Autoimmune diseases tend to be viewed as separate conditions, rather than as the result of an underlying condition(s) that promotes immune dysfunction. Some of the possible contributing factors include:

Environmental exposures. Continued exposure to heavy metals and environmental pollution can result in overloading the immune system. Our air, water, and food in particular are full of toxic substances.
Oxidative stress plays a role in autoimmune diseases.
Chronic systemic inflammation is related to several autoimmune disorders, such as lupus, rheumatoid arthritis, Sjogren's syndrome, and fibromyalgia. Inflammation can be traced to destructive cell-signaling chemicals known as cytokines that contribute to many degenerative diseases. Certain nutritional supplements and low-cost prescription medications will often lower cytokine levels and control the inflammatory state.

There appear to be some issues which seem to come up more frequently in those with autoimmune disorders. Investigation of these areas and appropriate follow up may reduce the tendency toward these types of conditions and produce a general benefit. This is especially important when multiple autoimmune conditions exist in the same person.