRO syndrome, but the CT scan showed an anterior mediastinal mass that required a biopsy to exclude malignancy. She soon developed severe hemorrhagic diathesis and died of intracranial hemorrhage despite intensive treatment. She had multiple autoantibodies against platelets, which caused platelet destruction. An autopsy of the mediastinal mass revealed fibrous thymus tissues with infiltration by plasma cells. Our case suggests that thrombocytopenia could be attributed to antibody-mediated destruction and could be lethal. Hence, immediate treatment is imperative in cases of severe thrombocytopenia, even when accompanied by an anterior mediastinal mass.

BACKGROUND: Wilms' tumor 1 (WT1) mRNA expression is a universal marker of minimal residual disease in patients with acute myeloid leukemia (AML). The aim of this retrospective study was to evaluate the ability of serial measurement of peripheral blood WT1 mRNA levels to predict relapse in patients with AML in remission. PATIENTS AND METHODS: From April 2012 to May 2015, 131 patients with AML were admitted to our hospital. Among them, 55 were examined for WT1 mRNA at least 3 times during complete remission to assess minimal residual disease, and thus were included in the following analyses. RESULTS: With a median follow-up duration of 921 days, 34 remained in remission, but their WT1 values frequently increased to 100 copies/μg RNA. Therefore, we focused on the 40 posttreatment observation periods of 37 patients who experienced high WT1 values (defined as those above 100 copies/μg RNA) at least once after they achieved remission. The cumulative incidence of hematologic relapse was 75.8% at 6 months in 26 patients with 2 consecutive high WT1 values, whereas just 1 of the 14 patients with only 1 high WT1 value relapsed (P < .01). Similar results were obtained in subgroup analyses of allogeneic stem cell transplant recipients. CONCLUSION: Sequential monitoring of the WT1 mRNA is of value for the early detection of hematologic relapse in patients with AML in remission after chemotherapy or stem cell transplantation.

<title>Abstract</title> Background Following activation by recognition of foreign antigens, human T-cells alter their metabolic pathways to meet the increasing energetic demands for efficient immune response. Like cancer cells, alloreactive T-cells show a preference for aerobic glycolysis rather than oxidative phosphorylation, which is referred to as "Warburg effect". Until recently, it has been thought that extracellular fatty acid (FA) uptake and β-oxidation are severely reduced in alloreactive T-cells; however, some studies have indicated that lipid metabolism is rather increased in alloreactive mouse T-cells, and that metabolic pathway of FA can be a promising target for GVHD. To determine the role of lipid metabolism in human alloreactive T-cells after hematopoietic stem cell transplantation, we investigated the metabolic changes in human T-cells in vivo using human-into-mouse xenogeneic GVHD models. Methods NOG mice received 250cGy of total body irradiation (TBI) and were subsequently injected intravenously with human pan T-cells. All mice developed severe GVHD and died within 2 weeks, while mice that received TBI only survived without any symptoms of GVHD. Cells were harvested from GVHD target organs of mice at day 9 after transplantation. For the measurement of glucose and fatty acid (FA) uptake by flow cytometry, cells were stained with fluorescent-labeled deoxyglucose analogue (2-NBDG) and long-chain fatty acid analogue (BODIPY 500/510 C12), respectively. PCR array and extracellular flux analysis were performed according to manufacturer's instructions. Results Glucose uptake, determined by flow cytometry, was significantly increased in human T-cells obtained from GVHD mice. Extracellular FA uptake was also increased in human T-cells in GVHD mice, and was associated with cell proliferation rate. Effector memory T-cells followed by central memory T-cells showed a higher FA uptake than did naive T-cells. These findings were similarly observed in both human CD4+ and CD8+ T-cells. Robust T-cell proliferation was observed even in MHC class I/II deficient (MHC−/−) NOG mice after transplantation, although to a lesser extent than MHC+/+ NOG mice, in a process known as homeostatic proliferation. Extracellular uptake of FA as well as glucose in T-cells was significantly decreased in MHC−/− NOG mice. Of note, even when compared among only fully proliferated T-cells between MHC+/+ and MHC−/− NOG mice, FA uptake was still significantly decreased in MHC−/− NOG mice, suggesting that the recognition of host MHC molecules by allogeneic T-cells accelerate this process. To compare the ability of human naive and memory T-cells to incorporate extracellular FA, we isolated human naive (CD45RA high) and memory (CD45RA low) T-cells and separately injected into NOG mice. Although it has been shown that memory T-cells exhibit different effector functions, the FA uptake in memory T-cells was comparable to that in naive T-cells. This suggests that memory T-cells can also alter their lipid metabolism following encounter with alloantigens. Finally, we assessed the expression of genes associated with lipid metabolism in human T-cells obtained from GVHD mice. Quantitative real-time PCR analysis detected up-regulation of mRNAs encoding the enzymes involved in FA transport including carnitine palmitoyltransferase (CPT1B), fatty acid binding protein (FABP1-4, FABP6, and FABP7), and β-oxidation pathway including acyl-CoA synthase (ACSBG2) and acyl-CoA dehydrogenase (ACAD9-11, ACADS, and ACADL) when compared with T-cells in MHC−/− NOG mice. Similarly, the expression of genes encoding the enzymes in triacylglycerol metabolism such as glycerol kinase (GK, GK2) and lipoprotein lipase (LPL) was up-regulated in GVHD mice. Furthermore, the expression of genes associated with mevalonate pathways such as HMG-CoA synthase (HMGCS1, HMGCS2), was also upregulated. These observations suggest that T-cells activated by alloantigens in vivo promote lipid hydrolysis, mitochondrial FA transport, and β-oxidation, resulting in greater utilization of free FA. Conclusion Human alloreactive T-cells increased extracellular uptake of FA as well as glucose, and intracellular lipid metabolism in response to alloantigens (summarized in the graphical abstract). Therapeutic effects of specific inhibition of lipid metabolic pathways by pharmacological inhibitors including etomoxir are now being investigated in this model. Figure. Figure. <sec> <title>Disclosures</title> Fujiwara: Shire: Consultancy; Pfizer: Consultancy; Chugai: Consultancy; Kirin: Consultancy; Kyowa-Hakko: Consultancy; Astellas: Consultancy. Ohmine:Kyowa Hakko Kirin: Speakers Bureau; Takara Bio: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Takeda Pharmaceutical: Speakers Bureau; Celgene Corporation: Speakers Bureau; Chugai Pharmaceutical: Speakers Bureau; Alexion Pharmaceuticals: Speakers Bureau; Ono Pharmaceutical: Consultancy. Muroi:Japanese Red Cross Society: Speakers Bureau; Dickinson and Company: Speakers Bureau; Becton: Speakers Bureau; JCR: Speakers Bureau. Kanda:Astellas: Consultancy, Honoraria, Research Funding; Eisai: Consultancy, Honoraria, Research Funding; Taiho: Research Funding; Nippon-Shinyaku: Research Funding; Chugai: Consultancy, Honoraria, Research Funding; Dainippon-Sumitomo: Consultancy, Honoraria, Research Funding; Pfizer: Research Funding; Otsuka: Research Funding; Shionogi: Consultancy, Honoraria, Research Funding; Kyowa-Hakko Kirin: Consultancy, Honoraria, Research Funding; MSD: Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Asahi-Kasei: Research Funding; Ono: Consultancy, Honoraria, Research Funding; Sanofi: Research Funding; Novartis: Research Funding; Taisho-Toyama: Research Funding; CSL Behring: Research Funding; Tanabe-Mitsubishi: Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Mochida: Consultancy, Honoraria; Alexion: Consultancy, Honoraria; Takara-bio: Consultancy, Honoraria. </sec>

The 1,3-beta-D-Glucan (BDG) assay is widely used for the diagnosis of fungal infections, especially in patients with hematologic malignancies. Some antimicrobials have been reported to cause false-positive results for BDG, but there has been no report on the effect of penicillin G (PCG) on BDG levels. We experienced a patient who developed false-positive BDG elevation during the administration of PCG for osteomyelitis due to Streptococcus pneumoniae infection. The serum BDG level increased up to 81.0 pg/ml during the continuous administration of PCG at 24 million units per day. However, chest and paranasal CT scan showed no evidence of fungal infection. The BDG level decreased to 38.0 pg/ml at 14 hours after the discontinuation of PCG. The amount of BDG in one vial of PCG inferred from these serum BDG levels is very similar to the actual BDG concentration in a vial of PCG. Therefore, during the administration of PCG, elevated BDG levels should be interpreted with caution, as they may be false-positive results.

Although the CD34+ cell dose in allogeneic peripheral blood stem cell transplantation (PBSCT) is considered to be associated with transplantation outcomes, a lower acceptable threshold has not been defined. We retrospectively analyzed 2919 adult patients with hematologic malignancies who underwent related PBSCT in Japan between 2001 and 2014. According to the number of CD34+ cells in the graft, we categorized 2494 patients in the standard group (2 to 5 × 106 cells/kg), 377 patient in the low group (1 to 2 × 106 cells/kg), and 48 patients in the very low group (<1 × 106 cells/kg). Compared with the standard group, the low and very low groups showed delayed neutrophil recovery (93.8%, 89.5%, and 78.3%, respectively at day +28; P < .001) and platelet recovery (69.3%, 53.0%, and 45.5%, respectively at day +28; P < .001). The 2-year overall survival (OS) in the 3 groups was 45.5%, 45.3%, and 29.8%, respectively, with inferior survival in the very low group. However, a higher percentage of high-risk patients may account for the inferior survival in the very low group, and no significant difference in OS was found in a multivariate analysis. There were no differences in relapse, nonrelapse mortality, or the development of graft-versus-host disease among the 3 groups. In conclusion, allogeneic PBSCT with low CD34+ cell doses of 1 to 2 × 106 cells/kg gives acceptable results, whereas further investigations are needed to evaluate the effects of lower doses of <1 × 106 cells/kg owing to the smaller number and the higher percentage of patients with adverse prognostic factors in this cohort.

Bone marrow mononuclear cells from 93 patients with hematological malignancies after allogeneic hematopoietic stem cell transplantation (AHSCT) were analyzed using flow cytometry (FCM). The disease was acute myeloblastic leukemia (50 patients), acute lymphoblastic leukemia, and others. Conditioning was myeloablative (80 patients) or reduced intensity. The stem cell source was bone marrow (75 patients), peripheral blood stem cells, or cord blood. After AHSCT, granulocyte colony-stimulating factor was given to all patients. All patients showed engraftment of the donor cells. FCM was conducted on a median of 22 days after AHSCT. The gate was set around a granulocytic region consisting of immature granulocytes. The positivity rates of CD13, CD14, CD15, CD33, CD34, CD56, and HLA-DR in the cells were 59.9 ± 27.4%, 5.8 ± 8.8%, 98.3 ± 1.9%, 92.3 ± 12.4%, 2.6 ± 5.8%, 24.3 ± 16.7%, and 9.1 ± 6.6%, respectively. The greatest value of CD56 positivity was 73.1%. On the basis of CD56 expression, cases of more than 24% CD56 positivity were assigned to the CD56-high group (39 patients), while the rest were assigned to the CD56-low/negative group. There were no significant differences between the two groups in terms of disease status, sex, donor, hematopoietic stem cells, days of FCM analysis, or peripheral blood cell counts around the days of performing FCM. These results indicate that CD56 can be expressed in normal immature granulocytes at a variety of expression levels in regenerative bone marrow. Attention should be paid when evaluating aberrant antigen expression of CD56 in granulocytes. [J Clin Exp Hematop 53(3) : 247-250, 2013]