In rheumatoid arthritis (RA), the immune system gets a faulty signal that causes it to attack healthy joint tissue. Unless the signal is corrected or blocked, chronic inflammation sets in and over time can destroy the joint and other organs.
Permanent joint damage often occurs within the first two years of RA, so early control of the inflammation is important. However, treatment is tricky when the body’s defense system is the source of disease. Ideally, you want to block the part of the system that’s gone awry, not the whole system.
So, how exactly do biologics help people with RA? To answer this question, it helps to first look at what is going on in RA and how biologics work.
Biologics Fight Chronic Inflammation
Biologics are sophisticated medicines. They work like parts of the immune system and can disrupt the immune response that occurs in RA. Created from living organisms using molecular biology techniques, biologics function just like substances made by the body’s immune system.
Biologics were first used to treat RA in 1998. They have significantly improved the course of disease for many people with RA by offering greater disease control than is possible with traditional disease-modifying anti-rheumatic drugs (DMARDs) alone.
RA: An Autoimmune Disease
The immune system normally protects the body. Day in and day out, a network of specialized cells -- talking to each other through chemical messengers -- patrols for foreign intruders such as bacteria and viruses. When the system spots an intruder, word spreads to destroy the harmful substance. Immune cells rush to the site and release toxic molecules, resulting in inflammation.
Inflammation is usually tightly controlled. One set of chemicals turns on and keeps the process going by sending signals that call immune cells to the site of the threat. Another set of chemicals turns off the process by sending signals that stop the immune cells from attacking.
In RA, the immune system doesn't work that way. The system gets a faulty signal that an intruder is lurking in the joints. This triggers an immune response against healthy joints and tissue. Mistaking the body’s own cells as foreign is called an autoimmune response.
The attack starts in the cells lining the insides of the joints (synovial cells), causing inflammation (synovitis). Researchers don't know what sparks the autoimmune response in RA. Some believe that a genetic predisposition combines with some environmental trigger to set off an autoimmune response.
