Proficiency tests to evaluate the impact on assay outcomes of harmonized influenza-specific Intracellular Cytokine Staining (ICS) and IFN-ɣ Enzyme-Linked ImmunoSpot (ELISpot) protocols

Gwenn Waerlop, Geert Leroux‐Roels, Anke Pagnon, Sarah Begue, Bruno Salaun, Michel Janssens, Donata Medaglini, Elena Pettini, Emanuele Montomoli, Elena Gianchecchi, Teresa Lambe, Leila Godfrey, Maireid Bull, Duncan Bellamy, Håkon Amdam, Geir Bredholt, Rebecca Jane Cox, Frédéric Clément