Remember, Celiac Disease is an autoimmune disease.

From a book by recognized Celiac expert Dr. Peter Green:

There is some tantalizing evidence that having Celiac Disease actually disposes people to having the second (or third) autoimmune disorder. The evidence come from a study demonstrating that the age of diagnosis of celiac disease correlated with the risk of getting the associated autoimmune disorder. That is, children diagnosed with celiac disease before age two developed autoimmune diseases at the same rate as the rest of the general population (about 3 to 5 percent). There was a linear increase in the prevalence of autoimmune disease with the increasing age of diagnosis of celiac disease up to age twenty, where 30 percent of the individuals in this study had an autoimmune disorder. This is a compelling case for the early diagnosis of celiac disease and an urgent reason to educate the professional community in the symptoms and risks of celiac disease. Other studies have not confirmed that duration of gluten exposure is a significant risk factor for developing autoimmune disorders.
Celiac Disease: A Hidden Epidemic, p. 154, Peter H.R. Green, M.D., Director of the Celiac Disease Center at Columbia University in NYC

From MedicineNet.com:
Definition of Autoimmune disease
Autoimmune disease: An illness that occurs when the body tissues are attacked by its own immune system. The immune system is a complex organization within the body that is designed normally to "seek and destroy" invaders of the body, including infectious agents. Patients with autoimmune diseases frequently have unusual antibodies circulating in their blood that target their own body tissues.
Examples of autoimmune diseases include systemic lupus erythematosus, Sjogren syndrome, Hashimoto thyroiditis, rheumatoid arthritis, juvenile (type 1) diabetes, polymyositis, scleroderma, Addison disease, vitiligo, pernicious anemia, glomerulonephritis, and pulmonary fibrosis.
Autoimmune diseases are more frequent in women than in men. It is felt that the estrogen of females may influence the immune system to predispose some women to autoimmune diseases. Furthermore, the presence of one autoimmune disease increases the chance for developing another simultaneous autoimmune disease.
Autoimmune disease definition - Medical Dictionary definitions of popular medical terms