Class II major histocompatibility complex typing across the ethnic barrierin pemphigoid gestationis. A study in Mexicans

Background Pemphigoid gestationis (PG), also called herpes gestationis, is a rare autoimmune disease of pregnancy or puerperium (estimated 1 out of 50 ,000 pregnancies among Caucasians). A previous series has demonstrated an a ssociation of PG with human leukocyte antigen (HLA)-DR3 or HLA-DR4 haplotyp es. While these haplotypes are most commonly found in individuals of Europe an ancestry, they have also been found in African-American patients affecte d with PG. PG has rarely been reported in other ethnic groups, and the HLA association in non-Europeans has not been examined. Methods We have characterized eight patients of Mexican ancestry who have P G by clinical, histologic, and immunofluorescence criteria. Class I and cla ss Il major histocompatibility complex (MHC) antigens were studied by stand ard microlymphocytotoxicity assays. Class II MHC antigens were further stud ied by polymerase chain reaction (PCR) amplification of HLA-DRB1, DQA, and DQB genes and allele-specific oligonucleotide hybridization. For comparison purposes, we used results obtained from a group of 100 ethnically matched healthy individuals. Results We found that all eight patients had the HLA-DR3/DR4 phenotype; all HLA-DR3 haplotypes were HLA-DRB1*0301, DQA1*0501, and DQB1*0201, whereas h alf of the HLA-DR4 haplotypes were from the DRB1*0401 subtype and the other half were DRB1*0407. Conclusions These results suggest that, in Mexicans. the genetic susceptibi lity for the development of PG is strongly influenced by the genetic admixt ure of Caucasian origin, and the role of class II MHC antigens in the patho physiology of this disease is confirmed.