In medicine, condition where the body's 
immune responses are mobilized not against 
`foreign' matter, such as invading germs, but
against the body itself.  Diseases considered
to be of autoimmune origin include myasthenia
gravis, pernicious anaemia, rheumatoid 
arthritis, and lupus erythematosus.
In autoimmune diseases T-lymphocytes
reproduce to excess to home in on a target
(properly a foriegn disease-causing
molecule); however, molecules of the body's
own tissue that resemble the target may also
be attacked, for example insulin-producing
cells, resulting in insulin-dependent
diabetes; if certain joint membrane cells are
attached, then rheumatoid arthritis may
result; and if myelin, the basic protein of
the nervous system, then multiple sclerosis. 
In 1990 in Israel a T-cell vaccine was
produced that arrests the excessive
reproduction of T-lymphocytes attacking
healthy target tissues.

Subject by: Russell Webb