IL17A and psoriasis: Shan et al. [147] showed that CD1a+ antigen-presenting cells (APCs) from the lungs of patients with emphysema could induce autoreactive, pathological T helper 1 (Th1) and Th17 cell responses and cause overexpression for IFN-γ and IL-17A, which play a crucial role in psoriasis pathogenesis.