B cell infiltration and lymphonodular hyperplasia in bladder submucosa of patients with persistent bacteriuria and recurrent urinary tract infections.

PURPOSE: We defined chronic inflammatory cell types in bladder submucosa and the presence of umbrella cells on the surface of bladder epithelium in patients 5 to 21 years old with persistent bacteriuria due to neurogenic bladder and recurrent urinary tract infections associated with vesicoureteral reflux. MATERIALS AND METHODS: Bladder mucosa biopsies from 12 patients and 6 controls were fixed in Carnoy's solution and examined for T cells (CD3, CD4, CD8), B cells (CD79) and plasma cells (CD138). The number of cells in a defined area of submucosa was determined by counting all nuclei in the area. A contiguous section was also stained for uroplakin expression with a monoclonal antibody against uroplakin III to ascertain the integrity of bladder umbrella cells. RESULTS: B cells, plasma cells and lymphoid nodules were found only in patient biopsies. T cell expression was evident in patient and control biopsies. Uroplakin staining of surface epithelium was uniform from control biopsies but spotty or entirely absent from patient biopsies. CONCLUSIONS: Patients with persistent bacteriuria or recurrent urinary tract infections had significant B cell infiltration in the submucosa, including lymphoid nodules. These inflammatory changes are likely due to antigenic stimulation from repeated exposure to bacteria. These changes are associated with frequent absence of uroplakin on surface epithelium.