IgA nephropathy is a common primary glomerular disease with a highly variable clinical course. Soluble CD163 is a marker associated with monocyte and macrophage activation and may reflect inflammatory activity in kidney disease. This single-center observational study aims to evaluate the associations of serum and urinary soluble CD163 levels with clinical disease activity, histopathologic severity, and renal prognosis in patients with IgA nephropathy. Clinical, laboratory, and kidney biopsy findings will be assessed together with serum and urinary soluble CD163 measurements. Participants will also be followed for renal outcomes, including changes in kidney function and proteinuria. The study is expected to clarify whether soluble CD163 may serve as a noninvasive biomarker of disease activity and prognosis in IgA nephropathy.