Vitamin D binding protein gene polymorphisms and baseline vitamin D levels as predictors of antiviral response in chronic hepatitis C

Hepatology, 05/25/2012

in difficult to treat hepatitis C virus (HCV) genotypes, simultaneous pre treatment normal serum vitamin D levels and the carriage of binding protein (GC)–globulin wild type isoform strongly predicts the achievement of sustained viral response (SVR) after PEG–interferon plus ribavirin antiviral therapy.

Methods

  • Two hundred six HCV patients treated with a combination therapy of PEG–interferon plus ribavirin were retrospectively evaluated.
  • GC rs7041 G>T, GC rs4588 C>A and IL–28B rs12979860 C>T polymorphisms were genotyped.
  • Frequencies of GC rs7041 G>T and rs4588 C>A polymorphisms were: G/G=64 (31.1%), G/T=100 (48.5%), T/T=42 (20.4%) and C/C=108 (52.4%), C/A=84 (40.8%), A/A=14 (6.8%).
  • Patients were divided into those carrying ≥3 major alleles (WT+: G–C/G–C, G–C/T–C, G–C/G–A, N=100) and the remaining (WT–: G–C/T–A, T–A/T–C, T–A/T–A, T–C/T–C, N=106).

Results

  • Four groups were identified: vitamin D≤20 ng/mL and WT–, vitamin D≤20 and WT+, vitamin D>20 and WT–, vitamin D>20 and WT+.
  • In difficult to treat HCV genotypes the proportion of patients achieving SVR significantly increased with a linear trend from the first to the last group: 6/25 (24.0%), 9/24 (37.5%), 12/29 (41.4%), 19/29 (65.5%) (p=0.003).
  • At multivariate analysis having basal vitamin D >20 ng/mL plus the carriage of GC WT+ was found to be an independent predictor of SVR (O.R. 4.52, p=0.015).

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