#1347 Urinary uromodulin levels in febrile children: a prospective study

Abstract Background and Aims Uromodulin (UMOD) is the most abundant urinary protein, expressed exclusively in the kidney and excreted into both urine and blood. UMOD plays a role in urinary tract infection, blood pressure and stone formation prevention, in addition to local and systemic immunomodulatory functions. Normal serum UMOD levels in children and adults, as well as males vs females were found to be comparable. However, normal pediatric urinary UMOD (U-UMOD) values have not been established yet. In a preliminary study, we showed a decreased U-UMOD excretion (contrary to albumin) in children with transient febrile proteinuria. This study aimed to further investigate the trends in U-UMOD levels during inflammatory states such as febrile infectious diseases in children, compared to non-febrile healthy controls. Method This prospective study included children (age 0–16 years) admitted to our medical center with febrile disease of non-renal source and non-febrile children were controls. U-UMOD was analyzed using the Biovender Human UMOD ELISA kit. The study protocol was approved by Local Ethical Committee. Results Thirty-six febrile patients and 35 controls were recruited. Febrile patients were younger than controls (60 ± 52 vs 107 ± 53 months, P < 0.001). Maximal fever was 39 ± 0.780C, its length was 46 ± 30 hours, blood WBC was 12 ± 5.5 *103/uL, and median (IQR) CRP levels were 24.6 (10–59) mg/L. There was no difference in U-UMOD/creatinine levels between febrile vs control groups [median (IQR): 1011 (455–1678) vs 336.5 (108.5–802) pg/mg, P = 0.12]. No correlation between U-UMOD/creatinine to age, sex, length of fever or blood WBC was found in both groups. In the febrile group U-UMOD/creatinine was inversely correlated to CRP (R = 0.46) and was lower in patients with CRP >50 mg/L (n = 9) compared to others [425 (158–528) vs 868 (403–1518) pg/mg, P = 0.01]. Conclusion U-UMOD levels are inversely correlated with CRP in febrile patients with no kidney disease, suggesting a concurrent increase in UMOD secretion to circulation as a renal response to the systemic inflammation. Further simultaneous evaluation of urine and blood UMOD levels in febrile disease is warranted.