Budesonide

The goal of this clinical trial is to evaluate the efficacy and safety of probiotics combined with enteric-coated budesonide capsule in patients with IgA nephropathy on the basis of optimized RAS blockade therapy, and to explore the correlation between the efficacy of probiotics combined with enteric-coated budesonide capsule in the treatment of primary IgA nephropathy and intestinal homeostasis. The main questions it aims to answer are: Dose probiotics combined with enteric-coated budesonide capsule provide a durable reduction in urine protein creatinine ratio (UPCR) in participants, compared with probiotics placebo combined with enteric-coated budesonide capsule? What medical problems do participants have when taking probiotics combined with enteric-coated budesonide capsule? Participants will: Take probiotics combined with enteric-coated budesonide capsules or probiotics placebo combined with enteric-coated budesonide capsules every day for 9.5 month Participate in center site follow-up visits for 13 times Keep a diary of their symptoms and outcomes