Abstract
BACKGROUND: Immunoglobulin A nephropathy (IgAN) is the most prevalent primary glomerulonephritis (GN) worldwide and is often underdiagnosed because of its asymptomatic presentation. Proteinuria-based assessment in monitoring disease progression is limited. Early renal biopsy may fail to predict disease severity. So, the development of a non-invasive biomarker can predict early disease progression. OBJECTIVE: To evaluate urinary soluble cluster differentiation 163 (u-sCD163) in predicting short-term treatment response and its correlation with histologic activity in biopsy-proven IgAN. METHODOLOGY: This prospective observational study was carried out at the Department of Nephrology, Bangladesh Medical University (BMU), Dhaka, Bangladesh. A total of 55 patients with biopsy-proven primary IgAN were enrolled. Urine routine microscopic examination (R/M/E), 24-hour urinary total protein (UTP), and serum creatinine were measured at baseline, and at each follow-up (every three-month interval, up to six months). u-sCD163 was measured at baseline and at the sixth month. Patients were managed according to the KDIGO, 2021guideline and followed up in the third and sixthmonths. RESULTS: Mean age of the study patients was 31.3 ± 5.61 years. The sex distribution highlights a male predominance, as the male-to-female ratio was 1.7:1. Baseline u-sCD163 was 3.78 ± 0.96 ng/mg in the partial response group and 7.82 ± 4.00 ng/mg in the no-response group (P < 0.001). The receiver operating characteristic (ROC) curve analysis of urinary sCD163 level for predicting no response at the third month showed an optimal cutoff value of 4.80, providing a sensitivity of 76.7% and specificity of 83.3%. At six months, urinary sCD163 levels were highest in the no-response group (7.22 ± 3.41 ng/mg, P < 0.001). u-sCD163 was markedly elevated in patients with endocapillary hypercellularity and crescents (P < 0.05). CONCLUSIONS: u-sCD163 may be a potential biomarker to predict the short-term treatment response status and histologic activity in biopsy-proven IgAN. Elevated biomarkers at baseline were associated with more proteinuria and risk of response failure.