Our immune system is one of the most complex and essential systems of the human body. It is comprised of cells, proteins and chemical reactions that enable us to ward off infection and pathogenic infiltration.
White blood cells comprise much of the immune system and are manufactured in the bone marrow and move through the blood and tissue throughout the body. Our bodies are constantly under attack by many pathogens, be it viruses, bacteria, fungi etc. Each time the immune system destroys a pathogen, it is remembered and if the same pathogen enters the body again, it is quickly destroyed due to the immune system quickly acknowledging it as foreign.
Important proteins called antibodies, aid in the neutralisation of infections or the toxins that some pathogens can produce.
Another complex component of the immune system is the lymphatic system. This system is comprised of hundreds of lymph nodes, that trap microbes and the spleen, which is an organ that filters blood. Cells called lymphocytes are also found in the lymphatic system.
The immune system has a strong influence on our body’s thermostat and when certain pathogens/infections are present, our core body temperature rises, to destroy the microbes and aid in the body’s repair process.
A simple example of how the immune system functions in the situation of an abrasion is:
- When the skin is broken, microbes can enter the cut. The immune system builds its defence system to halt the microbial invasion.
- White blood cells register that there has been an immune system breach, due to a signal that is released from the damaged cells, in this case, the skin.
- The white blood cells travel to the cut and start destroying the bacteria. The development of pus is a combination of dead white blood cells and microbes.
- B lymphocytes attempt to identify the microbe. If the microbe has been defeated before, the lymphocytes know which antibodies are required to kill the microbe.
- Other cells such as helper cells assist the B lymphocytes to produce antibodies. Killer cells are also produced to attack the infection. Suppressor cells also assist in stopping the immune system response once the pathogen has been destroyed.
In today’s day and age, we are exposed to a multitude of various factors that are constantly bombarding our immune system on an hourly and daily basis. These factors can include, environmental pollutants and toxins, occupational glues, plastics, radiation, and the list goes on. As well as this, the over prescription of antibiotics has also lead to certain bacteria becoming resistant to treatment and as a result, infections are becoming more difficult to treat.
As well as this, we are living in a society where sanitation is on the list of everyday priorities, which is of course essential to reduce the spread of infectious diseases, however, at times, many of us can be guilty of being slightly germophobic. Providing too much of an everyday sterile environment can limit the immune systems exposure to pathogens and as a result, immune system memory is not matured, and there is an increased risk of the immune system being attacked.
Viruses can constantly mutate and because of this, our immune system doesn’t recognise many viruses and this causes a breach to the immune system’s equilibrium and as a result, the individual can fall ill. For example, influenza isn’t just caused by one virus but rather, many viruses can be the cause. The immune system doesn’t always have a ‘memory’ of viruses and as a result, it becomes difficult for the immune system to defend the body against it.
In some circumstances, the immune system can identify certain substances as harmful when in fact, they are quite harmless. A clear example of this is an allergic reaction. Allergic substances can include pollen, dust, or animal proteins. Other examples include autoimmune reactions, where the immune system identifies the body’s own structures as if they were foreign.
How Does Menopause Affect the Immune System?
As we age, many biological functions tend to decline, and immune activity is one of them. During the aging process, a general decline in immune function has been observed. The role sex hormones such as, oestrogen, progesterone and testosterone play on the immune system has been investigated over the years. The reduction in these hormones during menopause has been attributed to some degree, to a decline in immune function.
It has been proven that women are at a higher risk of developing autoimmune diseases, which indicate that sex hormones mediate certain disease conditions.
Both progesterone and oestrogen are the main regulators of the immune system of the female reproductive tract. Oestrogen receptors are located throughout the body and within certain tissues. Most immune cells and epithelial and stroma cells throughout the female reproductive tract are responsive to sex hormone stimulation.
Approximately 10-15% of women over the age of 60 suffer from an increased frequency of urinary tract infections. This is due to changes in the defence systems of the urogenital tract as well as changes in the acidity of the vaginal tract. This predisposes women to an increase in bacterial overgrowth.
Oestrogen can reduce the destruction of B cells, the essential check points of the immune system and as a result, allows for the accurate identification of pathogens that may be infiltrating the body. This process facilitates the destruction of pathogens and allows the immune system to be in check.
The declining levels of sex hormones, namely oestrogen and progesterone in the menopausal woman can contribute to changes in how the immune system functions and can predispose women to immune dysfunction be it, an increase in the frequency of the common cold and flu or the development of autoimmune conditions.
Hormone replacement therapy is not only beneficial for improving menopausal symptoms it can also assist and regulate the immune system, especially when women are supplementing with oestrogen.
There is still much to be researched in the area of immune dysfunction and menopause however, the research that is proving the link between hormone fluctuations and immune disturbances is quite strong.
- Giefing-Kroll et al. Sex and age affect immune responses, susceptibility to infections and response to vaccination. Aging Cell (2015) 14; 309-321
- Ghosh M, Rodriguez-Garcia M, Wira C. The immune system in Menopause: Pros and Cons of Hormone Therapy. J Steroid Biochem Mol Biol. 2014. 171-175