Working With the Immune System

Your immune system is the first line of defense against illness.

When bacteria and viruses enter the body, the immune system prepares to protect you from sickness. However, the immune system can become over- or under-active, contributing to chronic pain, inflammation, and health conditions. In this blog, we’re going to look into how the immune system works, how it can contribute to our pain, and whether inflammation is a help or a hindrance.

The Parts of the Immune System

The immune system is made up of various cells and organs in your body, and these parts work together to protect the body from illness. Some of the parts of the immune system that work to keep the body healthy every day are:

  • White blood cells – Also known as leukocytes, white blood cells police our bodies looking for harmful germs or pathogens that could potentially make us ill. They are one of the biggest parts of the immune system, and they activate the immune response when encountering a foreign invader within the body. There are several types of white blood cells, including B-cells, which produce antibodies, and natural killer (NK) cells, which kill infected and cancer cells. Depending on the type of cell, it can help with the seek-and-destroy function, which rapidly recognises germs and binds to them, then engulfs and destroys them.
  • Tonsils – As they are located in the throat, when we breathe in anything harmful, the tonsils can trap it to prevent infection. They also have their own immune cells that produce antibodies to protect against throat and lung infections.
  • Lymph nodes – Lymph nodes are glands that filter and remove harmful bacteria and viruses. The lymphatic system is a network of tubes that help control the body’s fluid levels and support the immune system, and lymph nodes are found all over the body. When these nodes are swollen, it is usually a sign that your body is dealing with an infection.
  • Stomach – Stomach acid kills many germs that enter your body, and there are many types of good bacteria in the intestines that destroy harmful bacteria.
  • Skin – Your skin and the mucous membranes it produces as a protective barrier prevent many viruses and microbes from entering the body in the first place. However, when they do find a way in, the body produces mucous membranes lined with hair-like structures called cilia. Cilia trap germs and help remove them from the body to prevent illness.
  • Spleen – The spleen filters blood to eliminate any dangerous microorganisms and old, damaged red blood cells. It also produces antibodies and lymphocytes of its own.
  • Bone marrow – Bone marrow contains stem cells, which develop into red blood cells, white blood cells, and plasma. It makes billions of new cells every day and releases them into the blood to help keep the body healthy.

Immune Function, Inflammation, and Chronic Pain

Chronic pain is typically associated with the nervous system. Even if there is no physical injury, the nervous system can become heavily sensitized to pain through changes to the structure of the brain and spinal cord. The brain can perceive pain even when no cause exists, and it can persist for months.

There is a close relationship between the immune system and chronic pain too. When you cut or scratch your hand, the skin around the wound becomes red and raised. This is inflammation, an immune response in which the blood vessels in the area dilate to allow white blood cells to reach it. These cells then help to remove any bacteria from the wound, and eventually, the inflammation recedes.

However, when this inflammation response lingers, it leaves our bodies in a constant state of alert. Over time, it can negatively impact our tissues and organs and even play a role in cancer development.[1]

Acute inflammation, such as the redness and swelling around a cut, is noticeable. Chronic inflammation can be much more subtle, causing symptoms such as:

  • Fatigue
  • Gastrointestinal complications
  • Weight loss or gain
  • Persistent infections
  • Bodily aches

The relationship between chronic pain and the immune system is bidirectional: either one can influence the other. The immune system doesn’t play a role in how we sense painful stimuli, such as a scratch, but it does contribute to persistent pain. One study published in Nature Reviews Neuroscience found that after a peripheral nerve injury, immune cells began to release cytokines and chemokines that contributed to further pain.[2]

Chronic pain can also interfere with our immune systems. Research has found that chronic pain is associated with T cells, which play different roles in attacking cells infected with a pathogen or supporting B cells in producing antibodies. Those with chronic pain may have a different phenotypic style of T cells, which may contribute to the development of pain.[3]

Inflammation: Help or Hindrance?

The immune system and chronic pain have a close relationship, and addressing one can address the other. Some types of chronic pain can result from chronic inflammation; however, some new research suggests inflammation may curb pain instead of contributing to it.

The study, published in Science Translational Medicine, suggests that inflammation can help heal the body from pain and using painkillers to suppress it can be harmful. It focused on lower back pain and compared biological markers in blood cells between the two groups. At the end of the study, half of the participants had recovered from their pain. In the half who still struggled with it, researchers saw a lack of inflammation, compared to a lot of activity in the group who recovered.

Other evidence from the UK Biobank (a database of health information) supports this theory. An analysis of 2,624 people with acute back pain showed that those taking non-steroidal anti-inflammatory drugs (NSAIDs) were 1.7 times more likely to develop chronic back pain.[4] More research is needed on this, although it is a promising avenue to explore for chronic pain sufferers.


Sources:

[1] Furman, D., Campisi, J., Verdin, E. et al. Chronic inflammation in the etiology of disease across the life span. Nat Med 25, 1822–1832 (2019). https://doi.org/10.1038/s41591-019-0675-0

[2] Marchand, F., Perretti, M. & McMahon, S. Role of the Immune system in chronic pain. Nat Rev Neurosci 6, 521–532 (2005). https://doi.org/10.1038/nrn1700

[3] Laumet G, Ma J, Robison AJ, Kumari S, Heijnen CJ, Kavelaars A. T Cells as an Emerging Target for Chronic Pain Therapy. Front Mol Neurosci. 2019 Sep 11;12:216. doi: 10.3389/fnmol.2019.00216. PMID: 31572125; PMCID: PMC6749081.

[4] Inflammation may curb, not cause, chronic pain. (n.d.). Retrieved January 18, 2023, from https://www.nidcr.nih.gov/news-events/nidcr-news/2022/inflammation-may-curb-not-cause-chronic-pain

Sign up to our mailing list

To stay up to date on our latest posts, learning packs and educational resources.

Our Sponsors

Shopping Cart
Scroll to Top