HLA-DPB1 TCE (exon 2–encoded) and HLA-DP expression (exon-3 and rs9277534-linked) (mis)matching model types. The immunogenicity TCE model involves the most immunogenic TCE groups in the recipient and donor (TCE 1 being the most immunogenic and TCE 3 being the least). Between these groups, matching is TCE permissive and mismatching is nonpermissive. Expression-favorable mismatching (applicable only to HLA-DPB1 single mismatches) involves the expression of the mismatched HLA-DP of the recipient inferred from a 7-SNP motif in exon 3 of HLA-DPB1. Low expression is more favorable than high expression.