Severe flu infections linked to underlying genetic variation

Flu virusesThe Center for Disease Control estimates that influenza virus–related illnesses account for more than 200,000 U.S. hospitalizations and 12,000 deaths annually. Young children, the elderly and people with respiratory, cardiac and other chronic health conditions are at particularly high risk for being hospitalized for influenza-related complications. Until now, there has not been a clear reason to explain why some individuals become severely ill from flu and not others.

New findings published in Nature Medicine, however, might change that.

“We’ve identified a genetic variant that we believe may put people at risk of getting life-threatening influenza infections,” says Adrienne Randolph, MD, MSc, a senior associate in pediatric critical care medicine at the Boston Children’s Hospital.

Randolph and others from a multi-institutional team of scientists, including St. Jude Children’s Research Hospital, looked at the genetic makeup of 393 flu patients, including infants and adults up to the age of 70.

They found that individuals who inherited a certain gene variant were more likely to develop severe influenza symptoms and complications. They identified the gene as regulating IFITM3, an anti-viral protein that helps prevent infection of lung cells and clear infection from the airway.

Preparing for future flu pandemics

Randolph is also researching the underlying factors that contribute to Staphylococcus aureus, a leading cause of pneumonia, bloodstream infections, bone and joint infections and surgical site infections and the #1 cause of skin and soft tissue infections. Learn more.

Because IFITM3 is essential to protect people from the flu, identifying this high-risk gene variant could pave the way for development of drugs that can boost the gene’s activity in people who carry it.

Additionally, the discovery could one day prove very useful during an influenza pandemic, according to Randolph, who was co-author on the Nature Medicine paper.

“Flu pandemics are inevitable — and when one starts to take off, we don’t usually have a strain-specific vaccine available right away,” Randolph says. “Then, as vaccines or antibody serums are developed, these therapies are limited in supply. Being able to detect this IFITM3 variant could help triage distribution of therapies to the individuals most likely to get the sickest.”

Read St. Jude’s press release about the findings.