In this model, E. lenta exacerbated arthritis severity by enhancing the immune response to type II collagen, which led to increased levels of pro-inflammatory cytokines in the serum, including interleukin (IL)-9, IL-17, IL-23, interferon (IFN)-γ and tumor necrosis factor (TNF)-α. The gene discussed is IFNG; the disease is arthritic joint disease.