Impact of pretransplant donor-specific anti-HLA antibodies in HLA-mismatched peripheral blood stem cell transplantation

Abstract: The cut-off levels of donor-specific anti-HLA antibodies (DSAs) that are considered to predict a high risk of graft failure remain unclear. Using peripheral blood stem cell transplantation (PBSCT) data from the Japanese Society for Transplantation and Cellular Therapy/Japanese Data Center for Hematopoietic Cell Transplantation (JSTCT/JDCHCT), we examined the role of DSAs, and performed a retrospective analysis of patients whose recipients underwent related PBSCT between 2010 and 2014 with pre-transplant anti-HLA antibodies. Patients were divided into 3 groups using a mean fluorescence intensity (MFI) of 5,000 as a cut-off value: DSA positive (n = 8), anti-HLA antibody-positive (n = 137) and anti-HLA antibody-negative (n = 3657). There was a significant difference in the number of CD34-positive cells (median: 4.31, 3.97, and 5.33×10⁶/kg, respectively; p < 0.05). Regarding the eight DSA-positive patients, only two underwent therapeutic intervention, and neutrophils were engrafted in all but one patient (median, 10 days). Although there was a statistically significant difference in neutrophil and platelet engraftment among the 3 groups (both p < 0.05), neutrophil engraftment was faster in the DSA group, with no significant difference in the overall survival (p = 0.46). Our results, based on JSTCT/JDCHCT data, suggest that DSAs may not affect the risk in related PBSCT.