Introducing the immune system. What is the sought-after good immunity?


If your body were a country, the immune system would be its army: this is how we would start introducing the immune system. The immune system is defined primarily by its function. Beyond that, we can identify its components in different parts of the body.

As entities, we, human beings, need strict boundaries and good protection against invasion. Nobody wants germs multiplying in our tissues and eventually destroying them. That’s why we have the defence system, a.k.a. immune system.

The immune system is the totality of cells and molecules (substances) that protect individuals from structures recognised as foreign. Recognition is a key aspect, because some of the identified enemies are truly foreign, while others are actually the individual’s own self structures, but they are just recognised as foreign by the immune system (thus initiating a reaction called autoimmunity). Autoimmunity is an unwanted type of immune reaction, but more on this in a follow-up article.

What is ‘foreign’? 

Well, as suggested, microbes are perhaps the first thing that comes to mind when speaking of foreign invaders. Looking at infections or infestations in more detail, we can include bacteria, viruses and parasites.

The list doesn’t end here, though. There are non-infectious substances that are foreign. These can either come from outside the body, or they can originate in our own damaged cells. So, the immune system is also responsible for eliminating the cellular debris and transformed cells (e.g., tumour cells). This happens more or less efficiently and will be discussed later on in this series of articles.

What do we mean when we say good immunity?

Good immunity may be defined as an efficient and appropriate immune function.

This means eliminating the foreign invaders and not damaging self structures

A good immune response starts with an initial amplification phase. This allows fighting the invaders. The following, self-limiting, control phase, prevents excessive immune activation and the possible targeting of innocent by-standers (damage to normal structures or reactivity against self).

Unfortunately, this process can go wrong in either direction.

An inefficient immune response can characterise immune-deficient states. The same is true for situations when disease-causing germs manage to evade the immune response, even in individuals with normal-functioning immune systems.

At the other end of the spectrum, there are situations when a systemic (whole-body) reaction occurs in response to an infection, like in sepsis or systemic inflammatory syndrome. Uncontrolled inflammation (immune response) can also lead to the activation of specific immune cells that recognise self structures, thus initiating an autoimmune reaction. 

In conclusion, after introducing the immune system…

The immune system is a complex network of cells and chemical mediators that are able to circulate throughout the body. Going back to the analogy with a country, our bodies have clearly defined borders. These are the skin and the linings of the digestive, respiratory, genital and urinary tracts. Whatever lies beneath the surface of these borders, that’s what we call ‘the internal environment’. The immune system patrols the internal environment and has troops concentrated around the borders.

This makes sense because the main function of the immune system is protection against foreign invasions. As soon as a foreign structure is detected in the internal environment, the immune system is activated, ready to fight.

We need the good immunity:

  • to have protection against disease-causing agents,
  • to efficiently eliminate abnormal cells, and
  • to accurately identify our own structures in order to prevent an attack against self.

Knowledge solves problems

The immune system has a straight-forward job. However, in order to achieve success in performing it, an incredible complexity is needed to fine-tune every interaction. This is a fascinating world inside every one of us. What you have just read is the first in a series of articles that will analyse relevant aspects in turn and translate the complicated science in everyday language. This will be the story of health itself, because the function of the immune system is, essentially, to ensure health. We now discover more and more about the immune system’s crucial involvement in many diseases. This includes not only infections, but conditions like cardiovascular disease (1), diabetes (2), Alzheimer’s disease (3) and many more. Once we understand its complexity, we can discover ways to influence immune function.

Immunologists will probably be the new generalists. Functional immunologists, like at The Allergy-Immunology Doctor, will luckily have a much larger toolkit, so interventions targeting the immune system have the best chance of success.

For good health, it is essential to have a good immune function.

Thank you for reading the first article in the series, introducing the immune system and getting a first glimpse of what is good immunity. Hopefully you’ll stick around as we unravel the complexity of the fundamentals of health. Enjoy the journey!

Tailored specialist support to achieve good immunity

We are all different and so are our immune systems. You may have a diagnosis of autoimmunity or allergies. Or, perhaps, you are the one that seems to always catch every cold or the one who reacts quite badly to infections that others don’t even notice. Perhaps you just know that something isn’t right in how your body functions, despite the normal test results. Or, maybe everything seems perfectly fine with you, but you would like to be even better, and to fine-tune everything for optimal health.

Wherever you are in your health journey, at The Allergy-Immunology Doctor, we are here for you and your immune system.

You may want to book a free discovery call to find out how suitable is our approach for your current goals.


1.        Sorriento D, Iaccarino G. Inflammation and cardiovascular diseases: The most recent findings. Int J Mol Sci. 2019;20(16):5–8. 

2.        Tsalamandris S, Antonopoulos AS, Oikonomou E, Papamikroulis GA, Vogiatzi G, Papaioannou S, et al. The role of inflammation in diabetes: Current concepts and future perspectives. Eur Cardiol Rev . 2019;14(1):50–9. 

3.        Kinney JW, Bemiller SM, Murtishaw AS, Leisgang AM, Salazar AM, Lamb BT. Inflammation as a central mechanism in Alzheimer’s disease. Alzheimer’s Dement Transl Res Clin Interv. 2018;4:575–90.