CD8‐positive adult T‐cell leukemia cells with an integrated defective HTLV‐I genome show a paracrine growth to IL‐2

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Abstract
We describe a 50‐year‐old man with adult T‐cell leukemia complicated by laryngeal tuberculosis whose tumor cells proliferate in response to IL‐2 in a paracrine manner. On admission, the patient's white blood cell count was 17,900/mm3; 73% were abnormal lymphocytes with convoluted nuclel. FACS analysis showed that the tumor cells were CD4‐negative, CD8‐positive T cells. Southern blot analysis of tumor cells revealed integration of a defective HTLV‐I genome lacking gag and pol genes. He was diagnosed with chronic ATL complicated by laryngeal tuberculosis. The primary leukemic cells expressed IL‐2Rα and IL‐2Rβ detected by FACS and Northern blot analysis and showed marked growth in response to exogenously added recombinant IL‐2 in short‐term cultures. Northern blot analysis did not show any IL‐2 mRNA. We have previously demonstrated that primary leukemic cells from some ATL patients grow in response to IL‐2 in an autocrine or paracrine manner. These results suggest that in CD8 ATL, IL‐2 may beinvolved in a paracrine manner.
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