Psoriatic arthritis (PsA) is considered a complex illness because doctors believe many different elements work together to cause its development. In addition to the presence of certain genes, one critical factor is a malfunctioning immune system. Certain environmental factors that trigger the immune system to malfunction are also critical elements.
The Immune System
Doctors first recognized a link between the immune system and psoriasis in the late 1970s. While using a drug called cyclosporine to suppress the immune system in patients who had undergone bone marrow transplantation, the doctors saw that a case of psoriasis abated at the same time. They realized the immune system was involved in what had been thought to be purely a skin disease.
In a healthy immune system, a type of white blood cell called a T-cell circulates throughout the body and protects it from infection and disease by destroying bacteria, viruses and other foreign substances collectively known as antigens. The presence of an antigen activates the T-cell, which then initiates an immune response to neutralize the cell. Autoimmune diseases, such as rheumatoid arthritis, psoriasis and psoriatic arthritis, cause the immune system to accelerate, and it begins attacking the very cells, organs and tissues in the body that it is designed to protect.
Part of this response involves the release of interleukins, which are any of a class of lymphokines.
Copyright 2009 NBC Health
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