Brief report: Why did two patients who type for HLA-B13 have antibodies that react with all Bw4 antigens except HLA-B13?

► B*44:02 induced antibodies are specific for a pair of self eplets: 145R + 82LR. ► This is an exception for the HLAMatchmaker algorithm. ► The nonself-self paradigm of HLA epitope immunogenicity offers a ready explanation. ► The 145R of the immunizing B*44:02 is a mismatch for the antibody producer's B*13:02. ► The remainder of the structural epitope of 145R consists of self residues.