TNF and Bone marrow hypocellularity: In addition, mouse models of acquired bone marrow failure have demonstrated that IFN-γ induces tumour necrosis factor alpha (TNF-α) (12) and CCR5 expression (13) in BM resident macrophages, inducing further IFN-γ expression and setting up a positive feedback loop of IFN-γ/TNF-α production and a hyper-inflammatory state.