WHAT IS THE RELEVANCE OF CIRCULATING CYTOKINES IN SEPSIS ?
The sensitivity of monoclonal antibodies and assays to detect cytokines in plasma, the bound versus free cytokine ratio, and cytokine renal clearance are the most important factors influencing cytokine plasma levels. In fact, the presence or absence of detectable levels of cytokines within biological fluids reflects a complex balance between enhancing and inhibitory signals acting on producer cells, production and catabolism, cytokine binding to target cells, and the modulation of their receptors on the cell surface5. Furthermore, their presence does not necessarily parallel their activity, and a possible interplay between a given cytokine and its relative inhibitor (if known) should be considered5. Despite the fact that high plasma levels may reflect increased production, these levels do not necessarily represent enhanced bioactivity. There are several factors that may help to explain the incongruities seen in the cytokine-bioactivity story. One such factor is genotypic predisposition