Mechanism Behind Autoimmune Diseases Found

Triggering of harmful immune B cells starts inflammatory process, researchers say

FRIDAY, Oct. 21, 2005 (HealthDay News) -- A mechanism that could result in autoimmune diseases such as rheumatoid arthritis, lupus or diabetes has been identified by researchers at National Jewish Medical and Research Center.

They found that a form of potentially harmful immune system B cells circulating in the body are not permanently inactivated as previously believed. It turns out these harmful B cells can reactivate and launch attacks on the body's own tissue.

"Keeping self-reactive B cells in a quiescent state is crucial for the prevention of autoimmunity. Our findings show how these cells can be reactivated and suggest lines of research that may lead to therapies for autoimmune diseases," research leader John Cambier, chairman of the integrated department of immunology at National Jewish and the University of Colorado Health Sciences Center, said in a prepared statement.

Normally, these dangerous B cells are kept in a state of suspended animation, which prevents them from attacking body tissue. However, this study suggests that an active bacterial infection may draw self-reactive B cells to lymphoid organs -- such as the tonsils or lymph nodes -- where a strong immune/inflammatory response to the infection causes the cells to reawaken and trigger an autoimmune disease.

The findings were published online in Nature Immunology.

"There have been reports linking the onset of autoimmunity with a preceding bacterial infection," study author Stephen Gauld, a postdoctoral fellow in Cambier's lab, said in a prepared statement.

"We are now conducting experiments to determine the role of pro-inflammatory or bacterial products in the loss of B-cell anergy (suspended animation). We are also seeking to better understand the intracellular events that lead to anergy and its loss. Either of these lines of research could uncover potential targets for autoimmune therapy," Gauld said.

More information

The U.S. National Women's Health Information Center has more about autoimmune diseases.

SOURCE: National Jewish Medical and Research Center, news release, October 2005
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