Circulating immune complexes in untreated psoriasis. A comparison of Raji-cell radioimmunoassay and polymorphonuclear leukocyte phagocytosis.

Three different in vitro assays for the demonstration of circulating immune complexes were compared in 49 patients with psoriasis. Granulocytes from psoriatic subjects contained immune complex-like material in 25 patients (51%). When psoriatic serum was incubated with granulocytes from healthy blood donors, phagocytosed material was found in 18 patients (37%). The Raji-cell assay was only positive in two of 27 subjects (7%). Of the patients 71% tested positively with one of the granulocyte phagocytosis tests. Both tests were positive simultaneously in 16% and negative in 29% of the patients. The pathogenetic significance of the immune complex-like material is unclear.