Malgorzata Sobczyk-Kruszelnicka

Occurrence and Impact of Minor Histocompatibility Antigens' Disparities on Outcomes of Hematopoietic Stem Cell Transplantation from HLA-Matched Sibling Donors

We have examined the alleles of eleven minor histocompatibility antigens (MiHAs) and investigated the occurrence of immunogenic MiHA disparities in 62 recipients of allogeneic hematopoietic cell transplantation (allo-HCT) with myeloablative conditioning performed between 2000 and 2008 and in their HLA-matched sibling donors. Immunogenic MiHA mismatches were detected in 42 donor-recipient pairs: in 29% MiHA was mismatched in HVG direction, in another 29% in GVH direction; bidirectional MiHA disparity was detected in 10% and no MiHA mismatches in 32%. Patients with GVH-directed HY mismatches had lower both overall survival and disease-free survival at 3 years than patients with compatible HY; also higher incidence of both severe acute GvHD and extensive chronic GVHD was observed in patients with GVH-directed HY mismatch. On contrary, GVH-directed mismatches of autosomally encoded MiHAs had no negative effect on overall survival. Results of our study help to understand why posttransplant courses of allo-HCT from siblings may vary despite the complete high-resolution HLA matching of a donor and a recipient.

Progress in Hematopoietic Stem Cell Transplantation

Transplantation of autologous or allogeneic hematopoietic stem cells is a method currently used to treat many malignant and nonmalignant hematological diseases. The indications, methods, goals of therapy have evolved since the introduction of transplantation to the clini‐ cal practice. Progress that has been achieved allowed for the improvement of results. Thanks to the availability of various conditioning regimens, various hematopoietic cells sources as well as variable possibilities of anti-GvHD prophylaxis the individualization of the trans‐ plantation procedure has been more and more widely used in the recent years. This chapter summarizes current clinical practices and presents major clinical problems that have to be optimally managed in order to improve the outcomes of transplantation.

Comparable safety profile of BeEAM (bendamustine, etoposide, cytarabine, melphalan) and BEAM (carmustine, etoposide, cytarabine, melphalan) as conditioning before autologous haematopoietic cell transplantation.

Introduction BEAM (carmustine, etoposide, cytarabine, melphalan) is the most frequently used high-dose chemotherapy regimen for patients with lymphoma referred for autologous haematopoietic cell transplantation (autoHCT). Recently, a novel conditioning protocol containing bendamustine instead of carmustine (BeEAM) has been proposed to potentially increase the efficacy. Aim of the study The aim of this study was to retrospectively compare the safety profile of BEAM and BeEAM based on single-centre experience. Material and methods A total of 237 consecutive patients with lymphoma treated with either BEAM (n = 174) or BeEAM (n = 63), between the years 2011 and 2016, were included in the analysis. Clinical characteristics of both groups were comparable. Patients with Hodgkin’s lymphoma (HL) constituted 49% of the BEAM group and 40% of the BeEAM group. Results Median time to neutrophil > 0.5 × 109/l recovery was 10 days in both groups (p = 0.29), while median time to platelet > 50 × 109/l recovery was 13 and 14 days after BEAM and BeEAM, respectively (p = 0.12). The toxicity profile was comparable except for arterial hypertension and severe hypokalaemia, which occurred more frequently after BeEAM compared to BEAM (p = 0.02 and p = 0.004, respectively). The rate of early mortality was 1.7% and 1.6%, respectively. The probabilities of the overall and progression-free survival were comparable for both groups (p = 0.73 and p = 0.55, respectively). Conclusions Administration of bendamustine instead of carmustine as part of conditioning does not affect the engraftment or the toxicity profile of the regimen. Therefore, BeEAM may be safely used in patients with lymphoma undergoing autoHCT. Its efficacy requires evaluation in prospective studies.

The Role of Complement Activating Collectins and Associated Serine Proteases in Patients With Hematological Malignancies, Receiving High-Dose Chemotherapy, and Autologous Hematopoietic Stem Cell Transplantations (Auto-HSCT)

We conducted a prospective study of 312 patients (194 with multiple myeloma, 118 with lymphomas) receiving high-dose conditioning chemotherapy and autologous hematopoietic stem cell transplantation (auto-HSCT). Polymorphisms of MBL2 and MASP2 genes were investigated and serial measurements of serum concentrations of mannose-binding lectin (MBL), CL-LK collectin and MASP-2 as well as activities of MBL-MASP-1 and MBL-MASP-2 complex were made. Serum samples were taken before conditioning chemotherapy, before HSCT and once weekly after (totally 4-5 samples); in minority of subjects also 1 and/or 3 months post transplantation. The results were compared with data from 267 healthy controls and analyzed in relation to clinical data to explore possible associations with cancer and with chemotherapy-induced medical complications. We found a higher frequency of MBL deficiency-associated genotypes (LXA/O or O/O) among multiple myeloma patients compared with controls. It was however not associated with hospital infections or post-HSCT recovery of leukocytes, but seemed to be associated with the most severe infections during follow-up. Paradoxically, high MBL serum levels were a risk factor for prolonged fever and some infections. The first possible association of MBL2 gene 3′-untranslated region polymorphism with cancer (lymphoma) in Caucasians was noted. Heterozygosity for MASP2 gene +359 A>G mutation was relatively frequent in lymphoma patients who experienced bacteremia during hospital stay. The median concentration of CL-LK was higher in myeloma patients compared with healthy subjects. Chemotherapy induced marked increases in serum MBL and MASP-2 concentrations, prolonged for several weeks and relatively slighter decline in CL-LK level within 1 week. Conflicting findings on the influence of MBL on infections following chemotherapy of myeloma and lymphoma have been reported. Here we found no evidence for an association between MBL deficiency and infection during the short period of neutropenia following conditioning treatment before HSCT. However, we noted a possible protective effect of MBL during follow-up, and suspected that to be fully effective when able to act in combination with phagocytic cells after their recovery.

Increased Efficacy of Stem Cell Chemomobilization with Intermediate-Dose Cytarabine Plus Granulocyte Colony-Stimulating Factor (G-CSF) Compared with G-CSF Alone in Patients with Multiple Myeloma: Results of a Randomized Trial

Mobilization of hematopoietic stem cells for patients with multiple myeloma (MM) may be done using either steady-state granulocyte colony-stimulating factor (G-CSF) or a combination of chemotherapy with G-CSF. The goal of this randomized, open-label, phase 3 trial was to compare the efficacy of chemomobilization using intermediate-dose cytarabine (ID-AraC) plus G-CSF with G-CSF alone in patients with MM referred for tandem autologous stem cell transplantation (autoSCT). The percentage of patients with stem cell yield of at least 5 × 106 CD34+ cells/kg was the primary endpoint. Ninety patients were enrolled, including 44 assigned to the ID-AraC arm and 46 in the G-CSF arm. The threshold number of CD34+ cells was reached in 43 patients (98%) in the ID-AraC arm and in 32 patients (70%) in the G-CSF arm (P = .0003). The median number of collected CD34+ cells was 20.2 × 106 cells/kg in the ID-AraC arm versus 5.9 × 106 cells/kg in the G-CSF arm (P < .000001). A single apheresis was sufficient to achieve the required number of harvested CD34+ cells in 37 patients (86%) in the ID-AraC arm and in 13 patients (41%) in the G-CSF arm (P = .00008). The times to both neutrophil and platelet recovery after autoSCT were significantly shorter in the patients mobilized with ID-AraC. This study provides the first evidence of the advantage of chemomobilization over G-CSF monotherapy in terms of efficacy. ID-AraC with G-CSF should be the preferred chemomobilization protocol for patients with MM scheduled to undergo tandem autoSCT.

Immunological properties of bone marrow microenvironment 1 year after allogeneic hematopoietic stem cell transplantation

Regeneration of the bone marrow microenvironment after transplantation of allogeneic hematopoietic stem cells is poorly explored. The goal of our study was to investigate this process focusing on immunologic factors: concentrations of selected cytokines, expression of immunosuppressive proteins CD47 and CD274 on hematopoietic stem cells, and frequency of T regulatory lymphocytes (Tregs). Bone marrow samples were collected before transplantation, on the day of transplantation, and at the 1-year follow-up. As a control group, we used bone marrow from healthy donors. Prior to the conditioning, the percentage of Tregs and concentration of interleukin-10 were higher in the bone marrow of patients than in healthy donors. The conditioning regimen resulted in increased concentrations of interferon-γ and expression of CD274 on hematopoietic stem cells. Twenty-eight days after transplantation, level of Tregs, expression of CD47, and concentration of interleukin-10 and latency-associated peptide 1 were increased compared with the period before conditioning. Starting from day 100 after transplantation, the microenvironment tended to normalize; the level of Tregs and concentrations of most cytokines were similar to values in the bone marrow of healthy donors.