Published on March 5, 2013 at 4:55 AM
The second study is believed to be the largest genetic investigation ever conducted of people infected with HCV. In it, researchers at 13 medical centers in five countries, including Thomas' Johns Hopkins team, analyzed nearly 800,000 differences in the genetic code among 919 people whose immune systems showed antibody evidence of having successfully fought off HCV infection, and another 1,482 people who became infected with the disease.
Lead study investigator and genetic epidemiologist Priya Duggal, Ph.D., M.P.H., says 40 percent of people exposed to HCV, predominantly of white and Asian ancestry, "spontaneously fight off infection" without any need for drug therapy, suggesting a genetic basis to risk of infection.
The international team's analysis showed that 15 percent of study participants who failed to become infected with HCV had either or both of two genetic variants, one near the gene for interleukin-28B and the other near the genes for HLA class II. Duggal, an assistant professor at the Bloomberg School of Public Health, says this information may help explain "with a relatively high degree of genetic certainty" why racial differences exist among those who do become infected. However, she cautions that further research is needed to determine the full impact of these genetic variants on preventing and treating HCV in people of different ethnicities.
Thomas says the findings may help physicians predict the people who are most likely to self-recover from exposure to HCV, and those who will most likely require aggressive treatment right away.
Source: Johns Hopkins Medicine