Monocytes are a type of white blood cell produced in the bone marrow. Resembling like amoeboid, they fight certain infections and help out other white blood cells to remove damaged dead tissues. They also destroy cancer cells and help to regulate immunity against foreign substances. A monocyte count is component of a complete blood count and is denoted as a ratio of monocytes to the overall count of white blood cells or by absolute numbers. Both may be useful in determining or refuting a possible diagnosis
Monocytes – normal range
Monocytes represent about 1% to 10% of the white blood cells circulating in blood, that is about 200 to 600 monocytes present in every micro liter of blood. They remain in the bloodstream for a couple of hours after which they migrate to tissues such as the lungs, liver, spleen, bone marrow where they will mature into macrophages. Monocyte cells reside in tissues of the body, engulf pathogens and produce molecules.
Functions
When a tissue is damaged or infected, monocytes are recruited to the tissue, where they are broken down into tissue macrophages. Macrophages are plastic and have the ability to change their functional phenotype. They have the ability to clear pathogens and instruct other immune cells. These cells protect the host and contribute to the pathogenesis of inflammatory diseases.
Monocytes are a part of the immune response system. They carry out the function of phagocytosis. During phagocytosis, large molecules found within the blood are ingested and then they are broken down. The purpose of phagocytosis is to help protect the organism from attack by harmful pathogens and to remove dead or dying cells from the blood.
Pathogens cause an infection when they enter an organism. In many cases, the pathogens are usually viral or bacterial cells. Pathogens produce and release chemicals as they carry out their natural life processes. Those chemicals do attract white blood cells to the infected area, including those that carry out phagocytosis process. Proteins within the blood attach to the virus and bacteria, which makes the cells of the immune system to easily recognize the pathogens.
Monocyte surface is not smooth as it has specific proteins on it that allow it to bind to the virus cell or bacteria cell. Monocytes have a function of moving towards the specific pathogenic cell and finally adhering to it when it is close. Thereafter, a production of a pseudopodium occurs. This is due to the monocyte bending around the pathogen so that the pathogen is engulfed.
Inside the monocyte, the pathogen is then trapped. Once the cells or debris engulf, they are then broken down within the phagosome.
An increased number of monocytes in the blood is called monocytosis. It occurs in response to chronic infections and in certain cancers. A lysosome is a cellular organelle that is found within the monocytes. Lysosomes attach to phagosome when formed. They release digestive enzymes, which are known as lytic enzymes. These lytic enzymes break down the cell and the products that will remain are absorbed by the monocyte.
Low monocytes count
Anything that decreases the overall white blood cell count causes monocytopenia, a condition denoting low number of monocytes; for example, bloodstream infections or a bone marrow disorder. Humans with certain skin infections and human papillomavirus or infection of the genitals can also have monocytopenia.
A low number of monocytes within the blood is common in patients undergoing chemotherapy. However, it is important to understand that having a low number of monocytes is not an indication of a disease or condition by itself. It however represents a warning sign that there is an increased risk of having an infection or some blood disorder.
Diagnosis is by testing blood; this is done when a person has signs or symptoms of an infection. The condition can be discovered by chance when a complete blood count is done in a routine physical examination or when evaluating another condition.
Some of the conditions that reflect absolute low monocytes count indicate Vitamin B12 deficiency, lupus, tuberculosis, hairy cell leukemia, HIV/AIDS, chemotherapy, radiation and medications like corticosteroids.
Symptoms of low monocytes count
People with low levels of monocytes will experience general body weakness. When the number of monocytes is low, the immune system is burdened in fighting infectious agents and maintaining the body’s healthy. This contributes to extreme body weakness.
People suffering having low number of monocytes are more likely to feel tired or suffer chronic fatigue even after carrying out light duties. The fatigue can go throughout the day or a couple of days thus disrupting their daily routine.
Lower than normal monocytes is often followed by fewer levels of red blood cells. Having less RBCs leads to low oxygen levels in the blood system causing breathlessness. This is because red blood cells are the major component that circulates oxygen in our body.
Reduced monocyte count can also increase the chances of re-occurrence of infections. This is because they play a major role in protecting the system from pathogens. People with reduced monocytes take more time to recover after infections.
Treatment
The kind of medication to be administered will depend on the extent of monocytopenia, health status of the person, cause of the low count, presence of secondary infections and related symptoms.
The level of white blood cells can be raised using WBC growth factor, while infections are treated by administering antifungal drugs and antibiotics among other medications. Other options could include intravenous globulin and corticosteroid therapies. Patients are advised to eat a healthy balanced diet, especially during medication to ensure the infections do not spread or reoccur.
