Studies have shown that patients with ARDS treated with dexamethasone developed VAP earlier, and monocyte human leukocyte antigen DR expression and circulating CD4+ cell counts were significantly reduced.[13] NLR is an indicator of immune balance related to the prognosis of ARDS,[23] and patients with high NLR (NLR ≥ 14.8) had shorter days free of mechanical ventilation and higher in-hospital and 30-day mortality. This evidence concerns the gene CD4 and ventilator-associated pneumonia.