Benedetta Mariotti

Pre-transplant persistence of minimal residual disease does not contraindicate allogeneic stem cell transplantation for adult patients with acute myeloid leukemia

Despite progress in treatment and supportive therapies, outcome of high-risk adult AML remains dismal with ~ 20% of patients becoming long-term survivors. Since the pretreatment genetics/cytogenetics of AML do not always anticipate the individual outcome, there is a strong rationale to implement laboratory techniques capable of exploring the quality of CR and allowing post-remission therapy to be optimally directed. In this view, minimal residual disease (MRD) assessment promises to be a robust approach. It captures the diversities of the underlying genetic/cytogenetic features of AML and recapitulates other patient heterogeneities regarding drug bioavailability, metabolism and resistance. Multiparametric flow cytometry (MFC) is one of the leading techniques successfully exploited to quantify MRD in AML expressing leukemia-associated immunophenotypes (LAIP). This assay applies to the vast majority of patients after chemotherapy-induced morphologic CR and has been shown to predict the clinical outcome when measured at several time points, potentially prompting prospective treatment adjustments. Recent studies have demonstrated that pretransplant MRD levels negatively affect post-transplant outcome. Years ago, we showed that MRD persistence at the end of consolidation was associated with an unfavorable outcome and that autologous stem cell transplantation (AuSCT) was not able to alter such an unfavorable course. More recently, other authors have extended this observation to either pediatric or adult patients receiving allogeneic stem cell transplantation (ASCT), showing that pretransplant MRD is a major determinant of prognosis, regardless of the occurrence of graft-versus-leukemia (GVL). Nevertheless, whether MRD positivity is an indication or a contraindication to deliver ASCT is still a matter of debate. On the basis of these premises, we analyzed a retrospective series of MRD-positive adults with AML who were submitted to ASCT. Our aim was to evaluate the impact of pretransplant MRD status on overall survival (OS) and DFS. We analyzed 230 consecutive patients achieving CR after the induction cycle of intensive EORTC/GIMEMA protocols and who harbored in their leukemic cells a LAIP suitable for MRD monitoring. The present series represents an extension of a cohort of patients already analyzed for different purposes and reported previously. Following our previous experience, MRD positivity was defined if ⩾ 3.5 × 10 4 (0.035%) residual leukemic cells (RLCs) were detected in the BM upon full hematological recovery after consolidation cycle. According to this definition, 176/230 patients (76.5%) were classified as MRD positive (MRD) and 54/230 (23.5%) as MRD negative (MRD). In the overall series, 84/230 patients (36.5%) received no transplant because of age, poor performance status or insufficient stem cell harvest, 28/230 (12.2%) relapsed before transplant delivery whereas 118/230 (51.3%) underwent ASCT (N= 50) or AuSCT (N= 68) in first CR. For the purpose of the present analysis, we focused on the 81 patients who tested MRD and who were submitted to ASCT (N= 45) or AuSCT (N= 36), respectively. The same analysis was not feasible for MRD patients due to the low numbers in the ASCT group (N= 5), preventing any statistical significance from being demonstrated. The clinico-biological characteristics of the patients are detailed in Table 1. The two groups were balanced regarding white blood cell count (WBCc), ELN risk category, FLT3 and NPM1 mutational status. Karyotypic analysis was available in 77 (95%) out of 81 patients. Intermediate risk category accounted for 78%

Development of cellulitis caused by Aeromonas hydrophila in allogeneic hematopoietic transplantation: a case report.

Development of cellulitis caused by Aeromonas hydrophila in allogeneic hematopoietic transplantation: a case report