Extractable immune complex in soluble substances from psoriatic scales

Soluble substances of psoriatic scales (Pso-exts) were analysed immunologically to detect immune complex (IC) related to the immune reactions in psoriatic lesions and compared with extracts of scales from a patient with erythroderma due to pityriasis rubra pilaris (PRP-exts) as control. Immunoelectrophoretically IgG, IgA and C3 were detected in Pso-exists, but in PRP-exists only IgG was seen as immunological reactive substances. When analysed by Sephadex G-200 column chromatography, IgG and IgA eluates were found in Pso-exts with a molecular weight of more than 200,000 daltons. By Raji cell assay, the IgG and IgA eluates were shown to have IC characteristics and they were the IC composed of IgG-IgA, which was also confirmed using anti-IgG affinity chromatography. The IC seemed to be binding the epidermal proteins as antigen. These findings suggest that deposits of immunoglobulins and complement in the stratum corneum of psoriatic lesions are not just secondary to the underlying inflammation in the dermis but that the IC detected is related to the immune reactions in psoriatic lesions.