Ankylosing spondylitis is a chronic inflammatory arthritis. Spondylitis patients suffer from joint stiffness, pain and extra bone growth that can result in partial or complete fusion of the spine. The bones of the spine may growth together, causing the spine to become rigid and inflexible. Other joints such as the hips, shoulders, knees or ankles also may be affected.

Spondylitis and other inflammatory diseases are linked to the immune system, the body’s natural protection against infection and toxins. In these patients, the immune system attacks the body’s own healthy cells, mistaking them for cells that don’t belong.

Tumor necrosis factor (TNF) is one of the chemical messengers that helps regulate the inflammatory process. When the body produces too much TNF, it overwhelms the immune system’s ability to control inflammation in the joints or other parts of the body.