Check into these examples and sites:

What is Autoimmunity?: Johns Hopkins Autoimmune Disease Research ...By this approach, Rose and Bona (Immunology Today, 14: 426-430, 1993) have distinguished the evidence for an autoimmune etiology at three different levels: ...
http://autoimmune.pathology.jhmi.edu/whatisautoimmunity.html

Cloning of the cat TSH receptor and evidence against an autoimmune ...Cloning of the cat TSH receptor and evidence against an autoimmune etiology of feline hyperthyroidism. Lynda Q NGUYEN, Onur Karamanoglu ARSEVEN, ...
http://cat.inist.fr/?aModele=afficheN&cpsidt=13445507


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Note added at 10 mins (2006-12-08 16:09:45 GMT)
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Both forma exist: aetiology and etiology. Also, you may find self-immune and autoimmune, although the latter is more frequent.

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Note added at 12 mins (2006-12-08 16:11:04 GMT)
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Typo: forms, not forma. Additional examples:

[PDF] Cyclic Thrombocytopenia of Apparent Autoimmune Etiology
File Format: PDF/Adobe Acrobat
Cyclic. Thrombocytopenia. of Apparent. Autoimmune. Etiology. Blood,. Vol 73,. No6. (May. 1), 1989:. pp 1561-1569. 1561. By Jay. E. Menitove, ...
www.bloodjournal.org/cgi/reprint/73/6/1561.pdf

Autoimmune etiology of complex regional pain syndrome (M. Sudeck)
2, 3 To evaluate a possible autoimmune etiology of CRPS, we tested sera from CRPS patients for autoantibodies against structures of the autonomic nervous ...
www.neurology.org/cgi/content/full/63/9/1734