IL28B Gene Pattern May Influence Susceptibility to Hepatitis C Virus Genotypes

IL28B Gene Pattern May Influence Susceptibility to Hepatitis C Virus Genotypes

SUMMARY: People with different IL28B gene patterns may be more or less susceptible to infection with specific hepatitis C virus (HCV) genotypes, according to a Spanish study described in the July 2010 issue of Hepatology. Researchers found that the protective CC IL28B pattern was significantly more common among people with easier-to-treat non-1 HCV genotypes.

In 2009, researchers first reported that a variation or polymorphism in the IL28 gene -- which encodes interleukin 28, also known as interferon lambda -- was associated with both spontaneous clearance of HCV and better response to interferon-based therapy for chronic infection.

The protective variation, known as the CC pattern -- a human genotype, not to be confused with viral genotypes -- is more common among people of European descent than those of African descent, which may help explain the difference in response rates between white and black hepatitis C patients.

In the present study, Marco Antonio Montes-Cano from Instituto de Biomedicina de Sevilla and colleagues looked at the relationship between IL28B gene variations and outcomes of HCV infection.

The study included 731 participants in Spain. Within this group were 284 patients with chronic or persistent HCV infection, 69 individuals who naturally cleared the virus without treatment, and 378 uninfected control subjects. The investigators performed genotypic analysis of the rs12979860 polymorphism in the IL28B gene locus.

Results

The protective CC pattern was over-represented among patients infected with HCV genotypes other than 1 (odds ratio [OR] 0.32):

	Non-1 HCV genotypes: 66.7%;
	HCV genotype 1: 39.1%.

Participants who spontaneously cleared HCV were more likely to carry the CC pattern than those who developed persistent infection (72.5% vs 45.6%; OR 0.32).

Patients who achieved sustained response to interferon-based treatment were more likely to have the IL28B CC pattern compared with non-responders (60.2% vs 32.1%; OR 0.31).

Based on these findings, the study authors concluded, "We have found different rates of viral genotype infection depending on the IL28B variant as well as an association of this locus with natural and treatment-mediated response."

Servicio de Inmunología, Hospital Universitario Virgen del Rocío/Instituto de Biomedicina de Sevilla, Sevilla, Spain; UCM de enfermedades digestivas y Ciberehd, Hospital Universitario de Valme, Universidad de Sevilla, Sevilla, Spain; Servicio de Digestivo Hospital Universitario Virgen del Rocío, Sevilla, Spain.

8/27/10

Reference
MA Montes-Cano, JR García-Lozano, C Abad-Molina, and others. Interleukin-28B genetic variants and hepatitis virus infection by different viral genotypes. Hepatology 52(1): 33-37 (Abstract). July 2010.