Safety and efficacy of high-dose cytarabine MEAM therapy and other treatments for auto-peripheral blood stem cell transplantation: A retrospective comparative study.

AIM: The MEAM regimen consisting of ranimustine (MCNU), etoposide (ETP), cytarabine (Ara-C), and melphalan (MEL) is widely used before auto-peripheral blood stem cell transplantation (auto-PBSCT) for malignant lymphoma in Japan. The MEAM regimen generally consists of 200-400 mg/m2 for 4 days, but we decided to increase the dosage of Ara-C from the standard to 2 g/m2 for 2 days with the aim of increasing drug transferability to the central nervous system. We evaluate the safety and therapeutic efficacy of high-dose Ara-C MEAM therapy. METHODS: The high-dose Ara-C MEAM protocol consisted of MCNU 300 mg/m2 on day -7, ETP 200 mg/m2 on days -6, -5, -4, -3 and Ara-C 2 g/m2 on day -4 -3, and MEL 140 mg/m2 on day -2. We retrospectively analyzed 37 cases of malignant lymphoma at our institution between May 2014 and July 2020. RESULTS: All patients got engraftment and there were no cases of treatment-related mortality. In all cases, the 3-year overall survival (OS) and progression-free survival (PFS) after transplantation were 80.6% and 65.7%, respectively. Twenty-one cases of diffuse large B-cell lymphoma recurrence, for which there is proven usefulness of auto-PBSCT, showed good results after transplantation, with the 3-year OS and PFS after transplantation being 100% and 74.3%, respectively. CONCLUSION: The safety and efficacy of high-dose Ara-C MEAM therapy were demonstrated, but the expected therapeutic effect on central nervous system lesions could not be fully evaluated owing to the small number of cases.

The SLAMF3 rs509749 polymorphism correlates with malignant potential in multiple myeloma.

The signaling lymphocytic activation molecule family 3 (SLAMF3) is highly expressed on plasma cells from patients with multiple myeloma (MM) and induces high malignant potential by ERK signaling mediated via the interaction with adaptor proteins SHP2 and GRB2. This study focused on the single-nucleotide polymorphism (SNP) of the SLAMF3 gene (rs509749, 1804A>G, M602V) in MM. The SNP G allele was a major type, and the frequencies of the GG, GA, and AA genotypes were 61.8%, 29.4%, and 8.8%, respectively, in patients with MM, which was almost the same as in healthy the control group in the Japanese population. Interestingly, patients with GG genotypes had significantly shorter overall survival times than patients with GA/AA genotypes. Consistent with those results, SLAMF3-overexpressing KMS-34 cells with the G allele (V602) had higher cell proliferation potential and were more resistant to anti-MM agents than those with the A allele (M602). When those cells were subcutaneously inoculated into NOG mice, tumor sizes in mice receiving V602 cells rapidly increased, and survival was significantly shorter than in mice injected with M602 cells. Furthermore, SLAMF3 V602 molecules bound more tightly to SHP2 and GRB2, with increased SHP2 and ERK phosphorylation compared with M602 cells. The mRNA expression of cell cycle-related genes (CCND1 and CCNE1) and anti-apoptotic genes (BCL2L and p21) was increased in V602 cells compared with M602 cells. The results thus suggested that the G allele of SLAMF3 SNP rs509749 may be associated with MM disease progression.

[Amebic liver abscesses developing during R-CHOP chemotherapy in a patient with mantle cell lymphoma].

A 51-year-old man was diagnosed with stage IV mantle cell lymphoma based on terminal ileum biopsy and treated with the R-CHOP regimen. Abdominal CT to assess continuous fever after three courses of R-CHOP revealed three low-density areas in the liver. PCR of the fluid obtained by percutaneous drainage revealed Entamoeba histolytica positivity, although the cultures were negative. Metronidazole treatment achieved cure. The patient was not a homosexual but had an 8-month stay in Lesotho 21 years ago, leading to the possibility that E. histolytica infection at the time continued as an asymptomatic colonization until the initiation of corticosteroid-containing chemotherapy.

Clinical impact of serum soluble SLAMF7 in multiple myeloma.

The signaling lymphocytic activation molecule family (SLAMF7; also known as CS1 or CD319) is highly expressed on plasma cells from multiple myeloma (MM) as well as natural killer (NK) cells and is a well-known therapeutic target of elotuzumab. The objective of this study was to evaluate the clinical significance of serum soluble SLAMF7 (sSLAMF7) levels in patients with MM (n=103) and furthermore the impact of sSLMF7 on the antitumor activity of anti-SLAMF7 antibody. Thirty-one percent of MM patients, but not patients with monoclonal gammopathy of undetermined significance and healthy controls, had detectable levels of serum sSLAMF7, which were significantly increased in advanced MM patients. Further, MM in sSLAMF7-postive patients exhibited aggressive clinical characteristics with shorter progression-free survival times in comparison with sSLAMF7-negative patients. In responders to MM therapy, the levels of sSLAMF7 were undetectable or decreased compared with those before treatment. In addition, the anti-SLAMF7 antibody-mediated antibody-dependent cellular cytotoxicity of NK cells against MM cell lines was inhibited by recombinant SLAMF7 protein. Thus, our findings suggest that high concentrations of sSLAMF7, which could transiently suppress the therapeutic effects of elotuzumab, may be a useful indicator of disease progression in MM patients.