ABSTRACT
Despite the considerable progress achieved in cytokine research and the major breakthroughs on the role of cytokines in the pathophysiology of a wide array of diseases as demonstrated in this volume, there is not yet a consensus as to which cytokine/cytokine receptor assays may be mandatory for diagnosis and prognosis in the clinic. This may be attributed to several reasons. Unlike hormones that are characterized by a permanent though physiologically regulated secretion by specialized cells, most cytokines are produced by a large variety of cells during a short period of time following an activating signal. They act preferentially in the microenvironment of their production sites according to a paracrine and autocrine fashion explaining thus their low circulating levels. Moreover, their half-life in blood is very short and is profoundly altered by their association with various ligands (soluble receptors, antibodies, binding proteins). In
addition, the cytokine network is so redundant that the determination of a single cytokine at a given time is unlikely to reflect the complex dynamics of a coordinated cytokine response or its dysregulation. Despite all the above mentioned difficulties, the literature on cytokine alterations in many diseases including infection, cancer, autoimmune disorders and inflammatory diseases or in immunotherapy is so abundant that it overcomes any attempt of reviewing.
