IL17A and rheumatoid arthritis: Dietary administration of propolis ethanolic extract (6.7 and 20 mg/g) was found to reduce the severity of this autoimmune disease in vivo by inhibiting production of IL-17 [75], a pro-inflammatory cytokine produced by Th cells (Th17 cells) strongly implicated in RA pathogenesis (e.g., joint inflammation and destruction of bone and cartilage) [76].