Rare Gene Mutation Which Protects
Against HIV, Ups HCV Risk

CHICAGO (Reuters Health) - A genetic mutation known to protect against HIV appears to make people more susceptible to hepatitis C, according to a study presented here on Tuesday at the 8th Conference on Retroviruses and Opportunistic Infections here.
Hepatitis C is a life-threatening viral infection of the liver that can cause cirrhosis, liver failure and cancer. It affects about 170 million people worldwide and is common among HIV-infected patients and intravenous drug users.
The mutation affects a receptor found on immune system cells known as CCR5. HIV uses this receptor, along with the CD4 receptor, as a sort of ``door'' to gain access and wreak havoc in the cell's interior.
People with two mutated copies of the CCR5 gene--one from each parent--are much less likely to become infected with HIV than those who have no mutations. People who have one mutated copy of the gene can become HIV infected, but progress to AIDS much more slowly than other patients. About 1% of whites have two mutated copies of CCR5.
Now a new study suggests that those gene mutations--so helpful in avoiding deadly HIV--actually may make carriers more vulnerable to hepatitis C.
In a new study, Dr. Rainer P. Woitas and colleagues at the University of Bonn in Germany looked at 130 hepatitis C-infected patients, 102 HIV-infected patients and 130 patients infected with both viruses.
``On average, about 30% of HIV-infected patients also have HCV infection,'' he told conference attendees.
Woitas saw a ``striking increase'' in CCR5 mutations in patients infected with hepatitis C, compared with uninfected patients. The number of CCR5 mutations in the hepatitis C-infected patients was 3 to 7 times higher than would be expected in the general population.
Hepatitis C levels in the blood--which can indicate more serious or advanced infections--were much higher in those who had two CCR5 mutations compared with those who did not.
The reason why CCR5 mutations may increase the risk of hepatitis C infection is unknown. However, Woitas suggests that ''it is conceivable that cell-related immune response is altered by this mutation.''
The findings of the Bonn researchers ``suggest that this mutation is associated with a worse outcome for hepatitis C infection,'' Dr. David D. Ho of the Aaron Diamond AIDS Research Center commented. ``This certainly is a novel observation and will shed some light on the mechanism of control for hepatitis C virus, which is a frequent co-infection in AIDS patients.''

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