Demonstration of tissue 90 kD glycoprotein as antigen in circulating IgG immune complexes in dermatitis herpetiformis and coeliac disease.

Mannose-rich 90 kD glycoprotein, a constituent of skin and small-bowel mucosa, was identified as antigen in circulating IgG-type immune complexes in dermatitis herpetiformis and coeliac disease by means of an enzyme-linked immunosorbent assay. High levels of 90 kD glycoprotein-IgG complexes were found in 7 out of 12 patients with dermatitis herpetiformis and in 10 out of 20 patients with coeliac disease but in only 2 out of 20 patients with systemic lupus erythematosus. The highest levels of 90 kD antigen-IgG complexes were found in patients with dermatitis herpetiformis. The amount of these complexes did not correlate with the degree of jejunal villous atrophy. The 90 kD glycoprotein-containing immune complexes with targets in skin and gut may be involved in the pathogenesis of dermatitis herpetiformis and coeliac disease.