Why Isn't Fibromyalgia Considered an Autoimmune Disease?

"Autoimmunity" is Often Misunderstood

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Question:

"Since I've had fibromyalgia, I've noticed that I'm staying sick a lot longer. I've read that the immune system is involved and I definitely believe that, based on my own experience. But I've also read that this condition isn't autoimmune. If the immune system really is involved, why isn't fibromyalgia considered an autoimmune disease?"

Answer:

It's true that at this time, fibromyalgia is not classified as an autoimmune condition.

We do have some evidence suggesting that some cases may involve autoimmunity, but that work is preliminary and likely would apply only to a subgroup.

Many fibromyalgia experts believe that this conditionĀ involves dysregulation of the immune system. The nature of this dysregulation is not yet well-understood, but it's not believed to be autoimmune in nature.

What is Autoimmunity?

Part of the answer to this question involves a common misunderstanding when it comes to autoimmunity. A lot of people seem to be confused about what "autoimmune" means and think it applies to anything with immune system involvement. In truth, immune system dysfunction can take many forms, and autoimmunity is just one of them.

In an autoimmune condition, the immune system mistakenly identifies a normal, healthy part of your body as a dangerous invader (such as a virus or bacterium). It then develops specialized antibodies against that type of tissue and actively tries to destroy it.

Autoimmune diseases are characterized by the presence of these autoantibodies and by abnormally self-reactive T lymphocytes, a type of immune cell that normally helps fight infection. Because inflammation is a natural part of the immune response, many autoimmune diseases cause inflammation, which leads to markers in the blood that can be identified by tests.

Fibromyalgia & Autoimmunity

Thus far, fibromyalgia research has not uncovered solid evidence of autoimmunity in the majority of cases. Inflammatory markers are not consistently elevated; no autoantibodies have been discovered, and the damage typical of autoimmune activity has not been observed.

However, a significant overlap between fibromyalgia and certain autoimmune conditions indicates that autoimmunity may be a risk factor for developing fibromyalgia. These frequently overlapping conditions include:

Why the Confusion?

Part of the confusion about fibromyalgia and autoimmunity comes from a misunderstanding of what "autoimmunity" means. However, it also could be due to several similarities between fibromyalgia and conditions such as those listed above.

  • Similar Symptoms: These conditions all involve pain, fatigue, and many other common symptoms.
  • Difficult Diagnoses: Like fibromyalgia, autoimmune conditions can be tricky to diagnose and the process can take a long time.
  • Poor Understanding: Because the public, and even many members of the medical community, don't understand fibromyalgia, it's often inaccurately lumped in with autoimmune diseases that, on the surface, appear to be similar.
  • Classification as Rheumatic: We've learned over the years that fibromyalgia is actually a neurological condition, but it was originally thought to be rheumatic and it most often treated by rheumatologists. Most rheumatic diseases are autoimmune.

As we uncover more about fibromyalgia and exactly what's going on in our bodies, we may find that it actually is autoimmune. We may eventually recognize that certain subgroups are. Or we may learn that autoimmunity isn't a factor at all.

Sources:

American College of Rheumatology. Fibromyalgia. Accessed May 2012.

U.S. Department of Health and Human Services Office on Women's Health. Autoimmune diseases fact sheet. Accessed May 2012.

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