Preliminary serological studies comparing immunofluorescence assay with radioimmunoassay

Abstract

We assayed serum from 12 patients with untreated cicatricial pemphigoid affecting the conjunctiva for circulating autoantibodies directed against the epithelial basement membrane zone. We employed a conventional indirect immunofluorescence assay, with monkey esophagus and human conjunctiva as substrates, and compared the results with those obtained employing a radioimmunoassay measuring antibasement membrane zone antibody binding to COLO-16 and to SCaBER tumor cell lines. The indirect immunofluorescence assay on normal human conjunctival substrate detected circulating antibodies to conjunctival epithelium in 6 of 12 CP patient serum specimens. Monkey esophagus failed to detect antibodies to the epithelial basement membrane zone. In contrast, autoantibodies were detected in all 12 specimens by the radioimmunoassay. Specificity, as demonstrated by appropriate controls and assay of normal human serum, was 100%. These results demonstrate that radioimmunoassay employing COLO-16 or SCaBER cells is an exquisitely sensitive and specific assay for detection of circulating antibasement membrane antibodies in patients with cicatricial pemphigoid affecting the conjunctiva.

Treatment of ocular cicatricial pemphigoid with tacrolimus (FK 506)

“…Immunohistochemical analysis of biopsied inflamed conjunctiva disclosed immunoglobulin and/or complement deposition at the epithelial basement membrane zone of each patient. All patients had circulating autoantibodies which bound to the epithelial BMZ of normal human conjunctiva [9] and to the epidermal side of salt-split skin preparations on indirect immunofluorescence [10]. The circulating autoantibodies recognized a 205-kDa protein, previously identified as β4-integrin, in an immunoblot assay using normal human conjunctival lysates [11].…”