CD4 and peanut allergic reaction: By using frequencies of Ara h 2- or Ara h 1, 3, and 6-reactive effector-TH2 cells with a cutoff value of 1.05 or 1.35 specific T cells per million CD4+ T cells, respectively, the test could discriminate the PA and sNPA subjects in our cohort with 100% sensitivity and specificity, which validate the fact that a Ara h-specific CD4 TH2 cell response is linked to peanut allergy.