Class II MHC typing in pemphigoid gestationis

Summary Pemphigoid gestationis (PG) is a rare, autoimmune skin disease associated with pregnancy or the immediate postpartum period, previously shown to be associated with the HLA class II antigens DR3 and DR 4. Advances in molecular analytical techniques now allow the identification of HLA alleles previously difficult to define by serological assays. Unsuspected polymorphism within the HLA‐DR 3 and DR 4 classes can, therefore, be identified. The aim of our study was to apply these newer techniques to the question of genetic predisposition in PG by re‐evaluating the association with DR 3 and by studying a possible link with DQ. We have investigated by restriction fragment length polymorphism, the DQA, and by sequence specified oligonucleotide probing the DQB and DRB 1 (HLA DR) specificities of 41 women with immunofluorescence‐confirmed PG. The principal finding of this study is that there is an association between PG and DRB 1*0301 (DR3) and DRB 1*0401/040X (DR4). Although there is also an increase ( P = 0.06) in the concurrent presence of both antigens, this appears to be due to the association with either antigen alone. We also found an increase in the frequency of DQA1*2 ( P = 0.016 vs. control) and a decrease in frequency of DQB 1*0201 ( P = 0.022 vs. controls) and DQB1*0602 ( P = 0.026 vs. controls).