(a–c) Illustration of the number of CD8⁺ T cells staining with each tetramer (P3 A, P5 B, P6 C) per million CD8⁺ T cells for each of the subject groups. NA, nonatopic; AA, atopic asymptomatic; S, atopic symptomatic. (d) An example of tetramer staining of PBMCs from an A*0201–positive atopic symptomatic donor with the P6-based tetramer: x axis represents staining with tetramer and y axis represents staining with anti-CD8. In this example, 0.12% of CD8⁺ T cells stained with the tetramer. (e and f) Examples of negative control staining with e showing PBMCs from an A*0201–positive nonatopic donor and f showing PBMCs from an A*0201–positive atopic stained with an A*0201-tetramer containing a peptide derived from hepatitis B core. The horizontal gates have been applied to include the CD8-high population.