Effects of ABO incompatibility in allogeneic hematopoietic stem cell transplantation.

INTRODUCTION: The impact of ABO mismatch on outcomes following allo-HSCT remains controversial. In this study, our aim is to define the effect of ABO mismatch on post-transplant outcomes, engraftment kinetics and complications in a large cohort. PATIENTS AND METHODS: We retrospectively identified 1000 patients who underwent allo-HSCT from either bone marrow or peripheral blood stem cells at our center between 1988 and 2016. P<0.05 was considered statistically significant. RESULTS: Five hundred and ninety (59%) patient-donor pairs were ABO matched, 164 (16.4%) were ABO major mismatched (MM), 191 (19.1%) were ABO minor MM, and 55 (5.5%) were ABO bi-directionally MM. ABO matched pairs were more common in transplants from related donors (P<0.001) and using bone marrow as a stem cell source (P<0.001). In minor ABO MM transplantations, mild delayed hemolytic reaction occurred more frequently compared to major and bidirectional ABO MM transplantations (47% vs 35% and 18%, P<0.001). Neutrophil engraftment was slightly delayed in ABO MM patient-donor pairs when compared ABO matched donor pairs according to median engraftment time in all group (167/410, 41% vs 204/590, 35%, P=0.046). Pure red cell aplasia was diagnosed in 6 patients (1%). Higher risk of death was shown in ABO MM transplants compared to ABO matched transplants in overall survival (OS) analysis (HR:1.201, 95% CI:1.004-1.437, P=0.045). The non-relapse mortality (P=0.546) and cumulative incidences of acute graft versus host disease (aGVHD) and chronic (c) GVHD were comparable between ABO MM and ABO matched patient-donor pairs (for aGVHD, P=0.235; for cGVHD, P=0.137). CONCLUSION: ABO MM transplants were associated with decreased OS and slightly delayed neutrophil engraftment. NRM and the risk of GVHD were not related to ABO incompatibility.

Older age and capacity of colony forming unit in autologous peripheral derived hematopoietic cells.

BACKGROUND: Aging decreases bone marrow cellularity and alters the frequencies of stem cells. Aged hematopoietic stem cells can differ from their younger counterparts in functional capacity. STUDY DESIGN AND METHODS: We aimed to evaluate the relation between the age and the ability of colony forming capacity of peripheral blood-derived hematopoietic cell products collected for autologous stem cell transplantation (AHSCT). RESULTS: Elderly patients could be mobilized with lower total collected CD34+ cells. Colony forming capacity did not differ between young and old patients. CONCLUSION: This results can be translated into clinic as higher numbers of AHSCT candidates over age 60.

Impact of age and diagnosis on viability during centrifugation and cryopreservation of peripheral blood stem cell products.

BACKGROUND: The viability of the hematopoietic stem cells infused to the patient is important for transplant outcome. STUDY DESIGN AND METHODS: We evaluated 31 peripheral blood stem cell product collected from 15 patients. We aimed to check the viabilities of the cells from patients with different age and diagnosis, in different stages of the cryopreservation procedure. RESULTS: We showed a markedly decreased viability rate after centrifugation and addition of DMSO. Percentages of viabilities were similar between young and old patients in each step. Type of hematological malignancy did not make a significant influence on the viability. CONCLUSION: High speed centrifugation has a negative impact on the viability.