Cytokine quantitation: technologies and applications.

Assessment of cytokines in body fluids, cells or tissues provides important information in understanding of disease process and designing treatment strategies. Today, wide range of cytokine assays are available, including; measurement of levels of cytokines (direct) or cytokine soluble receptor levels (indirect) in body fluids or cellular supernatants (immunoassays and cytokine bioassays), measurement of cytokines produced by population of cells (multiparametric flow cytometry, magnetic beads based quantitation of cytokine producing cells, mRNA based assays), measurement of cytokines produced by single cells (Enzyme-linked immunospot (ELISPOT), Intra-cytoplasmic cytokine staining (ICC), mRNA based assays) and detection of cytokines in tissues (immunostaining). Improved understanding of cytokine interactions has led to a consensus that simultaneous assessment of many cytokines in a biological sample provides more comprehensive information rather than assessing a single cytokine. Thus, technologies that measure one cytokine at a time are being gradually replaced by multiplex-type formats (DNA and protein microarrays).