Systemic lupus erythematosus (Lupus) is a chronic disease that causes inflammation in the tissues which provide strength and flexibility to structures throughout the body. The signs and symptoms of Lupus vary among affected individuals, and can involve many organs and systems, including the skin, joints, kidneys, lungs, central nervous system. Lupus is one of a large group of conditions called autoimmune disorders that occur when the immune system attacks the body's own tissues and organs. It affects predominantly women of child-bearing age and has population differences in both disease prevalence and severity. Genetic factors are known to play key roles in the disease through the use of association and family studies.
Most of the genes associated with Lupus are involved in immune system function. Sex hormones and a variety of environmental factors including viral infections, diet, stress, chemical exposures, and sunlight are also thought to play a role in triggering this complex disorder. About 10 percent of Lupus cases are thought to be triggered by drug exposure, and more than 80 drugs that may be involved have been identified.
The STAT4 gene provides instructions for a protein which attaches to specific regions of DNA and helps control the activity of certain other genes. The STAT4 protein is turned on by immune system proteins called cytokines, which are part of the inflammatory response to fight infection. When activated, the STAT4 protein increases the activity of genes that help immune cells called T-cells mature into specialized T-cells. These specialized T-cells, called Th1 cells, produce specific cytokines and stimulate other immune cells to get rid of foreign invaders in the cell.