Monocytes - What they are and Reference Values
Monocytes are a group of cells of the immune system that have the function of defending the organism from foreign bodies, such as viruses and bacteria. They can be counted through blood tests called leukogram or complete blood count, which brings the amount of defense cells in the body.
Monocytes are produced in the bone marrow and circulate for a few hours in the circulation, and proceed to other tissues, where they undergo a differentiation process, receiving the name of macrophage, which has 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.
The increase in the number of monocytes, also called monocytosis, is usually indicative of chronic infections, such as tuberculosis, for example. In addition, there may be an increase in the number of monocytes due to ulcerative colitis, protozoal infection, Hodgkin's disease, myelomonocytic leukemia, multiple myeloma and autoimmune diseases such as lupus and rheumatoid arthritis.
The increase in monocytes does not normally cause symptoms, being noticed only through the blood test, the complete blood count. However, there may be symptoms related to the cause of monocytosis, and should be investigated and treated according to the doctor's recommendation. Understand what the blood count is and what it is for.
When monocyte values are low, a condition 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 can also cause a decrease in the number of monocytes.
The appearance of values close to 0 of monocytes in the blood is rare and, when it occurs, it can 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, treatment is done with drugs to fight infection, such as antibiotics, and it may also be necessary to have a bone marrow transplant to cure the genetic problem.
The reference values may vary according to the laboratory, but it usually corresponds to 2 to 10% of the 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 in the patient, who only feels the symptoms of the disease that causes the increase or decrease in monocytes. In addition, in some cases the patient also only discovers that there is some change when doing a routine blood test.