IAA also decreased the incidence and severity of ankylosing spondylitis in mice, inhibited the production of pro-inflammatory cytokines (TNF-α, IL-6, IL-17A, and IL-23), increased the production of anti-inflammatory cytokine IL-10, and decreased the ratio of pro-inflammatory/anti-inflammatory cytokines (34). The gene discussed is IL17A; the disease is ankylosing spondylitis.