Immunoglobulin levels and antibody-coated bacteria in urines from patients with urinary tract infections.

The presence of antibody-coated bacteria in urines from patients with urinary tract infections has previously been reported to correlate with renal infection as opposed to bladder infection. Urine specimens from 12 patients with pyelonephritis and 12 patients with cystitis were studied to determine whether the antibody coating the bacteria is associated with elevated urine levels of total protein or of particular classes of immunoglobulins. The classes of antibody bound to the infecting bacteria in urines from the patients with pyelonephritis were compared to the levels of unbound antibody in the urine. Each specimen was found to contain antibody-coated bacteria, but not all of the specimens had elevated levels of total protein or immunoglobulins. Thus, the occurrence of antibody-coated bacteria in pyelonephritis did not depend on marked elevations of total urinary protein or immunoglobulins. Studies of patients with cystitis showed that immunoglobulins and protein present in the urines, even in elevated quantities, did not react with the infecting bacteria in patients with bladder infections, as each of these patients had negative FA tests for antibody-coated bacteria.