The effect of DPB1 matching on disease relapse. Matched pairs are significantly more at risk of relapse than are mismatched pairs. This can be seen (A) in those pairs matched for HLA-A, -B, -C, -DRB1, and -DQB1; (B) in the group overall, irrespective of matching status for HLA-A, -B, -C, -DRB1, and -DQB1; and (C) in only those pairs mismatched for one or more of HLA-A, -B, -C, -DRB1, and -DQB1.