Secretory immunoglobulin A and inhibitory activity of bacterial adherence to epithelial cells in urine from patients with urinary tract infections.

To assess the role of local immune response against bacterial invasion of the urinary tract we studied 168 patients with bacteriuria. Urinary secretory immunoglobulins A (sIgA) were measured using radial immunodiffusion or enzyme-linked immunosorbent assay (ELISA). In particular, ELISA is a very suitable assay for measuring the low levels of sIgA in urine. Furthermore, we used a quantitative in vitro adherence assay to investigate the attachment of Escherichia coli to human uroepithelial cells after incubation in urine from patients with urinary tract infection. Urine from patients with ileocystoplasty was significantly more potent in inhibiting bacterial adherence than was urine from other groups of patients with urinary tract infection. The presence of high urinary sIgA may help explain the increased antiadherence activity of urine in patients with ileocystoplasty. Mean urinary sIgA in patients with upper urinary tract infection was higher than in patients with uncomplicated infection in the lower urinary tract. Alterations in mucosal immune functions may account for the propensity toward bacterial colonization in women prone to uncomplicated urinary tract infection.