IFNL3 and chronic hepatitis C virus infection: Furthermore, it has been reported that treatment outcomes could be significantly influenced by serum vitamin D levels and single nucleotide polymorphisms (SNPs) near the interleukin 28B (IL28B) gene (20), which is the strongest predictor of response to PEG-IFN/ ribavirin therapy for patients with chronic hepatitis C of genotype 1 (21-23).