[HLA class II in Mexican patients with pemphigus vulgaris: shared epitope for autoimmunity].

Introduction: Pemphigus is an autoimmune blistering disease of skin and mucous membranes characterized by presence of IgG antibodies against desmoglein 3, and 1. Desmoglein 3 and 1 are presented in pemphigus vulgaris and pemphigus foliaceous, respectively. Desmoglein are transmembrane proteins that form part of cellular junctions called desmosomes. Major histocompatibility complex class II molecules have been related to autoimmune disease; in pemphigus vulgaris, different human lymphocyte antigens (HLA) were associated among different ethnic groups, such as HLA-DR4, HLA-DR14, and HLA-DR1.

Objective: to determine the allele HLA-DR genetic frequencies in Mexican patients with pemphigus.

Method: Patients with clinical, histological, and immunofluorescence diagnosis monitored at the Dermatology Department of the Mexican General Hospital were included. DNA was extracted from blood samples and genetic recognition of HLA-DRβ1 was performed by polymerase chain reaction and hybridization. Forty-three patients with pemphigus were included: 35 (81.4%) women and eight men (18.6%) between 16 and 85 years old.

Results: The HLA-DR14 and HLA-DR1 genetic frequencies were elevated among pemphigus patients and these alleles confer risk to pemphigus 2.2 and 3.3, respectively.

Conclusion: These findings suggest that pemphigus vulgaris susceptibility is part of a general predisposition to present autoimmune diseases.