Antibodies to lipid A during urinary tract infection.

Serum levels of antibodies to lipid A were determined with an enzyme-linked immunosorbent assay in 26 girls with their first known symptomatic urinary tract infection (UTI) and in 15 girls with asymptomatic bacteriuria (ABU). Also included were six female patients with recurrence of acute upper UTI, five of whom had renal changes after the infections; 28 female patients with renal scarring but not symptomatic UTI at the time of investigation; and uninfected individuals. IgG and IgM antibodies to lipid A were found in approximately 50% of the uninfected children older than two years of age. Girls with acute cystitis, acute pyelonephritis, or ABU showed significantly elevated levels of IgG antibodies to lipid A as compared with children with no history of UTI. High levels of IgG antibodies to lipid A may be indicative of severe renal infection and development or progression of renal parenchymal reduction. The diagnostic value of determining levels of antibodies to lipid A is discussed.