Double filtration plasmapheresis combined with rituximab for donor‐specific antibody desensitization in haploidentical haematopoietic stem cell transplantation

Summary Donor‐specific anti‐HLA antibodies (DSA) are a major cause of engraftment failure in patients receiving haploidentical haematopoietic stem cell transplantation (Haplo‐HSCT). Double filtration plasmapheresis (DFPP) avoids the unnecessary loss of plasma proteins and increases the efficiency of purification. To investigate the effectiveness of the desensitization protocol including DFPP and rituximab, we conducted a nested case–control study. Thirty‐three patients who had positive DSA were desensitized by the protocol and 99 patients with negative DSA were randomly matched as control. The median DSA mean fluorescence intensity values before and after DFPP treatment were 7505.88 ± 4424.38 versus 2013.29 ± 4067.22 ( p < 0.001). All patients in DSA group achieved haematopoietic reconstitution and the median neutrophils and platelets engraftment times were 13 (10–21) and 13 (10–29) days respectively. Although the cumulative incidence of II–IV aGVHD (41.4% vs. 28.1%) and 3‐year moderate to severe cGVHD (16.8% vs. 7.2%) were higher in DSA cohort than in the control, no statistical significance was observed. The 3‐year non‐relapse mortality and the overall survival were 6.39% and 72.0%, respectively, in the DSA cohort, which were comparable to the negative control. In conclusion, DFPP and rituximab could be effectively used for desensitization and overcome the negative effects of DSA in Haplo‐HSCT.