Understanding RA

Rheumatoid arthritis (RA) can be a challenge, as anyone who has it knows. RA is a chronic, long-term disease that occurs because the body's immune system doesn't work the way it should. Most people associate the immune system with fighting infections. While it does this, in people with RA, the immune system also attacks the body. That's why RA is called an autoimmune disease.

What happens in RA?

When the immune system attacks the body like it does in RA, it leads to the symptoms that people with RA experience — from joint pain and stiffness to fatigue. Over time, the joints can become permanently damaged. Without proper treatment, this kind of damage can lead to disability. New, targeted therapies in RA provide hope for people with this condition.

Fortunately, doctors know a lot about RA and are constantly learning more about how to treat it.

The Immune System

The immune system is made up of a complex collection of organs and cells. Here are some things you should know about the cells and other substances used by the immune system that have a considerable effect on RA.

White blood cells: The body uses white blood cells to attack infections. They do this by producing a substance called antibodies. Antibodies are also responsible for causing inflammation. Two types of white blood cells involved in RA are:

• B cells: Some B cells make rheumatoid factor (RF), an antibody important for the normal functioning of the immune system. In many people with RA, B cells don't function properly, and produce too much RF.
• T cells: T cells are also very important for fighting infections. There are different kinds of T cells, each with a different function. In people with RA, T cells responsible for inflammation are seen in large numbers.

Cytokines: These are substances in the blood that communicate with white blood cells. Some of these cytokines organize the attack on harmful events like infections, which results in inflammation. When the immune system is working normally, the attack is ended once the infection has been fought off. However, people with RA have levels of certain cytokines that are too high. This means that the attack and the inflammation go on and on. It's this constant inflammation that causes the signs and symptoms of RA.

There are several cytokines involved in RA. Three of the most important are:

• TNF: This is an abbreviation for tumor necrosis factor. In people with RA, TNF is a cytokine that plays a large role in maintaining inflammation.
• IL-1: This is an abbreviation for interleukin 1. Interleukins are also cytokines. IL-1 plays a role in the immune system by communicating with white blood cells. People with RA have too much IL-1 in their systems, which is another factor in inflammation.
• IL-6: This is an abbreviation for interleukin 6. In people with RA, there is more IL-6 than any other cytokine in the lining of the joints. IL-6 is a major driver of inflammation in people with RA.

Next — Signs and symptoms of RA