What is a basophil activation test (BAT)?


Basophil granulocyte. Image source: Wikipedia.

Basophil activation test (BAT) relies on CD63 (tetraspanin) - a marker for flow cytometric quantification of in vitro activated basophils.

This figure explains the principle of the basophil activation test by flow cytometry (triple staining): http://bit.ly/3WYD0W and http://bit.ly/fW5Dm

CD63-based basophil activation test (BAT) for diagnosis of food allergy is still in its infancy http://bit.ly/11F0ll

Basophil activation test can be useful for in vitro diagnosis of NSAIDs hypersensitivity: specificity is 100%, sensitivity is 42.85% http://bit.ly/4vnFy1

More markers that can be used in BAT:


  • Basophil-specific ectoenzyme CD203c is a marker for cell activation and a target for flow cytometry-based tests http://bit.ly/3AAtDf

  • CD123 is an interleukin-3 receptor found on pluripotent progenitor cells http://bit.ly/JbxDR

  • CD14 acts as a co-receptor (along with TLR 4 and MD-2) for the detection of bacterial lipopolysaccharide (LPS) http://bit.ly/3CYbPy

  • CD41( Integrin, alpha 2b or platelet glycoprotein IIb of IIb/IIIa complex) participate in cell-surface signalling http://bit.ly/nyQg8

  • CD41 defects (IIb of IIb/IIIa complex) may lead to Glanzmann's thrombasthenia - platelets lack glycoprotein IIb/IIIa http://bit.ly/1xGYG

CD63 and CD203c are used to identify the basophils during activation.

Our innate immune system recognizes LPS via the LPS signal transduction pathway, which has the trimolecular complex of CD14/TLR4/MD2 at the core. CD14 was the first described pattern recognition receptor (PAMP receptor).

Mnemonic:

TLR4 (for LPS)
CD14

Example: Clinical efficacy and immune regulation with peanut oral immunotherapy. Jones SM et al. J Allergy Clin Immunol. 2009 Jul 2.

Basophil activation test compared to skin prick test (SPT) and enzyme immunoassay http://goo.gl/kHhyz - SPT is still the "gold standard".

Basophil activation test in Oxford handbook of clinical immunology and allergy By Gavin Spickett:

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