Quantitation of urinary Tamm-Horsfall protein in children with urinary tract infection.

It has been suggested that urinary Tamm-Horsfall protein (THP) prevents colonization of the urinary tract by binding uropathogens. We tested the hypothesis that low urinary THP levels may predispose to urinary tract infection (UTI) by measuring THP levels in children. We studied a cohort of 35 girls with uncomplicated recurrent UTI (group 1) that was compared with 27 patients with myelomeningoceles undergoing clean intermittent catheterization (group 2) and 16 female controls (group 3). We measured urinary THP in both aggregated (aTHP) and disaggregated form (dTHP), leukocyte esterase activity, urine chemistries and culture. No significant differences in dTHP or aTHP levels were seen between groups 1 and 3, but group-1 patients had higher dTHP levels than group-2 patients (p < 0.008). History of reflux or the presence of bacteriuria or pyuria at the time of urine collection did not affect dTHP levels; in contrast, pyuria or bacteriuria at the time of sampling was associated with markedly lower aTHP levels when compared with sterile samples (p < 0.0001). For all groups, measured quantities of dTHP did not correlate with aTHP levels. We conclude that excretion of dTHP in children with history of recurrent UTI is not reduced. In contrast, concentrations of aTHP are profoundly depressed in children during times of UTI, suggesting a role for THP in the pathogenesis of UTI. Assaying THP in its aggregated form may prove valuable when studying its physiologic function and merits further investigation.