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 (IF). 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.