Plasma exchange combined with anti-B-cell therapy enables comparable outcomes between DSA-positive and DSA-negative aplastic anemia after haplo-HSCT: a propensity-score-matched cohort study

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains the only curative treatment for aplastic anemia (AA). For patients lacking a matched sibling donor (MSD) or matched unrelated donor (MUD), haploidentical HSCT (haplo-HSCT) has become an alternative with comparable efficacy. However, donor-specific anti-HLA antibodies (DSAs) remain the principal barrier. In this study, we compared transplant outcomes in DSA-positive recipients after desensitization with plasma exchange (PE) combined with anti-B-cell therapy. Between January 2019 and December 2023, we enrolled 30 DSA-positive AA patients who underwent haplo-HSCT at our center. All received a desensitization regimen combining PE with anti-B-cell agents. By propensity-score matching (1:2 ratio, caliper 0.02), we additionally enrolled 60 DSA-negative controls matched for key clinical variables to compare therapeutic efficacy and long-term outcomes between the two groups. This study enrolled 90 AA patients who underwent haplo-HSCT: 30 were DSA-positive and 60 were DSA-negative. Baseline characteristics were comparable between the two groups. After desensitization with PE combined with anti-B-cell agents, the DSA-positive group achieved outcomes equivalent to those of the DSA-negative group. Specifically, EBV reactivation (46.7% vs. 68.3%; P = 0.002) was significantly better in the DSA-positive group. Engraftment, aGVHD, Effacacy, OS, and GRFS rates were similar between two groups. However, the risk of cGVHD remains higher in the DSA-positive group (40% vs. 12%; P = 0.009). For DSA-positive AA patients who are candidates for haplo-HSCT and for whom no DSA-negative donor can be identified, desensitization with PE combined with anti-B-cell agents represents an established strategy to improve transplant outcomes; nevertheless, close surveillance for cGVHD is warranted after transplantation.