Adult T-cell leukemia/lymphoma with two distinct clones in the peripheral blood and lymph node

A case of adult T-cell leukemia/lymphoma (ATL) with two different clones in the peripheral blood and lymph nodes is reported here. When cellular DNA from the lymph node was digested with EcoRI, one band larger than 9 Kb was detected. Digestion of the cellular DNA with PstI resulted in one clear band in addition to three internal fragments. In contrast, when cellular DNA from malignant peripheral blood lymphocytes (PBL) was digested with the same endonucleases, distinct bands at positions different from those observed in the lymph node were detected, indicating two separate malignant clones in the patient. Monoclonality of the tumor cells was shown by T-cell receptor-beta (TCR-beta) gene rearrangement in both PBL and lymph node. Furthermore, there was a difference in the surface phenotype between tumor cells taken from peripheral blood (CD4+, CD8-) and lymph node (CD4+, CD8+). These findings suggest the presence of two different ATL clones in PBL and lymph node in a single patient simultaneously, which is distinguishable by the integration pattern of human T-cell leukemia virus type I (HTLV-I) proviral DNA.