Table 1. Clinically relevant antigens expressed in basophils.
Antigen | CD | Function | Biologic/clinical relevance |
---|---|---|---|
Surface | |||
LAMP-3 | CD63 | TIMP1R | Activation antigen (basotesta) |
C5aR | CD88 | C5aR | Complement-dependent activation |
IL-3 RA | CD123 | IL-3 R | Basophil differentiation and viability as well as basophil activation/function |
ENPP3 | CD203c | n.k. | Basophil detection and enumeration; and activation antigen (basotesta) |
FcERI | n.c. | IgE-R | IgE-dependent activation |
Cytoplasm | |||
2D7 | n.c. | n.k. | Basophil detection in tissue sectionsb |
Basogranulin (=BB1) | n.c. | n.k. | Basophil detection in tissue sectionsb |
Histamine | n.c. | Bioactive amine | Clinical symptoms of anaphylaxis |
Tryptase (alpha pro-tryptase) | n.c. | n.k. | Marker of immature basophilsc (also expressed in mast cells) |
HGF | n.c. | Cytokine | Mediator of angiogenesis (highly upregulated in CML) |
VEGF | n.c. | Cytokine | Mediator of angiogenesis and vascular permeability |
IL-4 | n.c. | Cytokine | Multifunctional regulator of the immune system |
Abbreviations: C5a, complement factor 5a; ENPP3, ectonucleotide pyrophosphatase/phosphodiesterase 3; HGF, hepatocyte growth factor; IL-3R, interleukin-3 receptor; LAMP-3, lysosome-associated membrane protein-3; n.c., not yet clustered; n.k., not know; TIMP1, tissue inhibitor of metalloproteinase 1; VEGF, vascular endothelial growth factor.
Both CD63 and CD203c are widely used as markers of IgE-dependent activation of basophils. In response to IgE-dependent activation, the levels of CD63 and CD203c on basophils increase.
Using conventional stains, basophils are not detectable in routinely processed (formalin-fixed) tissue sections, therefore, immunohistochemistry is required for basophil detection.
In CML tryptase is a valuable marker of immature basophils.