Antibody to kidney antigen in the urine of patients with urinary tract infections.

One hundred six urine specimens from 26 patients with acute and chronic pyelonephritis and cystitis were tested by radioimmunoassay to determine (1) whether antibody to normal human kidney antigen was present and (2) whether the presence or absence of this antibody correlated quantitatively with antibody to the patient's own infecting organism. Of the 106 urine specimens tested, 55 (52%) contained elevated antibody to human kidney antigen. For 80 (75%) of 106 urine specimens there was a correlation between the results of quantitative assays for antibody levels to kidney antigen and to the bacterial antigen. Indirect fluorescent antibody studies of thin sections of normal human kidneys and a patient's urine containing elevated levels of antibody to kidney antigen and to bacterial antigen demonstrated diffuse renal localization. Results indicate the occurrence of antibody to kidney antigen, particularly in urine specimens from patients with chronic pyelonephritis and from urine specimens containing elevated levels of antibody to bacterial antigen.