IL13 and silicosis: Treg cytokines (TGF-β and IL-10) and Th2 cytokines (IL-4, IL-5, and IL-13), but not Th1 cytokines (IFN-γ, IL2, and IL-12) and pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α), were found to be increased in the sera of patients with silicosis.