Introduction to Autoimmune Diseases

00:01 We’re now going to look at autoimmune disease.

00:04 Autoimmune disease is a pathological reaction against a normal body component.

00:12 Around about 5% of people develop an autoimmune disease.

00:17 Overall, autoimmune diseases occur more commonly in females than males.

00:23 Perhaps most extreme example is systemic lupus erythematosus, where the ratio of females to males is around about ten to one.

00:32 Usually the dominance in females over males is somewhat less than that.

00:37 And sometimes autoimmune diseases are more common in males than females.

00:43 So for example, ankylosing spondylitis is twice as common in males than females.

00:50 Autoimmune diseases can be either organ specific or systemic depending on the location of the target autoantigen. By far the vast majority of autoimmune diseases are polygenic in nature. That means many different genes contribute towards their development. Concordance rates in identical twins is typically around about 30-50%. What this tells us is that genetics is very very important and plays a major role, but non-genetic factors must also be playing a role. The non-genetic factors are not that well understood, but may include infection, diet and stress. Autoimmune disease develops typically in the middle years of life, suggesting a breakdown in immunological tolerance rather than initial failure to actually establish immunological tolerance. You can develop autoimmune disease at any point in your life. Young infants can develop it, elderly can develop it. But the most typical time is in the middle years of life. Autoimmune disease is usually lifelong following onset. Although, often with periods of relative disease inactivity. The severity of an autoimmune disease can be influenced by pregnancy.