Pemphigus is a rare, devastating, bullous autoimmune disease that damages the skin and mucous membranes, and has high morbidity and mortality. Studies have shown associations of pemphigus vulgaris (PV) and pemphigus foliaceus (PF) with human leukocyte antigen (HLA) class II polymorphisms.This study examined the frequency of Major Histocompatibility Complex, Class II, DR Beta 1, a Protein Coding gene (HLA-DRB1) and Major Histocompatibility Complex, Class II, DQ Beta 1 (HLA-DQB1) alleles in Vietnamese PV and PF patients, and the association of these polymorphisms with pemphigus subtypes and disease severity.The study enrolled 31 unrelated Vietnamese who underwent HLA typing using Sanger sequencing. HLA-DRB1 * 14:54 was the most frequent allele in both PV (20.5%) and PF (33.3%) patients. The percentage of HLA-DQB1 * 03:02 was significantly higher in PF than PV patients, while the percentage of HLA-DQB1 * 05:03 was approximately 10 times higher in PV patients. Pemphigus patients who have the HLA-DRB1 * 04 alleles are more likely to have mild or moderate disease.The HLA-DRB1 and DQB1 alleles may influence susceptibility to pemphigus subtypes, with DQB1 * 05:03 being specific for PV and DQB1 * 03:02 for PF. Our findings suggest that the DRB1 * 04 alleles are likely to be associated with mild and moderate disease.Abbreviations: HLA = human leukocyte antigen, PDAI = pemphigus disease area index, PF = pemphigus foliaceus, PV = pemphigus vulgaris.

Background: Pemphigus is a group of rare, life-threatening bullous autoimmune diseases that affect the skin and mucous membranes and are associated with high morbidity and morbidity. HLA class II genes, particularly HLA-DRB1 and HLA-DQB1, play roles in pemphigus. Objectives: To investigate the susceptibility of HLA class II DRB1 and DQB1 alleles in Vietnamese patients with pemphigus vulgaris (PV) or pemphigus foliaceus (PF). Methods: The study enrolled 31 participants (22 with PV, 9 with PF) with diagnoses confirmed by clinical manifestations, histopathology, and direct immunofluorescence from November 2019 to June 2020. The HLA polymorphisms were determined by Sanger sequencing. The HLA-DRB1 and HLA-DQB1 profiles of the 101 healthy individuals in the control group have been published previously. Results: The frequencies of HLA-DRB1*14, DRB1*13:07, DRB1*04:04, DRB1*03:02, DQB1*02:02, and DQB1*05:03 were significantly higher, whereas those of DRB1*09:01, DRB1*12:02, DQB1*03:03, DQB1*05:01, and DQB1*06:01 were significantly lower, in the PV group than in the controls. The frequencies of DRB1*14:54, DRB1*13:07, and HLA-DQB1*03:02 were significantly higher in the PF group than in the controls. Conclusions: Alleles HLA-DRB1*14:54, DRB1*14:04, DRB1*14:03, DRB1*14:01, DRB1*14:12, DRB1*13:07, DRB1*04:04, DRB1*03:02, DQB1*02:02, and DQB1*05:03 were associated with an increased risk of PV, whereas alleles DRB1*09:01, DRB1*12:02, DQB1*03:03, DQB1*05:01, and DQB1*06:01 might protect against PV. In PF, DRB1*14:54, DRB1*13:07, and HLADQB1* 03:02 are promising susceptibility alleles.