Inflammatory bowel disease (IBD) includes two conditions that cause chronic, or long-lasting, inflammation in your gastrointestinal (GI) tract. These two conditions are called Crohn’s disease and ulcerative colitis.
According to the Centers for Disease Control and Prevention (CDC),
Researchers don’t know what exactly causes IBD to develop. What they do know is that a dysfunctional immune response leads to the increased levels of inflammation in the GI tract.
But is IBD an autoimmune disease? While it has similarities with autoimmune diseases, IBD is a little different. Keep reading below as we take a deeper dive into IBD, the immune system, and what we know so far.
Your immune system protects you from disease-causing germs and other potentially harmful substances in the environment. It’s activated when it finds something in the body that it doesn’t recognize as “self.” This is called an antigen.
Once an antigen has been identified, the immune system then works to generate an immune response to it. The overall goal is to neutralize the potential threat before it can cause you harm.
However, sometimes the immune system malfunctions and mistakenly responds to healthy tissues. This is called autoimmune disease.
IBD falls under the umbrella of immune-mediated inflammatory diseases (IMIDs). Generally speaking, IMIDs are conditions in which chronic inflammation happens due to an atypical immune response.
In addition to IBD, autoimmune disease is another type of IMID. Asthma and other allergic conditions can also be classified as IMIDs.
Autoimmune diseases are characterized by an inappropriate immune response to healthy organs and tissues in the body. For example, many people with RA have autoantibodies that attack healthy joint tissue. IBD is a little different.
IBD is generally accepted to be caused by an atypical immune response to environmental triggers in a genetically susceptible person. This leads to chronic inflammation in the GI tract and the symptoms of IBD, which can include:
- abdominal pain
- frequent diarrhea, which may include mucus or blood
- unintentional weight loss
- low grade fever
What’s up with the immune system?
You may not think about it this way, but your GI tract contains a lot of potential antigens. These include the food you eat, some of the medications you take, and healthy bacteria called commensals.
Commensals are important for your GI health. For example, they aid with digestion and help to protect your GI tract from disease-causing germs. They also play a role in immune system development.
Usually, your immune system tolerates the factors we’ve mentioned above. That means it typically sees them as harmless and leaves them alone.
However, in IBD, a trigger causes the immune system to mount a response against factors that are typically harmless, such as commensals. This leads to increased, persistent inflammation in the affected part of the GI tract.
The lining of the GI tract also becomes compromised in IBD. This means that immune cells can flood into the area in an effort to eliminate what’s mistakenly seen as a threat. This causes further inflammation and damage.
An imbalance of bacteria, called dysbiosis, also happens in people with IBD. Whether dysbiosis is a cause or effect of IBD is unknown. Regardless, changes in the types of bacteria in the GI tract may also affect immune activity and inflammation.
As mentioned earlier, the exact cause of IBD is unclear. It appears to be a very complex combination of the immune response, genetics, and environmental factors.
We’ve already talked about the immune system, so let’s cover genetics and environmental factors now.
Your individual genetics can predispose you to developing IBD. One 2019 research review notes that first-degree relatives of people with IBD can have
This means that if a close family member like a parent or sibling has IBD, you may be at an increased risk of developing it yourself.
Researchers have looked at the types of genes associated with IBD. Many that have been identified have to do with processes that may be important for the development of chronic inflammation in the GI tract. These include genes related to:
- immune system regulation
- maintenance of the GI tract lining
- oxidative stress
- antimicrobial defenses
This suggests certain environmental risk factors may trigger or at least contribute to IBD in people that are genetically susceptible. Some examples of environmental factors that are associated with IBD risk are:
- GI infections, such as those due to Campylobacter or Salmonella
- certain types of medications, like antibiotics, nonsteroidal anti-inflammatory drugs (NSAIDs), and hormonal birth control
- diets rich in fats, sugars, or meat
- smoking, for Crohn’s disease
Types of IBD
There are two different types of IBD. These are Crohn’s disease and ulcerative colitis.
Crohn’s disease can affect any area of the GI tract, but is more common in the small intestine and the first part of the large intestine. As it progresses, it can cause scarring, narrowing, and fistula formation in the affected areas.
Ulcerative colitis causes ulcers to form on the inside of your large intestine, which commonly leads to bloody diarrhea. Some of the potential complications of ulcerative colitis include anemia, bowel perforation, and colorectal cancer.
Both IBD and autoimmune disease are IMIDs. As such, many of the ways that they cause disease may overlap. If this is the case, could having IBD put you at an increased risk of developing an autoimmune disease?
While additional studies are needed, some research indicates that having IBD increases the risk of autoimmune disease. Let’s take a look at some examples.
A 2016 study found that, compared with people without IBD, those with IBD had a higher incidence of autoimmune disease. Severe IBD was associated with an increased risk of developing autoimmune disease.
IBD doesn’t raise your risk of contracting the novel coronavirus or becoming seriously ill with COVID-19. However, if you have IBD, keeping it in remission is important during this time. This means carefully sticking to your treatment plan.
Regardless of when it occurs, an IBD relapse can further damage your GI tract. Additionally, if you need medical care for a relapse during the pandemic, it’s possible that medical resources may be limited. This will depend on the level of COVID-19 activity in your area.
Because some IBD medications can weaken your immune response, you may have concerns about taking your IBD medications during the pandemic.
According to the Crohn’s and Colitis Foundation, people with IBD should continue to take IBD medications as directed by their doctors. Discuss any concerns about IBD medications in relation to the pandemic with a doctor.
If you test positive for the coronavirus or become ill with COVID-19, it’s possible that you may need to temporarily stop taking certain medications until you recover. Never make any adjustments to your medications without consulting your doctor.
The goal of IBD treatment is to lower inflammation in your GI tract, which will keep you in remission and prevent the disease from progressing. Medications are often an important part of IBD treatment.
Several types of medications may be used to treat IBD, including:
- aminosalicylates like mesalamine and sulfasalazine
- corticosteroids like prednisone
- immunosuppressant drugs like azathioprine and 6-mercaptopurine
- biologics like adalimumab (Humira) and infliximab (Remicade)
Additionally, other interventions can help manage IBD, including:
- bowel rest for severe Crohn’s disease
- surgery to remove parts of your GI tract that have been severely affected by IBD
- dietary adjustments like:
- avoiding foods that trigger symptoms
- eating smaller meals more frequently
- using nutritional supplements if you’re not receiving enough nutrients
IBD is an immune-mediated disease that causes persistent inflammation in the GI tract. Without treatment, it can continue to damage the GI tract and may lead to potentially serious complications.
The exact cause of IBD is still unknown. Generally speaking, it appears to be caused by an atypical immune response to an environmental trigger in genetically predisposed people.
The current treatments for IBD focus on reducing GI tract inflammation, which can lead to a remission of symptoms. Following your treatment plan is vital for maintaining remission and preventing progression of IBD.