Hapten and kidney antibodies in serum from children with urinary tract infection

The presence of antibodies against the synthetic hapten dinitrophenol (DNP) was investigated in sera from healthy children and adults. Such antibodies were found in all sera. The serum levels were significantly lower in healthy children than in adults. Serum samples from a pilot group of pediatric patients with acute E. coli urinary tract infection (UTI) contained significantly higher DNP antibody levels compared to healthy children and similar to those of the adults. Furthermore, 10 of 17 patients had a significant change in antibody levels in connection with the infection as judged from consecutive serum samples. Relations were found between age and minimum as well as maximum serum DNP antibody values. In a second group of children with E coli urinary tract infection beside DNP antibodies, antibodies against the Tamm-Horsfall urinary protein and a pool of O antigens from E. coli common in urinary tract infections were also investigated. In these patients similar findings as for the pilot group were made for the levels of the DNP antibodies. An IgG but not IgM antibody response to the Tamm-Horsfall protein was also found in sera from all the patients over 1 year with acute pyelonephritis. The highest antibody levels against Tamm-Horsfall protein were noted in patients with vesico-ureteric reflux. No relation could be recorded between the DNP antibodies and the Tamm-Horsfall protein antibodies. The antibodies to the pool of O antigens recorded did not correlate to the DNP antibodies. It was concluded that the DNP antibody formation could partly be due to polyclonally stimulatory activities of bacterial substances exposed during infections.