Although previously viewed as a pro-inflammatory agent in settings of sepsis and microbial challenge (48), our work and that of others demonstrate that its role is context-dependent, so that in the presence of the pivotal type 2 cytokine IL-4, MIF will synergize to induce characteristic M2 products including Chil3, RELMα and Arginase-1 (16, 17). Here, ARG1 is linked to Sepsis.