Monocytes are the biggest of all white blood cells that play an important role in the defense against germs and in inflammation. Read more below to learn about these cells and health effects of having higher or lower levels of monocytes.
- Monocyte Production in the Body
- Optimal Reference Range for Monocytes
- High Levels of Monocytes (Monocytosis)
- Health Effects of Having A High Monocyte Count
- Low Levels of Monocytes (Monocytopenia)
- Health Effects of Having A Low Monocyte Count
- Ways to Increase Monocytes Levels
- Ways to Decrease Monocytes Levels
Monocytes are the largest type of white blood cells (leukocytes). Approximately 2-10% of white blood cells are monocytes (R).
Monocytes protect against viral, bacterial, fungal and protozoal infections (R).
Monocyte Production in the Body
In adults, blood cells are produced mainly in the bone marrow (R).
The process of production of monocytes is called myelopoiesis (R).
Factors that control this process are:
- Transcription factor PU.1 (R1, R2, R3, R4)
- Cytokines: SCF (Stem Cell Factor), GM-CSF (granulocyte-macrophage colony-stimulating factor), M-CSF (macrophage colony-stimulating factor, CSF1), IL-3, IL-6, and IFN-gamma (R, R2, R3, R4)
After Monocytes Fulfill Their Job, What Happens Next?
Monocytes live for an average of 3 days before undergoing programmed cell death (R).
Optimal Reference Range for Monocytes
Children have various normal ranges depending on age, ranging from 0.5–1.8×109/L in newborns, and gradually decreasing to 0.2–0.8×109/L in adolescents (R).
High Levels of Monocytes (Monocytosis)
In monocytosis, the number of monocytes circulating in the blood is increased to more than 0.8×109/L in adults.
Conditions Associated with Monocytosis
- Hematologic malignancies (myelodysplastic disorder, acute monocytic, chronic myelomonocytic leukemia, Hodgkin and non-Hodgkin lymphoma) (R, R2, R3)
- Infections (tuberculosis, viral infections, bacterial endocarditis, brucellosis, malaria, syphilis) (R, R2, R3, R4, R5, R6)
- Autoimmune diseases (systemic lupus erythematosus, rheumatoid arthritis, inflammatory bowel disease) (R, R2, R3)
- Sarcoidosis (R)
- Cancers (ovary, breast, rectum) (R, R2)
- Heart attack (R, R2)
- Appendicitis (R)
- HIV infection (R, R2)
- Depression (R)
- Childbirth (R, R2)
- Obesity (R)
- Severe pneumonia (R)
- Alcoholic liver disease (R)
Health Effects of Having A High Monocyte Count
1) Monocytosis Increases Risk of Atherosclerosis
As hardening of the arteries progress, the number of monocytes in the blood rises (R).
2) Monocytosis May Increase Inflammation in Diabetes
Monocytes may induce inflammation in diabetes.
3) Monocytosis is Associated with Increased Risk of Death in the Elderly
Increased number of monocytes is associated with an increased risk of cardiovascular and cancer-related risk of dying in the elderly (R).
4) Monocytosis Facilitate Healing Process After A Heart Attack
Low Levels of Monocytes (Monocytopenia)
In monocytopenia, the number of monocytes circulating in the blood is decreased to less than 0.2×109/L in adults.
Conditions Associated with Monocytopenia
- Aplastic anemia (R)
- Leukemia (hairy-cell leukemia,
- MonoMAC syndrome (monocytopenia and mycobacterium avium complex syndrome) (R)
- Severe burn injuries (R)
- Rheumatoid arthritis (R)
- Systemic lupus erythematosus (R)
- Vitamin B12 deficiency (R)
- Corticosteroid therapy (transient monocytopenia) (R)
- Administration of INF-alpha and TNF-alpha (R)
Health Effects of Having A Low Monocyte Count
1) Monocytopenia Lowers The Risk of Cardiovascular Disease
Out of all white blood cells, monocyte count has the strongest relationship with overall cardiovascular disease development in people with no symptoms.
Lower levels of monocytes are associated with a lower cardiovascular risk (R).
2) Monocytopenia Increases Susceptibility to Infections
Low monocyte counts increase susceptibility to infections.
3) Monocytopenia is Associated with a Risk of Hematologic Disorders
Monocytopenia is associated with a high risk of development of hematologic disorders (cancers of blood cells) such as myelodysplasia, acute myelogenous leukemia, chronic myelomonocytic leukemia, and lymphomas (R).
4) Monocytopenia Increases Risk of Cervical Cancer
Ways to Increase Monocytes Levels
1) Acute Strenuous Exercise
3) Cold Exposure
Prolonged cold exposure increases the number of monocytes which through the “fight or flight” (sympathetic) nervous system activation (R).
4) Growth Hormone
7) Vitamin B12
Vitamin B12 helps increase white blood cell count, including monocytes in rats with protein deficiencies. However, supplementation with vitamin B12 does not change white blood cell count in rats that ate normal level of protein (R).
9) Vitamin C
10) Calcitriol (Vitamin D3)
Garlic increases total white blood cell count. Rats fed with garlic have significantly more monocytes, neutrophils and lymphocytes than rats not fed with garlic (R).
12) Chronic Alcohol Drinking
Alcohol consumption causes leaky gut, which allows lipopolysaccharides from Gram-negative bacteria in the gut to cause inflammation. Acute alcohol consumption initially mitigates the inflammation from LPS. However, chronic alcohol consumption can lead to a gradual increase of monocytes and inflammatory proteins, contributing to a general body state of inflammation (R).
Ways to Decrease Monocytes Levels
1) Acute Alcohol Intake
Acute alcohol exposure influences immune functions, particularly monocyte function (R).
Studies suggest that acute alcohol consumption decreases inflammation in response to LPS in the gut (R).
These mechanisms may contribute to the beneficial effects of moderate alcohol use on atherosclerosis.
2) Regular Exercise
Regular exercise is anti-inflammatory. Monocytes significantly decrease after a six-week course of moderate intensity cycling in overweight sedentary women.
3) Weight Loss
4) Omega-3 Fatty Acids
People taking fish oil supplements were less likely to have inflammation in the blood vessel walls caused by monocytes. This effect was not as pronounced in people already taking medication to treat peripheral artery disease (R).
5) Mediterranean Diet
The Mediterranean diet may protect against inflammation caused by monocytes (R1, R2). The Mediterranean diet is comprised of foods such as seeds, nuts, vegetables, fruits and whole grains, and a lot of monounsaturated fats from olive oil.
6) Cortisol And Glucocorticoids
A single dose of cortisol decreases monocytes by 90% at 4 to 6 hours after treatment. This reduction persists for about 24 hours. Subsequently, monocyte levels return to normal 24 to 72 hours after treatment (R).
This decrease is thought to be a consequence of redistribution of monocytes.
7) Estrogen And Progesterone
Infliximab kill monocytes, which may help reduce inflammation in patients with chronic inflammatory diseases (R).
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