P159 Clinical–serological correlation of Pemphigus Disease Area Index and desmoglein antibodies in patients with pemphigus in skin of colour: experience from a teaching hospital of northern India

Abstract

The Pemphigus Disease Area Index (PDAI) is a validated clinical tool for assessing disease activity in pemphigus. Enzyme immunoassay (EIA) measurement of anti-desmoglein (Dsg)1 and anti-Dsg3 antibodies is increasingly used for diagnosis, disease assessment and monitoring. However, data correlating Dsg antibody levels with PDAI scores in patients with skin of colour remain limited. Our aim was to evaluate the correlation between serum anti-Dsg1 and anti-Dsg3 antibody levels and disease severity as assessed by PDAI. This retrospective observational study included 24 patients with biopsy-proven pemphigus vulgaris (PV) or pemphigus foliaceus (PF) treated at a tertiary care centre between January and December 2025. Data on demographics, disease severity assessed by PDAI, and serum anti-Dsg1 and anti-Dsg3 antibodies (using EIA) were analysed and associations were assessed using appropriate statistical tests. The 24 patients had a mean age of 49.4 years (SD 13.4). The female-to-male ratio was 2 : 1. Twenty-one (88%) had PV and three (13%) had PF. The median total PDAI score was 30.0, with 29% having mild (PDAI 0–15), 46% having moderate (16–45) and 25% having severe (> 45) disease. A positive correlation was observed between anti-Dsg3 antibody levels and both mucosal PDAI (r = 0.71, P < 0.001) and total PDAI scores (r = 0.51, P = 0.01). Anti-Dsg3 antibody levels demonstrated a sixfold increase between mild-to-moderate and severe disease, whereas anti-Dsg1 antibody levels showed no significant association with severity (P = 0.41). Our findings demonstrate a strong association between anti-Dsg3 antibody levels and both mucosal and overall disease activity measured by PDAI in a South Asian cohort. Although interindividual variability in antibody titres exists among patients with similar PDAI scores, anti-Dsg antibodies appear to be a reliable marker of disease severity at the individual level. These results support the use of combined PDAI scoring and quantitative serological markers to optimize assessment of pemphigus across skin types and to guide treatment of the disease.