Incidence of antibody to adult T-cell leukemia-virus-associated antigen among T-cell malignancies in the Kyoto District, with a report of two unusual cases.

Titration of antibody to adult T-cell leukemia (ATL)-virus-associated antigen (ATLA) is of much help for diagnosing ATL, because almost all patients with ATL are seropositive even in an ATL-nonendemic area such as Kyoto. In T-cell lymphoma, anti-ATLA antibody was thought to be related to the birthplace of the patients and the epidermotropism of their skin lesions, but it was not confirmative because the number of cases was so small. We present here two curious cases of anti-ATLA-negative T-cell leukemia/lymphoma. A 53-yr-old man, born in a nonendemic area, had manifestations similar to those of ATL except for the lack of skin involvement, but the morphology of his leukemic cells was less like that of ATL cells than that of prolymphocytic leukemia cells. Therefore, his leukemia was not diagnosed as ATL. A 52-yr-old woman, whose parents' hometown was in an endemic area, showed typical manifestations of nonleukemic T-cell lymphoma, and her biopsied lymph node was compatible with diffuse, pleomorphic lymphoma histologically. In the latter patient, the negative anti-ATLA finding might be due to titration sensitivity. Therefore, the clinical and hematologic features are still informative for distinguishing ATL from other T-cell malignancies.