藤原 慎一郎

Rapidly progressing ALL, a potentially fatal disease, demands timely diagnosis and treatment. On the other hand, spontaneous remission/regression (SR) is reported in various cancers including aggressive tumors like ALL. Infection or trauma-mediated immune system activation is assumed to cause SR, with the duration in cases of ALL typically being short. Indolent T-lymphoblastic proliferation (i-TLP) exhibits the uniform proliferation of TdT-positive T-cells, despite being a non-neoplastic disease, underscoring the significance of distinguishing it from T-cell acute lymphoblastic leukemia (T-ALL). i-TLP is expected to gain wider recognition and further advancements in understanding its pathology. Here, we present the case of a 59-year-old woman with T-ALL characterized by cycles of progression and SR followed by a rapid blast proliferation. This is the first reported case of T-ALL with repeated SR for more than one year, making this case an extremely rare clinical presentation. This challenging case will enhance comprehension of T-cell tumor pathogenesis.

The fludarabine/intravenous busulfan 12.8 mg/kg (FB4) regimen is an effective conditioning regimen in allogeneic hematopoietic stem cell transplantation for myelodysplastic syndrome (MDS); however, limited data is available on the prognostic impact of FB4 with low-dose anti-thymoglobulin (ATG ≤ 5 mg/kg) or low-dose total body irradiation (TBI ≤ 4 Gy). Therefore, we retrospectively evaluated the outcomes in 280 adults with de novo MDS who underwent their first transplantation from an unrelated donor between 2009 and 2018. Median age was 61 years (range, 16 to 70 years). In the FB4 alone (FB4), FB4 plus ATG (FB4-ATG), and FB4 plus TBI (FB4-TBI) groups, 3-year overall survival (OS) rates were 39.9, 64.8, and 43.7 %; 3-year non-relapse mortality (NRM) were 32.1, 22.1, and 27.1%; and 3-year relapse incidences were 34.7, 21.2, and 28.9%, respectively. The multivariate analyses showed that FB4-ATG group significantly correlated with better OS (hazard Ratio [HR], 0.51; 95% confidence interval [CI], 0.27-0.95; P=0.032) than FB4 group. FB4-ATG group tended to correlate with lower NRM (HR, 0.36;95% CI, 0.13-1.06; P=0.063) than FB4 group. In comparison with FB4-TBI group, FB4-ATG group showed better OS (HR 0.52, 95% CI 0.27-0.99, P=0.049) and NRM (HR 0.034, 95% CI 0.11-0.92, P=0.034). No significant differences were observed in OS and NRM between the FB4-TBI and FB4 groups. The present study demonstrated that the FB4 plus low-dose ATG regimen improved OS and NRM, but FB4 plus low-dose TBI regimen had no clear benefit over FB4 alone, in MDS patients who used unrelated donors.