IMPAIRMENTS IN COMPLEMENT RECEPTOR-MEDIATED AND FE RECEPTOR-MEDIATED FUNCTIONS IN-VIVO IN PATIENTS WITH PSORIASIS

The function of the fixed macrophage system in 18 psoriasis patients w as evaluated by measuring the elimination rate of injected autologous erythrocytes coated with iC3b or IgG. The mean half-life of iC3b-coate d erythrocytes was significantly prolonged in patients with psoriasis compared with healthy controls (4.7 +/- 0.8 vs 2.7 +/- 0.2 min, P = 0. 01). There was also a decrease in the total number of cells eliminated from the circulation (2.5 +/- 0.2 x 10(8) vs 3.3 +/- 0.2 x 10(8), P = 0.01). There was an even more pronounced increase in the half-life of IgG-coated erythrocytes (85 +/- 18 vs 20 +/- 5 min, P < 0.001), with normal values in only 5 of 15 patients, and 4 of these 5 patients were receiving systemic treatment. The slow elimination was interpreted as being caused by primary or secondary defects in receptor function rat her than by blocking of the receptors by immune complexes, since patie nts with psoriasis show normal levels of circulating immune complexes. Further studies are needed to elucidate the nature of these defects.