Different inflammatory cytokines are involved in the pathogenesis of the anemia of chronic disease (ACD), by inhibiting the proliferation of erythroid progenitors. Leukemia inhibitory factor (LIF), is an important inflammatory cytokine, and the purpose of this study was to evaluate its effect on the proliferation and viability of human erythroid progenitors. We have found that LIF slightly increased the survival of human early progenitor cells cultured under serum free conditions. LIF also slightly costimulated in vitro growth of human erythroid colonies. This last effect seems to be a direct one, because we found that LIF receptor (LIF-R) is expressed in cells isolated from growing in vitro human erythroid BFU-E colonies. These data, and the data reported by others in in vivo models, where LIF administration to experimental animals did not change the values of erythropoietic parameters, demonstrate that this inflammatory cytokine itself is not involved in the pathogenesis of ACD.