[Cytokine assays].

There is growing interest in the use of immunoassays or bioassays for the measurement of cytokines in body fluids in the assessment of disease. Since bioassays are time-consuming and have problems of reproducibility and specificity, the ELISA method, including commercially available kits, is currently in widespread use. The results of cytokine measurements by these ELISA kits have been found to be consistent and reproducible. However, the detection limit of these kits for almost all cytokines is not sensitive enough to measure cytokine levels in various body fluids in which picogram levels of cytokine variation may be significant. In addition, the effects of soluble cytokine receptors and inhibitors in body fluids on the results of cytokine measurements determined by the ELISA system remain to be clarified. Cytokines have been measured in clotted serum. However, because the serum generates a variety of proteases, the clotting of blood may affect the basal levels of cytokines in the blood. The blood collected in EDTA may be optimal for measuring circulating cytokine levels in blood, as compared with other commonly used anticoagulant methods of blood collection. The measurement of cytokines in body fluids has been of clinical value in several area, including (1) the indication of disease activity and response of therapy in certain diseases, (2) the prediction of prognosis in certain diseases, (3) providing possible explanations for the mechanisms of tissue damage in certain diseases, and (4) the elucidation of pathogenesis of certain diseases.