Correlation of antimuscarinic acetylcholine receptor antibody titers and antidesmoglein antibody titers with the severity of disease in patients with pemphigus

Background Acetylcholine receptor (AchR) antibody levels significantly correlate with disease severity at initial pemphigus diagnosis and during follow-up. However, it is not clear if they are just an epiphenomenon or a potential trigger of the known pathogenic process in pemphigus vulgaris. Objective We sought to assess the changes in anti-muscarinic (M3) AchR and anti-desmoglein (Dsg) antibody titers with therapy. Methods This was a hospital-based cohort study involving 45 patients with active pemphigus. Disease was graded clinically using Pemphigus Disease Area Index. Antibody titers were estimated using enzyme-linked immunosorbent assay at baseline, 3 months, and 15 months. Results All patients with pemphigus had significantly higher anti-M3 AchR titers when compared with a control group. Only 95.5% of patients had anti-Dsg1 antibodies and 84.4% of patients had anti-Dsg3 antibodies. A statistically significant reduction in all 3 antibody titers from baseline to follow-up with treatment was observed. There was a good correlation between all 3 antibody titer and Pemphigus Disease Area Index score at baseline and after therapy and between anti-M3 AchR and anti-Dsg1 antibody titers. Limitations Sample size was small and follow-up period was short. Conclusions Anti-M3 AchR antibodies are strongly associated with pemphigus. They significantly correlate with disease activity and their titers decline with therapy along with anti-Dsg antibodies.