CYTOKINE EXPRESSION IN LARGE-CELL LYMPHOMA ASSOCIATED WITH ACQUIRED-IMMUNODEFICIENCY-SYNDROME

Cytokine expression was examined by reverse transcriptase-polymerase c hain reaction (RT-PCR) in a retrospective sampling of 16 AIDS-associat ed large cell, lymphomas (LCL). IL-6 receptor (IL-6R) and IL-10 expres sion was detected in a majority of the tumor specimens tested, IL-6 ex pression was detected in 5 of 16 lymphomas that also expressed IL-6R, suggestive of an autocrine mechanism of disease, A subset of tumor sam ples described as mixed immunophenotype contained large numbers of inf iltrating T lymphocytes and macrophages, Immunoperoxidase staining of a representative tumor of mixed immunophenotype demonstrated the prese nce of HIV-infected macrophages that also stained with anti-IL-6. This finding suggests that IL-6 produced by nonlymphoid cells may act as a paracrine growth factor for tumor cells that express IL-6R. Although earlier studies of AIDS Burkitt's lymphoma cell lines suggested that I L-10 expression required EBV infection, 7 of 12 AIDS LCLs that express ed IL-10 did so in the absence of EBV by EBER in situ hybridization, B ecause AIDS LCLs frequently express cell surface CD5, we speculate tha t IL-10 may act as an autocrine or paracrine growth factor for this cl ass of lymphoma. These studies suggest that IL-6 and IL-10 are involve d in the pathogenesis of AIDS-associated large cell and mixed immunoph enotype lymphoma.