Cytokines in infectious diseases.

Cytokines are heterogeneous group of proteins that are produced by a wide variety of cells in the body and act as signals between the cells of the immune system. The recent discovery of two distinct subsets of T-helper cells led to the development of a conceptual framework of complex network of cytokine pathways in the regulation of immune responses against a variety of infectious agents. In this brief review, we have attempted to present a concise summary of the current state of knowledge of this complex interaction among cytokines that result in a cascade of biological events leading to inflammatory response and host defense against pathogens.