Atopic dermatitis. II. The status of complement proteins and the pathogenetic role of anaphylatoxins C4a, C3a and C5a

Eighty-eight patients with atopic dermatitis have been examined for the complementary proteins C3 (C3c), C3act., C4, C1inact. by radial immunodiffusion; in 36 of these patients anaphylatoxins C3a des Arg, C5a des Arg, and C4a des Arg have been radioimmunoassayed. Increased levels of C4a des Arg have been revealed in 50% of the examinees. C3a des Arg levels did not differ significantly from the reference values, and C5a des Arg level has been within the normal range in all the patients. C4a des Arg has been related to the severity of the skin inflammation and did not depend on the serum IgE content. C3 (C3c), C3act., C1inact. have been elevated and C4 reduced. These findings evidence activation of the complementary system in atopic dermatitis and indicate the role of anaphylatoxin C4a des Arg in the maintenance of the inflammatory reactions.