TNF and infection: Can the measurement of circulating, host-derived markers of inflammation and infection such as IL-4, IL-6, IL-10, TGF-β, TNF/TNFR, CRP, SAA, procalcitonin (PCT), and sTREM, as well as HLA-DR expression on circulating monocytes, be used, in association with clinical scoring systems, to provide potentially valuable information regarding the pro-inflammatory status of the patient at the time of admission and during the course of antimicrobial therapy?