T-cell mediated polyclonal B-cell activation in a case of B-cell lymphoma associated with polyclonal...

The mechanism of abnormal immunoglobulin production in non-Hodgkin's lymphoma is still poorly understood. We report a case of B-cell type non-Hodgkin's lymphoma associated with marked elevated polyclonal hyper-gammaglobulinemia (serum IgG was 7598 mg/dl; IgM, 455 mg/dl). We conducted a mixed lymphocyte culture test using peripheral lymphocytes obtained from the patient and a healthy volunteer. After co-culture with the patient's CD3+ cells, not only the patient's CD3- cells but also control CD3- cells produced greater amounts of IgG and IgM. Elevated IL-6 was also detected from the patient's CD3+ cells. This strongly suggests that B-lymphoma cells stimulate CD3+ cells to produce IL-6 and hence activate normal CD3- cells.