After ischemic stroke, TREM2-KO mice exhibit reduced microglial activity, with decreased transcription of pro-inflammatory cytokines TNFα, IL-1α, and IL-1β, as well as reduced transcription of chemokines CCL2 (MCP1), CCL3 (MIP1α), and chemokine receptor CX3CR1. The gene discussed is CCL3; the disease is ischemic stroke.