Immunologic response of the prostate to bacteriuria and bacterial prostatitis. I. Immunoglobulin concentrations in prostatic fluid.

We investigated the impact of bacteriuria and bacterial prostatitis on the immunoglobulin content of prostatic fluid. Using an indirect solid-phase radioimmunoassay, we assayed samples of expressed prostatic secretion (EPS) from 20 men with no histories of bacteriuria and from 13 men with histories of culture proven bacteriuria for IgG, IgA and IgM concentrations. Five of the bacteriuric men had culture proven bacterial prostatitis. The concentrations of each immunoglobulin varied widely and were unrelated to age, race, history of urologic instrumentation, presence of benign prostatic hyperplasia, leukocyte content of EPS or EPS aerobic bacterial culture results. The mean concentration of IgG for samples from the bacteriuric patients, 44.3 mg/ml., was similar to that of the uninfected patients, 58.4 mg./dl. (p less than 0.5). The mean concentrations of IgA and IgM for samples from the bacteriuric patients, 89.2 and 1.44 mg./dl., respectively, were greater than those of the uninfected patients, 25.2 and 0.95 mg./dl., respectively. These differences, however, did not achieve statistical significance, p less than 0.025 and p less than 0.3, respectively. However, the mean ratio of IgA:IgG for samples from the bacteriuric patients, 1.67, was significantly greater than that of the uninfected patients, 0.34 (p less than 0.005). The fraction of IgA in the form of secretory IgA was greater than 60 per cent for samples obtained from both the uninfected and bacteriuric patients. These data suggest that bacteriuria is associated with increased secretion of IgA in the prostatic fluid.