Interleukin-10 gene expression and adult T-cell leukemia.

Numerous studies have shown spontaneous IL-10 gene expression and synthesis in a variety of peripheral blood or bone marrow-derived leukemic cells. These include B-cells derived from various lymphoproliferative disorders. Since little is known regarding IL-10 expression in leukemic T-cells, we examined clinical specimens of patients with adult T-cell leukemia (ATL) for IL-10 expression. Sera from ATL patients show increased levels of IL-10 when compared with sera from healthy donors. IL-10 is constitutively produced by ATL cells and also by human T-cell leukemia virus type I (HTLV-I)-infected cell lines. It is thought that HTLV-I infection induces gene expression for IL-10. In this review, a transcriptional regulation of IL-10 gene expression by HTLV-I Tax and the possible role of the NF-kappaB pathway are described.