Immunity and Allergy

The immune system is the mechanism within the body that enables it to protect itself against harmful substances likely to trigger illness or disease. It is in effect the body’s first line of defence. Not only does the immune system protect the body from the infiltration of micro-organisms and other materials that are detrimental to the body, but it also provides protection against cancer by destroying defective cells.



The work of the immune system is not always benign, however. It can sometimes lead to overreactions which can trigger allergic responses leading to conditions such as eczema, hay fever and asthma. A weakened immune system can make the body more susceptible to infection. At its worst, a compromised immune system can lead to auto immune conditions such as systemic lupus erythematosus (SLE) that are activated when the body treats it own cells as if they were harmful and the immune system begins to attack them.



Work of the Immune System

The helpful versus harmful nature of the immune system is determined by type of immunity- whether it is active or passive. In addition, the immune system itself can either be overactive or underactive as follows:


Active immunity occurs when the body uses its own defence cells to deal with invading micro-organisms and chemicals.


Passive immunity takes place either through the development of antibodies in a foetus prior to birth or via vaccination.


Overactivity can result from allergy and hypersensitivity to chemicals outside the body, autoimmunity, and adverse reactions to blood transfusions.


Underactivity can include inherited or acquired immunodeficiency caused by drugs, radiation, environmental toxins, or HIV infection.


Constituent Parts of the Immune System

The important components of the immune system include cells, chemicals, and tissues.


Cells - the most important cells within the immune system are T cells, B cells, antigen-presenting cells (APCs), neutrophils and mast cells.

T cells are a type of white cell (lymphocyte). They are found in the blood, bone marrow and lymph nodes. They stimulate another group of white cells known as B cells to produce antibodies. They can also directly destroy antigens such as viruses that invade the body’s cells.


B Cells as referred to above are also found in blood, bone marrow and lymph nodes. When stimulated by the T cells they turn into plasma cells and secrete antibodies.


Antigen-presenting cells (APCs) are found in the skin and throughout lymph tissues. They process antigens so that they can be identified and dealt with by the T cells. Another type of APC are macrophages which are responsible for disposing of foreign matter and debris resulting from the immune processes.


Neutrophils are the commonest form of white blood cell; they also have a similar function to macrophages. Mast cells are found throughout the body and release chemicals such as histamine that trigger inflammation in response to an immune reaction.


Chemicals - antibodies are also known as immunoglobulins such as IgG, IgM, IgA, IgE and IgD are proteins secreted by plasma cells that activate enzymes triggering the destruction of bacteria and other pathogens by blood and tissue cells.


Tissues - although many immune reactions occur in the bloodstream, lymph tissue is also important to immunity, for example lymph nodes (found throughout the body in such as neck, armpits, and groin).


Triggers for immunity

Immune reactions are caused by the release of histamine and other chemicals from mast cells in the immune system which result in inflammation, swelling and contraction of smooth muscle. This response is an immediate response to foreign organisms and chemicals and can lead to asthma, eczema, hay fever, food allergies. Severe reactions can cause nausea, wheezing, itching, low blood pressure, abdominal pain, nettle rash and in sever cases, loss of consciousness.


Examples of Conditions affecting the Immune System

The following conditions develop in response to immune system activity:

Heart - rheumatic fever

Lungs -asthma

Gastro-intestinal system and liver-coeliac disease, ulcerative colitis

Skin - dermatitis

Endocrine - diabetes, Addison’s disease

Ear Nose and Throat - hay fever, otitis media (glue ear)

Eyes - allergic conjunctivitis

Blood - pernicious anaemia, thrombocytopenia

Reproductive - rhesus disease of the newborn, infertility

Kidney - glomerulonephritis

Joints - rheumatoid arthritis

Nerves - multiple sclerosis


Boosting The Immune System

This article has highlighted that the immune system is incredibly complex.

Despite its complexity, there are lifestyle practices that can assist promoting a healthy immune system that help the body fight off infections and illnesses. Below are five ways to boost your immune system:

1. Eat Healthily

A healthy diet is key to a strong immune system. This means making sure you eat plenty of vegetables, fruits, legumes, whole grains, lean protein, and healthy fats.


In addition to providing the energy necessary for a healthy immune system, a healthy diet should include essential micronutrients. Important nutrients include vitamin C, magnesium, and B vitamins, particularly B5. The best way to support your immune system is to eat a well-balanced diet as the body absorbs vitamins more efficiently from dietary sources, rather than supplements.


2. Exercise Regularly

In addition to building muscle strength and releasing stress, regular exercise will also promote immune system health. By improving overall circulation, it is easier for immune cells and other infection-fighting molecules to travel more easily within the body.


Studies have shown that engaging in as little as 30 minutes of moderate-to-vigorous exercise every day helps stimulate your immune system. Keeping active and exercising regularly are important keys to immune system health.


3. Drinking Water

Water is a vital component of a healthy immune system. The lymphatic system which contains the most important infection-fighting immune cells is largely made up of water. Therefore, insufficient intake of water on a regular basis can have a detrimental effect upon the immune system.


Water is lost through normal activities in the body such breathing, sweating, urine and bowel functions. Drinking 6-8 cups of water daily will help support your immune system, by replacing the water you lose.


4. Sufficient Sleep

There are many important activities taking place within body during sleep. For instance, important infection-fighting molecules are created while you sleep.


Studies have shown that people who don't get enough quality sleep are more prone to getting sick after exposure to viruses, such as those that cause the common cold. To give your immune system the best chance to fight off infection and illness, it's important to know how much sleep you should be getting every night, as well as the steps to take if your sleep is suffering.


5. Minimize Stress

Prolonged stress has a detrimental impact upon the immune system. The body by initiating a stress response which suppresses the immune system which in turn, increases the risk of infection or illness.


Self-awareness and early identification of stress is key to managing it and reducing the impact upon our health. Recognising the situations and factors that trigger stress will help to manage, mitigate, or minimise it. Methods to manage stress include deep breathing, relaxation techniques, prayer, or exercise.

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