A Prospective, Single Arm, Open Label, Proof of Concept Clinical Study of Sulfasalazine in the Treatment of Active Systemic Lupus Erythematosus

The goal of this clinical trial is to learn if sulfasalazine is safe and feasible in the treatment of active lupus erythematosus (SLE). The main questions it aims to answer are: Does drug sulfasalazine with stable background treatment help lower the disease activity (SLEDAI) at week 16? How many patients can reach SRI-4 at week 16? Can this regimen help lower the prednisone dosage the patients need at week 16? What about the change of the type I interferon related genes expression at week 16? Participants will: Take sulfasalazine 750mg/dose, twice a day for 16 weeks. The dosage will be increased to 1000mg/dose within one month, twice a day if the patient could tolerate. Visit the clinic once every 4 weeks for checkups and tests.