Table 1.

Basophil identification and activation markers

	Marker	Cell expression	Description and gating strategy	Reference
Identification markers	CCR3	Basophils, mast cells, Th2 lymphocytes	Stable marker for identification, may need further differentiation from other cells such as use of CD3	[6–9]
	CD203c	Basophils, mast cells, CD34+ progenitor cells	Widely used identification marker and expressed in low levels of resting cells. Upregulation has been reported to be representative of piecemeal degranulation	[10, 11]
	CD123	Basophils, plasmacytoid dendritic cells	Highly expressed in these cells; HLA-DR can be used to differentiate between HLA-DR+ dendritic cells	[12, 13]
	IgE	Basophils, monocytes, dendritic cells	Other cells expressing high affinity IgE receptor FcɛRI can be differentiated by also using HLA-DR. High variability in individuals has been reported	[6, 14]
	CRTH2	Basophils, eosinophils, Th2 lymphocytes	Differentiation from eosinophils by side scatter or T lymphocytes by CD3 is reported	[15]
Activation markers	CD63	Basophils, mast cells, platelets, macrophages	Widely used activation marker and an accurate marker of anaphylactic degranulation	[7, 11, 16, 17••]
	CD107a, CD107b	Various cell types including basophils, mast cells, T cells and NK cells	CD107a and CD107b was found to be only expressed by activated basophils and its upregulation was similar to CD63. CD13 and CD164 has an expression profile comparable to CD203c	[18]
	CD13	Basophils, myeloid cells
	CD164	Basophils, CD34+ progenitor cells
	CD69	Basophils, lymphocytes, neutrophils, monocytes, eosinophils	Expressed progressively when stimulated with IL-3; however, found to be weakly expressed to IgE mediated stimulation	[19, 20]
	p38 MAPK, STAT5	Various cell types	Basophilic phosphorylation of intracellular molecules can alternatively be used to measure basophil activation	[21, 22]