[Negative effects of donor specific anti-HLA antibody on poor hematopoietic recovery in patients with hematological diseases receiving haploidentical stem cell transplantation and rituximab for desensitization].

Objective: To investigate the incidences and risk factors of poor hematopoietic reconstitution (PHR) in patients with hematological diseases who underwent haploidentical allograft and were treated with rituximab for desensitization. Methods: Eight-three donor specific anti-HLA antibody (DSA, 2000 ≤MFI<10 000) positive patients who underwent haploidentical allograft were prospectively enrolled. Rituximab (375 mg/m2) was used for desensitization day-3 of conditioning regimen. Incidence and factors associated with PHR, including primary poor graft function and prolonged thrombocytopenia, were investigated. Results: There were 22 males and 61 females with a median age of 39(range: 1-65) years. Kaplan-Meier analysis showed that the 100 day cumulative incidences of neutrophil and platelet engraftment were 93.0% and 90.7%, respectively. The incidences of PHR were 14.7%. The 3-year relapse rate, non-relapse mortality (NRM) rate, event-free survival (EFS), leukemia-free survival (DFS) and overall survival (OS) were 6.5%, 15.1%, 70.8%, 79.4% and 79.4%, respectively. Patients with DSA MFI<5 000 (group A, n=46) experienced lower PHR (4.4% vs. 27.5%, P=0.003), and higher 3-year EFS (79.5% vs. 59.8%, P=0.020) compared to those with DSA MFI≥5 000 (group B, n=37). Multivariate analysis showed that DSA MFI≥5 000 was correlated with PHR (HR=6.101, P=0.021). PHR was associated with higher NRM (HR=4.110, P=0.026), lower DFS (HR=3.656, P=0.019) and OS (HR=3.656, P=0.019). Conclusion: Our data suggest that high pre-transplant DSA level is a risk factor for PHR in patients with hematological diseases receiving haploidentical allograft and rituximab for desensitization.