Monocytes are a group of cells of the immune system that have the function of defending the body from foreign bodies such as viruses and bacteria. They can be detected through blood tests called leukogram or a complete blood count, which gives you the amount of defense cells in the body.
The monocytes are produced in the bone marrow and remain a few hours circulating in the blood, and follow to other tissues, where they undergo a differentiation process, receiving the name of macrophage, which have different names according to the tissue in which it is found: Kupffer cells, in the liver, microglia, in the nervous system, and Langerhans cells in the epidermis.
High monocyte levels
The increase in the number of monocytes, also called monocytosis, is usually indicative of chronic infections, such as tuberculosis. In addition, there may be increased numbers of monocytes due to ulcerative colitis, protozoal infection, Hodgkin's disease, myelomonocytic leukemia, multiple myeloma, and autoimmune diseases such as lupus and rheumatoid arthritis.
An increase in monocytes usually does not cause symptoms, only being perceived through a blood test, such as a blood count. However, there may be symptoms related to the cause of monocytosis and so it should be investigated and treated according to the physician's recommendation. See what is a complete blood count and when it is recommended.
Low monocyte levels
When monocyte values are low, the condition is called monocytopenia, it usually means that the immune system is weakened, as in cases of blood infections, chemotherapy treatments, and bone marrow problems such as aplastic anemia and leukemia. In addition, cases of skin infections, use of corticosteroids, and HPV infection may also cause decreased numbers of monocytes.
It is rare for the amount of monocytes to be close to 0 in the blood and, when it occurs, may mean the presence of monoMAC Syndrome, which is a genetic disease characterized by the absence of production of monocytes by the bone marrow, which can result in infections, especially on the skin. In these cases, the treatment is done with medication to fight the infection, like antibiotics, being necessary to also do a bone marrow transplant to cure the genetic problem.
Reference values may vary according to the laboratory, but usually corresponds to 2 to 10% of total leukocytes or between 300 and 900 monocytes per mm³ of blood.
In general, changes in the number of these cells do not cause symptoms, you may only feel the symptoms of the disease that is causing the increase or decrease in monocytes. In addition, in some cases you may only discover that there is an alteration when you do a routine blood test.