Immunological aspects of psoriasis.

Abstract

An anti-Ig[immunoglobulin]G activity was previously reported at the cellular level in patients with psoriasis. This activity was demonstrated by the so-called rheumatoid rosette test. In the present work the nature of rheumatoid rosette-forming cells was studied in comparison with other EA [erythrocyte-antibody] rosette techniques. Purified cell populations showed that lymphocytes participating in the rheumatoid rosette phenomenon were lacking conventional T [thymus derived] and B [bone marrow-derived] cell membrane markers, and were referred to as null cells. Such mononuclear cells bearing a receptor for the Fc part of IgG acted as killer cells to IgG-coated target cells. The cytotoxic activity was mainly restricted to a small proportion of lymphocytes forming rheumatoid rosettes which had a high avidity for EA complexes. Such cytotoxicity could contribute to the etiology of lesions in psoriasis.