Serum Podocalyxin Level as a Potential Biomarker for Diagnosis of Nephrotic Syndrome and Prediction of Steroid...

Idiopathic nephrotic syndrome (NS) is a common pediatric glomerular disorder. Podocyte damage constitutes a central mechanism in its pathophysiology. Podocalyxin, a major sialoglycoprotein expressed on podocytes, has been found to be elevated in urine samples from patients with glomerular diseases. However, its potential role in serum and its association with steroid responsiveness in NS remain unexplored.

This observational study included 17 children diagnosed with NS and age-matched controls without kidney pathology. Serum podocalyxin levels were measured at diagnosis using enzyme-linked immunosorbent assay. Patients received standard corticosteroid therapy at a dose of 2 mg/kg/day for four weeks, followed by a gradual taper. Based on clinical response, patients were classified as steroid-sensitive or steroid-dependent NS (SDNS). Serum podocalyxin levels were compared between patients and controls, and among subgroups based on treatment response.

Serum podocalyxin levels were significantly higher in NS than in the control group [1.87 ng/dL [interquartile range (IQR: 0.87)] vs. 1.54 ng/dL (IQR: 0.29), p=0.031]. All patients initially achieved remission with corticosteroids; however, six patients subsequently developed SDNS. Among these, 4 responded to calcineurin inhibitors, while 2 required rituximab to achieve remission. Current results indicate that serum podocalyxin levels do not provide sufficient predictive value for estimating steroid response or disease course. No significant correlations were found between podocalyxin levels and other laboratory parameters.

Serum podocalyxin levels are elevated in pediatric NS and may reflect the degree of podocyte injury. However, current findings indicate that serum podocalyxin levels are insufficient for predicting disease severity or steroid response. Additional studies involving larger patient cohorts are needed to further substantiate findings.