Urine TREM-1 as a marker of urinary tract infection in children.

Objective Triggering receptor expressed on myeloid cells (TREM)-1 is a receptor that is thought to improve recognition of patients with true infection. In this study, we investigated whether Triggering receptor expressed on myeloid cells (TREM-1) is present in urine samples from children with urinary tract infection (UTI) and in samples from healthy children. Methods A total of 128 samples met the inclusion criteria for the study. Urine samples were processed for culture and urinalysis as a regular protocol for patients with UTI. Samples were classified according to culture and urinalysis results. TREM-1 protein expression was detected with flow cytometry and sTREM-1 was assessed by ELISA. Results Flow cytometry showed detectable expression of TREM-1 in 100% of samples, UTI and non-UTI groups ( p < 0.001). Mean fluorescence intensity of TREM-1 was different between the groups ( p < 0.001). Levels of sTREM-1 were detected in patients with UTI, but not in non-UTI patients. Conclusions All of our patients (healthy and diseased) showed TREM-1 expression. However, TREM-1 levels in patients with UTI tend to be higher and are associated with increased neutrophils and cytokine activity induced by bacteria.