I want you to think about getting that cold in the fall when the seasons change, or again in the spring when the weather is a bit unpredictable. Have you ever thought to yourself, “Wow! I am so glad I have this cold right now. My immune system is a rock star!” Probably not, right? We’re probably thinking, “Wow! I take being healthy for granted. I love being able to breathe in and out of my nose properly”. We feel like our immune system has let us down and now we suffer the consequences. This is so not true!
The symptoms that you get in a cold or flu is actually your immune system working! It is your immune system fighting the virus or bacteria. If you have no symptoms that means you have the bacteria and viruses on you but your body is not doing anything about it! No Bueno.
A healthy immune system is designed to protect us. In order to have a healthy immune system and response, we want to get sick at least once per year. Our immune system is there to protect us from both big and small external ‘attacks’ and we can only learn through experience (Yes, your immune system has a memory). Before you think I’ve lost it, read on as I breakdown our immune system and explain the difference between a healthy and unhealthy immune response.
White Blood Cells 101
Red blood cells are commonly talked about with low iron levels, energy and anemia, but have you heard about the white ones? They’re some of the first-line responders when we have an invasion by an infection, injury or cut. We can also measure these white blood cell counts through our blood work to differentiate what’s going on in our bodies. Cool, right?! Below I’ve listed the major types of white blood cells, what they do, and their effect on our body.
- Leukocytes are also known as white blood cells. When we look at our blood work and look at our leukocyte levels an increase in this number beyond normal range would indicate leukocytosis, meaning all different types of white blood cells are raised. This would lead us to look at the individual levels of other more specific white blood cells.
- Think of these guys as firefighters responding to a house fire. They are the first to the scene, particularly to bacterial and fungal infections. They consume and kill the invading organism much like a firefighter’s water hose consumes flames. Neutrophils are also largely found in the pus formed around an infection, giving it the white colour. Since they’re only one part of the puzzle they are not able to take care of all infections; that’s where other white blood cells come into play.
- Neutrophils can also be involved with autoimmunity. If you have a known autoimmune condition and your neutrophils count is low in your blood work it may indicate a flare. If you are having a lot of symptoms of pain, fatigue, digestive issues, brain fog, weight changes and skin changes, along with a low neutrophil, count you may want to be tested for autoimmune antibodies.
- Allergies, asthma and parasites are all things to think of when you see an increase in eosinophils. Although a very small component of overall white blood cell-count, eosinophils are a critical number to track in the conditions mentioned. When eosinophils are activated they secrete chemicals to kill large parasites that are too large for other white blood cells to consume and kill.
Fun fact, eosinophils also change with your menstrual cycle, because yes ladies, that is an inflammatory process!
- Basophils are involved in the allergic response as well as injury healing. Basophils release compounds called histamine and heparin. Histamine is involved in hives, swelling and the classic allergic response. It does this by allowing more blood to flow to the area and it actually changes your blood vessel to encourage more neutrophils to leave your blood and enter the affected tissue around the area. Heparin works to prevent blood clotting so that more blood and therefore more immune support can enter the area required.
- Lymphocytes are involved in viral infections and also in autoimmune conditions. There are 3 main cell types here, the B cells, the T cells and the Natural Killer cells (NK cells). These system is where things get more complex so I am going to take the creative license to simplify here!
- B cells are involved in the antibody response, is you have ever had antibodies measured, now you know where they start. They block the invasion of pathogens and also activate other immune systems.
- T cells are broken down into 4 different types, regulating the immune response to a significant degree. Here we have immune cells that are strongly involved with a push towards autoimmunity and then there are also some that push towards allergies. They do this by releasing cytokines. Cytokines are the hormones of the immune system, giving the body instructions on what to do. T cells are also involved in immune system memory.
- Natural killer cells are a rapid responder to virally infected cells, they also respond to tumor formation. They are also involved in immune system memory formation.
- Monocytes are very similar to neutrophils except they are much bigger, they live longer and then have one additional function. They not only kill the invader but they take that invader to the T cells presenting it so that the body knows how to kill it faster if it ever sees it again. When monocytes leave the blood stream and enter the tissue they are known as macrophages and become the garbage man, cleaning everything up.
Different Immune Systems
When you think of the complement system I want you to think of four steps: identify, ingest, inflammation, and attack. If you have a skin infection, your complement system is going to identify that there is an infection, ingest the pathogen causing the infection to kill it, start an inflammatory response, and attack the pathogen itself to stop further growth.
Cytokines are a group of small proteins that send signals to different parts of the body. They are kind of like the hormones of the immune system. Some types of cytokines cause fever, other cytokines cause new cells to be formed, and others up-regulate certain anti-inflammatory processes, just to name a few.
When the complement system and cytokines work together you normally get a fever, which is a sign of infection, and you also get swelling at the site. Certain cytokines, specifically IL-1, IL-6 and TNF, send signals to your brain to increase your core temperature to fight off infection. You want these things like a fever to happen in order to efficiently handle what’s going on.
Allergies seem to be the bane of our existence in the springtime, am I right? Itchy eyes, runny nose, maybe our throat feels like it’s tightening. Or what about when you break out in hives after eating something new? If you’ve taken an over-the-counter medication for allergies, you know that they’re normally anti-histamines and histamine is what we’re going to talk about here.
Another type of white blood cell not outlined above is mast cells. When there is an allergen, let’s say pollen, floating around you consume it, and put simply it activates these mast cells. These mast cells can release a number of different granules with different effects, but here we’re going to talk about histamine specifically. Histamine is responsible for the itch, constriction of your throat, and what feels like a rush of blood to the site affected due to the dilation of our blood vessels in the area. That’s where those anti-histamines come into play to offset these reactions.
The easiest way to think about these different types of cells is to think about falling and scraping your knee. Do you ever remember taking a massive spill on the sidewalk when you were out playing with your friends in the ‘good old days’? (Massive spill was my middle name, right Mom?)
You look down and see a nice big scratch that’s starting to bleed. Boom, that’s where neutrophils, leukocytes, and macrophages come in to play. Like I said before, neutrophils are our firefighter response to the house fire. They’re going to try and tackle some of the injury on their own. Then we have leukocytes, which are that broad category of white blood cells looking to manage the situation. Macrophages on the other hand are the real troops. They’re going to the site of injury and taking a piece of the potential infection back to other cells of your immune system so that all of the other key players know what to look for and fight. All of these cells working together are going to cause the classic pain, swelling, and redness, but they’re going to make sure your immune system is helping us heal and repair.
A time where we may not think of our immune system having an effect is during a woman’s menstrual cycle. During menstruation, prostaglandins are released and they act like hormones. When your body realizes you aren’t pregnant by a drop in progesterone levels, the lining of your uterus is shed and ta da, your period arrives! Prostaglandins are also released during this time and contribute to the symptoms of pain and the contraction of the uterus, AKA cramps! Prostaglandins are also responsible for changing the body temperature and when they run a-muck, in the case of chronic inflammation, you can experience a fever, nausea and even vomiting with your period.
Take Home Message
Wrapping up this article in a bow, they key thing to remember is that the immune response, and symptoms of the immune response are trying to work with you! You just need to understand the messages they are trying to send.
A complete blood count, or CBC, is one of the most inexpensive tests available! Add in some inflammatory markers that we will talk about next week and you have a great baseline for understanding your immune function.
If you have had blood work done recently go grab it, were any of your white blood cell markers off? What can it tell you about your health?
That’s all for now! Next week we will dive into what many of you experience, which is chronic inflammation.