Rheumatoid Arthritis (RA) is a complex, systemic autoimmune disorder likely triggered
by an infectious organism that initiates the interplay of genetic factors and inflammatory
mediators . Chronic inflammation,
the hallmark of RA, is thought to be the result of the body’s long term exposure
to an antigen. The body’s initial attack is unsuccessful and over time development
of autoantibodies occurs. The autoantibodies attack the body’s own tissues resulting
in painful, chronic inflammation
. The exact cause of the disorder has yet to be identified despite
The disease process of RA is related to an immune complex-mediated hypersensitivity
reaction, commonly referred to as Type III hypersensitivity
(Rote, 2007). According
to Rote (2007, 127), an antibody binds to a soluble antigen that is released into
blood or body fluids. It is then transported through the circulatory system and
eventually deposited into the body’s tissues. These deposits are called antigen-antibody
complexes; in patients with RA, they are referred to as rheumatoid factors (RF).
In RA, these antigen-antibody complexes are deposited in the synovial membrane which
lines the joint cavity .
Once the antigen-antibody complex is in the synovial membrane, it triggers a reaction
called the complement cascade. The end result of the cascade is the release of chemotactic
factors that attract neutrophils and other lymphocytes to the area to attack the
antigen . Neutrophils mount
a defense by attempting to ingest the immune complex using lysosomal enzymes. In addition, cytokines
are attracted to the area stimulating the synthesis of proinflammatory compounds
which in turn prompt chondrocytes to attack the cartilage. The synovium digests
the cartilage, stimulating a release of inflammatory molecules.
The body’s immune system is designed to recognize any sign of cellular injury and
act promptly to mitigate the damage. In the case of RA, the immune response perpetuates
the damage with the activation of B and T lymphocytes.
The B lymphocytes develop additional RF which again deposit into
the synovial membrane. The T lymphocytes stimulate the production of enzymes that
amplify and reinitiate the inflammation process . A vicious cycle of deposition of antigen-antibody complexes and
resultant inflammation is created.
The chronic inflammation impacts the joint by causing the synovial membrane to thicken
and the cells to mutate and proliferate. The mutated cells occlude the blood supply
leading to hypoxia and metabolic acidosis. Further erosion of the joint and surrounding
tissues occurs eventually leading to the development of granulation tissue called
pannus. Pannus leads to scar tissue
formation and eventually immobilizes the joint