Coexistence of psoriasis and an unusual IgG-mediated subepidermal bullous dermatosis: identification of a novel 200-kDa lower lamina lucida target antigen.
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.
Chen
K R
KR
Division of Dermatology, Kawasaki City Hospital, Japan.
Shimizu
S
S
Miyakawa
S
S
Ishiko
A
A
Shimizu
H
H
Hashimoto
T
T
D000368:Aged; D001323:Autoantibodies / Q000032:analysis*; D001324:Autoantigens / Q000276:immunology; D001327:Autoimmune Diseases / Q000150:complications* / Q000473:pathology; D001485:Basement Membrane / Q000276:immunology; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D015151:Immunoblotting; D007074:Immunoglobulin G / Q000032:analysis*; D016253:Microscopy, Immunoelectron; D011565:Psoriasis / Q000150:complications* / Q000473:pathology; D012872:Skin Diseases, Vesiculobullous / Q000150:complications* / Q000276:immunology / Q000473:pathology
D001323:Autoantibodies; D001324:Autoantigens; D007074:Immunoglobulin G