Assessment of immune reconstitution status in recipients of a successful hematopoietic stem cell transplant from peripheral blood after reduced intensity conditioning

Outcomes of second hematopoietic stem cell transplantation using reduced-intensity conditioning in an outpatient setting

Relapse and graft failure after autologous (auto) or allogeneic (allo) hematopoietic stem cell transplantation (HSCT) are serious and frequently fatal events. A second HSCT can be a life-saving alternative, however, information on the results of such intervention in an outpatient setting is limited. Outpatient second hematoprogenitors transplant after reduced-intensity conditioning (RIC) at a single academic center was analyzed. Twenty-seven consecutive adults who received an allo-HSCT after an initial auto- or allo-HSCT from 2006 to 2019 were included. Data were compared using the χ² -test. Survival analysis using Kaplan-Meier and Cox proportional hazard models was performed; cumulative incidence estimation of transplant-related mortality (TRM) was assessed. Hodgkin lymphoma was the most frequent diagnosis for the group with a first auto-HSCT with 5/12 (41.7%) cases, and acute myeloid leukemia for those with a first allo-HSCT with 6/15 (40%). One-year overall survival and disease-free survival (DFS) was 66.7% (95% CI 27.2-88.2) and 59% (95% CI 16-86) for 12 patients with a first auto-HSCT; and for 15 patients with a first allo-HSCT, it was 43.3% (95% CI 17.9-66.5) and 36% (95% CI 13.2-59.9), respectively. Eight (29.6%) patients died of TRM and the cumulative incidence of TRM at 1 year was 22% (95% CI 8.6-39.27). Chronic graft-versus-host disease and late (>10 months) second transplantation were protective factors for longer survival. Neutropenic fever was more common in the group with a first allo-HSCT (p = 0.01). In conclusion, outpatient second allo-HSCT using RIC after auto- or allografting failure or relapse is feasible and offers a reasonable alternative for patients with severe life-threatening hematological diseases.

Immunological effects of nilotinib prophylaxis after allogeneic stem cell transplantation in patients with advanced chronic myeloid leukemia or philadelphia chromosome-positive acute lymphoblastic leukemia

Allogeneic stem cell transplantation remains the standard treatment for resistant advanced chronic myeloid leukemia and Philadelphia chromosome–positive acute lymphoblastic leukemia. Relapse is the major cause of treatment failure in both diseases. Post-allo-SCT administration of TKIs could potentially reduce relapse rates, but concerns regarding their effect on immune reconstitution have been raised. We aimed to assess immune functions of 12 advanced CML and Ph+ ALL patients who received post-allo-SCT nilotinib. Lymphocyte subpopulations and their functional activities including T-cell response to mitogens, NK cytotoxic activity and thymic function, determined by quantification of the T cell receptor (TCR) excision circles (TREC) and TCR repertoire, were evaluated at several time points, including pre-nilotib-post-allo-SCT, and up to 365 days on nilotinib treatment. NK cells were the first to recover post allo-SCT. Concomitant to nilotinib administration, total lymphocyte counts and subpopulations gradually increased. CD8 T cells were rapidly reconstituted and continued to increase until day 180 post SCT, while CD4 T cells counts were low until 180−270 days post nilotinib treatment. T-cell response to mitogenic stimulation was not inhibited by nilotinib administration. Thymic activity, measured by TREC copies and surface membrane expression of 24 different TCR Vβ families, was evident in all patients at the end of follow-up after allo-SCT and nilotinib treatment. Finally, nilotinib did not inhibit NK cytotoxic activity. In conclusion, administration of nilotinib post allo-SCT, in attempt to reduce relapse rates or progression of Ph+ ALL and CML, did not jeopardize immune reconstitution or function following transplantation.

Flow cytometry data analysis of CD34+/CD133+ stem cells in bone marrow and peripheral blood and T, B, and NK cells after hematopoietic grafting

This article provides flow cytometry information regarding levels of expression for hematopoietic stem cell markers CD34 and CD133 obtained simultaneously of the bone marrow and peripheral blood from recipients of allogeneic and autologous transplants of PB hematoprogenitors for treating hematological malignancies and who were clinically healthy after ≥100 days following the procedure. CD34 and CD133 expression is compared regarding type of transplant (autologous vs. allogeneic) and sample cell source (bone marrow vs. peripheral blood). Patients were conditioned with a reduced-intensity conditioning regimen. Also shown is the flow cytometry analysis of mononuclear cell and lymphocyte populations in the peripheral blood of both types of recipients, as well as the characterization of immune cells, including T lymphocyte antigenic make up markers CD3, CD4 and CD8, B lymphocytes and NK cells, including total NK, bright and dim subtypes in the peripheral blood of both types of recipients. For further information and discussion regarding interpretation and meaning of post-transplant flow cytometry analysis, please refer to the article "Assessment of immune reconstitution status in recipients of a successful hematopoietic stem cell transplant from peripheral blood after reduced intensity conditioning" [1].