Scleroderma - Risk Factors

Highlights	Prognosis	Treatment for Lung Complications
Introduction	Treatment	Treatment for Gastrointestinal Problems
Risk Factors	Medications	Resources
Symptoms and Complications	Other Treatments	References
Causes	Treatment for Raynaud's Phenomenon	References
Diagnosis	Treatment for Skin Thickening

Causes

Most likely this disease is caused by a number of inherited (genetic) abnormalities, which are triggered by environmental factors.

Inflammatory Response and Autoimmunity

The disease process leading to scleroderma appears to occur as an autoimmune response, in which an abnormal immune system attacks the body itself. In scleroderma, this response produces swelling (inflammation) and too much production of collagen. Collagen is the tough protein that helps build connective tissues such as tendons, bones, and ligaments. Collagen also helps scar tissue form. When normal tissue from skin, lungs, the esophagus, blood vessels, and other organs is replaced by this type of abnormal tissue, none of these body parts work as well, and many of the symptoms previously described occur.

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Antigens are large molecules (usually proteins) on the surface of many cells -- both human cells, and cells of viruses, fungi, bacteria, and some non-living substances such as toxins, chemicals, drugs, and foreign particles. When the immune system recognizes an antigen as being foreign (not part of the human body), it starts offensive and defensive actions against them by producing antibodies and other chemicals such as cytokines that destroy any cells in the area.

Much of this activity is directed by white blood cells known as T cells, which are subdivided into killer T cells and helper T cells (TH cells).

The actions of the helper T cells are of special interest in scleroderma. For some unknown reason, the T cells become overactive in scleroderma and mistake the body's own collagen for a foreign antigen. This triggers a series of immune responses to destroy the collagen. When the body creates antibodies against itself in this way, it is called an autoimmune response.

Genetics

Research has demonstrated that systemic sclerosis is a polygenic (involving more than one gene) autoimmune (involving the immune system response) disease. Several genes and gene-gene interactions have been identified as playing a role in systemic sclerosis. Many of these same genes are linked to related diseases, such as rheumatoid arthritis and systemic lupus erythematosus.

The genes are involved in the regulation of the immune system.