Immunoglobulin abnormalities in malignant non-Hodgkin's lymphoma.

The association of monoclonal gammopathy and lymphoma was investigated in 100 consecutive, untreated cases of chronic lymphocytic leukaemia (CLL) and non-Hodgkin's lymphoma (NHL) of B-cell type, classified according to the criteria of Lukes & Collins (9). The overall incidence of monoclonal immunoglobulins (Ig) was 24%. The highest incidence (57%) was seen in plasmacytoid lymphocytic lymphoma and the lowest (7.9%) in cases of CLL. IgM was the predominant class of monoclonal Ig. It is concluded that the presence of monoclonal gammopathy in NHL reflects the stage of differentiation and maturation of the malignant B-cell clone.