Cytotoxic activity in a case of adult T-cell leukemia/lymphoma with spontaneous regression.

We report a patient with adult T-cell leukemia/lymphoma ATL/L diagnosed by lymph node biopsy, Ga scintigram and monoclonal integration of HTLV-1 proviral DNA. As lymphadenopathy and skin eruption spontaneously improved and disappeared after admission without any treatment, we considered that spontaneous regression had occurred. An immunological study revealed that the cytotoxic activity of the peripheral mononuclear cells in this ATL/L patient at the time of spontaneous regression were significantly higher than those in a healthy control, when tested against cultured ATL cells (Sez627c). As the disease progressed, the cytotoxic activity decreased. These findings suggest that there may exist an immunological response against ATL cells during spontaneous progression suppressing the progression of the disease.