Evaluation of interleukin-8 in expressed prostatic secretion as a reliable biomarker of inflammation in benign prostatic hyperplasia.

OBJECTIVES: To evaluate the efficacy of interleukin-8 (IL-8) as a possible biomarker for diagnosis and treatment of benign prostatic hyperplasia (BPH) with chronic prostatitis. Histologic inflammation can be demonstrated in most BPH pathologic specimens. To provide objective parameters of inflammation, this prospective study quantified the IL-8 in expressed prostatic secretion (EPS) from BPH patients with or without histologic inflammation.
METHODS: White blood cell (WBC) count and enzyme-linked immunosorbent assays of the EPS for IL-8 were done in 44 patients who underwent transurethral prostatic resection because of benign prostatic enlargement before the operations. The correlation between IL-8 and WBC count in EPS; prostatic specific antigen; and International Prostate Symptom Score, irritative, and obstructive subscores was determined by Pearson correlation analysis.
RESULTS: IL-8 was detectable in all patients (the threshold of detection for IL-8 is 5 pg/mL). Twenty-one (47.7%) BPH patients had chronic prostatitis. The mean level of IL-8 in EPS was higher in BPH with chronic prostatitis than in simple BPH (median +/- SE, 8175 +/- 3789 pg/mL vs 2806 +/- 1009 pg/mL). The catheter and age seemed to have no impact on the level of IL-8 in EPS. Statistically significant correlation was only found between IL-8 and WBC count. The sensitivity and specificity of IL-8 in EPS identifying the BPH with chronic prostatitis from the simple BPH were 85.7% and 91.3% respectively, at a cut-point of 3992 pg/mL.
CONCLUSIONS: IL-8 is significantly elevated in BPH patients with chronic prostatitis. IL-8 in EPS can serve as a reliable biomarker applicable to identifying BPH with chronic prostatitis from simple BPH.