Autoimmune disorders: MedlinePlus - An autoimmune disorder is a condition that occurs when the immune system mistakenly attacks and destroys healthy body tissue.
http://www.nlm.nih.gov/medlineplus/ency/article/000816.htm more info...
Immune Disorder - An immune disorder is a dysfunction of the immune system.
http://en.wikipedia.org/wiki/Immune_disorder more info...