Challenging the idea of autoimmunity
Dr. Andrew Mason's research has been a flashpoint for controversy. This University of Alberta researcher and AHFMR Senior Scholar is a hepatologist, a physician who treats patients with liver disease. He has been challenging the widely held belief that many gastrointestinal diseases are caused by the body turning against its own cells. He suspects that at least some of these diseases are really viral diseases, and his evidence comes from his own research. He has identified a virus associated with primary biliary cirrhosis (PBC), a disease in which the bile ducts of the liver are slowly destroyed, and scarring of liver tissue results. Although medication can slow the progression of the disease, a substantial proportion of patients will eventually require liver transplants. PBC is the reason behind more than 10% of all liver transplants worldwide. It is considered an autoimmune disease.
"I've always been skeptical about how autoimmunity is hypothesized as the cause for so many diseases," says Dr. Mason. "If you take a look at livers from patients with PBC or autoimmune hepatitis and compare them to livers from patients with hepatitis B or C, they don't look that much different. We know that hepatitis B and C are viruses—so why not look for viruses?"
That's exactly what he has done. Dr. Mason has found a virus, called human betaretrovirus, associated with PBC. He has isolated the virus in patients, grown it in the lab, and has also shown that it causes a similar disease in animals. To prove that the virus actually infects patients with PBC, he has identified "integration sites" where the virus puts a copy of itself into the human genome. However, clinical trials using antiviral therapy to treat PBC have not been conclusive. While patients have shown significant improvement in biochemistry and symptoms, there was not enough improvement to demonstrate a substantial change in the disease.
Undeterred, Dr. Mason is attempting to organize another clinical trial, this time using highly active antiretroviral therapy (HAART), the powerful therapy behind the drop in the AIDS-related death rate in developed countries. He is also conducting "virus discovery" studies on a number of other diseases. His team has already identified a virus associated with primary sclerosing cholangitis, another disease that damages bile ducts.
Not everyone buys into the hypothesis. "People are always skeptical when someone claims that they have discovered a virus that causes 'autoimmune' disease but it also took a long time for the scientific community to accept that ulcers were caused by bacteria. Long-term, I hope I see antiviral therapy as a routine treatment for PBC. I believe it's our best chance of eradicating this disease as a progressive disease that usually leads to a liver transplant."