RESUMO
BACKGROUND: Pemphigus is a group of chronic blistering autoimmune diseases of which pemphigus vulgaris (PV) is the more frequent clinical form. The association of PV with the HLA serotypes suggests that there is a genetic predisposition to the disease. OBJECTIVES: To determine the frequency of class I and class II HLA antigens and the allelic variants of the class II HLA antigens, DR and DQ, in patients with PV and to determine the relative risk. METHODS: An observational, prospective, transverse, and controlled study carried out between 1995 and 1999. Forty-seven patients with a diagnosis of PV and a control sampling of 199 unselected individuals from the same ethnic group were included. The HLA alleles were determined by polymerase chain reaction. RESULTS: No significant associations were detected between HLA A, B, or C and our patients. The DR and DQ molecular alleles positively associated with PV were two different haplotypes: DRb1* 0402/DQb1* 0302 and DRb1* 1401/DQb1* 0503. CONCLUSIONS: In patients with the haplotype DRb1* 0402/DQb1* 0302 the affectation of 10%-30% of the corporal surface prevailed (ACS). In patients with DRb1* 1401/DRQb1* 0503, involvement of <10% of the ACS prevailed.
