Interleukin-4 and Tumour Necrosis Factor-alpha Produce Non Isotype Specific Partial Differentiation of Peripheral Blood B-Cells in Myeloma

Abstract

In a previous study, culture of peripheral blood mononuclear cells (Pbmc) from myeloma patients with interleukin(IL)-4 and tumour necrosis factor(TNF)-alpha resulted in the appearance of clonal plasma cells, thus suggesting the presence of circulating myeloma cell precursors in the peripheral blood. Using the same cytokine combination, we cultured Pbmc and purified peripheral blood B-cells from myeloma patients. In nearly all cases, partial differentiation of B-cells occured but, similarly to results for normal controls, both kappa and lambda light chain (L.C.) cytoplasmic positive lymphoid and lymphoplasmacytoid cells were detected rather than clonal plasma cells. These results suggest that IL-4 and TNF-alpha cause partial differentiation of residual normal polyclonal B-cells rather than of circulating myeloma cell precursors in the peripheral blood of myeloma patients.

Key Words:

• Myeloma
• B-cells
• differentiation
• TNF-alpha
• IL-4