A new offender has been proposed to cause the autoimmune disease rheumatoid arthritis: naturally-occurring carbohydrates called glycosaminoglycans (GAGs), which compose parts of the body‘s connective tissues and are also found in the fluid within the joints.

What is rheumatoid arthritis?

Rheumatoid arthritis is a chronic disease in which the immune system attacks the tissue lining the joints. It is more common in women, tends to strike between the ages of 36 and 50 and results in chronic destruction and deformity of the joints.

Why was GAG studied?

GAGs‘ role in rheumatoid arthritis was studied because the carbohydrates are a major component of joint tissue, and because people with the disease are known to have higher levels of certain GAGs in their joints.

How was GAG studied?

The researchers found that mice injected developed chronic rheumatoid arthritis-like symptoms, including inflammation and swelling of the membranes lining the joints, the tissue surrounding the tendons and the skin. Some animals developed erosion of the bone. Antibodies were found to bind to GAGs and accumulating in the animals‘ joints.

Have GAG antibodies been found in humans?

The researchers have since found GAG antibodies in tissue from rheumatoid arthritis patients. These antibodies may be part of the body‘s response to bacterial infection. Many bacteria carry GAG-like molecules on their surface, and the body‘s own immune cells also secrete GAG when fighting infection. These similarities may prime immune cells to target the body‘s own GAGs.

What else is being discovered about GAGs?

Wang is testing potential blocking drugs and also working at adapting the GAG test developed to detect the antibodies as a screening tool to determine if a patient is at risk.

Annual Meeting, American Chemical Society Boston, MA; August 21, 2002