Urinary IL-6 is elevated in patients with urolithiasis

To evaluate the possible role of cytokines interleukin (IL)-1beta, IL-1alpha and IL-6 in patients with urolithiasis.

Fifty-six patients currently with stone disease, 63 patients with bacterial cystitis, and 66 normal individuals were evaluated for urinary IL-1alpha, IL-1beta and IL-6. Clean catch urine samples were obtained and evaluated for cytokine levels using enzyme immunoassays for the respective cytokines. Statistical analysis of the results was carried out using the Kruskal-Wallis test followed by Newman-Keuls test and the chi-squared test.

The patients with stone disease had significant elevations in IL-6 (p value< 10(-7)) relative to normal subjects. The levels of IL-6 in stone patients were lower than those of patients with bacterial cystitis. Neither IL-1beta nor IL-1alpha was elevated in stone patients relative to normals. By contrast, bacterial cystitis patients showed significant elevations in all three cytokines relative to normal subjects. Chi-squared analysis confirmed that stone patients had elevated IL-6 without elevation in either IL-1alpha or IL-1beta relative to normal subjects.

Stone patients show significant elevations in IL-6 without marked increases in either IL-1beta or alpha relative to normal subjects. This elevation in IL-6 is not from infection as is seen in bacterial cystitis subjects. The elevation in IL-6 may be useful in the understanding of the pathogenesis of urolithiasis or as a potential marker for stone disease and we are currently investigating these possibilities.