Detection of allele specific differences in IFNL3 ( IL28B) mRNA expression

Background Variants of the interferon-lambda3 ( IFNL3 ) gene have been associated with both spontaneous and treatment induced clearance of HCV infection. Attempts to link polymorphisms of the IFNL3 gene with variation in the level of IFNL3 expression have been inconclusive. This is partially due to the difficulty to design assays distinguishing IFNL3 from IFNL2 . Methods In this study an allele specific real-time PCR (RT-PCR) assay was developed which allows the relative quantification of the two IFNL3 transcripts in cells heterozygous for SNP IFNL3.rs4803217 in the 3'UTR of the IFNL3 gene. This SNP is in strong linkage disequilibrium (LD) with the predictive marker rs12979860 . Results Raji cells showed two-fold increased levels of IFNL3.rs4803217 C-allele expression. In peripheral blood mononuclear cells (PBMCs) of eight uninfected donors, two donors showed increased IFNL3.rs4803217 C-allele expression. Conclusion This indicates that allele specific differences in IFNL3 expression vary between individuals and might contribute to the variety of outcomes in HCV infected patients.