What are Monocytes and which blood tests check Monocytes levels?

What Are Monocytes?

Monocytes are the largest type of white blood cell in the human body and can differentiate into one of two different cells. Monocytes are produced in the bone marrow and are part of the immune system where they work to kill micro-organisms which harm the body.[1]

Which tests include this marker?

Why Take A Monocyte Blood Test?

Monocytes are usually analysed as part of a full blood count where the numbers of red cells, white cells and platelets are calculated. Abnormalities in any of the different cell types can indicate medical disease or disorders.[2] 

Monocytes are important cells in the innate immune system, a nonspecific defence mechanism within the body which is activated immediately or within hours of an invading pathogen. Therefore, increased monocyte levels could indicate infection, while low levels may signify an issue with the bone marrow as well as increased susceptibility to infection.

You can check your level of monocytes together with other white blood cells within Forth’s Vitality and Ultimate blood tests. 

What Function Do Monocytes Have In The Body?

Monocytes form part of the main white blood cells in the body alongside neutrophils, basophils, eosinophils and lymphocytes. Each type of white blood cell has a key role in defending the body against invading pathogens which could harm and cause disease.

Monocytes are a subgroup of cells which can develop into two cell types, macrophages or dendritic cells.[3]

Macrophages are phagocyte cells which means they are capable of engulfing and absorbing bacteria. They are like neutrophils in their function but are larger in size and have a longer lifespan. Mononuclear phagocytes account for up to 12% of the total white blood cell population.

Dendritic cells, on the other hand, are antigen-presenting cells, meaning they flag foreign body cells, so lymphocytes can destroy them.[4]

Monocytes, therefore, have three main functions in the human body:

  1. Phagocytosis
  2. Antigen presentation
  3. Cytokine production

Monocytes carry out phagocytosis, the process whereby microbes and particles are taken up, digested and destroyed. Monocytes use proteins including antibodies and complement to directly bind to the invading pathogen through pattern recognition receptors. Any fragments left after phagocytosis can be used as antigens and can be presented to the monocyte surface in a process called antigen presentation. Another type of white blood cell, the T lymphocyte is then activated to form an immune response against the antigen. Monocytes can also produce proinflammatory and in some cases anti-inflammatory cytokines upon presentation with specific microbial products.

​How Do Changes In Monocytes Affect Health And Wellbeing?

Alterations in monocyte counts can indicate infection or bone marrow problems, both of which can cause unpleasant symptoms. For example, monocytosis is where there are excess monocytes in circulation and may be indicative of chronic inflammation. During muscle injury, monocytes move to the injury site and clear cells which have gone through apoptosis or programmed cell death, the process helps to maintain tissue homeostasis.[5] However, once these apoptotic cells have been removed, the monocytes switch from being pro-inflammatory to anti-inflammatory  which helps to regenerate the injured muscle.[3]

Monocytopenia, on the other hand, is a deficiency in circulating monocytes and can be caused by injury to the bone marrow or could be a sign of some forms of leukaemia.[6] Low monocyte levels also leave us more susceptible to infection.

If you are worried about your immune levels or just want to check where you fall on the range, you can test your monocytes level with Forth’s leading blood test service.

What Can Cause Monocytes To Change?

Increases in monocyte levels are caused by various disease states, including:

  • Chronic inflammation
  • Stress
  • Atherosclerosis
  • Cushing’s syndrome

Chronic inflammation is often caused by infections such as tuberculosis, syphilis and subacute endocarditis. However other causes of increased monocytes include protozoa infections like malaria.[7]

Low levels of monocytes in circulation, termed monocytopenia, is usually a result of bone marrow failure.

What Are The Most Common Symptoms?

The symptoms associated with monocytosis depends on the cause. For example, if it is caused by pulmonary tuberculosis, the symptoms may include:

  • Lack of appetite and weight loss
  • Fever
  • Night Sweats
  • Fatigue
  • Persistent cough
  • Breathlessness[8]

Low monocyte numbers can be caused by bone marrow failure, a major cause of which is aplastic anaemia. In aplastic anaemia, the bone marrow doesn’t produce enough healthy red cells, white cells or platelets. If there are too few white cells, this can leave the body susceptible to infection. Usually, anaemia refers to the fact that the body is not producing enough red blood cells to meet demands. Therefore, it is unable to deliver as much oxygen to the cells and tissues as may be required. However, in aplastic anaemia, blood cell production is reduced because the stem cells in the bone marrow, where all blood cells are derived from, are damaged.[9] A major symptom of aplastic anaemia is recurrent infections, like those which affect the sinuses, chest or throat.

How To Keep Monocytes In The Healthy Range

Monocytes are an important part of the body’s innate immune system. Although you may not be directly able to influence your monocyte count, there are some healthy lifestyle choices you can make to help keep them within normal parameters.

Nutrition is an important aspect of our immune status and deficiency in some nutrients can weaken the system. It is essential to eat a healthy, balanced diet incorporating the following macronutrients:

  • Zinc
  • Selenium
  • Iron
  • Copper
  • Vitamins A, C, E and B6
  • Folic acid[10]

Smoking has also been implicated in damaging the immune system. Therefore, it is important to stop smoking if you currently do, particularly as the damage is reversible if you quit.[11]

Exercise is key to a healthy lifestyle. However, participating in intense exercising can cause immunodepression during recovery. One exercise bout can change the white blood cell composition and this can remain changed even during recovery. Therefore, it is essential to have enough rest between exercise sessions to prevent illness and injury.[12]

Because monocytes are part of the innate system there are certain things you can do to help prevent pathogens from entering your body. For example, always remember to wash your hands after visiting the lavatory as well as before and after handling food. Equally, keeping yourself hydrated can help to prevent illness. You should aim to drink approximately 2 litres of water per day.

Monocytes are an important part of the body’s innate immune system. Although you may not be directly able to influence your monocyte count, there are some healthy lifestyle choices you can make to help keep them within normal parameters.

Nutrition is an important aspect of our immune status and deficiency in some nutrients can weaken the system. It is essential to eat a healthy, balanced diet incorporating the following macronutrients:

  • Zinc
  • Selenium
  • Iron
  • Copper
  • Vitamins A, C, E and B6
  • Folic acid[10]

Smoking has also been implicated in damaging the immune system. Therefore, it is important to stop smoking if you currently do, particularly as the damage is reversible if you quit.[11]

Exercise is key to a healthy lifestyle. However, participating in intense exercising can cause immunodepression during recovery. One exercise bout can change the white blood cell composition and this can remain changed even during recovery. Therefore, it is essential to have enough rest between exercise sessions to prevent illness and injury.[12]

Because monocytes are part of the innate system there are certain things you can do to help prevent pathogens from entering your body. For example, always remember to wash your hands after visiting the lavatory as well as before and after handling food. Equally, keeping yourself hydrated can help to prevent illness. You should aim to drink approximately 2 litres of water per day.

Tests that include this marker

Vitality

With over 45 biomarkers, this health check empowers you to gain a deep understanding about your inside health.

£139

Ultimate

Our most advanced health check which analyses over 50 biomarkers. For those who want a deep understanding of their health.

£349

References

[1] PubMed Health. (2018). Monocytes. Available at: https://www.ncbi.nlm.nih.gov/pubmedhealth/PMHT0022057/

[2] Lab Tests Online UK. (2015). Full Blood Count (FBC). Available at: https://labtestsonline.org.uk/tests/full-blood-count-fbc

[3] Karlmark, K, R., Tacke, F and Dunay, I, R. (2012). Monocytes in Health and Disease-Minireview. European Journal of Microbiology and Immunology: 2, pp 97-102.

[4] Diabetes.co.uk. (2019). White Blood Cells. Available at: https://www.diabetes.co.uk/body/white-blood-cells.html

[5] Poon, I, K, H et al. (2014). Apoptotic Cell Clearance: Basic Biology and Therapeutic Potential. Nat Rev Immunol: 14(3), pp 166-180.

[6] Saeed, L., Patnaik, M, M., Begna, K, H., Al-Kali, A., Litzow, M, R., Hanson, C, A., Ketterling, R, P., Porrata, L, F., Pardanani, A., Gangat, N and Tefferi, A. (2017). Prognostic Relevance of Lymphocytopenia, Monocytopenia and Lymphocyte to Monocyte Ratio in Primary Myelodysplastic Syndromes: A Single Center Experience in 889 Patients. Blood Cancer Journal: 7.

[7] Zini, G. (2011). Abnormalities in Leukocyte Morphology and Number. In: Blood and Bone Marrow Pathology (Second Edition).

[8] NHS. (2016). Symptoms Tuberculosis (TB). Available at: https://www.nhs.uk/conditions/tuberculosis-tb/symptoms/

[9] National Institute of Diabetes and Digestive and Kidney Diseases. (2014). Aplastic Anemia and Myelodysplastic Syndromes. Available at:https://www.niddk.nih.gov/health-information/blood-diseases/aplastic-anemia-myelodysplastic-syndromes

[10] Chandra, R, K. (1997). Nutrition and the Immune System: An Introduction. American Journal of Clinical Nutrition: 66, pp 460S-463S

[11] Brodin, P and Davis, M, M. (2017). Human Immune System Variation. Nature Reviews: Immunology: 17(1), pp 21-29.

[12] 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.


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