Irritable Bowel Disease: A condition in which there is a tendency to overactivity of the bowel emptying activity, accompanied by abdominal pain and diarrhea; the cause of the condition is unknown but psychological and allergic factors are generally believed to play a role.

Autoimmune diseases: A disease that results when the immune system attacks the body's own tissues, as in rheumatoid arthritis.

Epstein-Barr Virus: A common virus that remains dormant in most people. It has been associated with certain cancers, including Burkitt's lymphoma, immunoblastic lymphoma, and nasopharyngeal carcinoma.Epstein-Barr Virus.