Basophilic granulocytes are the smallest subgroup of granulocytes , which belong to the white blood cells, the so-called leukocytes . They are called basophilic granulocytes because they are characterized by basophilic vesicles in the cytoplasm.
Vesicles are spherical or egg-shaped cell structures. The term “basophil” comes from chemistry. It is used for substances that have functional groups or properties that react acidically to bases and produce an acid-base reaction with them.
Basophilic granulocytes – the smallest unit of the white defense
Like the rest of the leukocytes, the basophilic granulocytes have the task of immune defense and belong to the non-specific cellular immune system.
Formation and physiology of basophilic granulocytes
Basophilic granulocytes arise from oligopotent myeloid stem cells (CMP) located in the bone marrow. Uni- or bipotent stem cells develop from the CMPs and combine to form cell colonies (CFU).
The cell colony in which basophilic granulocytes are formed is called CFU-BASO. The basophiloblasts arise from this cell colony. Through differentiation, they develop into basophilic granulocytes. The messenger substances histamine, heparin, serotonin and other mediators are contained in the vesicles of the basophilic granulocytes.
The messenger substances are released via receptors located on the cell surface. Basophils interact with other white blood cells in an immediate allergic reaction such as hay fever.
Purpose and normal value of basophilic granulocytes
Basophils play an important role in the human immune system. They are responsible for controlling allergic reactions and fighting off parasites.
A differential blood count normally shows up to 50 or up to 100 basophilic granulocytes per microliter. This accounts for one percent of the total leukocytes. The phenomenon of different values from different laboratories is related to the respective reference values. If there is an increase in basophilic granulocytes, the physician speaks of basophilia, and if they decrease, of basopenia.
Values for increased basophilic granulocytes?
The isolated increase in the level of basophilic granulocytes is extremely rare. More often, basophilia is associated with an increase in eosinophilic granulocytes . Possible causes for reduced values are:
- allergic diseases ,
- Ulcerative colitis, a chronic inflammatory bowel disease,
- rheumatoid arthritis that occurs in young adulthood,
- diseases caused by parasites,
- Blood diseases such as chronic myelogenous leukemia (CML), polycythemia and idiopathic myelofibrosis,
- Diseases associated with the symptom of hyperlipidemia such as nephropathies, myxedema and diabetes mellitus.
If a patient has CML, increasing basophilia indicates that the disease is becoming more severe.
Low basophil granulocyte values?
The level of basophilic granulocytes usually falls together with the total granulocyte level. Possible causes of basopenia include:
- an increased level of the steroid hormone glucocorticoid, as occurs in Cushing’s syndrome,
- an overactive thyroid gland, known as hyperthyroidism,
- a radiotherapy,
- Stress,
- the influence of drugs.
In women, there is a 50 percent drop in basophilic granulocytes during ovulation compared to the previous value. If the values remain permanently low, a possible immune deficiency is the result.
The individual values are only meaningful if the attending physician interprets them with regard to previous illnesses and the general state of health of the patient. Other blood values in the differential blood count must also be considered. Particularly low values are interpretative since the normal value of the basophilic granulocytes is already so low.
