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
protective CC pattern was over-represented among patients
infected with HCV genotypes other than 1 (odds ratio [OR]
HCV genotypes: 66.7%;
genotype 1: 39.1%.
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).
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).
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,
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