Interferon λ 3 and 4 Genotyping Using High-Resolution Melt Curve Analysis Suitable for Multiple Clinical Sample Types

Many people living with hepatitis C virus (HCV) infection will continue to rely on interferon-based regimens until effective strategies to minimize the cost of directly acting antivirals (DAAs) and to improve treatment access are implemented. Host single-nucleotide polymorphisms related to IFNL3 and IFNL4 are associated with spontaneous clearance of HCV, and pegylated interferon- and DAA-based treatment outcomes. We describe a simple and rapid genotyping method for IFNL rs12979860, rs8099917, and rs368234815 using high-resolution melting analysis for DNA extracted from whole blood, buffy coat, plasma, serum, and dried blood spots. This assay successfully detected all three polymorphisms on DNA extracted by the automated platform easyMAG from all samples when compared to sequenced amplicons. Analysis of 126 participants with recent HCV infection from the Australian Trial in Acute Hepatitis C study demonstrated the prevalence of favorable single-nucleotide polymorphisms were 62%, 51%, and 45% for rs8099917 TT, rs12979860 CC, and rs368234815 TT/TT, respectively. The genotyping assay described here provides a rapid and affordable IFNL3 and IFNL4 genotyping method for a range of clinical sample types. Until global access to DAAs is achieved, IFNL3 and IFNL4 genotyping could identify those likely to clear naturally and in whom treatment could be delayed, or help prioritize DAA treatment to those less likely to respond to interferon-containing regimens.