P fimbria-specific B cell responses in patients with urinary tract infection.

Local immune response may be important in defense against urinary tract infection (UTI). P fimbria, an important virulence factor of Escherichia coli, is a noteworthy candidate for use in a vaccine against pyelonephritis (PN). Eleven patients with PN and 14 patients with lower urinary tract infection (LUTI) caused by E. coli were studied for mucosa-derived antibody-secreting cells (ASCs) and for urinary antibodies. In the 10 patients with P-fimbriated (P+) E. coli, an ASC response to P fimbria was found in 5 of 5 patients who had PN and 1 of 5 patients who had LUTI. The response to P fimbria was stronger among patients with P+ PN than among patients with PN caused by non-P-fimbriated E. coli (P-) (P<.001) or patients with P+ LUTI (P<.001). The response to P fimbria was also stronger than the response to outer-membrane protein A among all patients with PN. P fimbria-specific urinary immunoglobulin A antibody levels were higher among patients with P+ PN than those with P- PN. The results show a P fimbria-specific local immune response, which further encourages the use of P fimbria in locally administrable UTI vaccines.