[Classes of antibody and complement coating bacteria in the urinary tract infections of the child]

Urine specimens from 88 children with urinary tract infections were tested by direct immunofluorescence for the presence of antibody coated bacteria and were positive. They were further tested to determine the classes of antibody complexed with the bacteria: 75% were coated with IgA, 62% with IgG and 9% with IgM. In 47 children, C1q, C3 and C4 coated bacteria were also studied: negative results were found in 30 children and positive in 17. The ACB test may be positive without any IgG present; therefore it must be used a antihuman globulin and not only a antihuman IgG.