Connecting the Dots Between Hepatitis C and the Aging Immune System

Wednesday, March 25, 2015 - 3:00pm

Dr. Lisa Barrett is shedding light on how the immune system could be boosted to regain vitality into old age. An infectious diseases specialist, she is studying how new-generation antivirals help the immune system bounce back from hepatitis C infections.

Since arriving in Halifax in January 2014, clinician scientist Dr. Lisa Barrett has been busy seeing patients in Capital Health’s HIV and hepatitis C outpatient clinics, consulting on the infectious diseases inpatient service, setting up her new research lab in the Sir Charles Tupper Medical Building at Dalhousie and analyzing blood and liver samples from patients with hepatitis C.

“It’s every clinician researcher’s wish, to have that fit between their clinical duties and their research focus,” says Dr. Barrett, who studies how the immune system responds to hepatitis C and new treatments for the infection. “This, the opportunity to have the great majority of my time protected for research and to work with amazing colleagues, is what brought me back to Halifax - it’s a rare opportunity in Canada.”

Originally from Newfoundland and a graduate of Memorial University, Dr. Barrett completed her residency training in internal medicine at Dalhousie Medical School, followed by sub-specialty training in infectious diseases at the University of Toronto. After that, she headed to the National Institutes of Health in Maryland, U.S.A., to complete a scientific and clinical fellowship in the area of hepatitis C. Now, she brings her expertise back to the Maritimes, where she’s laying the groundwork for clinical trials of brand new, highly effective oral antiviral treatments for hepatitis C she helped test in early-stage trials in Maryland.

You’re only as old as your immune system - Hepatitis C virus is mysterious in that it doesn’t stimulate a robust-enough immune response to kill the virus or build up protective immunity. “You can kill hepatitis C virus with antivirals and make it go away, but the person can always be re-infected, like the flu,” she says. “Except, unlike influenza, there is no vaccine against the hepatitis C virus.”

By studying how the immune system responds to hepatitis C treatment, her lab work may yield insights into a vaccine strategy against the disease, which can lead to irreversible liver disease and liver cancer. At the same time, she is uncovering clues to protecting the immune system from the ravages of aging.

“When you have hepatitis C, your immune system looks old,” Dr. Barrett explains. “You could be 40, with the immune system of an 80 year old.”

Remarkably, treatment with new-generation antivirals seems to reverse this “aging” process, revitalizing flagging immune cells and allowing immune cells to flourish after the virus is vanquished.

“We’re looking at individual cells from hepatitis C patients to see if, how and when they regain this vitality after treatment,” she says. “If we can find the mechanism, we may have the key to boosting any person’s aging immune system, whether it’s exhausted from fighting infection or simply from advancing age.”

Keeping the immune system young in the face of advancing age would be a major advance in preventive health care. “Older people with worn immune systems are more vulnerable to all sorts of infections and don’t develop very efficient immunity in response to vaccines,” notes Dr. Barrett. “I’m hopeful my work will help people age well with fewer infections.”

Infectious diseases clinician scientist Dr. Lisa Barrett and research scientist Dr. Sharon Oldford study immune cells isolated from patients with hepatitis C. They’re seeking clues to a vaccine for the virus, while learning how the immune system recovers from the “aging” effects of the infection. They hope the work will lead to ways of revitalizing older people’s worn-out immune systems.