Notably, although CD8+ T cells have been only occasionally described in patient cohorts or animal studies in the allergy fields38–41, the percentage of CCR4+CXCR3 ̄ type-2 cytotoxic CD8+ T cells (CD8+ Tc2, Fig. 3d, e)42 among living cells was also higher in VAP vs. HC at each time point including baseline, while the percentage of CCR4 ̄CXCR3+ type-1 CD8+ T cells (CD8+ Tc1) was modestly but significantly decreased (Supplementary Fig. 3A). Here, CCR4 is linked to ventilator-associated pneumonia.