Competitive repopulation and allo-immunologic pressure determine chimerism kinetics after T Cell-depleted allogeneic stem cell transplantation and donor lymphocyte infusion

After allogeneic stem cell transplantation (alloSCT), patient-derived stem cells that survived the pretransplantation conditioning compete with engrafting donor stem cells for bone marrow (BM) repopulation. In addition, donor-derived alloreactive T cells present in the stem cell product may favor establishment of complete donor-derived hematopoiesis by eliminating patient-derived lymphohematopoietic cells. T cell-depleted alloSCT with sequential transfer of potentially alloreactive T cells by donor lymphocyte infusion (DLI) provides a unique opportunity to selectively study how competitive repopulation and allo-immunologic pressure influence lymphohematopoietic recovery. This study aimed to determine the relative contribution of competitive repopulation and donor-derived anti-recipient alloimmunologic pressure on the establishment of lymphohematopoietic chimerism after alloSCT. In this retrospective cohort study of 281 acute leukemia patients treated according to a protocol combining alemtuzumab-based T cell-depleted alloSCT with prophy-lactic DLI, we investigated engraftment and quantitative donor chimerism in the BM and immune cell subsets. DLI-induced increase of chimerism and development of graft-versus-host disease (GVHD) were analyzed as complementary indicators for donor-derived anti-recipient alloimmunologic pressure. Profound suppression of patient immune cells by conditioning sufficed for sustained engraftment without necessity for myeloablative conditioning or development of clinically significant GVHD. Although 61% of the patients without any DLI or GVHD showed full donor chimerism (FDC) in the BM at 6 months after alloSCT, only 24% showed FDC in the CD4+ T cell compartment. In contrast, 75% of the patients who had received DLI and 83% of the patients with clinically significant GVHD had FDC in this compartment. In addition, 72% of the patients with mixed hematopoiesis receiving DLI converted to complete donor-derived hematopoiesis, of whom only 34% developed clinically significant GVHD. Our data show that competitive repopulation can be sufficient to reach complete donor-derived hematopoiesis, but that some alloimmunologic pressure is needed for the establishment of a completely donor-derived T cell compartment, either by the development of GVHD or by administration of DLI. We illustrate that it is possible to separate the graft-versus-leukemia effect from GVHD, as conversion to durable complete donor-derived hematopoiesis following DLI did not require induction of clinically significant GVHD. (c) 2023 The American Society for Transplantation and Cellular Therapy. Immunobiology of allogeneic stem cell transplantation and immunotherapy of hematological disease

Autologous stem cell transplantation for progressive systemic sclerosis: a prospective non-interventional study from the European Society for Blood and Marrow Transplantation Autoimmune Disease Working Party

Three randomized controlled trials in early severe systemic sclerosis demonstrated that autologous hematopoietic stem cell transplantation was superior to standard cyclophosphamide therapy. This European Society for Blood and Marrow Transplantation multicenter, prospective, non-interventional study was designed to further decipher efficacy and safety of this procedure for severe systemic sclerosis patients in real-life practice and to search for prognostic factors. All consecutive adult patients with systemic sclerosis undergoing a first autologous hematopoietic stem cell transplant between December 2012 and February 2016 were prospectively included in the study. The primary endpoint was progression-free survival. Secondary endpoints were overall survival, non-relapse mortality, response and incidence of progression. Eighty patients with systemic sclerosis were included. The median duration of the follow-up was 24 (range, 6-57) months after stem cell transplantation using cyclophosphamide plus antithymocyte globulin conditioning for all, with CD34(+) selection in 35 patients. At 2 years, the progression-free survival rate was 81.8%, the overall survival rate was 90%, the response rate was 88.7% and the incidence of progression was 11.9%. The 100-day non-relapse mortality rate was 6.25% (n=5) with four deaths from cardiac events, including three due to cyclophosphamide toxicity. Modified Rodnan skin score and forced vital capacity improved with time (P24 and older age at transplantation were associated with lower progression-free survival (hazard ratios 3.32 and 1.77, respectively). CD34(+)-cell selection was associated with better response (hazard ratio 0.46). This study confirms the efficacy of autologous stem cell transplantation, using non-myeloablative conditioning, in real-life practice for severe systemic sclerosis. Careful cardio-pulmonary assessment to identify organ involvement at the time of the patient's referral, reduced cyclophosphamide doses and CD34(+)-cell selection may improve outcomes.Immunobiology of allogeneic stem cell transplantation and immunotherapy of hematological disease

Proteomic markers with prognostic impact on outcome of chronic lymphocytic leukemia patients under chemo-immunotherapy: results from the HOVON 109 study

Despite recent identification of several prognostic markers, there is still a need for new prognostic parameters able to predict clinical outcome in chronic lymphocytic leukemia (CLL) patients. Here, we aimed to validate the prognostic ability of known (proteomic) markers measured pretreatment and to search for new proteomic markers that might be related to treatment response in CLL. To this end, baseline serum samples of 51 CLL patients treated with chemo-immunotherapy were analyzed for 360 proteomic markers, using Olink technology. Median event-free survival (EFS) was 23 months (range: 1.25–60.9). Patients with high levels of sCD23 (>11.27, p = 0.026), sCD27 (>11.03, p = 0.04), SPINT1 (>1.6, p = 0.001), and LY9 (>8.22, p = 0.0003) had a shorter EFS than those with marker levels below the median. The effect of sCD23 on EFS differed between immunoglobulin heavy chain variable gene-mutated and unmutated patients, with the shortest EFS for unmutated CLL patients with sCD23 levels above the median. Taken together, our results validate the prognostic impact of sCD23 and highlight SPINT1 and LY9 as possible promising markers for treatment response in CLL patients

cART Reverses Hyposplenism in HIV-1 Infection

Immunobiology of allogeneic stem cell transplantation and immunotherapy of hematological disease

Primary Antibody Responses Against the Novel Pandemic H1N1 and Secondary Antibody Responses Against Seasonal H1N1 Can Be Induced by Vaccination In Patients Early After Allogeneic Stem Cell Transplantation

Immunobiology of allogeneic stem cell transplantation and immunotherapy of hematological disease

Effectiveness of a Strategy to Proceed to Allogeneic Stem Cell Transplantation in All Elderly AML Patients Treated with Intensive Chemotherapy: Only Patients in Complete Remission After First Induction Show Long Term Survival

Immunobiology of allogeneic stem cell transplantation and immunotherapy of hematological disease