The IL28B gene codes for the interferon-lambda protein, a cytokine that plays an important role in the body’s immune response. Research has shown that a mutation in the IL28B gene influences the likelihood of the body responding effectively to a treatment involving PEG-interferon and ribavirin. The likelihood of spontaneous remission of a hepatitis C infection is also influenced by the IL28B gene.
A combination of PEG-interferon and ribavirin is frequently used to treat hepatitis C and in particular acute hepatitis C infections. Nowadays, patients with chronic hepatitis are mainly treated with new, direct-acting antiviral drugs.
Genetic predisposition
The likelihood of treating hepatitis C successfully with PEG-interferon and ribavirin can differ from person to person. This variation can be explained in part by genetic variations. Mutations in the IL28B gene are partly responsible for these.
IL28B positivity in the homozygous form (*POS/*POS) is found in around 10% of Europeans. The likelihood of treating hepatitis C successfully with PEG-interferon and ribavirin is significantly lower for this group. The heterozygous form (*NEG/*POS) of IL28B positivity also slightly reduces the likelihood of a successful treatment. This form is found in around 40% of Europeans.
In Asians IL28B positivity is less common; the percentages for the homozygous and heterozygous forms are 1-5% and 15-35% respectively.
At iGene we determine the following genotypes:
- IL28B negative
- IL28B positive (heterozygous)
- IL28B positive (homozygous)
For this we use the marker rs12979860.