Identification of Urinary CD44 and Prosaposin as Specific Biomarkers of Urinary Tract Infections in Children With Neurogenic Bladders

Forster, Catherine S; Haffey, Wendy D; Bennett, Michael; Greis, Kenneth D; Devarajan, Prasad

Here, we used mass spectrometry to identify novel urinary proteins that are candidate markers for UTI in children with neurogenic bladder. Of the 5 differentially expressed proteins that were measured in the urine samples, 2-CD44 and prosaposin-show potential to serve as markers to aid in the differentiation between UTI and UTC. Three of the proteins identified as proteins of interest were not included in the validation phase due to limitations in the amount of urine available. Liver fatty acid-binding protein was identified as a protein of interest, but not included as it is a known marker of tubular injury, 18 and therefore had the potential to confound our results. Similarly, we chose not to further investigate inter-a-trypsin inhibitor heavy chain H4 as it is also elevated in patients with decreased renal function. 19 Urine haptoglobin has been reported to be elevated in multiple conditions, including lupus nephritis, 20 diabetic nephropathy, 21 and urothelial cancer. 22 Given the presence of haptoglobin in multiple other conditions, it likely would not be a specific marker in UTI and therefore was not chosen as a protein of interest.