The Applicaiton of Immune Repertoire in the Diagnosis and Disease Monitoring of IgA Nephropathy

Inclusion Criteria: 1\. IgA nephropathy: 1. Age: 18-80 years. 2. Patients diagnosed with primary IgA nephropathy by renal biopsy. 3. Estimated glomerular filtration rate (using the 2009 CKD-EPI formula) ≥30ml/min/1.73/m\^2. 4. Obtain informed consent from patients. 2. Healthy Control: Gender, age and ethnicity matched health volunteers. 3. IgAN patients were further divided into 4 groups, as defined below: 1\) Long-term stable patients: Follow-up for at least 15 years and meet at least one of the following: 1. Annual eGFR loss rate \<3ml/min/1.73m\^2. 2. eGFR\>90ml/min/1.73m\^2. 2) Non-progressive IgAN patients: Meet at least one of the following: 1. eGFR decrease of more than 50% from baseline (in the absence of other possible causes of kidney damage). 2. Annual eGFR loss rate \>5ml/min/1.73m\^2. 3. Progress to ESRD. 3) IgAN patients at low risk of disease progression: Proteinuria ≤ 1g/24h after 3 months of optimized supportive care. 4) IgAN patients at high risk of disease progression: Proteinuria \> 1g/24h despite 3 months of optimized supportive care. Exclusion Criteria: 1. Kidney biopsy shows crescentic IgAN or MCD-IgAN.; 2. Patients with secondary IgAN; 3. During pregnancy or lactation; 4. After kidney transplantation; 5. More than one serious acute infection in the psat 12 months; 6. Chronic infection; 7. Use of glucocorticosteroids and other immunosuppressive drugs within the last 6 months; 8. Incomplete medical history or clinical data.