Bacterial adherence and humoral immune response in women with symptomatic and asymptomatic urinary tract infection.

PURPOSE To determine the role of humoral immune response and bacterial adherence in the pathogenesis of symptomatic and asymptomatic urinary tract infection in women. METHODS The study population consisted of 30 women with symptomatic UTI, 30 women with asymptomatic UTI and 30 healthy women as controls. Bacterial adherence to vaginal epithelial cells was studied and the concentration of serum and urine antibodies to mixed coliform antigen and clinical isolate was determined by ELISA. Surface hydrophobicity of the urine isolates was determined. Student's unpaired t test and Pearson's correlation coefficient test were used in the statistical analysis. RESULTS Compared to asymptomatic UTI, significantly more number of bacteria adhered to the epithelial cells of women with symptomatic UTI (P< 0.001). All cases of UTI had significantly high concentration of urinary IgG antibody to mixed coliform antigens. Asymptomatic UTI cases had higher concentrations of urinary IgG, IgM and IgA antibodies to clinical isolate. Concentration of sIgA level was more in symptomatic UTI. Significant correlation was observed between urinary IgG and adherence of clinical isolate in case of asymptomatic UTI. CONCLUSIONS The present study showed that greater receptivity of epithelial cells to bacteria may increase the susceptibility to UTI. Humoral immune response and local immunity may modify the pathogenesis of UTI.