Studies on the composition and elimination of circulating immune complexes in leukaemia.

Longitudinal studies for the detection of circulating immune complexes (CIC-s) were performed in leukaemic patients using three methods in parallel. Results of these studies indicated that immune complexes in leukaemia are heterogeneous and their composition changes in the course of the disease. These results were supported by the changes in the concentration of a complement component (C1) and in the IgG subclasses in the immune complex-enriched fraction prepared by polyethylene glycol precipitation from different serum samples of individual patients with leukaemia. CIC-s from leukaemic patients are normally engulfed by granulocytes of healthy donors. The phagocytic capacity of leukaemic blast cells is hampered. The phagocytic activity through Fc and C3 receptors of peripheral mononuclear cells of leukaemic patients did not run parallel. On the basis of these studies it may be surmised that the total phagocytic capacity of the leukaemic patients cannot keep pace with the increased rate of immune complex formation.