Neutrophils are a type of white blood cell alongside monocytes, basophils, eosinophils and lymphocytes. Neutrophils help to protect the body from infection and are one of the first cells to travel to the infected site. They are also an example of a granulocyte – a cell that releases granules containing enzymes in response to infections and allergic reactions – and a type of phagocyte – they can engulf and absorb invading pathogens.
Neutrophils are the most abundant type of granulocyte and white blood cell in the body. They make up between 40 and 70% of the total white blood cell count. Neutrophils have an important role in the body’s inflammatory response as they help to remove invading micro-organisms and old and damaged cells. Neutrophils also release inflammatory agents to flag and kill infective sources. Usually, when the invader has been removed, the invasion of neutrophils ends so that the tissue can be repaired. However, in cases where this does not stop then tissues can become permanently damaged.
Neutrophilia is an elevated circulating neutrophil count. It usually occurs from an increased production of neutrophils. Generally, this happens in response to an infection, mainly bacterial, but other causes can include:
Incidentally, low levels of neutrophils or neutropenia can also be caused by an infection usually viral (HIV, malaria, TB). Other causes of neutropenia, include:
Symptoms of neutropenia may include:
You may not be able to directly influence your monocyte count but with a good lifestyle, you can improve the efficiency of your immune system.
Smoking can also damage your immune system and its response. However, some of the damage is reversible if you stop smoking.
Nutrition is an important factor in our health and immune status. If we are deficient in some nutrients, then this can make our immune system weak. Micronutrients including zinc, selenium, iron, copper, vitamins A, C and E, B6 and folic acid all have important influences on our immune responses. Therefore, it is essential to maintain a healthy and balanced diet incorporating all these micronutrients.
Exercise is key to a healthy lifestyle. However, intense exercise can also induce immunodepression during recovery. Therefore, it is essential that you take rest periods between bouts of intense exercise to prevent illness.
 PubMed Health. (2018). Neutrophils. Available at: https://www.ncbi.nlm.nih.gov/pubmedhealth/PMHT0022058/
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 Peake, J, M., Neubauer, O., Walsh, N, P and Simpson, R, J. (2016). Recovery of the Immune System After Exercise. Journal of Applied Physiology: 122, pp 1077-187.