Single step multiple genotyping by MALDI-TOF mass spectrometry, for evaluation of minor histocompatibility antigens in patients submitted to allogeneic stem cell transplantation from HLA-matched related and unrelated donor

The outcome of patients underwent to allogeneic stem cell transplantation (allo- SCT) is closely related to graft versus host disease (GvHD) and graft versus leukemia (GvL) effects which can be mediated by mHAgs. 23 mHAgs have been identified and reported to be differently correlated with GVHD or GVL and the aim of this work was develop a method to genotype the mHAgs described so far. For this study we used MALDI-TOF iPLEX Gold Mass Array technology. We tested 46 donor/recipient matched pairs that underwent allo-SCT because of Philadelphia positive (Ph+) chronic myeloid leukemia (n=29) or Ph+ acute lymphoblastic leukemia (n=17). Our data show that sibling pairs had a lesser number of mHAgs mismatches compared to MUD pairs. Notably, donor/recipient genomic mismatch on DPH1 was correlated with an increased risk of acute GvHD and LB-ADIR-1R mismatch on graft versus host direction was correlated with a better RFS with no increase of GvHD risk. Our work provides a simple, accurate and highly automatable method for mHAgs genotyping and suggest the role of mHAgs in addressing the immune reaction between donor and host.