Detection of circulating immune complexes in patients with atopic dermatitis and psoriasis

Sera from 32 patients with atopic dermatitis and 22 patients with psoriasis were examined for the presence of circulating immune complexes (CIC) in comparison to 51 healthy controls using a PEG-precipitation laser nephelometer technique. Different patterns of the precipitated proteins were found in both diseases. In atopic dermatitis C3 and IgG were significantly elevated in CIC. Furthermore, significantly increased amounts of IgE were found in the precipitates. Groups with high and low serum IgE levels showed no significant differences in the quantity of precipitated proteins. Skin involvement did not correlate with CIC. In psoriasis patients, a different pattern with significantly increased IgA, IgG, IgM and C3 was found in the precipitates. IgE was also significantly increased in comparison to the controls. No difference was found between patients with psoriasis vulgaris and psoriasis guttata. CIC in psoriasis and in atopic dermatitis thus showed a characteristic composition. However, a detection of CIC was not directly related to the cutaneous manifestation of the disease.