CD26−/low CD4+ T cells contain effector lymphocytes with an advanced differentiation stage. (a) CD4+ T cells were identified by using the same strategy as in Fig. 1a. Then, CD127 and CD26 markers were used to delimitate three CD4+ lymphocyte subsets (right dot plot): CD26−/low (including CD127− and CD127‘+ cells), CD26int and CD26high. (b) Phenotyping of CD26−/low, CD26int, and CD26high subsets according to the surface expression of CD27, CD28, CCR7, CD45RA, and CD127. Data were obtained from 6 donors (3 healthy subjects and 3 moderate-severe allergic asthmatics) and expressed as % of positive cells for each marker (median ± IQR1-3). Kruskal-Wallis test followed by Dunn’s multiple comparison post-hoc analysis was used to assess significant changes between groups. *P < 0.05, **P < 0.01, ***P < 0.001. (c) Expression of each marker (Percentage of positive cells; median ± IQR1-3) in CD26−/low lymphocytes between healthy subjects (HC; N = 3) and moderate-severe allergic asthmatics (MSAA; N = 3). t-test was used to assess significant changes between HC and MSAA. *P < 0.05.