IFITM1 and graft versus host disease: Analysis of differential gene expression between the monocytes of patients with GVHD and healthy controls showed upregulation of monocyte chemoattractant receptor CCR5 and MRC1 (macrophage mannose receptor, CD206), FCGR3A/B (Fc receptor/CD16), GNLY (granulysin), and IFN-response genes IFITM1 and GBP1 (Figure 5C).