Evaluation of urinary IL-1α and IL-1β in gravid females and patients with bacterial cystitis and microscopic hematuria

Abstract

Objectives: to determine IL-1α and IL-1β levels in patients with bacterial cystitis, microscopic hematuria, and gravid females relative to a control group of normal subjects. Methods: enzyme immunoassays were used to measure concomitantly urinary IL-1α and IL-1β in clean catch urine samples from normal subjects (n=31) and study patients (n=46). All normal subjects and patients underwent urinalysis, urine culture, and urine creatinine level determination. Since the IL-1α assay was developed for serum, the utility of the assay for urine specimens was unknown. The key parameters of urine collection, processing and sample storage for IL-1α were evaluated in detail. Results: mean values ± SEM (pg/mg) for IL-1α/Cr and IL-1β/Cr were control group (0.25 ± 0.10 and 0.17 ± 0.06), bacterial cystitis (9.97 ± 1.15 and 42.45 ± 1.86), and microscopic hematuria (2.81 ± 0.65 and 2.82 ± 0.70). Differences in cytokine levels between the control group and patients with either bacterial cystitis or microscopic hematuria were statistically significant for both IL-1α/Cr (P<0.026; P<0.007, respectively) and IL-1β/Cr (P<0.0004; P<0.014, respectively). IL-1β/Cr correlates better with pyuria than IL-1α/Cr (P=0.02 vs P=0.44). In gravid females, only IL-1α was significantly elevated relative to non-pregnant females (IL-1β elevation approached statistical significance). Gravid females with positive urine cultures could not be distinguished from those with negative cultures based on either interleukin (P>0.05). Conclusions: Significant elevations of IL-1α and IL-1β occur in patients with bacterial cystitis and microscopic hematuria. Correlation between pyuria and cytokine elevation was stronger for IL-1β than for IL-1α. Changes in IL-1α may reflect changes in the bladder epithelium rather than in the inflammatory leukocytes. The ability of IL-1α and IL-1β to serve as markers for bacterial cystitis in gravid females is diminished due to high basal levels during pregnancy.