Anemia of chronic disease is a complication accompanying many inflammatory diseases. The proinflammatory cytokine IFN-γ has been implicated in this form of anemia, but the underlying mechanism remains unclear. Here we describe a novel mouse model for anemia of chronic disease, in which enhanced CD27-mediated costimulation strongly increases the formation of IFN-γ-producing effector T cells, leading to a progressive anemia. We demonstrate that the anemia in these mice is fully dependent on IFN-γ and that this cytokine reduces both the life span and the formation of red blood cells. Molecular analysis revealed that IFN-γinduces expression of the transcription factors of interferon regulatory factor-1 (IRF-1) and PU.1 in both murine and human erythroid precursors. We found that, on IFN-γ stimulation, IRF-1 binds to the promoter of SPI.1 (PU.1) and induces PU.1 expression, leading to inhibition of erythropoiesis. Notably, down-regulation of either IRF-1 or PU.1 expression is sufficient to overcome IFN-γ-induced inhibition of erythropoiesis. These findings reveal a molecular mechanism by which chronic exposure to IFN-γ induces anemia.,
Erasmus MC: University Medical Center Rotterdam

Libregts, S., Gutiérrez, L., de Bruin, A., Wensveen, F., Papadopoulos, P., van IJcken, W., … Nolte, M. (2011). Chronic IFN-γ production in mice induces anemia by reducing erythrocyte life span and inhibiting erythropoiesis through an IRF-1/PU.1 axis. Blood, 118(9), 2578–2588. doi:10.1182/blood-2010-10-315218