Caspase-cleaved fragments of cytokeratin-18 as a marker of inflammatory activity in chronic hepatitis B virus infection

The differential diagnosis between inactive carrier and active hepatitis is important in patients with chronic hepatitis B (CHB) virus infection. Serum cytokeratin (CK)-18 fragments (M30-antigen) are proposed as biomarkers of apoptosis.We investigated whether serum M30-antigen levels might help to characterize the various phases of CHB and predict the state of significant inflammation in patients with CHB.A total of 339 CHB patients who underwent liver biopsy, were included. Serum M30-antigen levels were compared between inactive carriers (n=21), patients with HBeAg-negative hepatitis (n=95), HBeAg-positive hepatitis (n=141) and liver cirrhosis (n=82).Serum M30-antigen levels were correlated significantly not only with AST (r=0.544, p0.001) and ALT (r=0.315, p0.001) and but also inflammatory grading score on liver biopsy (r=0.240, p0.001). Serum M30-antigen level in HBeAg-negative CHB was significantly higher than that of inactive HBV carrier (399.78 U/L vs 148.90 U/L, p0.001). Multivariate analysis showed that AST (p0.001), albumin (p=0.009) and M30-antigen (p=0.020) were the independent predictors of significant inflammation. Combined serum M30-antigen level (344 U/L) and AST (78 IU/L) measurement provided the most accurate identification of significant inflammation, showing 38.2% sensitivity, 96.1% specificity, 91.0% positive predictive value and 56.1% negative predictive value.Serum M30-antigen can be a predictive marker for distinguishing between inactive carrier and HBeAg-negative CHB. Serum M30 levels are associated with the presence of significant inflammation, especially in patients with normal or minimally elevated ALT in CHB patients.