Monoclonal gammopathy in adult T-cell leukemia/lymphoma: a report of three cases.

Adult T-cell leukemia/lymphoma (ATL/L) is clustered in southwestern Japan, especially in the Nagasaki and Kagoshima areas. It was shown that this clustering correlated with the presence of antibodies to antigens of a new C-type RNA leukemia virus. Surface marker analysis of neoplastic T-cells of ATL/L patients shows the helper/inducer phenotype (Leu-1+, Leu-2a- and Leu-3a+). On the other hand, the association between T-cell malignancy including ATL/L and monoclonal gammopathy is very rare. Three unique cases of ATL/L with monoclonal gammopathy are reported. Yet the meaning of an M-component in T-lymphocytic proliferation remains uncertain. The relationship between the leukemia virus, ATL/L-cells and monoclonal gammopathy is discussed.