Serum level of interleukin-6 (IL-6) and N-terminal propeptide of procollagen type I (PINP) in patients with liver diseases.

Introduction: The aim of this study was to evaluate the concentration of interleukin-6 and N-terminal propeptide of procollagen type I and their relationship in liver diseases of different etiologies.

Material And Methods: Serum samples were obtained from 30 healthy volunteers and patients suffering from alcoholic cirrhosis (AC) - 31, non-alcoholic cirrhosis (NAC) - 28 and toxic hepatitis (HT) - 23 patients. Cirrhotic patients were classified according to Child-Pugh score. IL-6 and PINP concentrations were determined according to the electrochemiluminescence immunoassay.

Results: The mean serum IL-6 concentration was significantly higher in AC (mean ± SD:21.52 ± 15.01 pg/mL), NAC (20.07 ± 32.12 pg/mL) and HT (15.14 ± 17.18 pg/mL) when compared to the control group (C) (1.67 ± 0.42 pg/mL) (Mann-Whitney U test: p < .001 for all comparisons). The mean serum PINP concentration was significantly higher only in patients with AC (104.32 ± 54.50 ng/mL) in comparison with the control group (54.70 ± 19.83 ng/mL; p < .001). The mean values of IL-6 and PINP significantly differed between liver diseases (ANOVA rank Kruskal-Wallis test: p = .020 and p < .001, respectively). Accordingly, the serum levels of IL-6 and PINP were significantly higher in patients with AC than that in NAC (p < .001 and p = .022, respectively). IL-6 and PINP concentrations appeared to vary depending on the severity of liver damage (p < .001 for both). The concentrations of IL-6 and PINP were significantly higher in class C (31.88 ± 21.51 pg/mL; 132.73 ± 65.63 ng/mL, respectively) than that in class A (6.12 ± 9.00 pg/mL; 57.32 ± 28.85 ng/mL, respectively) (p < .001 for both). There were also significant differences in IL-6 concentrations between Child-Pugh class B (27.88 ± 24.45 pg/mL) and class A (6.12 ± 9.00 pg/mL; p < .001).

Conclusions: We conclude that serum concentrations of IL-6 and PINP change in liver diseases, and those changes reflect the severity of liver disease.