The role of intestinal mucosal B cells in the pathogenesis and activity of IgA nephropathy
IgA nephropathy
This is an observational quantitative cross-sectional study including patients with biopsy-proven IgA nephropathy and controls from the general population. Blood, urine, and intestinal biopsy samples (Peyer’s patches) will be collected during colonoscopy. Peripheral blood mononuclear cells and intestinal immune cells will be isolated and analyzed using flow cytometry, ELISA, and RNA sequencing (bulk RNA-seq and single-cell RNA sequencing) to characterize B cell subpopulations and GdIgA1 production. In vitro B cell stimulation and co-culture models will be used to evaluate mechanisms of GdIgA1 production and B cell activation. Immunofluorescence microscopy will be used to analyze intestinal lymphoid tissue. Clinical and laboratory data will be collected and compared between study groups. Statistical analysis will be performed to identify differences between groups and associations between immunological markers and disease activity.
Cases – IgAN group: 1. Adults (≥18 years) 2. Biopsy-proven IgA nephropathy 3. eGFR ≥45 ml/min/1.73 m² 4. Proteinuria <1 g/day 5. Indication for colonoscopy (anemia, change in bowel habits, abdominal pain, positive fecal occult blood test) Controls: 1. Adults (≥18 years) 2. Individuals from general population undergoing screening colonoscopy 3. Positive fecal occult blood test 4. No pathological findings in colonoscopy (no polyps, tumors, inflammation)
1. Age <18 years 2. Pregnancy or breastfeeding 3. Secondary IgA nephropathy 4. IgA vasculitis 5. Liver disease 6. Alcoholism 7. Type 1 or type 2 diabetes mellitus 8. Chronic inflammatory diseases 9. Malignancy 10. Acute myocardial infarction or stroke within the last 6 months 11. Active gastrointestinal bleeding For control group: polyps, tumors, or inflammatory changes detected during colonoscopy