Thus, our objective was to compare in parallel the effects of the same batch of IL-17A and IL-17F, in combination or not with TNF and IL-1β, on pro-inflammatory cytokine production (IL-6 and IL-8) by several cell types [RA synoviocytes, psoriatic skin fibroblasts, myoblasts, hepatocytes and human umbilical vein endothelial cells (HUVEC)], with the effect on synoviocytes as reference. The gene discussed is IL17A; the disease is rheumatoid arthritis.