Using BP180 NC16a enzyme-linked immunosorbent assay as an adjunct diagnostic tool for bullous pemphigoid

Bullous pemphigoid (BP) is an acquired autoimmune subepidermal blistering disease caused by autoantibodies against bullous pemphigoid antigen 1 (BPAg1, 230 kD) and bullous pemphigoid antigen 2 (BPAg2, 180 kD). It usually affects an elderly population. Recently, a novel commercial enzyme-linked immunosorbent assay (ELISA) against the noncollagenous (NC) 16a domain of BP180 has been established and found to be extremely sensitive and specific. Up until now, the usefulness of BP180 NC16a ELISA in the diagnosis of BP in Chinese population has never been reported. In this study, BP180 NC16a ELISA was performed in 49 patients with BP and 62 non-BP patients. Thirty-six (73.5%) sera from BP patients were positive, while only 3 (4.8%) sera from other non-BP patients exceeded the cut-off value. Thus the sensitivity and specificity of BP180 NC16a ELISA were 73.5% and 95.2%, respectively. The correlation between ELISA scores and disease activity along the time course was examined in 5 BP patients, and there was a positive correlation between ELISA scores and disease activity. These findings indicate that BP180 NC16a ELISA may be an adjunct tool for the initial diagnosis and monitoring of patients with BP.