COPD Is An Immune Response, Future Medicines May Block It
COPD is a disease that affects the respiratory system. This we talk about a lot. Less talked about is that it also affects the immune system. In fact, COPD is caused by an immune response. So, let’s discuss the impact of your immune system on COPD and potential medicines that might help block this response.
What causes COPD?
About 95% of COPD cases are preventable (About 5% have genetic COPD). They are caused by chronic (day after day) exposure to harmful airborne substances. These substances include chemicals in tobacco and wood smoke. They may also include chemicals from fumes or gases in the air at your work.
How does the immune system work?
Your immune system responds to these harmful substances with the goal of getting them out of your lungs. Immune cells release inflammatory chemicals. These chemicals are also sometimes called mediators of inflammation. This means that they mediate inflammation, either by stopping or causing it.
This inflammation is meant to trap harmful substances which are then balled up in mucus. It’s then moved to your upper airway. You can swallow it and let your stomach juices destroy it. You can also spit it out.
Progression of COPD
Under normal circumstances, this response is beneficial. It’s how our bodies keep harmful substances out of our lungs. It’s meant to keep us healthy. But with COPD, exposure to harmful substances continues occurring. This means these chemicals continue to be secreted.
Again, these chemicals are meant to keep us healthy. But when they are continuously being secreted into your airways, they can increase in number. When this happens they can be damaging to cells. This damage is what ultimately leads to the gradual development and progression of COPD.
What are these chemicals?
Researchers are learning more and more about these chemicals. This is important because this kind of information may lead to future treatment options for COPD. A future medicine might block the effects of these chemicals to prevent COPD, improve lung function, or slow the progression. Such a medicine might help people gain better COPD control.
Chemicals secreted by your immune system are proteins and are often called mediators of inflammation. The scientific name for them is a chemokine. They are also called biological markers because they are involved in biological processes. This means their numbers can be determined by sputum sample or blood draw.
Key biological markers
Below are some of the key biological markers researchers are currently studying. These are chemicals found to be elevated in people living with COPD.
Interleukin 8 (IL8). I talked about this in my post “Danirixin May Offer New Hope For COPD.” Lining airways are receptors called CXCR2 receptors. IL8 is an interleukin that binds to these receptors. Once this happens, white blood cells called neutrophils are recruited to airways. They cause an aggressive type of inflammation called neutrophilic inflammation.1-4
At the present time, there is no treatment for this type of inflammation. However, researchers are looking into a medicine called Danirixin. This is what was discussed in the article noted above. This medicine would bind with the CXCR2 receptor to prevent IL8 from binding with it. So, this medicine may help reduce neutrophilic inflammation.1-4
Interleukin 6 (IL6). It’s secreted by airway epithelial cells when they are stressed or injured. This can happen when they are exposed to harmful substances in the air inhaled. They are also secreted by specialized immune cells, such as macrophages. Researchers have found IL6 levels elevated in people living with COPD. They have discovered their levels may be increased during COPD flare-ups.1,5
Tocilizumab is a biologic currently being studied. This biologic that binds with IL6 receptor sites along airways. This biologic has already been studied and approved for rheumatoid arthritis. It is now being studied on COPD patients. The hope is it will help reduce inflammation in COPD lungs.5-6
Tumor necrosis factor-α (TNF-α). It’s another pro-inflammatory chemokine that is often elevated in people living with COPD. Levels of TNF-α are elevated in people with COPD. They may also be elevated even more during COPD flare-ups.1,7
TNF-α is secreted by specialized white blood cells called macrophages. TNF-α may cause inflammation directly although it’s also known as a recruiter. It travels through your bloodstream to recruit white blood cells such as eosinophils, neutrophils, and more macrophages. These, in turn, cause eosinophilic and neutrophilic inflammation. Eosinophilic inflammation responds well to corticosteroids. Neutrophilic inflammation responds poorly to corticosteroids.7
TNF-α may also tell airway cells to secrete more chemicals that recruit these and other white blood cells. The ultimate objective is honorable, as it’s to keep us healthy. But, in the case of COPD, this response is overblown. The reason it’s overblown is that you’re constantly being exposed to harmful inhaled substances.7
Etanercept is a medicine that would block the effects of TNF-α. It prevents them from binding to TNF-α receptors lining airways. So, studies are ongoing to see how this medicine might help reduce airway inflammation in COPD. It’s also being studied for other diseases caused by inflammation, such as rheumatoid arthritis.7
Our quest to help people
I described here some of what researchers are learning about our disease. It’s a lung disease, but it’s caused by an overactive immune response. IL6, I8, and TNF-α are some of the chemicals implicated in COPD. Medicines are being studied to bock their effects, improve lung function, and slow the progression of COPD. This is all in our quest to help people live better and longer despite COPD.
Do you live with any sleep disorders (eg. insomnia, RLS, sleep apnea) in addition to COPD?