Fw: Autoimmune Diseases Result of Mutations and Infection, StudySuggests

[Guest guest]

From: ilena rose <ilena@...>

Subject: Autoimmune Diseases Result of Mutations and Infection,

StudySuggests

> ~~~ this is the same noel rose who speaks on behalf of the silicone

> manufacturers regarding implants. thanks to ms. lorenn for finding this

for

> us. ~~~

>

>

>

http://www.drkoop.com/news/stories/2000/dec/hs/19_immune.html?nl=dkc & sct=top

& dt=

> 010201

>

> Fear and Self-Loathing in Your Immune System

>

> Autoimmune Diseases Result of Mutations and Infection, Study Suggests

>

>

> Dec 19 2000 16:07:28

> Adam Marcus

> HealthSCOUT

>

> PHILADELPHIA -- Scientists who study the immune system say they've taken a

> big step toward understanding why your body's defensive cells sometimes

> turn against you.

>

> Chance mutations, coupled with a viral infection, can trigger autoimmune

> reactions that create a potentially deadly family feud within your body.

>

> The finding, which appears in the current issue of the Journal of

> Experimental Medicine, is preliminary and unlikely to produce any help for

> patients in the near future. However, researchers say, it could one day

> lead to treatments for lupus, rheumatoid arthritis and early-onset, or

Type

> I, diabetes. Together, autoimmune diseases are among the top 10 killers of

> women in America.

>

> The notion that infections may be at the root of autoimmune disorders has

> been around for a century, says Dr. Noel Rose, a specialist in the

> disorders at s Hopkins University.

>

> " It's really very plausible, but when you get down to it there's really

not

> much evidence that it truly occurs, " says Rose, who is also chairman of

the

> scientific advisory panel of the American Autoimmune Related Diseases

> Association.

>

> A prime example of the link is rheumatic heart disease, an autoimmune

> attack on heart tissue that's thought to result from repeated strep

> infections during childhood.

>

> The latest study offers at least one explanation of how your immune system

> can turn into your worst enemy.

>

> The research, led by Caton, of the Wistar Institute in

Philadelphia,

> hinges on a class of immune agents called memory B cells. They are the

> first dominoes in the cascade of reactions that make up an immune

response,

> and they have two key jobs.

>

> The first is to recognize an invading organism, such as a virus, and warn

> other immune cells of its presence. They do this by generating proteins,

> called antibodies, which are specific to the microbe. They can also

> neutralize the invader by attaching themselves to it. B cells " help keep

> you from dying " within days from the initial infection, says Caton.

>

> But there's a subset of B cells that, when they meet an invader, don't do

> anything immediately. Instead, they retreat to the spleen, and with the

> help of other immune cells, they begin to mutate randomly and with

> remarkable haste, he explains.

>

> In clusters known as germinal centers, they refine themselves into highly

> specific cells that flood the bloodstream and defeat the infection. This

> process, which occurs about a week after initial infection, also gives the

> body a " memory " of the invader, Caton says. That helps them fight off

> subsequent attacks from the same organism.

>

> It's also the reason vaccines work, since these B cells live a long time

> and " do a better job of recognizing the virus than the ones you have

> inherited, " he says.

>

> In the latest study, Caton and his colleagues showed that, during their

> time in the spleen, these B cells can mutate and become hostile to your

> body. Using a strain of mice genetically modified to express an influenza

> protein, hemagglutinin, they were able to disguise the viral protein as

> part of the body.

>

> The modified mice appeared to be healthy. But when they infected the

> animals with flu, their immune cells launched a muted attack against the

> transferred protein.

>

> Since B cells in the first wave of attack die off, the autoimmune reaction

> had to originate with the B cells produced in the second phase, Caton

says.

>

> In other words, the combination of random mutations with a viral invasion

> sparked an autoimmune response, albeit a mild one, he says.

>

> What's not clear is why autoimmune reactions choose to pick on particular

> tissues, like the joints in arthritis or pancreas in diabetes.

>

> " What makes it harmful rather than benign is similar to saying, 'Why are

> some cell masses benign and others malignant?' " Caton says. " How that

> decision is made is a big mystery. "

>

> If infections do indeed spark autoimmune reactions, then vaccination would

> be the obvious answer.

>

> Yet Rose says at least one other new study seems to show the incidence of

> autoimmune disease rises with more immunization.

>

> " That makes life very interesting for people who study these illnesses, "

he

> says.

>

> SOURCES: Interviews with J. Caton, Ph.D., associate professor,

> Wistar Institute, Philadelphia; Noel R. Rose, M.D., Ph.D., professor of

> pathology and immunology, s Hopkins University, Baltimore; Dec. 18,

> 2000 Journal of Experimental Medicine.

>

>