Impact of Treatment Prior to Allogeneic Transplantation of Hematopoietic Stem Cells in Patients with Myelodysplastic Syndrome: Results of the Latin American Bone Marrow Transplant Registry.

It has been suggested that bridging therapy with intensive chemotherapy and/or hypomethylating agents followed by hematopoietic stem cell transplantation (HSCT) can be valuable in the treatment of patients with myelodysplastic syndromes (MDS). However, the influence of this approach on HSCT outcomes remains poorly defined. Therefore, our objective was to investigate the influence of treatment before HSCT in patients with MDS. We retrospectively analyzed data from the Latin American registry of 258 patients from 17 Latin American centers who underwent HSCT from 1988 to 2019. Our data showed that there was pre-HSCT. We detected no significant difference regarding the impact on overall survival of treated and untreated patients before HSCT. Despite these data, the type of previous treatment among treated patients showed a significant difference in overall survival. Treatment with hypomethylating agents together with pre-HSCT chemotherapy seems to result in better survival of the studied population. These data correspond to the first results obtained through cooperative work between various centers in Latin America comparing the different approaches to patients and reflecting their reality and challenges. Therefore, the selection of pretransplant bridge therapy should be analyzed and focus given primarily to those approaches that result in better survival of patients with MDS.

GVHD-derived plasma as a priming strategy of mesenchymal stem cells.

BACKGROUND: Mesenchymal stem cell (MSC) therapy is an important alternative for GVHD treatment, but a third of patients fail to respond to such therapy. Therefore, strategies to enhance the immunosuppressive potential of MSCs constitute an active area of investigation. Here, we proposed an innovative priming strategy based on the plasma obtained from GVHD patients and tested whether this approach could enhance the immunosuppressive capacity of MSCs. METHODS: We obtained the plasma from healthy as well as acute (aGVHD) and chronic (cGVHD) GVHD donors. Plasma samples were characterized according to the TNF-α, IFN-γ, IL-10, IL-1ß, IL-12p40, and IL-15 cytokine levels. The MSCs primed with such plasmas were investigated according to surface markers, morphology, proliferation, mRNA expression, and the capacity to control T cell proliferation and Treg generation. RESULTS: Interestingly, 57% of aGVHD and 33% of cGVHD plasmas significantly enhanced the immunosuppressive potential of MSCs. The most suppressive MSCs presented altered morphology, and those primed with cGHVD displayed a pronounced overexpression of ICAM-1 on their surface. Furthermore, we observed that the ratio of IFN-γ to IL-10 cytokine levels in the plasma used for MSC priming was significantly correlated with higher suppressive potential and Treg generation induction by primed MSCs, regardless of the clinical status of the donor. CONCLUSIONS: This work constitutes an important proof of concept which demonstrates that it is possible to prime MSCs with biological material and also that the cytokine levels in the plasma may affect the MSC immunosuppressive potential, serving as the basis for the development of new therapeutic approaches for the treatment of immune diseases.