Your doctor orders a CBC, you go to the lab, and they draw a syringe of blood from your forearm. A few hours to days later, the results come back: your monocytes are high. Feeling afraid is nothing but ordinary, it is a human reaction, especially when you don’t know what it means. Our ancestors weren’t thrilled when they saw fire, they were terrified and it took them hundreds of thousands of years to use it on their advantage.
In this article, we will explain what does it mean when you have high monocyte count and any blood element in general.
Why do we have cells in our blood?
Blood is a tissue, which means it consists of cells, but unlike other tissues, it is in liquid form. Cells of the blood include red blood cells, almost always abbreviated as RBCs or erythrocytes, white blood cells -or WBCs- which are also termed leucocytes, and platelets. The fluid of our blood is called plasma, and it consists of water, proteins, glucose, and minerals. Each element of our blood has a specific function, and all of them are calibrated perfectly thanks to an advanced control system, both neurological and -to a greater extent- hormonal. The average volume of blood of an adult male is about 5 liters, and the cellular component makes up about 45%.
What is a CBC?
CBC is short for Complete Blood Count, and it remains to be one of the most common tests ordered by physicians worldwide. A venous blood sample is withdrawn into a sterile syringe or container with an added anticoagulant. Then, the number of cells is counted either manually or using a special machine called an analyzer. Next, the hematologist or the pathologist will look at your blood film through a microscope to detect any abnormal cells. Findings are then recorded, and normal values are placed to help the treating physician assess the abnormalities. The main elements of a CBC sheet include:
1. Hemoglobin
This is a measurement of the amount of the protein responsible for oxygen-carrying functions through red blood cells in the blood. A decreased hemoglobin is termed anemia, while an increased level is called polycythemia.
2. Hematocrit
Hematocrit is the ratio of the volume of red blood corpuscles to that of the whole blood. It gives a general look at how many cells the person has; it is low in anemia cases and high in polycythemia.
3. Erythrocytes
They represent the number of red blood corpuscles per cubic milliliters. It is of less clinical significance than the first two but is used to confirm the findings.
4. Platelets
Platelets are not cells by the known definition, but cellular fragments. They are formed of other big cells in the bone marrow called megakaryocytes.
5. Leucocytes or WBCs
Which is the number of white blood cells per cubic milliliter, it is indicative of the state of the immune system. Generally speaking, an increased WBCs count -also termed leukocytosis- means that the body is fighting something, be it bacteria, viruses, fungi, parasites, or tumor cells. Decreased WBCs count, on the other hand, indicates an immune deficiency, whether due to primary affection of the bone marrow or as a reaction to some bacterial and viral infections. It can also occur in some tumors whether those arising from the bone marrow cells or others that appeared elsewhere and spread -or metastasized- to the bone marrow.
White blood cells are then differentially counted according to their main subtypes, this is done by the help of a microscope and blood film with special stains, the primary normal white blood cells are:
a. Neutrophils
Neutrophils form most WBCs with a ratio ranging from 54-62%. Neutrophils are one of the first-line defenses against any offending agent entering the body and are generally increased in cases of bacterial infections and decreased in immune deficiency states namely: HIV infection, bone marrow failure and prolonged immunosuppressive drug therapy.
b. Lymphocytes
Lymphocytes are the second most abundant white blood cells with a ratio of 25-32%. Their level is elevated in viral infections and some cancers and decreased in immune deficiency.
c. Eosinophils
They form 1-3% of WBCs in a healthy human, but they may be elevated in some allergic conditions and parasitic infestations.
d. Basophils
They also form less than 1% of WBCs, but they may be elevated in some infections, such as smallpox and cancer.
e. Monocytes
Monocytes form 3-9% of WBCs and are elevated in many conditions; most of them are benign:
- Viral infections such as Epstein Barr virus, which is responsible for the development of infectious mononucleosis or “kissing fever.”
- Some parasitic infestations, although it is less commonly affected than eosinophils.
- Tuberculosis
- Sarcoidosis, which is a chronic inflammatory lung and lymph node disease.
- Some fungal infections
All the previous conditions see a mild increase in monocytes count. However, an abnormally high level of monocytes which exceeds tens of thousands per cubic milliliter especially if associated with other increase of other WBCs as neutrophils would point towards a possible malignancy. Leukemias are characterized by the uncontrolled high WBCs count and are divided into two main subtypes:
- Myeloid leukemias: which are characterized by increased levels of neutrophils, basophils, eosinophils, and monocytes.
- Lymphoid leukemias: which are characterized by increased levels of lymphocytes.
Both of these conditions are chronic and may be symptomless except for vague symptoms of fatigue and some abdominal pain owing to the enlarged spleen. On the other hand, acute leukemias only have extremely high levels of abnormal cells called blast cells -which are only found in the bone marrow of healthy adults, in the peripheral blood-. Acute leukemias have the typical symptoms of malignancy, with weight loss, abdominal pain, excessive sweating and fever.
How to treat high monocytes?
Contrary to popular belief, doctors don’t treat findings; for example, jaundice is a potentially harmless condition in adults, while the condition that caused jaundice can be life-threatening. Therefore, monocytes are not treated as a separate entity, but as a part of a disease and the main therapy is directed towards the control/eradication of the original condition that caused the monocytes to increase in the first place.
The new trend of using natural remedies to treat separate findings is not only misleading but harmful. An increased monocyte count can’t be treated by diet modifications nor by exercise. Such lifestyle changes are directed towards keeping a healthy body to prevent the conditions that caused their elevation from occurring, but once they are elevated, doctors must search and treat the cause. Therefore, if the cause is tuberculosis for example, an anti-tuberculous antibiotic regimen will suffice to control both the disease and the reaction of monocytes produced.
Leukemias are treated by various regimens depending on the cells affected and whether they are acute and chronic, but for chronic myelocytic leukemias -in which the number of monocytes is very high-, treatment has two goals:
- The first is to control the abnormally high levels of leucocytes which can produce life-threatening conditions called leukostasis. This is achieved by using drugs like Busulfan.
- The second goal is to treat the genetic defect that produced cancer in the first place, and this is done by a group of revolutionary drugs called tyrosine kinase inhibitors, the most commonly used of which are Imatinib and Nilotinib.
The diagnosis of leukemia especially chronic leukemias can never be achieved based on CBC findings alone. Your doctor will order a battery of investigations if he suspects leukemia most commonly bone marrow biopsy and Philadelphia chromosome -which is the main genetic aberration of chronic myeloid leukemia-, which is why self-diagnosis based on CBC alone is entirely wrong. If you did a CBC without a doctor’s consult and found abnormal findings, consult your family physician and save yourself a mostly misplaced worry.