Epitope analysis of DQ6-reactive antibodies in sera from a DQ6-positive transplant candidate sensitized during pregnancy

This case report describes DQ6-reactive serum antibody reactivity in a patient who types as DQ6. DNA typing showed DQB1*06:09 on the antibody producer and serum reactivity with DQB1*06:01, *06:02 and *06:03 but not with *06:04 and *06:09. HLAMatchmaker serum analysis showed antibody reactivity with a new antibody-verified 85VA eplet on DQB but additional reactivity with DQB1*02:01 could not be readily interpreted. After applying the nonself-self algorithm of HLA immunogenicity we have identified a new DQB epitope structurally described as 140A2 + 130R + 135D and shared by DQB1*02:01 and DQB1*05:01 and DQB1*06:02 of the immunizer.