Written by Tiffany Westrich – Robertson
When I was first diagnosed with Rheumatoid Arthritis (RA), I was perplexed. I was relatively young, athletic, ate healthy, exercised – I did not understand how this happened to me. After some research, I learned that these diseases are partly caused by genetics, and that any family history of autoimmune disease of the 80+ possibilities constituted ‘genetic predisposition’. There are people in my family with autoimmune issues (not RA), so that makes sense. But autoimmune diseases are also the result of a faulty acquired immune system, which means they are triggered by a learned, or adapted, response that is generated by something in the environment*. Examples of some environmental triggers include smoking, infections, gut bacteria, dental decay, and even extreme emotional or physical stress. But as of now, researchers cannot prove any one environmental trigger as the cause, and they admit some triggers are still unknown.
So how can patients understand how this happened to them, and more so, how do they explain it to others?
Shortly after diagnosis, I heard Dr. John O’Shea, Scientific Director at the National Institute for Arthritis and Musculoskeletal and Skin diseases (NIAMS), give a presentation about autoimmunity. Much to my surprise, it was not a speech riddled with scientific jargon, but rather an analogy that brilliantly answered the question how does autoimmunity happen.
“What if I invited every person in this room to come to a party at my house next month?” Dr. O’Shea asked. “How would you get there? Would you take a plane, a train, a bus, a cab? Which route would you take? The highway or the side streets? Direct route or scenic?” He gave everyone some time to ponder that answer, then continued by guessing that most of us did not live together, hence our starting points would vary and so would our paths to arrival. “This is much the same way autoimmunity works,” he added. The explanation that followed helped me learn an easy way to understand and describe it to others.
Here’s what I took away from the analogy:
Let’s say that everyone reading this post is genetically predisposed to possible autoimmune disease and you are all invited to my house for a party. Your house is the starting point, which symbolizes your unique genetics – no one else is starting from your house except for you. The different methods of travel and routes you take to get to the party represent the potential environmental influences – smoking, infections, gut bacteria, dental decay, and even extreme emotional or physical stress, etc. Even though you all will leave from different places, at certain times some of you will cross paths – or in the case of the analogy, will be exposed to similar environmental triggers. Upon arrival, some of you will develop an autoimmune disease and some of you will not, even though you all were genetically predisposed and some of you, at times, even took similar “environmental routes”. Additionally, in those who do develop disease, even if it’s the exact same diagnosis, you will still have your own individual genetic + environmental journey and, therefore, will have a slightly unique presentation and treatment response.
His presentation did eventually branch into the relevancy of genetic + environmental onset in research and the challenges associated with finding pathways in populations where outcomes are somewhat individualized. But advancements in genetic mapping, such as the work being conducted in Dr. O’Shea’s lab, are sure to keep us on the road to the treatments that narrow down solutions.
I have a better idea now how I got to the party. I thank Dr. O’Shea for this great explanation, and additionally for the work he and other researchers are doing to identify the paths most traveled. Hopefully, in time, the routes to the party will be filled with known roads to avoid, and more and more people will arrive without ever developing an autoimmune disease.
*Note: Those affected by autoinflammatory diseases, such as Behcet’s Disease and Still’s Disease, can still use this explanation, but with minor adjustments. Autoinflammatory diseases are a result of a faulty innate immune system, which means that genetic mutations are the primary cause of the immune response, with little environmental influence. Learn more about the differences between autoimmune and autoinflammatory.
Environmental Triggers and Autoimmunity, Aristo Vojdani et al. PMCID: PMC4290643, National Library of Medicine at National Institutes of Health. 2014 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4290643/
Smoking and rheumatoid arthritis: What’s the risk? Chang-Miller, Mayo Clinic. 2014 http://www.mayoclinic.org/diseases-conditions/nicotine-dependence/expert-answers/rheumatoid-arthritis-smoking/faq-20119778
Rheumatoid Arthritis and Gum Disease, Dunkan A. Arthritis Foundation, 2016 http://www.arthritis.org/living-with-arthritis/comorbidities/gum-disease/ra-and-gum-disease.php