Initiating-clone analysis in patients with acute myeloid leukemia secondary to essential thrombocythemia.

Most of essential thrombocythemia (ET) patients have the clone harboring a mutation in one of the JAK2, CALR, or MPL gene, and these clones generally acquire additional mutations at transformation to acute myeloid leukemia (AML). However, the proliferation of triple-negative clones has sometimes been observed at AML transformation. To clarify the clonal evolution of ET to AML, we analyzed paired samples at ET and AML transformation in eight patients. We identified that JAK2-unmutated AML clones proliferated at AML transformation in three patients in whom the JAK2-mutated clone was dominant at ET. In two patients, TET2-mutated, but not JAK2-mutated, clones might be common initiating clones for ET and transformed AML. In a patient with JAK2-mutated ET, SMARCC2, UBR4, and ZNF143, but not JAK2, -mutated clones proliferated at AML transformation. Precise analysis using single-cell sorted CD34+/CD38- fractions suggested that ET clone with JAK2-mutated and AML clone with TP53 mutation was derived from the common clone with these mutations. Although further study is required to clarify the biological significance of SMARCC2, UBR4, and ZNF143 mutations during disease progression of ET and AML transformation, the present results demonstrate the possibility of a common initial clone involved in both ET and transformed AML.

[Cellular kinetics and outcome of tisagenlecleucel for diffuse large B-cell lymphoma].

CD19-targeted chimeric antigen receptor T-cell (CAR-T) therapy has shown promise as treatment of relapsed or refractory B-cell malignancies. However, the clinical utility of early CAR-T monitoring within 1 month after infusion has not been elucidated. In this study, we quantitatively measured CAR-T kinetics in peripheral blood on days 2, 4, 7, 9, 11, 14, 21, and 28 post-infusion using flow cytometry and quantitative polymerase chain reaction in 13 patients with relapsed refractory diffuse large B-cell lymphoma (DLBCL) treated with tisagenlecleucel (tisa-cel). No relationships were identified between bulk CAR-T kinetics and treatment outcomes. Interestingly, the magnitude of CD4+ CAR-T expansion was higher in responders than in nonresponders, while CD8+ CAR-T expansion was minimal in responders. Additionally, CAR-T proliferation was more pronounced in patients with cytokine release syndrome. Our results suggest that CD4+ CAR-T cellular kinetics within 1 month after CAR-T infusion may predict its efficacy after tisa-cel therapy in adult patients with DLBCL.

Comparison of clonal architecture between primary and immunodeficient mouse-engrafted acute myeloid leukemia cells.

Patient-derived xenografts (PDX) are widely used as human cancer models. Previous studies demonstrated clonal discordance between PDX and primary cells. However, in acute myeloid leukemia (AML)-PDX models, the significance of the clonal dynamics occurring in PDX remains unclear. By evaluating changes in the variant allele frequencies (VAF) of somatic mutations in serial samples of paired primary AML and their PDX bone marrow cells, we identify the skewing engraftment of relapsed or refractory (R/R) AML clones in 57% of PDX models generated from multiclonal AML cells at diagnosis, even if R/R clones are minor at <5% of VAF in patients. The event-free survival rate of patients whose AML cells successfully engraft in PDX models is consistently lower than that of patients with engraftment failure. We herein demonstrate that primary AML cells including potentially chemotherapy-resistant clones dominantly engraft in AML-PDX models and they enrich pre-existing treatment-resistant subclones.

[Bacillus cereus bacteremia in patients with hematological disorders].

Bacillus cereus bacteremia is an infectious disease that may sometimes be fatal with a rapid clinical course. We performed a retrospective analysis on 12 patients with Bacillus cereus bacteremia recruited from January 2010 to March 2015. The primary diseases were acute leukemia (n=5), myelodysplastic syndromes (n=3), malignant lymphoma (n=3), and hemophagocytic syndrome (n=1). Neutrophil count at the onset of this bacteremia was less than 500 cells/µl in 9 patients. At the onset of bacteremia, we observed neurological symptoms (n=7), gastrointestinal symptoms (n=6), and findings suspected of infection at the venous catheter insertion site (n=6). Vancomycin was administered to all the patients; 10 patients showed improvement whereas 2 died early after allogeneic hematopoietic stem cell transplantation owing to bacteremia. Three patients had sequelae of central nervous system disorders. Neurological and gastrointestinal symptoms with fever may be predictors for this bacteremia, and early administration of appropriate antibacterial drugs may improve the prognosis. Future research should be aimed toward the identification of the clinical features of poor prognosis and establishment of remedies for Bacillus cereus bacteremia.

Retrospective survey and evaluation of first-line antibiotics for chemotherapy-induced febrile neutropenia in patients with acute myeloid leukemia.

Patients with acute leukemia are susceptible to chemotherapy-induced severe myelosuppression, and therefore are at a high risk for febrile neutropenia (FN). In such cases, the use of broad-spectrum antibiotics such as fourth-generation cephalosporins and carbapenems is recommended as first-line antimicrobial treatment; however, the effectiveness of these agents in patients with acute myeloid leukemia (AML) has not been investigated in detail. We retrospectively examined and evaluated the effectiveness of first-line antibiotic treatment regimens for chemotherapy-induced FN in patients with AML in Japanese Red Cross Nagoya Daiichi Hospital. The evaluated first-line treatment regimens were as follows: cefozopran (CZOP) + amikacin (AMK) in 38 cases, cefepime (CFPM) alone in 2 cases, CFPM + AMK in 2 cases, piperacillin (PIPC) + AMK in 2 cases, and CZOP alone in 1 case. Additionally, prophylactic antifungal agents were administered in all cases. Markedly effective, effective, moderately effective, and ineffective responses occurred in 31.1%, 8.9%, 8.9%, and 51.1%, respectively, of the treated cases. The response rate, defined as the combination of markedly effective and effective outcomes, was 40.0%. In 11 cases, impairment of renal functions were observed, and they were associated with combination treatments including AMK; nine of these were associated with a glycopeptide. The combination of CZOP with AMK (84.4%) was the most commonly used first-line treatment for FN in patients with AML; carbapenem or tazobactam/PIPC has never been used for treatment of such cases. Our findings demonstrate that fourth-generation cephems will be an effective first-line treatment for FN in patients with AML in our hospital.

Donor Lymphocyte Infusion for Relapsed Hematological Malignancies after Unrelated Allogeneic Bone Marrow Transplantation Facilitated by the Japan Marrow Donor Program.

To evaluate the safety and efficacy of donor lymphocyte infusion (DLI), we retrospectively analyzed 414 recipients who received unrelated DLI (UDLI) for the treatment of relapsed hematological malignancy after unrelated bone marrow transplantation (BMT). UDLI was administered for acute myelogenous leukemia (n = 184), myelodysplastic syndrome (n = 69), acute lymphocytic leukemia (n = 57), chronic myelogenous leukemia (CML, n = 36), lymphoid neoplasms (n = 38), adult T cell leukemia/lymphoma (n = 18), and multiple myeloma (n = 12). Sixty-five patients (16%) were in cytogenetic/molecular relapse and 349 (84%) were in hematological relapse after BMT. In total, 266 out of 414 (64%) patients received chemotherapy and/or molecular-targeted agents in combination with UDLI. The median time from BMT to UDLI was 244 days. The median number of infused CD3+ cells was 3.51 × 107/kg. Response and survival rates were evaluated at 100 days after UDLI. Complete response was obtained in 37 (57%) of 65 patients with cytogenetic/molecular relapse and in 69 (20%) of 349 patients with hematological relapse (P < .001). Two hundred forty-seven patients (60%) were alive, whereas 110 (26%) had died because of disease progression, 26 (6%) because of infections, 12 (3%) because of graft-versus-host disease (GVHD), and 13 (3%) because of organ failure. Multivariate analysis identified molecular/cytogenetic relapse, GVHD after UDLI, and CML but not combination with chemotherapy as significant prognostic factors. These results indicate that UDLI may have efficacy in relapsed patients with CML, low tumor burden, or occurrence of GVHD after UDLI.

[Clinical Analysis of Combination Chemotherapy Using High Dose Methotrexate, Rituximab, and Vincristine with or without Procarbazine for Elderly Patients with Diffuse Large B-Cell Lymphoma of the Central Nervous System].

We studied the clinical effects of high-dose methotrexate(HD-MTX)combined with rituximab and vincristine in 5 elderly patients, aged 65-83 years, with diffuse large B-cell lymphoma of the central nervous system(DLBCL CNS). Patients aged 65- 71 years were given 3.0 g/m2 of HD-MTX, while patients aged 75-83 years were given 1.5 g/m2 of the drug. All patients showed responses; 1 CR and 1 PR in MTX 3.0 g/m2 group, and 2 CRs and 1 PR in MTX 1.5 g/m2 group.