The vertical transmission of Hepatitis C Virus (HCV-VT) is a major route of HCV infection in children, but the risk factors remain incompletely understood. This study analyses the role of IL28B in HCV-VT and in the spontaneous clearance of HCV among infected infants. Between 1991 and 2009, 145 mothers were recruited to this study: 100 were HCV-RNA+ve/HIV-ve, with 128 children, and 33 were HCV-RNA-ve/HCV antibody+ve, with 43 children. The infants were tested for HCV-RNA at birth and at regular intervals until the age of 6 years. IL28B (single nucleotide polymorphism rs12979860) was determined in the mothers and children. HCV-VT was assumed when children presented HCV-RNA+ve in two subsequent blood samples.
HCV-VT infected infants were categorized as: (A) transient viremia with posterior HCV-RNA-ve and without serum-conversion; (B) persistent infection with serum-conversion. Of the 31 mothers with CC polymorphism, 19(61%) were HCV-RNA+ve whereas among the 68 mothers with non-CC polymorphism, 56(82%) were HCV-RNA+ve. 26 of 128(20%) infants born to the HCV-RNA+ve mothers acquired HCV infection, but only 9(7%) were chronically infected. The rate of HCV-VT was higher among the mothers with higher HCV viremia. No HCV-VT was detected in the HCV-RNA-ve women. Neither the mothers' nor the children's IL-28 status was associated with an increased risk of HCV-VT. The factors influencing viral clearance among the infected children were genotype non-1 and genotype CC of the IL28B. In logistic regression, child CC polymorphism was the only predictor of HCV-clearance in HCV genotype-1.
CONCLUSIONS: High maternal viral load is the only predictive factor of HCV-VT. IL28B plays no role in HCV-VT, but IL28B CC child polymorphism is associated independently with the spontaneous clearance of HCV genotype-1 among infected children.