A novel lateral flow immunoassay for the rapid detection of anti-Dsg3 IgG serum autoantibodies in pemphigus vulgaris.

Pemphigus vulgaris (PV) is a severe autoimmune blistering disease of the skin and mucous membranes. As autoantibodies play an essential role in the disease pathogenesis, the serological detection of anti-desmoglein 3 IgG represents a central tool in the diagnosis of the disease. In this study, we show the validation of a novel lateral flow immunoassay (LFIA) which rapidly detects anti-desmoglein 3 (Dsg3) IgG in human serum. In contrast to other diagnostic procedures, the assay is compact and simple to perform and delivers a fast "yes" or "no" answer within 10 minutes without additional hardware requirements for test evaluation. For validation, a blinded collection of 200 sera including 100 sera from 14 PV patients, 75 sera from 24 bullous pemphigoid patients and 25 sera from 6 patients with pemphigus foliaceus collected at different time points during disease was used. Presence or non-presence of anti-Dsg3 IgG within sera was confirmed using a commercially available Dsg3-ELISA. For qualitative evaluation, Dsg3-LFIA test results were assessed by two independent groups of human observers. Furthermore, quantitative evaluation using POCScan reader was applied. The Dsg3-LFIA demonstrated reliable test results with a sensitivity and specificity of 78.1% and 97.1%, respectively. Test results from POCScan and human observers showed a substantial agreement. The Dsg3-LFIA represents a new diagnostic tool for the immediate and reliable detection of anti-desmoglein 3 serum IgG autoantibodies that does not require additional hardware. Further prospective trials are warranted to validate the Dsg3 LFIA in pemphigus.