[Detection of myeloma cells in the peripheral blood using flow cytometry]

Bone marrow plasma cells from patients with multiple myeloma express monoclonal cytoplasmic immunoglobulin, strongly express CD38 and usually coexpress CD56 and CD54. The aim of this study was to learn the relationship between the number of CD38+CD56+ and CD38+CD54 positive cells in peripheral blood with the activity of multiple myeloma. We evaluated the number of these cells in patients with monoclonal gammopathy and in the control group, as well. We used the two-color flow cytometry for this purpose. The peripheral blood of 57 patients with multiple myeloma and 4 patients with monoclonal gammopathy of unknown significance was repeatedly analyzed. Patients with high activity of multiple myeloma had the highest percentage of CD38+CD56+ and CD38+CD54+ cells. Patients with lower activity of the disease had lower count of these cells. But in 4 (11%) patients with high disease activity the count of CD38+CD56+ cells was zero. We conclude, that the longitudinal flow cytometric analysis of CD38+CD54+ and CD38+CD56+ cells is a useful method for estimation of disease activity in patients with multiple myeloma. Single analysis of these parameters cannot be used as a strict criterium for differential diagnosis.