immune system

I am notoriously bad at being sick. I am impatient, I don’t follow the advice that I give to customers, and I complain to my wife at the drop of a hat. Now, I have a good fortitude, unlike a 19th century protagonist who falls unwell after a walk in the rain. I thought I would take a little while to unpack the immune system to you today.

The immune system is comprised of white blood cells which make up your body’s first level of defence when you are confronted with infection. As you can imagine, if you have a good immune system, you will rarely be unwell. If you’ve got a bad immune system, you should probably buy shares in cold and flu tablets. There is a type of white blood cell called a phagocyte that works by destroying the invading organisms. Then your body remembers them and is more effective when they next show up, thanks to a white blood cell called a lymphocyte. There are two kinds. The B lymphocytes start out in your bone marrow, and they are the generals who oversee the battle who direct the troops, the T lymphocytes to the site of the infection.

These blood cells can help us to develop immunity. There are three kinds.

  1. Innate immunity: Everyone has some level of immunity that you are born with. 
  2. Adaptive immunity: This is the kind we develop as you age. You become exposed to enough germs that your white blood cells figure them out. This is also the same process that makes vaccines such a worthwhile invention.
  3. Passive immunity: This is when you borrow another source. Breastfeeding is a great example of this, where the milk provides immunity from diseases that the mother has developed.

When you pick up the common cold, all the symptoms are actually evidence that your immune system is firing. Snot, mucus and phlegm are actually just depleted white blood cells. Cold and flu tablets contain a number of different ingredients which can help you get around these symptoms. Here is what you need to be on the lookout for.

  • Pseudoephedrine: This is a decongestant that works to dry up a runny nose. There is a process called vasoconstriction that takes the blood vessels in your nose and tightens them up so that you stop leaking from your nose. Helpfully, it also gives you a slight energy boost. Although, the blood vessels can bounce back after a few hours and this can leave you with a more blocked nose.
  • Phenylephrine: This is another decongestant, although it is slightly less powerful. Also, these really only hit the symptoms, not the infection.
  • Paracetamol: This is a medicine that numbs the pain receptors in your brain. This is wonderful news when you are feeling achey and weak in the heat of the fever.
  • Ibuprofen: For me, this is the pick. This is an anti-inflammatory which reduces swelling and inflammation and pain (think of the headaches, blocked noses etc). 

It is very worthwhile to think about the ingredients of cold and flu tablets because depending on what is in them, they can do different things.

There are a number of things that can go wrong with your immune system however.

Type 1 diabetes - This is when your immune system attacks your pancreas. That means you will not be able to make insulin which removes sugar from the blood.

Rheumatoid arthritis - This is when your joints get swollen because your immune system sends blood cells there unnecessarily.

Lupus - This is when your immune system attacks the lungs, kidneys and your skin.

Asthma - This is the result of when your immune system mistakes an irritant to be a foreign invading body. You end up coughing, wheezing and trouble breathing. Not fun.

Eczema: This is when an allergic reaction causes a rash on your skin which is super itchy and altogether unpleasant. 

Allergic rhinitis: You could experience anything from a runny nose, to sneezing from your immune system attacking dust or flakes of your pet’s skin.

Severe combined immunodeficiency: This is often referred to as SCID, and it is what happens when you are born without certain white blood cells. You cannot muster any fight against disease or viruses and it requires you to stay isolated away from the world. Any fans of Seinfeld might remember the episode where George plays trivial pursuit with the bubble boy. Whilst they probably don’t put too much thought into the writing, bubble boy most likely suffered from SCID.

Acquired immunodeficiency disease: Better known as AIDS. This is like SCID except you were not born with the condition, you picked up a viral infection which systematically destroyed your white blood cells. A regular cold can become extremely serious, and something like pneumonia can become fatal.

Leukaemia: Any cancer that affects the blood and bone marrow is going to affect your white blood cell count. They will prevent you from generating neutrophils and this is bad news. Additionally, some cancer treatments can end up reducing your white blood cell count, compounding the dangers.

This got fairly heavy. Luckily, there are things you can do to support your immune system.

  1. That old familiar advice from me, stop smoking.
  2. Make sure your diet is rich in fruits and vegetables
  3. Make sure you are getting enough exercise in
  4. Drink alcohol in moderation
  5. Ensure that you are getting the required 7-8 hours sleep a night
  6. Don’t put it to the test. Ensure that your hygienic practices are keeping you healthy at the best of times. I had a friend who, whenever he would get dirty, would mutter that it was good for his immune system. It turns out, this was not supported by the science.

So there you have it: a quick crash course in the immune system. As you get older, you immune system plays a crucial role in your quality of life, so I would very much advocate that you would look after yourself in your youth.


Floyd - Senior Pharmacist 


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Image Author @kjpargeter


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