Recombinant human interleukin-2(Beijing SL Pharmaceutical Co., Ltd.)

Rheumatoid arthritis (RA) is an immune-mediated inflammatory disease, characterized by symmetric poly-arthritis usually involving the small joints of the hands and feet. In addition, various extra-joint manifestations may develop. Several immunomodulating agents have been attempted in the treatment of RA without achieving satisfactory results. Dysfunction of regulatory T (Treg) cells has been detected in diverse autoimmune diseases, which can be promoted by interleukin-2 (IL-2). The investigators hypothesized that low-dose IL-2 could be a novel therapy in active RA patients. This clinical study will test the efficacy and safety of low dose IL-2 treatment in RA. The investigators perform a single-centre, double-blind pilot trial with hrIL-2 in RA. The investigators evaluate the effectiveness and safeness of low-dose hrIL-2 for RA by randomized controlled study (hrIL-2 (N = 23) + Methotrexate (MTX)+ Loxoprofen versus placebo+MTX + Loxoprofen group (N = 24)).