WHY DO PATIENTS WITH SICKLE CELL ANEMIA REFERRED TO HEMATOPOIETIC STEM CELL TRANSPLANTATION (HCT) AND WILLING TO UNDERGO TRANSPLANT MAY NEVER HAVE IT? CAN WE CHANGE THIS REALITY?

Abstract

Introduction: HCT is the only curative option for patients with sickle cell anemia in our country. Unfortunately, few have an unaffected HLA-identical sibling donor. Haploidentical donors are a feasible and effective option. Objective: This study is to understand the reason why sickle cell patients with indication for transplantation were unable to undergo HCT. Methods: Retrospective evaluation of the reasons why patients were referred for HCT but did not have it performed. Results: Between September 2016 and May 2024, a total of 76 patients were referred for HCT. 34 patients underwent allogeneic HCT, 9 with a matched sibling (26%) and 25 (73%) with haploidentical donors; 15 (20%) could not be transplanted for a variety of non-exclusive reasons: 3 had only ABO incompatible donors, 2 had only old donors (≥50-years), 3 had family conflicts, including religious reasons to refuse the donation, 2 were not successful in the IVF process, 8 had high titers of positive anti-donor specific anti-HLA antibodies; despite desensitization (rituximab, bortezomib, daratumomab, plasmapheresis, immunoglobulin), the patients remained with very high MFI titers and were not transplanted due to high risk of rejection. Two children were so alloimmunized that it was very difficulty finding compatible red blood cell. In addition, patients with sickle cell anemia cannot be enrolled in REREME to search for an unrelated donor, which aggravates their situation, as they need to look for a donor only within the family. Conclusions: 20% of the patients were unable to perform HCT. Since allogeneic HCT is the only curative treatment available in our country, not performing it may impact the patients'quality of life and ultimately their survival. Despite the small number of patients, the importance of this survey is to understand the problems of our patients and, therefore, to implement strategies that can minimize some of the factors that prevented HCT from being performed. Universal leukodepletion of red blood cells has significantly decreased alloimmunization on other countries and must be considered in patients who may need a HCT or may need to be transfused for many years. The possibility of searching for an unrelated donor must be respected as a universal right of the patients in need for an allogeneic HCT.