Vitamin D and IL28B Genotyping as Predictors for Antiviral Therapy: A Retrospective Study in Egyptian HCV Genotype 4a

Purpose: To evaluate the role of pre-treatment vitamin D serum level and interleukin28B (IL28B) (rs 12979860) polymorphism in chronic hepatitis C (CHC) genotype 4a patients treated with pegylated interferon α2-A and ribavirin (peg IFN+RBV) as predictors of response.
Methods: A retrospective study of clinical and pathological data and stored blood samples of 150 naive chronic hepatitis C (CHC) genotype 4a patients, treated with pegylated interferon and ribavirin for 48 weeks. Follow-up to detect sustained virological response (SVR) was carried out. Based on SVR, two groups were studied; group 1 consisted of 75 responder patients to pegylated IFN + RBV therapy while group 2 comprised of 75 non-responder patients to standard hepatitis C virus (HCV) therapy. Vitamin D serum levels were assessed using Enzyme Linked Immunoassay (ELISA), quantitative reverse transcriptase- polymerase chain reaction (qRT-PCR for HCV RNA ), and IL28B gene polymorphism by Restriction Fragment Length Polymorphism Polymerase Cchain Reaction (RFLP-PCR).
Results: Pretreatment vitamin D level was significantly higher in group 1 than in group 2 (p < 0.001). The sensitivity and specificity of vitamin D level for prediction of SVR at a cutoff value of 29.75 ng/ml were 100 and 96 %, respectively, with area under the curve (AUC) of 0.995 (p < 0.001). A significant difference was detected between baseline vitamin D level for early versus advanced fibrosis stage (p = 0.01) in group 1.
Conclusion: Pretreatment vitamin D serum level (at a cutoff value of 29.75 ng/ml), IL28B gene polymorphism and quantitative HCV RNA are independent trait predictors of SVR.

Keywords
Vitamin D; Interleukin 28B; Chronic hepatitis C; Sustained virological response (SVR); Antiviral; Genotyping