Disparity for the minor histocompatibility antigen HA‐1 is associated with an increased risk of acute graft‐versus‐host disease (GvHD) but it does not affect chronic GvHD incidence, disease‐free survival or overall survival after allogeneic human leucocyte antigen‐identical sibling donor transplantation

Abstract

Disparity for the minor histocompatibility antigen HA‐1 between patient and donor has been associated with an increased risk of acute graft‐versus‐host disease (GvHD) after allogeneic human leucocyte antigen (HLA)‐identical sibling donor stem cell transplantation (SCT). However, no data concerning the impact of such disparity on chronic GvHD, relapse or overall survival are available. A retrospective multicentre study was performed on 215 HLA‐A2‐positive patients who received an HLA‐identical sibling SCT, in order to determine the differences in acute and chronic GvHD incidence on the basis of the presence or absence of the HA‐1 antigen mismatch. Disease‐free survival and overall survival were also analysed. We detected 34 patient–donor pairs mismatched for HA‐1 antigen (15·8%). Grades II–IV acute GvHD occurred in 51·6% of the HA‐1‐mismatched pairs compared with 37·1% of the non‐mismatched. The multivariate logistic regression model showed statistical significance (P: 0·035, OR: 2·96, 95% CI: 1·07–8·14). No differences were observed between the two groups for grades III–IV acute GvHD, chronic GvHD, disease‐free survival or overall survival. These results confirmed the association between HA‐1 mismatch and risk of mild acute GvHD, but HA‐1 mismatch was not associated with an increased incidence of chronic GvHD and did not affect relapse or overall survival.