Figure 2: Macrophage infiltration in T1D islets. Macrophages and other inflammatory cells are recruited to the islets of Langerhans in the pancreas by secreted cytokines such as CCL2. Within the islets, the macrophages secrete pro-inflammatory cytokines such as IL-1β and TNF- α. These secreted cytokines together with IFN-γ results in β-cell apoptosis. Together with islet associated DCs, macrophages activate islets auto-reactive T-cells and influence their polarization. These activated T-cells cells further enhance recruitment of additional macrophages through a positive feed-back loop which ultimately leads to development of T1D.