Web Zap*Germs Archive

June 05, 2005

Automimmune Diseases - "The Body's Friendly Fire"

Sunday's NYT [free online subscription req'd - visit BugMeNot for a login] has a good overview on autoimmune diseases, of which rheumatoid arthritis and lupus are perhaps the best known. Below are some excerpts.
There are at least 80 autoimmune diseases, ranging from familiar ones like rheumatoid arthritis, psoriasis, multiple sclerosis and Type 1 diabetes to more obscure ones like pemphigus vulgaris. They affect 5 to 8 percent of the American population, or up to 23.5 million people, say estimates from the National Institutes of Health. Patient advocacy groups often give much higher estimates, and there is evidence that the incidence of some of the diseases is increasing.

Most of the victims are women....There are at least eight women for every man who has lupus, scleroderma, thyroiditis and Sjogren's syndrome. Women also outnumber men, though not by as large a margin, for multiple sclerosis, rheumatoid arthritis and inflammatory bowel disease.
In autoimmune disease, something goes awry with the process in which the immune system learns to distinguish self from non-self, the body's own tissues from that of an invading germ.

The diseases can run in families and some people get more than one.
Scientists think that a combination of genes raises susceptibility. But evidence suggests that it takes an external factor to set off the disease. This could be something in the diet or a drug. But most attention is focused on infections by viruses or bacteria.

Rheumatic fever, for example, is a heart ailment incited by the bacterium that causes strep throat. In a small percentage of people, the immune system attacks a protein in the heart that closely resembles part of the bacterium.

As for the gender discrepancy, many scientists theorize that it results from women's hormones, like estrogen. This is partly because many of the ailments begin after puberty and tend to ease after menopause.

Another theory is that immune attacks are set off by the presence of cells from another person in the bloodstream; women retain some cells from fetuses after pregnancy.
Many autoimmune diseases are treated by suppressing the immune system with steroids or chemotherapy. But immune suppression leaves a person vulnerable to infections.
Newer treatments, many being developed by biotechnology companies, try to interfere with one part of the immune system rather than suppress it over all.
But while the new biotech drugs seem to be better than steroids - and more expensive, costing more than $10,000 a year - they still dampen the immune system enough to raise the risk of infections or certain cancers.
An ideal treatment would stop only the immune-system attack responsible for the disease while leaving the rest of the system working normally. In the future, it may also be possible to replace damaged tissue using stem cells.
Perhaps no disease presents as great a challenge as lupus, which is often described as the prototypical autoimmune disorder because it is clearly marked by antibodies that attack some crucial components of the body....Some scientists suspect that the disease is incited by infection with Epstein-Barr virus, which causes mononucleosis.
"There are probably going to be 10 to 15 [drug] trials launched in the next two years in lupus," said Dr. Jill P. Buyon, a lupus expert at the New York University Medical Center "I think it is finally receiving the attention it needs to receive."


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