Cytokines: Molecular keys to homeostasis, development, and pathophysiology

AbstractIdentification and definition of the role and diversity of action of cytokines, the regulatory proteins including lymphokines, monokines, interleukins, interferons, and a variety of other growth factors produced by virtually every nucleated cell into the body and having pleiotropic regulatory effects on hematopoietic and many other cell types [Thompson, 1991], are in the forefront of biomedical research. The explosive development of cytokine research is reflected by the inclusion of “cytokine,” first introduced as a term in 1974 to recognize that lymphokines could be produced by other than lymphoid cells in 4,267 biomedical articles published by the end of 1992. From the initial reference to cytokines in 1974 to inclusion in 45 articles in 1985, the doubling of citations each succeeding year, together with 45% of all the citations since 1974 occurring in 1992 alone, attests to the continued rapid expansion of this area of biological research. The important roles of cytokines in many physiological processes and pathophysiological conditions, although largely descriptive in nature, were recognized during the early development of this field of investigation [Balkwill and Burke