Herein, our finding of upregulated MIF expression in PFC from RIP-B7.1 mice at 8 days of immunization could indicate that peritoneal myeloid cells play an early role in the programmed autoimmune attack, which is in line with previous studies indicating a potential role for resident peritoneal immune cells populations such macrophages and B1-cells in the development of T1DM (Kendall et al. 2004; Silveira and Grey 2006; Emani et al. 2015). The gene discussed is CD80; the disease is type 1 diabetes mellitus.