Caspase-cleaved fragments of cytokeratin 18 in patients with chronic hepatitis B.

BACKGROUND

During hepatocyte apoptosis, intermediate filament protein cytokeratin 18 is cleaved by caspases at Asp396 which can be specifically detected by the monoclonal antibody M30 (M30-antigen). In this study, we sought to determine whether serum M30-antigen levels can serve as a useful biomarker of liver injury in the clinical spectrum of HBV infection.

METHODS

Serum M30-antigen levels were measured in inactive HBV carriers (n=54), patients with HBeAg-negative chronic hepatitis B (CHB, n=47), patients with HBeAg-positive CHB (n=42) and healthy controls (n=29). All subjects were treatment-naïve.

RESULTS

There were significant differences in serum M30-antigen levels across the study groups (P<0.001; Kruskal-Wallis test). Post hoc analyses revealed that M30-antigen levels did not differ significantly between inactive HBV carriers (median 109.6 U/L) and healthy controls (median 106.1 U/L). However, both patients with HBeAg-negative (CHB, median 182.9 U/L, P<0.001) and HBeAg-positive CHB (median 158.3 U/L, P<0.001) had significantly higher levels of M30-antigen compared with inactive HBV carriers.

CONCLUSIONS

Hepatocyte apoptotic activity--as reflected by serum M30-antigen levels--is increased in chronic active hepatitis B, but is not associated with the HBeAg status. In contrast, apoptosis does not appear to be a prominent feature of inactive HBV carriers.