The pathogenesis of AIDS-related non-Hodgkin's lymphomas (AIDS-NHL) involves accumulation of genetic lesions, stimulation and selection by antigen, as well as infection by viruses. Deregulation of cytokine loops has also been proposed to contribute to AIDS-NHL development, although data are available only for a limited number of cytokines. In this study we have utilized a panel of AIDS-NHL cell lines to investigate in detail the pattern of tumour expression and production of a wide spectrum of cytokines. The cytokines investigated included interleukin (IL)-1α, IL-1β, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-13, TNFα, TNFβ, IFNγ, TGFβ2, G-CSF, GM-CSF and SCF. The AIDS-NHL cell lines utilized were representative of both AIDS-related Burkitt lymphoma (AIDS-BL) and AIDS-related body cavity-based lymphoma (AIDS-BCBL). Overall, AIDS-NHL were found to produce IL-6, IL-10 and TNFβ, although with different patterns depending upon the biological features of the tumour. Production of high levels of IL10 preferentially associated with Epstein-Barr virus (EBV) positive AIDS-BL and AIDS-BCBL, although lower levels of the cytokine were also detectable among EBV-negative AIDS-BL. Production of IL-6 was restricted to EBV-positive AIDS-BL and AIDS-BCBL, whereas it was absent among EBV-negative AIDS-BL. Production of TNFβ clustered with AIDS-BL, whereas this was absent among AIDS-BCBL. These results define that the pattern of cytokine expression of AIDS-NHL depends upon the biological features of the tumour and may have implications for the pathogenesis of these disorders.