GPT and viral infectious disease: If limited reorganization of the keratin filament networks is also an indication of limited injuries in HCV livers, the basal level phosphorylation of Ser52 in non-cirrhotic HBV livers with relative low ALT activities (≤ 40 U/L) may indicate that in these hepatocytes viral infection does not cause injuries that trigger Ser52 phosphorylation and related cellular protection.