[Disturbances in granulocyte chemotaxis in patients with multiple myeloma].

a) Leukocyte chemotactic activity, b) cytotaxic activity of patients' sera and c) influence of patients' sera on chemotactic activity of control leukocytes was studied in 18 patients with multiple myeloma, one patient with monoclonal IgE-gammopathy of undetermined significance and 32 controls. Chemotactic activity of patient leukocytes against Zymosan-activated normal serum and against Casein was reduced significantly. In addition, in 66% of the patients a chemotaxis inhibiting serum factor was observed. The Zymosan-induced generation of cytotaxic factors did not differ in patients or control sera. These data show that leukocyte inherent defects as well as serum factors give rise to reduced leukocyte chemotactic activity in patients with multiple myeloma. This impairment is likely to contribute to the increased susceptibility to infections in that disorder.