Researchers study rare liver ailment

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Primary biliary cirrhosis (PBC) is a liver disease affecting eight times as many First Nations People in British Columbia as non-First Nations people.

PBC is a rare autoimmune disease that is believed to be caused by both genetic and environmental factors. Ninety per cent of diagnosed cases are middle-aged women, although it can also affect men. In British Columbia, several women who have been diagnosed with PBC are related.

A research team in the University of British Columbia's Department of Medical Genetics has undertaken a study to learn more about the genetic and environmental causes of PBC in First Nations people.

Dr. Laura Arbour and the other researchers spent a couple of years designing the study and doing preliminary investigations. About a year ago they received funding from the Vancouver Foundation to carry out the study, so are now trying to identify all the First Nations people in British Columbia who have been diagnosed with PBC and invite them to become part of it.

Usually, cirrhosis of the liver is thought of as primarily the disease of alcoholics, but alcohol is not the only cause. Often, PBC is misdiagnosed as alcoholic cirrhosis because it is very difficult to distinguish the symptoms.

"Clinically, it's hard," to tell them apart, Dr. Arbour said, although there may be "some laboratory tests that suggest liver failure.

"Often the features of primary biliary cirrhosis are simply the features of liver failure and liver compromise. These features include fatigue, itching, sometimes increased pigmentation of the skin and abnormal liver function studies.

"There is a particular antibody, which helps very much in the diagnosis, and it's quite a simple blood test that can be done to differentiate. And also liver biopsy differentiates, because it shows that the condition that is involved is actually involving the biliary ducts as opposed to just the liver cells. So I would just say that the liver biopsy is one way to be able to confirm whether it is primary biliary cirrhosis, and as well, a blood test, which is a test for an antibody, is a very easy way to determine that, since this antibody is specific to the condition."

PCB is a chronic disease that causes slow, progressive destruction of the bile ducts, which become inflamed when the immune system breaks down. Normally, bile, a substance that digests fat in the body, leaves the liver through the bile ducts, but when the bile ducts deteriorate, copper builds up in the liver, a condition that causes the normally soft liver tissue to become fibrous or granular.

A survey of a transplant society list shows that between 1989 and 1998, 25 per cent of people needing liver transplants because of PBC were Aboriginal, although in this province Aboriginal people make up slightly less than four per cent of the population.

The most recent statistics Dr. Arbour has at hand, covering all the referrals to the B.C. Transplant Society, show they have had "128 referrals for primary biliary cirrhosis, and 34 of those were people of First Nations descent."

When population rates are taken into account, she said, "the referral for primary biliary cirrhosis rate is about eight times higher for those that are of First Nations descent than non-First Nations descent. So what that tells us is that this is an important problem in the First Nations people of British Columbia.

"One of the things we don't know about is whether it actually is important across the country. We're not sure. We know that it sort of goes from north to south, and certainly there are clusters in the southwestern United States and Alaska, but we have no knowledge of whether this is something that is of concern also across the country, and it may not be. It may just be a particular genetic predisposition from the group that have migrated down."

She also said they don't know whether or not PBC is underdiagnosed in other areas because physicians are not aware of it.

The doctor said they want to rase awareness about their PBC study: "to understand why it occurs more often in First Nations people than not. We think that there are possibly both genetic and environmental reasons for it. There may be the genetic predisposition to autoimmune disease of the liver ... and we are suspicious that certain viruses may actually cause this condition to become more prevalent. So, you need the conditions of both genetic predisposition plus whatever environmental exposure is causing this.

"So, the purpose of the study is, number one, to raise the awareness of this as an important condition, and number two, to try to determine what the causes are."

She stressed the study will not look at everyone with liver disease to see how many people have PBC, only those who already have been diagnosed with PBC. The study has only been approved for British Columbia and will be complete in about one more year.

Another aspect of their work is to educate physicians and to alert them to consider PBC as a possible cause when liver disease is present in an Aboriginal person, particularly if the patient is a woman between 35 and 50, "and to look for an antimitochondrial antibody as a possibility."

The blood test for PBC will show an antimitochondrial antibody is present in 95 per cent of those who have PBC, "and it's not present if the condition is not present."

In British Columbia, the doctor said, it would probably be wise to screen any female Aboriginal person in this age group for PCB, "but across the country, I just don't know."

More information about the causes of PBC will lead to earlier diagnosis. Although at present there is no cure, proper treatment begun early can add a lot to a patient's quality and length of life.

Anyone who wants to contact Dr. Arbour in regards to this study can e-mail her at larbour@cw.bc.ca.