Granulocyte basophile

Small subgroup (in the differential blood count: 0-1%) of leukocytes) which are characterized by basophilic vesicles in their cytoplasm (basophilic - name for substances which have functional groups or properties which produce an acid-base reaction with bases) Basophilic granulocytes belong to the unspecific cellular immune system.

Basophilic granulocytes develop in bone marrow from oligopotent CD34 + myeloid stem cells. Under certain conditions, such stem cells mature into basophiloblasts, which differentiate into basophilic granulocytes. Growth factors for basophilic granulocytes are mainly IL-3(interleukin-3), IL-5(interleukin-5) and GM-CSF. The vesicles of basophilic granulocytes contain, among other things, histamine, heparin and serotonin. Furthermore, activated basophilic granulocytes produce mediators such as PAF, prostaglandin D2 and leukotrienes (LTC4, LTD4, LTE4).

Anaphylactoid degranulation and exocytosis with consecutive vascular permeability increase and edema formation is mediated by high-affinity IgE receptors on the cell surface. This reaction occurs when these receptors are cross-linked by IgE-bound allergens.

Basophilic granulocytes interact with other leukocytes and play an important role in the complex initiation and control of allergic reactions and in the defence against parasites. For example, basophilic granulocytes form a functional unit with mast cells and induce IgE synthesis in plasma cells.

It is remarkable that basophilic granulocytes in humans react much more sensitively to allergic reactions than the mast cell, which is much more common. Basophils also contain interleukin-4, which promotes the development of Th2 cells.

An increase of basophilic granulocytes is called basophilia, their decrease is called basopenia. Basophilic granulocytes can also occur in tissue, especially in the skin and the mucous membranes of the respiratory tract.

1. Raap U et al (2015) The role of basophils in allergic inflammation. Allergo J 24: 128-33