Keratin 8 mutations were associated with susceptibility to chronic hepatitis B and related progression.

BACKGROUND: Keratin 8/18 (K8/18) are the exclusively expressed keratins intermediate filaments pair in hepatocytes that protect against liver injuries and viral infection. We aimed to explore the genetic link between keratin variants and chronic hepatitis B virus (CHB) infection in a large cohort from a high epidemic area.

METHODS: Genomic DNA was isolated from patients, and sanger sequencing was applied to analyze variations in exon regions of K8/18. Biochemical and functional analysis of novel mutations was also performed.

RESULTS: The 713 participants comprised 173 healthy controls and 540 patients which covered chronic hepatitis (n=174), decompensated cirrhosis (n=192) and primary liver carcinoma (n=174). The frequency of mutations in keratin8/18 was significantly higher among patients than that among controls (8.15% vs 0.58%, P<0.001). Significant differences were found between the chronic hepatitis subgroup and controls in multiple comparisons (6.32% vs 0.58%，p=0.006). All 21 missense mutations (3.89%) were detected in the K8, including four novel conserved missense variants (R469C, R469H, A447V, K483T). Multivariate logistic regression analysis demonstrated a higher risk of acute-on-chronic liver failure (ACLF) and missense variants (OR=4.38, P=0.035). Transfection of these variants caused keratin network disruption in vivo.

CONCLUSION: Novel K8 cytoskeleton-disrupting variants predispose toward ACLF in CHB.