The purpose of this study is to:

• To access the efficacy of TW compared to Aza in the maintenance therapy for lupus nephritis
• To investigate the safety and tolerability of TW versus Aza in the maintenance therapy for lupus nephritis

Tripterygium (TW) is a Chinese traditional patent drugs in treating chronic glomerulonephritis. It has been used to treat lupus nephritis for many years with less side effects. We compare the efficacy and safety of TW vs Aza in the maintenance therapy of lupus nephritis.

Inclusion Criteria:

1. Patients who signed written informed consent form;

2. SLE patient, aged between 18-60 years, female or male;

3. Patients diagnosed lupus nephritis according to ISN/RPS 2003 classification criteria, class Ⅲ, Ⅳ,Ⅳ+Ⅴ, Ⅲ+Ⅴ or Ⅴ LN by renal biopsy;

4. All patients received induction therapy for 6-12 months, including MMF, CTX, FK506 or multi-target therapy;

5. When recruited in the study, patients received partial remission or complete remission for 3 months;

   • Complete remission: proteinuria < 0.4 g/24h, negative urine sediment, serum albumin > 35 g/L, elevated scr < 0.3 mg/dl, no extra-renal complications;
   • Partial remission: proteinuria < 1.0 g/24h, urine RBC < 500000/ml without casts, serum albumin > 35 g/L, elevated scr <0.3 mg/dl, no extra-renal complications.

Exclusion Criteria:

1. Patients who didn't sign written informed consent form or could not obey the protocol;
2. Patients who didn't received the CR or PR criterion;
3. Patients who have impaired liver function, with ALT/GPT or AST/GOT twice more than the normal upper limit;
4. WBC < 3000/mm3 in peripheral blood;
5. Patients with abnormal of central nervous system.