By Don Finley
San Antonio Express-News
October 26, 2011
A new study that included hundreds of San Antonio Hispanics found that that a person’s genes play a strong role in how the immune system responds to 13 common infections.
And while the findings might provide some clues to why some people are better able to resist certain infections and some are more susceptible, the researchers were cautious – saying it’s not yet clear.
The study, led by researchers at the Texas Biomedical Research Institute, measured blood levels of antibodies that target flu, chickenpox, herpes viruses, hepatitis A, Epstein-Barr and several others.
“I think the most significant finding is that with the majority of these pathogens, the antibodies were significantly heritable,” said Rohina Rubicz, lead author of the study and a geneticist at Texas Biomed. “They are under genetic control to some extent. And we found that they were significant for all the 13 pathogens we examined except for two.”
While several studies have looked at how big a role genes play in how people respond to vaccines, few have looked at how they influence the body’s defenses against natural infection – particularly in minority groups, the researchers said.
The blood samples were collected from 1,227 Hispanic volunteers in the San Antonio Family Heart Study, a large, local study looking at the genetics of heart disease. In this case, researchers were looking at the link between inflammation and heart disease, and the 13 infections were chosen because they too might affect the heart.
“Now for most of them the risk has not really been proven per se,” said Harald Göring, a geneticist at Texas Biomed and a co-author of the study. “But there’s been a large number of studies suggesting that atherosclerosis is at its core an inflammatory disorder. So the question that comes up is, what causes this inflammation? Microbes are an obvious potential candidate.”
Because the genetic profiles of the volunteers were documented, the researchers were able to match the levels of specific antibodies to different genetic patterns. The only two that didn’t show a connection were adenovirus 35, which causes respiratory infections and has been linked to obesity; and herpes simplex virus 2, a sexually transmitted infection.
The findings were then confirmed in samples from 648 volunteers of another local genetic study focusing on diabetes and gallbladder disease.
The results were published online earlier this month in the journal Human Heredity.