Neutrophils expressed very low levels of IL-10 at the steady-state (day 0) and throughout the course of infection, whereas a small proportion (5–20%) of CD11b+ DCs, alveolar and interstitial macrophages, and Ly6C− and Ly6C+ monocytes expressed detectable levels of IL-10 already at the steady-state, which greatly increased with infection (Fig. 1). The gene discussed is IL10; the disease is infection.