The incidence of autoimmune hemolytic anemia in pediatric hematopoietic stem cell recipients post-first and post-second hematopoietic stem cell transplant.

The reported incidence of post-allogeneic HSCT AIHA was between 4.4% and 6% following a single transplant. Cord blood transplantation, T-cell depletion, and chronic GvHD are significantly associated with post-transplant AIHA. During an 11-yr period, data for 500 pediatric HSCT recipients were eligible for evaluation of the incidence of AIHA post-first and post-second transplants. Demographic, transplant, and post-transplant-related variables were analyzed. Twelve of 500 (2.4%) recipients at a median of 273 days and seven of 72 (9.7%) recipients at a median of 157 days developed AIHA post-first and post-second HSCT, respectively. Post-first HSCT, none of the MRD recipients developed AIHA (0/175 MRD vs. 12/325 other donors, p = 0.04). Four of 12 required a second HSCT to control the AIHA. After the second HSCT, MUD was significantly associated with the development of AIHA. No other variables were associated with the post-second transplant AIHA. The incidence of AIHA post-first and post-second HSCT was less than the reported. The increased incidence of AIHA among recipients of second HSCT is most likely due to the profound immune dysregulation. A much larger, prospective study would be needed to evaluate the incidence, complications, and management of post-transplant AIHA.