Scleroderma

The reasons why women are so much more commonly affected by autoimmune disease have largely remained a complex mystery. Now, however, researchers from the University of Colorado have identified a previously unknown type of B cell in aged female mice and in young lupus-prone mice.

The cells, which the researchers dubbed age-related B cells, or ABCs, can secrete autoantibodies when stimulated in vitro.

But the role of ABCs in autoimmunity appears to go beyond the secretion of autoantibodies, the researchers wrote in the journal Blood. These cells also express major histocompatibility complex and co-stimulatory molecules and thus may be involved in the presentation of "self" antigens to T cells.

Similar B cells also can be found in the peripheral blood of older women with diseases such as rheumatoid arthritis and scleroderma.

The Colorado researchers, led by Phillipa Marrack, PhD, found that chronic stimulation of the receptor TLR-7 led to the accumulation of three times more ABCs in the spleens of female mice compared with male mice. And they noted that the gene coding for TLR-7 is found exclusively on the X chromosome in both mice and humans.

"ABCs may thus provide a clue to the phenomenon of the female bias in occurrence of many autoimmune diseases," they wrote.

Source: MedPageToday (2011). Original Article can be viewed here.