Gene Description

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Gene Description


IFNL3 (also known as IL28B) encodes interferon (IFN)-λ3, a member of IFN-λ family, playing important antiviral and immune-modulatory roles.1

Pegylated (PEG) IFN-α and ribavirin (RBV) are indicated to treat hepatitis C virus (HCV) infection. Eradication of HCV is measured by sustained virologic response (SVR).  Various studies have independently associated variations in IFNL3 with PEG-IFN-α and RBV-induced SVR.2  For patients treated with PEG-IFN-α and RBV alone, IFNL3 genotype is the strongest pretreatment predictor of HCV treatment response.3 In many countries including United States and countries of European Union, direct-acting antiviral agents, boceprevir and telaprevir, were approved to treat HCV genotype 1 infection in combination with PEG-IFN-α and RBV. Patients with favorable IFNL3 genotype have higher response rate to the combined treatment of PEG-IFN-α and RBV with boceprevir or telaprevir. The clinical pharmacogenetics implementation consortium (CPIC) guideline on the PEG-IFN-α-based treatment argues that for the patient who is considering whether to under HCV therapy with boceprevir regimen, IFNL3 is the most helpful predictor of the treatment response.3


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  1. Kotenko SV. IFN-λs. Curr Opin Immunol. 2011;23:583-90.
  2. Tanaka Y, et al. Genome-wide Association of IL28B with Response to Pegylated Interferon-alpha and Ribavirin Therapy for Chronic Hepatitis C. Nat Genet. 2009;41:1105-09.
  3. Muir AJ, et al. Clinical Pharmacogenetics Implementation Consortium (CPIC) Guidelines for IFNL3 (IL28B) Genotype and PEG Interferon-α-based Regimens. Clin Pharmacol Ther. 2014;95(2):141-6.