CXCL5 and empyema: Among the six different types of effusions, the mean concentrations of MIF, MIP-3α, IL-1β, and ENA-78 were highest and most significantly increased in CPPE/empyema relative to those in effusions of other etiologies, including UPPE, other exudates, transudates, and MPE (Fig. 1; Table 4).