Rheumatoid Arthritis
Causes and effectsWhat causes Rheumatoid Arthritis? Rheumatoid arthritis is not inherited in the usual sense. That is,
it is not passed directly from parents to children. A susceptibility or
tendency to develop RA can be inherited, but other factors (currently
under intense study) also are important. The gene that influences the
likelihood or a tendency to have RA is one of the genes that controls
the function of the immune system called the HLA-DR4 gene. However, not
everyone who inherits this gene will develop the disease.
Many physicians and scientists believe that RA might be triggered by
an infection, but there is presently no proof that this is fact.
Rheumatoid arthritis is not contagious. It is possible that a germ to
which everyone is exposed causes the body's immune system to react
abnormally in individuals who are susceptible to rheumatoid arthritis.
In RA, the white blood cells of the immune system move from the
bloodstream into the joint tissues. Joint fluid may increase, and the
white cells are found in the fluid as well. The white cells in the
joint tissue and fluid produce many substances, including antibodies
and other molecules, that lead to the joint damage and the sick feeling
that occurs in people with rheumatoid arthritis.
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