Interleukin-1 and tumor necrosis factor-alpha inhibit erythropoietin production in vitro

The effects of several immunomodulatory peptides (recombinant, human) on the in vitro production of erythropoietin (Epo) were studied in cultures of the human hepatoma cell line Hep G2. A dose-dependent decrease of up to 60% in Epo production was induced by interleukin-1 beta, interleukin-1 alpha, and tumor necrosis factor-alpha (in that order of potency). In contrast, moderately increased Epo levels resulted with interleukin-6 or interferon-gamma treatment at high concentrations. Concomitant measurements of the production of alpha-fetoprotein indicated that the observed effects were specific for Epo. Hence, we suspect a modulating role of the immune system in the in vivo control of Epo production and postulate that interleukin-1 and tumor necrosis factor-alpha are involved in some of the cases of lowered blood Epo levels in association with renal diseases, chronic inflammation, and malignancies.