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The Immune System

Immune System Graphic
How much do you know about your immune system? Where is it and why do we need one?

My Amazing Body is a podcast where we explore interesting, unknown and misunderstood parts of your body with help from medical experts and stories from real Queenslanders.

This episode is all about your immune system. What is your immune system, where is it and why do you need one? Dr Jane Peake, Director of the Queensland Paediatric Immunology and Allergy Service explains how the immune system works, and the types of conditions that can affect the immune system. We also hit the streets to find out what Queenslanders really know about their immune system.

Meet our guest

Dr Jane Peake

Episode material

Audio is great, but some things are best seen as well as heard, or might tempt you to do further reading. These materials provide more information about topics we touch on in the show.

Paediatric Immunology Service

Dr Jane Peake is the director of the Queensland Paediatric Immunology and Allergy Service. You can find more information about the allergy clinic below.

Queensland Paediatric Immunology and Allergy Service


Dr Jeanette Young talks about the long-term impact of COVID-19 in the video below.

Vaccination matters

Immunisation stops the spread of disease. It limits the impact of the disease and it saves around 3 million lives worldwide each year. The results speak for themselves. So, with nothing but proven facts, answers and useful information, this is your straightforward guide to immunisation.

Vaccination matters

Introducing foods and allergy prevention

Dr Peake says there are things you can do to lower your risk, or your child's risk, of developing allergies. You can find out more information on the links below.

Australasian Society of Clinical Immunology and Allergy (ASCIA)

Queensland Health

Queensland Health Blog – Starting your baby on solids

Growing Good Habits

Children’s Health Queensland Hospital and Health Service

Raising Children


Vox pop: It’s a system that protects you from sickness and germs.

Vox pop: It’s yours bodies defence against infections.

Vox pop: It alerts you or triggers you to say whether something is wrong with your body.

Vox pop: I think your immune system is a part of your body that fights off diseases, so germs, bacteria. Keeps you healthy.

Vox pop: Your immune system is a system in your body that helps you fight infections and bad things.

Host: Welcome to this episode of My Amazing Body, a podcast where we explore interesting, unknown and misunderstood parts of your body. This episode is all about your immune system. What is your immune system? Where is your immune system? How does it work, and what happens when it goes haywire? Listen on to find out.

Your immune system is a complicated network of body parts and processes. In fact, it's so complicated, it turns out that a lot of us have no idea what it really does. We hit the streets to find out just what Queenslanders know, and what they think they know, about their immune systems.

Vox pop: Your immune system is a really complex system that protects the body from external things.

Vox pop: I think your immune system is in your blood?

Vox pop: I think the immune system is everywhere in your body. It’s in every cell of your body.

Vox pop: Everywhere? It’s in your gut, I think?

Host: Luckily for us, there are immune system experts to help us tell fact from fiction. We spoke with Dr Jane Peake, Director of the Queensland Paediatric Immunology and Allergy Service, to get the lowdown on how our immune systems work.

Dr Peake: Hi, my name is Dr. Jane Peake. I'm a paediatric immunologist and allergist, and I work at Queensland Children's Hospital.

Host: Dr Peake explains that your immune system isn't just one thing but is made up of many parts of your body.

Dr Peake: The immune system is a little bit different to some of the other body systems in that it's not like the cardiovascular or the respiratory system whereby you can clearly understand what parts of the body that entails, because the whole body is involved as being part of the immune system.

Host: When it comes to your immune system, your first lines of defence are the parts of your body that stop things from the outside getting in if they shouldn't be there.

Dr Peake: So that's things like your skin, but also the lining of your gastrointestinal tract, the lining of your respiratory tract and your genital urinary tract. And there's a whole lot of things within that, that allow you to detect things from the outside environment and also is protecting you. So, there's various things like mucus that you have on those, and the microbes that are on your skin and on your linings are very good at also helping to protect you.

Host: The bulk of your immune system operates out of your blood system. Your blood is made up of red blood cells, platelets and white blood cells, and Dr Peake says it's the white blood cells that are particularly important when it comes to your immune system.

Dr Peake: It's your white cells that are important, but there's a number of different types of white cells that help protect you. The first type of white cell that is important is your group of cells called your neutrophils and your macrophages. And I think of these cells a little bit like the garbage collectors, but as well as picking up the garbage, they have to go and also help understand what is garbage. So, it's important when they meet something, they have to decide whether it's friend or foe. They have to decide whether this is part of you and therefore they should leave it alone, or whether it's part of something foreign and originating from outside your body.

Host: These cells can help identify bacteria, viruses and other nasties and quickly decide whether they belong in your body or not.

Dr Peake: So, when these cells encounter something that is not meant to be there, then they try and break it down and consume it. But in order to help recognize what parts of these cells and other things are not right, it relies on the other part of the white cells in the immune system to also help identify what is the foreigner. And so that is largely the cells called your lymphocytes. Now your lymphocytes are again, a few different types of cells. We talk about your T cells and your B cells, and there's also a group of cells called natural killer cells. And they all do slightly different things.

Host: If you're starting to think this is sounding complicated, that's because it is! We asked Dr Peake to break it down, starting with the T cells.

Dr Peake: The T lymphocytes.And the T lymphocytes, they’re kind of brains behind the business. And they can recognize viruses and other things directly, but they also tell the B cells what to do. And they are kind of also very, very important in working with all the other cells to keep them going. And to be honest, they're probably one of the more important cells, because if you're having problems with your T cells, then your immune system is often not working very well at all, because it's like the sort of the conductor of the orchestra, so it's missing and so the orchestra isn't working properly to keep things going properly.

Host: While your T cells identify threats and keep things running, your B cells are doing important work learning about the threats and building up antibodies and immunoglobulins to help protect you from germs in the future.

Dr Peake: Now your B cells are the ones that make antibodies, and antibodies, most people have heard of antibodies. So, the B cells make antibodies. And the other name for antibodies is also immunoglobulins. When we're talking about the whole group of these little pieces of protein called immunoglobulins that you have in your bloodstream, we talk about them as immunoglobulins. But when we're talking about specific protection, for instance, against a particular germ or response to an immunisation, we talk about an antibody.

So, the antibodies identify that this is something that isn't supposed to be there. So, the first time that it meets something, it's not very good at doing it. And then with time, it recognizes that it's seen it before, and it's created memory cells, memory B cells that can make more antibodies the same when you meet it again. Which is why the first time when you get an infection, you're often sicker and then we get what we call immunity, where your immune system has remembered that yes, I've seen this before and so can react more quickly.

Host: These days, we use vaccines to help people's immune systems learn about a virus or bacteria before they encounter it, so that the immune system is ready to respond if they come into contact again.

Dr Peake: So what we're doing with vaccines is because we don't want people to get infections like measles and smallpox and chicken pox and tetanus and various things, if they were to meet them for the first time, these illnesses can often be very serious and cause serious infections the first time somebody meets it. So what we're doing with immunisations is that we're giving them in such a way that the person's immune system will see it similar to as if they've had the infection, but they are not infected at the time, so can build a proper immune response to it. And so that's exactly what a vaccine does, is it allows your immune system to effectively see an infection without the person themselves being infected to it.

Host: And what about the third type of lymphocytes, your natural killer cells? Well, for them, it's really all in the name.

Dr Peake: The natural killer cells play an important role in deleting things like cancer cells and attacking some of those cells.

Host: Your immune system changes throughout your life. An unborn baby's immune system actually begins to develop in the womb, with immunoglobulin passing across from the mother, through the placenta and into the baby to give it a head start at fighting diseases when it's out in the world. Despite this, Dr Peake says that it's important to remember that babies are still very vulnerable to infections and disease when they are born.

Dr Peake: Some parts of the immune system, right from the very get go work quite well, but others seem to be slower to develop. And so, we know that the newborn is very, very vulnerable to infections and to diseases and it's probably one of the most vulnerable periods of a person's life is during those first few days and weeks.

As the baby gets a little bit older, the immunity that they've gained from the mother starts to slowly wear off and their own immune system needs to start to come into play. The baby's immune system hasn't seen a lot of infections, which is why most babies and toddlers seem to get everything that's going around. We say the average baby or young infant will get between 6 and 12 upper respiratory tract infections, gastrointestinal infections a year. And that's because they've not met all these infections. So, it does seem sometimes with a baby or an infant that you seem to go from one infection to the next. No sooner they're over one, than they seem to be getting another one.

Host: In older childhood and young adulthood, your immune system should be functioning at its peak.

Dr Peake: Your immune system between kind of later childhood and young adulthood is probably its most robust. And as people often get older, that's when the immune system can start to go wrong and a little bit in a different way. So that's where we are more likely as a person ages, although you can see them even in young children to develop things like auto immune diseases, where their body is no longer protecting themselves quite as well as they should be.

As you get older, as you're becoming more elderly and then the more geriatric population, again, your immune system doesn't seem to be working quite as robustly as it did when were younger. And so elderly people again can become more vulnerable to infections and things, and it's a bit like your immune system is getting a bit tired and worn out.

Host: Enjoying this episode of My Amazing Body? Don't forget to leave us a rating and review in your podcast app to help others find us and learn about their bodies, too!

Are you ready for this episode's mystery body part? See if you can guess the body part from the clues given. We'll reveal the answer at the end of the episode.

I'm made up of three thin structures, your ethmoid bone, vomer bone and quadrangular cartilage.

I rarely sit straight up and down, but I should be more symmetrical than not.

If you do extreme rhinotillexis, you could put holes in me, so be careful!

Do you know what I am?

Autoimmune conditions happen when the immune system stops working properly and starts damaging the body's healthy cells. Many diseases that become more common as we age, like thyroid disease, arthritis, diabetes and even psoriasis are all autoimmune conditions.

Dr Peake: So, their own immune system can start damaging some of their own cells. And that's where we develop a whole range of diseases that people don't always think about as autoimmune diseases, but things like thyroid disease is often your own immune system destroying your thyroid gland. Arthritis is often your own immune system destroying your joints. Diabetes is your own immune system destroying your pancreas. So many, many of these diseases actually involve the immune system.

Host: Allergies are also a consequence of your immune system going a bit haywire and trying to protect you from threats that don't exist.

Dr Peake: We know that the development of allergy is a complex relationship between your genetic makeup and your environment. And certainly, allergy is definitely on the increase. The biggest problem that we were having again pre COVID was immune problems in that what's on the real rise is the autoimmune diseases where our body is attacking our own cells and also allergy.

Host: It's not completely clear why allergies are on the rise in our population, and why some people will be allergic to a particular thing while others won't. But Dr Peake says there are things you can do to lower your risk, or your child's risk, of developing allergies.

Dr Peake: There are things that we're clearly doing to our immune system, which our bodies are not really liking. And whilst we don't really understand exactly what they are, we do, I think believe that there are certainly things, I think things like pollution, artificial things that we're adding to products, lots and lots of things that are in our environment that are changing and responding to our immune system, meaning that we have become more reactive to these things. Because we see as countries become more industrialised and as we change how we're doing things and how we're cooking things. So we're moving more from cooking homegrown vegetables and meats and things that we've caught and grown and things ourselves, where allergy is vanishingly rare, when those same people go and live in parts of the world where they're now eating pre-prepared meals and living in housing where there's lots of products used for cleaning and all sorts of other things, they’re driving cars, etc, then we start to see increasing amounts of allergy.

So there is a complex relationship between the environment and our genetics. And certainly, our man-made environment is definitely playing a role in upsetting our immune system, meaning that it's responding and reacting inappropriately more frequently than it used to in the past.

Host: When it comes to babies, Dr Peake says there is now good evidence to show that when you start introducing family foods to a baby it can influence their allergy risk.

Dr Peake: There's been a number of good studies that have shown that introducing solids into young babies from about four months of age when the babies are ready to start eating solids, and to give them a wide, broad variety of solids, but including within that allergenic solids. So, things like peanuts and milk and eggs and fish and the other nuts, seafood, sesame, getting all those foods in the first, preferably from about four to nine months, but certainly before 12 months. And once they'd been tried, then to keep giving them. So, there's no specific food you need to give them, it's more getting onto the normal family diet and to be giving a range of solids. But again, more home cooked things, cooking your own foods for your baby rather than relying on tins and sachets and other things. Certainly, if you can manage it preferable.

Host: Looking for more information on introducing foods to your baby? Check out our show notes for links to trusted sources.

If you think you have an autoimmune condition or an allergy, particularly if you've been reading about it on the internet, Dr Peake says that it's important to talk to your GP about what you've noticed and work with them towards an official diagnosis.

Dr Peake: I think you have to be extremely careful about advice from the internet, because a lot of these people do not have any qualifications or really don't know what they're talking about. And certainly, we sometimes, very sadly see people who've gone down a pathway and got themselves into more and more trouble because they've misdiagnosed themselves. I think if you see something on the internet and you think, well, that sounds like me, absolutely what you need to do is to go along to a general practitioner and you need to tell them what you think. Say, "Look, I've been reading about this. I wonder if I might have that. What do you think?" Tell them why you think you've got it, tell them what's been your concerns. Tell them about what you've read about. Tell them why you think you've got it.

Because you might be right. Maybe you have diagnosed yourself properly, but you need your doctor to confirm that. And to also make sure that what you're doing is appropriate. When you see your doctor again, often what the advice that we give is fairly boring, but it has been proven with evidence as to making most people that have got that condition better. Now, certainly it doesn't mean to say that your condition will be cured, or you may still have a number of problems and suffer from it. But I think at least you're not going to do anything where you're going to put yourself at increased danger. Or, perhaps delay an important diagnosis because it might not be what you've thought, but maybe have got some important symptoms and maybe you've got something else like, I don't know, an underlying cancer or something that you've misdiagnosed yourself with and missed an opportunity where your GP might have been able to diagnose that early for you.

Vox pop: I think it’s a bit like everything else. Where you should have a healthy diet, exercise, sleep. But I’ve also heard that you can drink teas, essential oils and supplements and things like that.

Vox pop: yeah, I take vitamins, I try to eat well and that’s about it.

Vox pop: Yeah, so I’ve heard a little bit about gut health and probiotics. That’s the main way that I know of.

Vox pop: Yes, I’ve definitely seen tablets you can take, supplements, vitamins and things.

Vox pop: I think when I was a kid I used to play in the dirt and get grubby. Maybe that’s why my immune systems really good.

Vox pop: You see lots of claims that this will boost your immunity, and that will boost your immunity. But I think being generally healthy is the best hope.

Host: Have you ever been told about a way to boost your immune system? Have you tried eating heaps of oranges, sitting in the sun or taking a special vitamin? Dr Peake says that while it's tempting to hope that these kinds of simple actions can help you create a superhuman immune system that never gets sick, that's not really how it works.

Dr Peake: One of the things that I get asked all the time and this isn't just with COVID is what can I do to boost my immune system? And unfortunately, there isn't anything specifically you can do to boost your immune system. Your immune system is incredibly complex. And as I explained, sometimes it's overreacting as well as under reacting and it's getting this balance that's correct.

Host: Dr Peake says that while the advice sounds pretty boring, the best things you can do for your immune system are all part of living a regular, healthy lifestyle.

Dr Peake: The best way to overcome infections when you meet them and to have the healthiest, in inverted commas, immune system is by following a fairly healthy lifestyle. So really eating in moderation, but eating healthy foods, eating fruits and vegetables, exercising, keeping your weight under control, keeping your blood pressure under control. All of those things have been shown to be important, and particularly nutrition.

I think we underestimate how important nutrition is for us and almost any disease you'd like to think about, but particularly with any disease that involves the immune system. If someone has good nutrition, in other words, they're not underweight, they're not overweight, but they're just right there in the middle, that is probably one of the most important things that they can do. That they've been getting a range of vitamins and minerals and good amounts of protein, but not overdoing any of them. I think there's very little evidence for having megadoses of any vitamin and that things like vitamin C or vitamin D, if you're talking about the sunshine. And whilst we want to keep those in the healthy range, more of a good thing doesn't really help. And there's no evidence that having lots of those things is going to actually do anything.

Dr Young: Unfortunately, as we learn more about the virus every single day. We’re learning that for a reasonable number of people they don’t fully recover. They have long-term consequences from the disease. And that’s because this virus doesn’t just affect the lungs. Unlike flu, this virus can affect every part of the body. That means that although someone might fully recover from the infection, they can have long-term consequences that affect not just their lungs, but their heart, their kidneys, their blood vessels and their brain and that can cause significant on-going disease.

Host: That was Queensland's Chief Health Officer Dr Jeannette Young talking about COVID-19. This year, you've probably heard a lot about the immune system when it comes to COVID-19. We asked Dr Peake to explain why it's such a big deal when a new virus comes along and why we're seeing some people have extremely serious side effects from this disease.

Dr Peake: Unfortunately, because we haven't met this virus, everybody is prone to it. So, nobody has any immunity to it. The first time any of us meet it, we're meeting it for the first time. This virus is a little bit more tricky than that, too. It obviously is a very contagious virus and it's quite an aggressive and nasty virus, but it also seems to have some unique aspects of how it's working on the immune system.

Host: When people have COVID-19, it's their immune system that creates the symptoms they experience. They might get a fever because their body is heating up to try and kill off the virus or develop mucus or a cough as a way of trying to expel the virus out through the airways. These are normal immune system responses. But with COVID-19, it seems that sometimes the immune system responds in a very abnormal way.

Dr Peake: So, the immune system, part of what it needs to do is to turn on appropriately. So, turn on when it needs to destroy something, but then also to turn itself off because otherwise it can be a bit like a bushfire that's out of control. And it seems like unfortunately with COVID, there seems to be an immune system that's become what we call dysregulated. In other words, we're not able to kind of pull it in as we should be and turning off the immune response to the virus. So, there's some direct effects from the virus in COVID, but there's also some indirect effects that the immune system once getting started, doesn't seem to be able to turn itself off and stop. And that certainly seems to be responsible for at least some of the fatalities, particularly in younger people and even in some children we're seeing an immune dysregulation syndrome that's occurring even a period of time after they've had the infection, which is what's making COVID particularly tricky.

But what we're hoping is that there is this race to develop a vaccine to COVID that once we have developed it, it will allow anybody who hasn't met the virus again, to have that immune memory from being given officially by a vaccine.

Host: In her role at the Queensland Paediatric Immunology and Allergy Service, Dr Peake works with children and their families dealing with lots of different types of significant health concerns. She says this variety, and the difference she can make in her patients’ lives, make her job fulfilling.

Dr Peake: What I really like about my job is a couple of things. I love working with children and their families. I think I've got a reasonably good balance in my work in that I've got this smaller group of patients with very serious medical problems where their immune system is not working properly. And these children, their conditions are often life threatening. And so, we're working with these families to get these children a very high quality of life, and we get to know them very well, and they often are frequent visitors, both as inpatients and outpatients. But they're very challenging, but so rewarding when we've got a child that would have an otherwise lethal condition and we can hopefully really help them to have a pretty much a normal life by trying to overcome those problems they've got with the immune system. And that's part of what I do.

And the other part of what I do is working with thousands of children and families, where they've got a problem with an allergy, which again creates a lot of problems for these children. It creates anxiety, it means they can't eat things as they normally would. There's always issues and problems with them growing. They've often got problems like eczema and hay fever and asthma that are inter playing as well. And with this group of patients, what we try and do is empower them and educate them so they can manage their own conditions better. So again, these problems that they have having the minimal impact on their quality of life. So again, we're doing our best to try and see if we can help them overcome them, help them to grow out of them. But if they've got those as ongoing issues to understand them and to manage them for themselves so that it's got the least impact on their lives and keeping them very safe.

Host: Thanks for listening to this episode of My Amazing Body. Did you guess our mystery body part? The thin wall of bone and cartilage is your septum! Congratulations if you figured it out.

Thank you to Dr Jane Peake and the team at the Children's Health Queensland for lending their time and expertise to this episode and to all the Queenslanders who spoke to us about what they know, and don't know, about their immune system.

My Amazing Body is brought to you by Queensland Health. Thanks to my podcast colleagues, producers Lauren and Jessica, Carol our audio technician and Helen on music and sound effects.

Last updated: 7 October 2020