[Cytological study of acid phosphatase activity of plasma cells in monoclonal gammopathies].

The activity of acid phosphatase in bone marrow plasma cells was investigated by a cytochemical method in 12 patients with multiple myeloma, in 12 patients with benign monoclonal gammopathy and in 5 normal controls. The activity of acid phosphatase was significantly higher in the multiple myeloma patients compared with the activity observed in controls and in benign monoclonal gammopathy patients (p less than 0.001). It is therefore suggested that this method may be a valuable adjunct in the differential diagnosis of monoclonal immunoglobulinemias .