Autoimmunity in psoriasis. Relation of disease activity and forms of psoriasis to immunofluorescence findings.

Immunofluorescence (IF) studies using the test providing information on the reactivity of stratum corneum (SC) antibodies and their in vivo binding have been performed in 193 cases of psoriasis and 89 cases with other dermatoses. It has been shown that: 1. Essentially all fully developed, active psoriatic lesions had IgG deposits in the stratum corneum at the sites of the SC antigen, presumably due to in vivo binding of SC antibodies. 2. In various forms of psoriasis SC antigen sites appeared to be completely or almost completely satured with in vivo deposits of IgG as seen in tests with SC antibodies. 3. In most but not all lesions complement components C3 and/or C4 was found in a comparable pattern in the SC, especially when multiple specimens of single cases were studied. Partial or complete saturation of the SC antigen could be observed by the performance of complement indirect IF tests for SC antibodies in such specimens. 4. In lesions with typical histology of psoriasis the above-mentioned immunologic characteristics appeared to be a constant finding. However, in specimens of recent lesions which had not yet developed typical histology a proportion (2 of 17) were negative both for IgG and complement deposits. In receding lesions weak deposits of IgG were present only in a few specimens and complement deposits were as a rule negative. 5. In a group of 89 control specimens of other dermatoses only occasional cases gave the psoriasiform IF pattern, but about 30% of the specimens gave positive reactions in the SC though these were usually of a different pattern.