Patient's Genes May Impact Hepatitis C Outcomes
Dec. 17, 1999 (Indianapolis) -- It has long been known that the outcome of
an infection with the hepatitis C virus (HCV) can vary greatly among
individuals. A report in the Dec. 18 issue of the journal The Lancet
indicates that a patient's genetic factors may explain much of this
"Infection with HCV can lead to anything from a self-limiting [mild and
noncontagious] infection to cirrhosis, or scarring of the liver, to
cancer," says lead author Mark Thursz, MRCP, from the Imperial College
School of Medicine in London. "In some patients, the rate of progression is
much faster than average, whereas in others, the rate of progression is
negligible. What determines the outcome of HCV infection is not clear."
Hepatitis C is a virus that can cause liver disease and liver cancer. It is
transmitted via blood, either from blood transfusions or IV drug use. It can
also be transmitted from sexual contact. Initially it may cause a mild illness,
but then resides in the body without symptoms. In at least 20% of cases, the
HCV will reactivate and eventually cause a liver disease called cirrhosis.
There are treatment options for HCV, many experimental, but there is no known
medication that kills the virus.
Using patients recruited from eight large hospitals across Europe, the
researchers looked at the distribution of a set of certain genes in patients
with a self-limiting infection that went away on its own and a matched set of
patients with a persistent infection. They also studied those with mild and
severe injury to the liver and those patients who responded to treatment with
interferon and those who did not.
Those with the self-limiting type of infection were more likely to have two
specific genes. Two other genes were associated with persistent infections.
These results were confirmed in a second-stage study. No significant
associations were found between the presence of certain genes and injury or
response to interferon.
"In the short term, this research has no direct relevance to the
patient," says Thursz in an interview with WebMD. "However, in the
future, identification of genetic factors which influence the outcome of
hepatitis C virus infection will be used to identify patients at most risk of
developing severe liver disease, identifying patients with a good chance of
responding to treatment, and identifying disease pathways as targets for
David L. Smalley, PhD, professor of pathology at the University of
Tennessee, Memphis, agrees with the researcher's statement that a complex mix
of genetic, environment, and virus factors determines the outcome of HCV
"Genetics is one component that affects the outcome of HCV," says
Smalley in an interview with WebMD. "This is one step in the right
direction to find the genetic effects that might allow us to determine an
intervention's success or failure. For us to fully understand a disease that
evolves over a 20- or 30-year period of time, it is clear that we have to look
at many other factors."
Leslye D. Johnson, PhD, who is with the National Institute of Allergy and
Infectious Diseases, tells WebMD in an interview that this will probably give
researchers a way to narrow the scope of future studies in an attempt to find
something that is useful in treating patients.
"I don't think the results of this will be clinically useful," says
Johnson, who was not involved in the study. "Although looking at these
genes might give you some idea of what was going to happen, it is not going to