IgAN is the most prevalent primary glomerulonephritis in China, is characterized by the deposition of IgA1 (particularly, galactose-deficient IgA1) in the glomerular mesangium. Galactosedeficient IgA1, supposed to be produced by Peyer patches in the mucosa-associated lymphoid tissue (MALT), is triggered by exposure to commensal or pathogenic bacteria, involved in the initial step in the pathogenesis of IgAN. Similar to intestinal flora, a disruption in oral flora is closely associated with the occurrence of many malignant tumors and autoimmune diseases. The relationship between oral and throat microflora and the occurrence of IgAN is unclear at present. The aim of the present study was to develop a preliminary model based on mucosa -specific microbes and clinical indicators to facilitate the early diagnosis of IgAN and obtain insights into its treatment.

IgAN-microbiome is an investigator-initiated，multi-center，Observational study. This study will recruit IgA nephropathy patients who have not been treated with glucocorticoids and immunosuppressants for 6 months and have not taken antibiotics for 1 month and their family members. Feces, urine, blood, oral mucosal swabs, and pharyngeal swabs will be collected and tested for microflora and metabolites in these areas.

Similar samples from IgA nephropathy patients were collected after 2 months and 6 months, respectively, for bacterial community detection and metabolite detection, and the relationship between bacterial community change and metabolite change and disease progression was analyzed.

Inclusion Criteria:

• (1) Pathological changes of IgAN were confirmed by renal biopsy (2) Age ≥16 years (3) IgA deposition caused by secondary factors such as non-purpura glomerulonephritis, liver cirrhosis, SLE, HIV infection and hepatitis B virus associated nephritis (4) No antibiotics and/or functional foods (probiotics and/or prebiotics) for at least one month prior to sampling (5) No hormone or immunosuppressant treatment in the six months prior to sampling (6) No significant changes in diet or medication for at least one month (7) No other immune or autoimmune diseases, such as systemic lupus erythematosus (8) Signed informed consent

Exclusion Criteria:

1. Type I or type II diabetes
2. Pregnancy and menstrual period
3. Mental illness and inability to assess follow-up
4. Medically diagnosed intestinal diseases such as irritable bowel syndrome and inflammatory bowel disease
5. Viral hepatitis or other infectious diseases
6. One month before specimen collection, use laxatives including but not limited to polyethylene glycol electrolyte dispersant, enema and other laxatives

IgA nephropathy confirmed by renal biopsy and family members living with them