CCL2 and type 1 diabetes mellitus: These M2 macrophages mainly mediate Th2 by secreting various regulatory cytokines such as IL-1Rα, IL-1α, IL-1β, CXCL2, MCP1, TNF-α and IL-10 et al, and play an immune regulatory and anti-inflammatory role [13], however, the potential role of macrophage in T1D islet transplantation still needs further investigation.