title: Reduced toll-like receptor 4 expression in children with asymptomatic bacteriuria.
abstract: Toll-like receptor (TLR) 4 is essential for the defense against infection with gram-negative pathogens, but reduced TLR4 expression has not been linked to altered disease susceptibility in humans. In mice, Tlr4 controls the mucosal response to Escherichia coli urinary tract infections. Inactivation of mouse Tlr4 causes an asymptomatic carrier state resembling asymptomatic bacteriuria (ABU). The present study compared neutrophil TLR4 expression levels between children with ABU (n=17) and age-matched control subjects (n=24), and significantly lower levels were detected in the patients with ABU. We also found elevated levels of the TLR4 adaptor protein TRIF and reduced levels of the TLR4-inhibitor SIGIRR in the patients with ABU, but MyD88 and TRAM levels were not significantly altered. Altered TLR4 and adaptor protein expression might impair TLR4 signaling and explain the weak mucosal response to urinary tract infection in patients who develop ABU rather than symptomatic disease.
authors.affiliation: Department of Microbiology, Immunology, and Glycobiology, Institute of Laboratory Medicine, Lund University, Lund, 22362, Sweden.
authors.forename: Bryndís
authors.initials: B
authors.lastname: Ragnarsdóttir
authors.forename: Martin
authors.initials: M
authors.lastname: Samuelsson
authors.forename: Mattias C U
authors.initials: MC
authors.lastname: Gustafsson
authors.forename: Irene
authors.initials: I
authors.lastname: Leijonhufvud
authors.forename: Diana
authors.initials: D
authors.lastname: Karpman
authors.forename: Catharina
authors.initials: C
authors.lastname: Svanborg
mesh_terms: D000293:Adolescent; D000328:Adult; D001437:Bacteriuria / Q000175:diagnosis / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005786:Gene Expression Regulation; D020022:Genetic Predisposition to Disease; D006801:Humans; D007223:Infant; D008297:Male; D012333:RNA, Messenger; D015398:Signal Transduction; D051197:Toll-Like Receptor 4 / Q000235:genetics / Q000378:metabolism*
chemical_list: D012333:RNA, Messenger; D051197:Toll-Like Receptor 4