Retrospective Evaluation of Patients Who Underwent Allogeneic Stem Cell Transplantation for Bone Marrow Failure

Background: Bone marrow failure is a disease that develops due to different etiologies. Aplastic anaemia (AA) and hypocellular myelodysplastic syndrome (HMDS) are the most common bone marrow failure disorders. Treatment options include supportive therapy, immunosuppressive therapy, and allogeneic hematopoietic stem cell transplantation (allo-HCT). Allo-HCT is the only curative treatment option. This study aimed to retrospectively evaluate the demographic characteristics, treatment, and transplantation results of patients who underwent Allo-HCT for bone marrow failure. Material and Methods: This single-centre retrospective study enrolled 11 patients (9 with severe AA and 2 with HMDS) who underwent allo-HCT for bone marrow failure. The patients' records until 17.08.2023 were analysed. Age, gender, diagnosis, donor age and gender, type of transplantation, pre-transplant ferritin levels, time to transplantation, volume of infused product, number of CD34+ cells in the infused product, post-transplant engraftment times, discharge time, transplant-related complications, post-transplant follow-up and overall survival times were obtained. Results: Eleven patients underwent 12 allo-HCTs for bone marrow failure. Seven patients were male, and four were female. The median age was 40, and seven patients were ≥40 years old at the time of transplantation. Eleven transplants were performed from HLA fully matched siblings and one from a 9/10 matched sibling donor. Bone marrow was used as a stem cell source in 8 transplants and peripheral blood in 4 transplants. The conditioning regimen was fludarabine/cyclophosphamide/anti-thymocyte globulin in all patients. The median time from diagnosis to transplantation was five months. The median time for neutrophil engraftment was 23 days. The median platelet >20.000/mm3 engraftment time was 16 days. A statistically significant positive correlation was found between ferritin levels and platelet >20.000/mm3 engraftment (days) (r=0.653, p=0.040) and platelet >50.000/mm3 engraftment (days) (r=0.720, p=0.029). There was a statistically significant negative correlation between the number of infused CD34 positive cells (10⁶/kg) and platelet >50.000/mm3 engraftment (days) (r=-0.670, p=0.024). Patients were discharged in a median of 23 days. Acute graft versus host disease (GvHD) was observed in one patient, while chronic GvHD was not observed in any patient. The median overall survival time was 48 months, and the median post-transplant follow-up was 37 months. Secondary malignancy and MDS were not detected in any patient during the follow-up period. All 11 patients who underwent Allo-HCT from a matched sibling donor are alive and continue to have a complete hematological response. There was no increase in mortality and morbidity in patients aged 40 years and older. Conclusions: In patients with severe AA and high-risk HMDS without comorbidities between the ages of 40 and 50, allo-HCT should be considered as first-line treatment in the presence of an HLA-matched sibling donor.