Lupus as the prototypical autoimmune disease, lupus occurs when the immune system malfunctions. The immune system is designed to protect the body from foreign invaders, such as bacteria and viruses. It performs this role by producing antibodies, or proteins, to fight off infections. In people with lupus, the immune system loses its ability to distinguish between these foreign substances, called antigens, and the body’s own cells and tissue. For reasons that are not yet fully understood, the immune system then makes antibodies that are directed against "self." The self-antibodies create immune complexes which lodge in the body’s tissue, causing inflammation and organ damage.
No one knows the exact cause of lupus. However, lupus is not infectious. Researchers believe people with lupus are born with a genetic predisposition to the disease. Certain environmental factors also play a role in triggering disease activity. These factors include infections, antibiotics, ultraviolet light, extreme stress, certain drugs, and hormones. Hormonal factors may explain why lupus occurs more frequently in females than in males. Although lupus is known to occur in families, researchers have not identified a specific gene or set of genes believed responsible for the disease. Likely there are many different genes involved in various combinations that make individuals susceptible to developing lupus. The impact of lupus varies widely from person to person.
There are several forms of true lupus. Systemic lupus can affect nearly any organ or organ system of the body. Cutaneous lupus affects the skin. Drug-induced lupus is brought on by certain medications, and resolves when the offending medication is discontinued. Neonatal lupus affects the fetus and can range from a rash that disappears with no ill effects to an irregular heart beat that requires the infant to have a pacemaker. The antiphospholipid syndrome comprises a combination of symptoms and is implicated in recurrent miscarriages and blood clots. Sometimes, people with inconclusive test results for lupus may instead be given a diagnosis of mixed connective tissue disease or undifferentiated connective tissue disease.
For more information on these and other developments in lupus research and education, visit the LFA website at http://www.lupus.org/ or call the LFA’s national toll-free information request line at 888-38-LUPUS (385-8787).