Defective monocyte chemotactic responsiveness in patients with multiple myeloma and benign monoclonal gammapathy.

The chemotactic responsiveness of peripheral blood monocytes was evaluated in three groups of subjects: 32 patients with multiple myeloma, 27 subjects with benign monoclonal gammapathy, and 64 normal controls. Monocyte chemotactic responsiveness was significantly depressed both in multiple myeloma patients (P less than 0.001) and in subjects with benign monoclonal gammapathy (P less than 0.001) as compared to that found in the control population. Although the results of chemotactic response obtained in multiple myeloma and in benign monoclonal gammapathy patients were largely overlapping, a significant difference was also found between the mean values of the two groups (P les than 0.025). The results support the hypothesis that myelomatosis, similarly to other neoplasms, may affect monocyte migratory activity thus hindering immunologically mediated destruction of tumour cells.