Objective: Although allogeneic hematopoietic stem cell transplantation (Allo-HSCT) is the only curative treatment option for sickle cell disease (SCD), healthy HLA-matched family donors can be found in less than 25% of patients. This study aims at detecting the frequency of finding HLA-matched family donors, evaluating the frequent HLA allele types, and the influence of high-risk alleles on transplant outcomes in adult SCD patients in the Eastern Mediterranean Region.

Material and Method: In this retrospective, single-center registry study, family HLA screening was done with low-intensity typing for 216 SCD patients and families. Pretransplant confirmation was done with high-resolution typing for 43 patients who underwent HSCT.

Results: A HLA full-matched family donor was found in 107 out of 216 patients (49.5%) and 43 patients with a median age of 31 (range 17-45) underwent allo-HSCT. The most common class I alleles were HLA-A*02, HLA-B*35, and HLA-C*04, and class II alleles were HLA-DRB1*11 and HLA-DQB1*03. One year of overall survival and disease-free survival was 97.7%. Graft versus host disease, mortality, and survival rates were found to be similar between the groups with or without HLA-B*51, HLA-C*14, and HLA-DRB1*11 alleles (p >0.05).

Conclusion: The frequency of reaching a full-matched family donor was higher in our region than in the literature. The alleles that were reported to have negative effects on transplant, HLA-B*51, HLA-C*14, and HLA-DRB1*11, were observed not to have a negative effect on our transplant outcomes. This was suggested to have been achieved through patients’ coming from a homogenous ethnicity, anti-thymocyte globulin-containing conditioning regimen, and post-transplant cyclophosphamide.