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 (meanSD:21.52 +/- 15.01pg/mL), NAC (20.07 +/- 32.12pg/mL) and HT (15.14 +/- 17.18pg/mL) when compared to the control group (C) (1.67 +/- 0.42pg/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 +/- 54.50ng/mL) in comparison with the control group (54.70 +/- 19.83ng/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 +/- 21.51pg/mL; 132.73 +/- 65.63ng/mL, respectively) than that in class A (6.12 +/- 9.00pg/mL; 57.32 +/- 28.85ng/mL, respectively) (p<.001 for both). There were also significant differences in IL-6 concentrations between Child-Pugh class B (27.88 +/- 24.45pg/mL) and class A (6.12 +/- 9.00pg/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.