Trial of Belimumab Combined With Multi-target Induction Therapy in Lupus Nephritis

Inclusion Criteria: * Active LN in accordance with the American College of Rheumatology (ACR) diagnostic criteria for SLE (1997), SLE-DAI\>10 points (except type Ⅴ LN). * Patients with active lupus nephritis (type Ⅲ, Ⅳ, Ⅴ, Ⅴ+Ⅲ, Ⅴ+Ⅳ) diagnosed by light microscopy, immunofluorescence microscopy, and electron microscopy according to the ISN/RPS2003 lupus nephritis classification criteria, with pathological chronicity index (CI) less than 3 points and no TMA like changes in interstitial vessels. * Proteinuria ≥1.5g/24h, with or without active urinary sediment (urinary sediment red blood cell count \>100/ul, or white blood cell count \>5 /HP, or red blood cell cast, excluding urinary tract infection). * Serum creatinine \<3.0mg/dL or eGFR\<30 ml/min/1.73m\^2 (CKD-EPI formula). * Received methylprednisolone pulse therapy within 2 weeks before enrollment, cumulative dose 1.5-3.0g). Exclusion Criteria: * Required renal replacement therapy or received renal replacement therapy within 3 months. * Abnormal liver function with elevated ALT, AST or bilirubin more than 2 times the upper limit of normal. * Abnormal glucose metabolism, defined as fasting blood glucose concentration ≥7.0mmol/L and/or 2-hour postprandial blood glucose concentration \>11.1mmol/L. * Mycophenolate mofetil, cyclophosphamide, tacrolimus, cyclosporine A, and high-dose intravenous immunoglobulin (IVIG) were used in the past 12 weeks; It did not include oral hormones, azathioprine or tripterygium wilfordii polyglycosides, or intravenous low-dose MP (less than 80mg/ day), or short-term use of cyclosporine A\<2 weeks, or leflunomide \<4 weeks. * Known allergy to or contraindication to MMF, tacrolimus, or belimumab; Patients with active infection or intravenous antibiotic use within 1 month before admission. * Current or past 3 months: active hepatitis B, hepatitis C, tuberculosis, cytomegalovirus pneumonia, active fungal infection, syphilis infection or HIV infection, etc.; Active peptic ulcer; A history of drug use and alcohol abuse; Severe malnutrition (BMI\<16 kg/m\^2). * Other active diseases, such as severe life-threatening cardiovascular diseases; Chronic obstructive pulmonary disease, or asthma requiring treatment with oral steroids; Bone marrow suppression caused by SLE activity was excluded: WBC\<3000/ul, absolute neutrophil count \<1300/ul, and platelet count \< 50 000/ul. Patients with active SLE who received double plasma filtration, plasma exchange or high-dose gamma globulin therapy within 4 weeks. * Patients with malignant hypertension. * Women who have fertility requirements, refuse contraception or are lactating. * Other investigators considered that they were not suitable for enrollment and may have rapid disease progression or severe disease complications.