PTGDR2 and ventilator-associated pneumonia: Simultaneously, the pathogenic allergen-specific Th2 cells, characterized as CRTH2+ Th2 cells (CD3+CD56-TCRgd-CD4+CD8-CD45RO+CD45RA ̄CXCR3 ̄CCR6 ̄CCR4+CRTH2+) based on the markers established by the previous works11,35,36, were also substantially more abundant in VAP (Figs. 2b, 3a, b).