Understanding the Immune System
To understand the role of TNF-alpha, it is first necessary to understand how the body’s immune system works. The immune system is a complex network of cells and organs whose overall job is to protect the body against attacks by foreign invaders, such as infections with bacteria and viruses. When a foreign substance, also known as an antigen, is present, it activates a specific type of white blood cell called T lymphocytes or T cells. These cells circulate through the body to protect it from infection, and they coordinate the immune response in order to neutralize the foreign substance.
When an autoimmune disease is present, the immune system malfunctions and can no longer distinguish between self and non-self cells. As a result, it starts attacking the body’s own healthy tissues and organs. This response stimulates the overproduction of T cells. When the T cells are overproduced and “activated” by the overstimulated immune system, they begin to release chemicals that bring about the destruction of the tissues surrounding the joints. This results in the pain, inflammation and damage to bone and cartilage that are the typical signs and symptoms of rheumatoid arthritis.
One part of this activation includes the release of interleukins, which are the types of cytokines that the immune system uses to communicate messages between cells. TNF-alpha is one of these cytokines.
Tumor necrosis factor-alpha is naturally produced in the body. Its job is to mobilize white blood cells to fight infections and other invaders. This mobilization temporarily causes inflammation in the affected area. A healthy body can rid itself of excess TNF-alpha, but the body of a patient with rheumatoid arthritis cannot. As a result, more and more white blood cells travel to the affected area. The build up of TNF-alpha, particularly in the rheumatoid joint, is what causes inflammation, pain and tissue damage.
