Clinical and Epidemiological Study of IgA Nephropathy in the Bulgarian Population: Insights into Disease Presentation and Potential Biomarkers

IgA nephropathy (IgAN) is the most common glomerulonephritis worldwide and a leading cause of chronic kidney disease and renal failure. However, the Bulgarian population has limited epidemiological data and biomarkers for IgAN. In this retrospective monocentric analysis, we investigated all the patients with biopsy-proven IgAN over 10 years in a tertiary Bulgarian institution. From the analysis of 762 kidney biopsies, the diagnosis of primary IgAN was established in 125, with an average age of 35.94 ± 11.91 years. Our study aimed to assess the clinical characteristics, histological features, and potential biomarkers of IgAN in the Bulgarian population. We evaluated parameters such as proteinuria, hematuria, serum creatinine, and glomerular filtration rate (GFR). In fifty IgAN patients and 30 healthy controls, serum levels of Gd-IgA1, IgA, C3, BAFF, and APRIL using ELISA were examined. The results revealed significant differences in serum concentrations of Gd-IgA1 (p < 0.001), Gd-IgA1/IgA (p = 0.022), IgA (p = 0.014), and IgA/C3 (p = 0.047) between patients and controls. However, no correlation was found between Gd-IgA1, IgA, Gd-IgA1/IgA, and IgA/C3 and chronic kidney disease progression. Our study reports evidence of the diagnostic value of Gd-IgA1 and contributes to the understanding of IgAN in the Bulgarian population and suggests potential biomarkers for disease diagnosis and prognosis.