Usefulness of BP230 and BP180-NC16a Enzyme-Linked Immunosorbent Assays in the Initial Diagnosis of Bullous Pemphigoid A Retrospective Study of 138 Patients

Objective: To investigate the diagnostic value of commercially available BP230 and BP180-NC16a enzyme-linked immunosorbent assays (ELISAs) in routine practice in patients with bullous pemphigoid (BP). Design: Single-center retrospective study. Setting: French academic dermatology department. Patients: The study population comprised 138 patients, who were admitted from January 1998 through December 2008. Interventions: Sera samples were analyzed by ELISA; clinical and immunopathological data were recorded from the patients' medical charts. Main Outcome Measures: BP230 and BP180-NC16a ELISA scores were evaluated with respect to clinical characteristics (number of blisters, mucosal involvement, localized or generalized disease, and outcome) and routine indirect immunofluorescence Results: Of the 138 study patients, 81 (59%) had a positive BP230 ELISA result and 119 (86%) had a positive BP180 ELISA result. There was no relationship between a positive ELISA BP230 result and the disease extent at diagnosis or the presence of mucosal involvement. Serum anti-basement membrane zone autoantibodies (indirect IF) were more frequently detected when the BP230 ELISA result was positive (P <.001). The median anti-basement membrane autoantibody titer as detected by indirect IF was higher in patients with a positive BP230 result (P <.001). The BP180 ELISA result was associated with disease extent at diagnosis as estimated by both the percentage of patients with extensive BP (P=.01) and the mean number of blisters (P=.03) but was not associated with mucosal involvement. Conclusions: The currently available BP230 ELISA is a reliable although less-sensitive test than BP180 ELISA in BP, and its diagnostic added value compared with BP180 ELISA alone is approximately 5%. Our results support the predominant contribution of the BP230-specific autoantibodies to anti-basement membrane zone antibody titer as detected by indirect IF.