CCL4 and infection: In our study, as the EV concentration in patients was lower than that in controls, we hypothesized that this might have led to a loss of function in the human immune response, which in turn contributed to infection persistence and severity, as in a previously described in vitro model of Pseudomonas aeruginosa infection where the infected cells released fewer EVs that, in turn, carried less CCL4 mRNA, contributing to a less effective immune response [39].