Within the first year of getting sick, before I even had a diagnosis, I knew that some sort of immune system problem was at the heart of whatever this mystery illness was. I saw the same pattern, over and over again, with recurring symptoms like sore throat, flu-like aches, and congestion, but it was obvious these weren't colds - the symptom pattern was exactly the same every time, signaling the start of another relapse (you learn to instinctively call them crashes pretty early - it's the perfect description). One Infectious Disease doctor told me I was just catching a lot of viruses, but I had never in my life had two viruses that were exactly the same, and now I'd had a half dozen in a year. I could predict what symptoms would occur day by day. The only thing that made sense was that my immune system wasn't working correctly.
When I finally got my diagnosis of ME/CFS, a full year after getting sick, I was hungry for information and devoured everything I could find about ME/CFS--in books, on websites, and through the other people I was gradually finding online. I discovered that my instincts had been correct and that a dysfunctional immune system is at the heart of ME/CFS. Although the exact cause of ME/CFS is still not known, its immune system abnormalities have been documented in dozens of research studies. Most experts agree that in most cases, there is some sort of infectious agent that triggers immune system dysfunction and that the dysfunctional immune system is the engine that sustains the illness and causes a cascade of domino effects in the endocrine and nervous systems that lead to our substantial and disabling symptoms.
Why Immune Dysfunction in ME/CFS is Unique
Most illnesses of the immune system fall into one of two categories. There are deficient immune system, like AIDS, where the immune system is suppressed and doesn't respond properly to infectious agents. On the other side, there are auto-immune diseases, like MS, lupus, rheumatoid arthritis, and others, where the immune system is over-active and not only over-reacts to infections but also attacks the body itself. Unfortunately, ME/CFS does not fit neatly into either of these categories. This means that established treatments for the two main types of immune problems, such as treating auto-immune disease with steroids, don't usually work for people with ME/CFS.
One of the most fascinating things that I learned in that second year of illness was that ME/CFS has characteristics of both types of immune system disorder: parts of our immune system are over-active and parts of it are under-active. This is sometimes referred to as a Th1-Th2 imbalance or a Th2 dominance. Now, AP Biology was many years ago for me, so I'm no expert, but here is my understanding from what I have read. The Th1 and Th2 referenced above refer to two different types of T-helper cells, part of the immune system. Th2 cells generally respond to viruses and allergens, among other things, while Th1 cells respond to bacterial infections (among other things).
Note that there is not complete agreement among scientists and experts on the role of Th1 and Th2; some sources say that Th1 are responsive to viruses and Th2 to bacteria. I have stuck with this explanation here because our own personal experience fits this theory perfectly; however, it might be different for you.ME/CFS is thought to be characterized by an imbalance, where our Th2 cells dominate. This means, in simple terms, that when someone with ME/CFS is exposed to viruses or allergens, our immune systems over-react, creating the kind of cold or flu-like immune response I described above, all signs that the immune system is responding (even in a healthy person, most viral symptoms are caused by the immune system response, not by the virus itself). This is why just being exposed to someone else's cold can cause a severe crash, even though we don't actually "catch" the cold and why many of us have problems with allergies and food intolerances that we didn't have before ME/CFS.
On the other hand, with fewer Th1 cells around, our immune systems under-react when exposed to bacterial infections. This is why people with ME/CFS are extra-susceptible to sinus infections, bronchitis, and other secondary bacterial infections. For instance, my son and I rarely catch colds, but if one of us got even a bit congested, we would quickly develop bacterial bronchitis, requiring treatment with antibiotics. (I am using past tense because treatments to normalize our immune systems have greatly improved this problem; we used to each get bronchitis 4-5 times a year, and now we each get it only every 18 months-2 years!)
This also explains why those of us with ME/CFS often have bad reactions to vaccines, causing lengthy relapses or even acting as the trigger that starts ME/CFS. It's not the fault of the vaccine: it is doing what it is designed to do, stimulating the immune system to create antibodies. But, with our overactive Th2 cells, we respond with a prolonged immune response (i.e. crash) that would not happen in a healthy person. I have long believed that allergy shots were the trigger for my own ME/CFS for this reason. I have also observed over the years, for both of my sons and me, that our worst, longest-lasting crashes are usually those triggered by exposure to a virus, like when kids at school have colds or my husband gets the flu.
This is a VERY simplified explanation of a very complex process that is happening in our immune systems. There have been lots and lots of research studies detailing dozens of different types of dysfunction in the immune systems of those with ME/CFS, and each of these problems causes other problems, in a cascade of cause-and-effect. People with ME/CFS generally have low Natural Killer Cell function and all sorts of problems with our cytokines (where levels of certain cytokines are high and others low). As an example, this study from Stanford looked at the cytokine "signature" in ME/CFS patients, as a way to predict disease severity, and this comprehensive study from Columbia Medical School (which involved a who's who of the nation's top ME/CFS experts) took a look at all sorts of immune system markers in ME/CFS and were able to differentiate between the early stages of illness and later stages.
To Share with Your Doctor
One of the best resources I have seen in all these years is an older but still excellent article written by Dr. Nancy Klimas, published in 2007 in Current Rheumatology Reports, that details all of the known (at the time) abnormalities in ME/CFS patients' immune systems and how these lead to dysfunction in the endocrine and nervous systems. The paper is brief but contains dozens and dozens of references to scientific research studies that document these abnormalities, making it perfect to share with your doctor. I especially like to give this article to doctors who don't understand ME/CFS or don't believe it is real because it provides lots and lots of hard scientific facts on the physiological basis of ME/CFS. Even though it is older and the science has advanced much further since it was written, it is still a good summary, all in one place. I think this one article alone can change the minds of skeptical medical professionals! You can look at an abstract of the article online or read or download a pdf file of the entire article (it's 6 pages long).
So that is a very general overview of immune system abnormalities in ME/CFS (please remember that I am not an expert in this field--if you see I have made a mistake in this post or know of other information that might be helpful to others, please share it in the Comments section or send me an e-mail).
So What Can You Do About It?