Premium
Coexistence of psoriasis and an unusual IgG‐mediated subepidermal bullous dermatosis: identification of a novel 200‐kDa lower lamina lucida target antigen
Author(s) -
CHEN KR.,
SHIMIZU S.,
MIYAKAWA S.,
ISHIKO A.,
SHIMIZU H.,
HASHIMOTO T.
Publication year - 1996
Publication title -
british journal of dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.304
H-Index - 179
eISSN - 1365-2133
pISSN - 0007-0963
DOI - 10.1111/j.1365-2133.1996.tb07625.x
Subject(s) - lamina lucida , hemidesmosome , antigen , autoantibody , pathology , basement membrane , biology , immunology , antibody , pemphigoid , bullous pemphigoid , medicine , ultrastructure , basal lamina
Summary Bullous pemphigoid (BP) is characterized by autoantibodies against 230‐ and 180‐kDa hemidesmosomal antigens located in the most superficial layers of the basement membrane zone (BMZ). Histologically. there is a predominance of eosinophils in the infiltrate. In a psoriatic patient, we identified an unusual autoimmune subepidermal bullous eruption which clinically resembled BP, but which was characterized by IgG autoantibodies against a novel 200‐kDa lower lamina lucida component, Histologically there was a predominance of neutrophils in the infiltrate. Direct immunofluorescence showed linear immunoglobulin (Ig)G and C3 deposition at the BMZ. The patient's IgG autoantibodies bound exclusively to the dermal side of salt‐split normal human skin. Indirect immunogold electron microscopy showed a marked deposition of IgG at the lower lamina lucida and minimal deposition at the hemidesmosomes. Immunoblot analysis identified a unique 200‐kDa autoantigen in dermal extracts and a faint band of the 230‐kDa BP antigen in epidermal extracts. The patient responded dramatically well to cyclosporin A. Although the patient's serum also reacted slightly with the 230‐kDa BP antigen, there were significant findings different from the usual immunopathological changes of BP. These included finding a novel 200‐kDa lower lamina lucida target antigen, the binding of IgG autoantibodies exclusively to the dermal side of the split skin and a predominance of neutrophils in blister infiltrate. The IgG autoantibodies against the 200‐kDa lamina lucida target antigen seemed to play a major role in the pathogenesis of this unique autoimmune subepidermal dermatosis.