Researchers at National Jewish Health have discovered a type of cell that may contribute to autoimmune disease and suggests why diseases such as lupus, multiple sclerosis and rheumatoid arthritis strike women more frequently than men. The cells, a subset of immune-system B cells, make autoantibodies, which bind to and attack the body's own tissue. The researchers reported in the August 4, 2011, issue of the journal Blood, that they found higher levels of these cells in elderly female mice, young and old mice prone to autoimmune disease, and humans with autoimmune diseases. National Jewish Health has applied for a patent for a method to treat autoimmune disease by depleting these cells.
"We believe these cells could be useful in the diagnosis and treatment of autoimmune diseases, and may help us understand general mechanisms underlying autoimmunity," said senior author Philippa Marrack, PhD, Professor of Immunology at National Jewish Health.
Autoimmune diseases occur when the immune system begins attacking its own tissues rather than external pathogens. Several autoimmune diseases, including lupus, rheumatoid arthritis and multiple sclerosis, afflict women anywhere from two to 10 times as often as they do males. Although sex hormones are known to play a role in autoimmune disease, other factors are involved in these gender differences.
The research team came across the new cells when they were examining differential expression of X-chromosome genes in healthy male and female mice. They discovered a previously undescribed type of B cell, which expressed the cell-surface protein CD11c. The protein is an integrin, which helps cells attach to other cells or to an extracellular matrix. The researchers are not certain what role integrin might play in autoimmunity or if it is merely a marker for another mediator of autoimmunity.
These cells increase as healthy female mice age, but remain at constant low levels in healthy male mice. As a result,
|Contact: William Allstetter|
National Jewish Health