Decrease of Fcγ and C3b receptor‐bearing granulocytes and of T lymphocytes in myelomatosis

Abstract

18 patients with myelomatosis had lower percentages of granulocytes bearing receptors for Fcγ (47.6%) and C3b (43.0%) than controls (80.4% and 75.0%). The percentage of T lymphocytes was decreased in patients when untreated sheep erythrocytes were used as indicator cells. Patients with high serum IgG levels had lower percentages of T lymphocytes. There was no significant difference in receptor profile between treated and untreated patients. The decrease in Fcγ and C3b receptor‐bearing granulocytes in myelomatosis is probably not due to serum or plasma factors since (a) the distribution of receptor‐bearing lymphocytes was not different from that of the controls; (b) extra washings of cells or overnight incubation did not enhance the percentage of receptor positive cells; and (c) incubation of normal granulocytes in sera or plasma from myelomatosis patients did not cause a more pronounced reduction in the proportions of Fcγ of C3b receptor‐bearing cells than incubation in normal sera or plasma.

Granulocyte Function in Malignant Monoclonal Gammopathy

“…The decreased chemiluminescence production by myeloma granulocytes phagocytosing opsonized zymosan particles in-dicates a decreased capacity of the granulocytes to phagocytose and/or kill microorganisms. This may be related to the reduction of Fc-and complement-receptor bearing granulocytes in myeloma patients (16).…”