Study of RC18 Administered Subcutaneously to Subjects With Systemic Lupus Erythematosus(SLE)

Inclusion Criteria: * Active SLE disease，and at least according with 4 of the 11 items of the American College of Rheumatology (ACR) criteria 1997. * Age \& Gender: Male or female between 18 and 65 years of age inclusive，and the sex ratio is not limited * Signed informed consent form，willing or able to participate in all required study evaluations and procedures. * SELENA-SLEDAI(Safety of Estrogens in Lupus Erythematosus National Assessment SLE Disease Activity Index) score ≥ 8 during the screening period.and if there is hypocomlement or the Anti-dsDNA score, SELENA-SLEDAI disease activity score should be at least 6 at screening . * Autoantibody-positive * on a stable SLE treatment regimen for at least 30 days prior to Day 1, which consisted of any of the following (alone or in combination): cortical hormone,anti-malarials,non-steroidal anti inflammatory drugs (NSAIDs),or any immunosuppressive and immunomodulator therapy(i.e.,azathioprine,mycophenolate ,cyclophosphamide,methotrexate,leflunomide, Tacrolimus ,ciclosporin ). Exclusion Criteria: * Severe lupus nephritis within two months(designed as:Urine protein\>6g/24h or serum creatinine ( SCr）\>2.5mg/dL or 221umol/L ) or needing for hemodialysis or recepting high dose cortical hormone ≥14 days( metacortandracin\>100mg/d or equivalent) * Central nervous system disease caused by SLE or non SLE within two months (including epilepsy， mental disease，organic encephalopathy syndrome，cerebrovascular accident, encephalitis, central nervous system vasculitis）; * there are serious heart, liver, kidney and other important organs and blood, endocrine system diseases and medical history; Evaluation criteria for severity : 1. Alanine aminotransferase（ALT）or aspartate aminotransferase (AST) ≥2 upper limit of normal (ULN); 2. Creatinine Clearance (Ccr)\<30ml/min; 3. White Blood Cell Count(WBCs)\<2.5x 10(9)/L; 4. hemoglobin\<85g/L; 5. Platelets\<50x 10(9)/L. * Have a historically active hepatitis or active hepatitis or medical history,hepatitis B :Patients with positive HBsAg are excluded.;Hepatitis C: Patients with hepatitis C antibody positive are excluded; * Immune deficiency, uncontrolled severe infection and patients with active or recurrent peptic ulcer; * Pregnant , lactating women and men or women who have birth plans in the past 12 months ; * Have a history of allergic reaction to human biological medicines. * Receipt of live vaccine within 1 month; * Have participated in any clinical trial in the first 28 days of the initial screening or 5 times half-life period of the study compound (taking the time for the elderly). * Have received treatment with B cell targeted therapy such as Rituximab or Epratuzumab etc. * Receipt of anti-tumor necrosis factor、interleukin receptor antagonist； * Receipt of IV immunoglobulin（IVIG）,prednisone\>100mg/d more than 14 days or plasma exchange; * There are active infections (such as herpes zoster, human immunodeficiency virus (HIV) virus infection, active tuberculosis, etc.) during the screening period; * Patients have depression or the significant suicide ideation; * Investigator considers candidates not appropriating for the study.