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SNP Variant Associated with Clearance of Hepatitis C Virus

An international research team has shown that a particular SNP genotype (C/C) near the IL28B gene appears to be associated with the ability of some people to defeat hepatitis C virus (HCV) infection and get rid of the virus with no treatment. HCV infection is the most common blood-borne infection in the United States, with estimates of 4 million HCV-infected individuals in the United States and 170 million worldwide. More than seventy percent of people who contract hepatitis C will live with the virus that causes it for the rest of their lives and some will develop serious liver disease including cancer. However, 30 to 40 percent of those infected somehow defeat the infection with no treatment. Previous work had shown that individuals with the C/C SNP genotype near IL28B were more likely to respond to treatment for hepatitis C, which can rid some patients of the virus. So, in the current work, the researchers investigated if the C/C variation—as opposed to the C/T or T/T alternatives—also played a role in some peoples' ability to get rid of the virus without the help of medication. To do this, the scientists assembled information from six different studies that had, over many years, collected DNA and hepatitis C infection information from people all over the world. The team then analyzed DNA in the IL28B gene vicinity from a total of 1008 patients: 620 persistently infected and 388 who had been infected but no longer carried any virus. DNA analysis revealed that of the 388 patients who no longer carried virus, 264 had the C/C variation. "This is the strongest clue to date to understanding what would constitute a successful immune response," said Dr. David Thomas, lead author of the article. "We don't yet know the significance of this C variant, but we know we need to do more work to find out what it means and whether it might be helpful to halting the disease." This research was reported on September 16 in the online edition of Nature. [Press release] [Nature abstract]