Can Pentraxin-3 be used as a biomarker in the differential diagnosis of lower and upper urinary tract infections?

Urinary tract infections (UTIs) are common infections in childhood and can cause permanent kidney damage if not treated with early and accurate diagnosis. The aim of this study was to evaluate the role of urinary PTX-3 levels in the diagnostic and differential diagnosis of children with UTIs, especially its usefulness in differentiating acute pyelonephritis (APN) and cystitis, and to examine the relationship between PTX-3 levels and the presence of vesicoureteral reflux (VUR) and renal scar. A total of 178 children with APN, cystitis and asymptomatic bacteriuria and a healthy control group were included in this study. Urinary PTX-3 levels were measured by ELISA, presence of VUR was evaluated by VCUG and renal parenchymal scar was evaluated by DMSA scintigraphy. The diagnostic performance of PTX-3 was analyzed by ROC analysis and the optimal cut-off point was determined. According to the results, urinary PTX-3 levels were significantly higher in the UTI group (median: 4.74 (3-9.14) pg/mL) compared to the healthy control group (median: 2.11 (1.83-2.57) pg/mL) and markedly elevated in the APN group (median: 9.14 (5.27 - 14.75) pg/mL), (p<0.001). The area under the ROC curve (AUC) for distinguishing APN from the healthy group was found to be 0.93, with 90% sensitivity and 88.3% specificity at the determined cut-off value. In addition, a positive correlation was observed between urinary PTX-3 level and the presence of VUR and renal scarring identified via DMSA. These results showed that urinary PTX-3 levels may be used as a potential biomarker in the diagnosis of UTI and differentiation of APN/cystitis in children. Furthermore, urinary PTX-3 levels were higher in the presence of renal scar and VUR in patients with UTI compared to those without, indicating that this potential biomarker may also have potential for predicting possible complications of UTI. Keywords: Urinary tract infection, urinary Pentraxin-3, acute pyelonephritis, cystitis, vesicoureteral reflux, renal scar, biomarker