In this context, in the experimental P. aeruginosa pneumonia model, we found that the administration of IgM-IG combined with colistin was useful in reducing the bacterial lung concentration, which points to the possible efficacy of antibiotics combined with IgM-IG to diminish the mortality of multidrug-resistant P. aeruginosa pneumonia in human beings, which may be as high as 33.3% in patients with ventilator-associated pneumonia treated with colistimethate sodium (Mogyoródi et al, 2022). Here, CD40LG is linked to ventilator-associated pneumonia.