Beyond IL-17: New cytokines in the pathogenesis of HIV infection

Purpose of the review: Alterations in cytokine production have been described since the dawn of HIV research. Cytokinology is rapidly evolving because the cytokine-like functions of arrays of proteins are being recognized. Thus, new cytokines are being investigated within the context of HIV pathogenesis. This review describes novel functions of 'old' cytokines and summarizes the potential role of 'new' cytokines in this disease. RECENT FINDINGS: Old cytokines, such as the common gamma (γ) chain cytokines, were shown to have previously unsuspected biological roles; new cytokines, for example, IL-18, IL-27, IL-32, were recognized as important players in the immunopathogenesis of HIV infection. Finally, hepatocytes were demonstrated to be the main producers of IL-7 in response to various inflammatory signals, transforming overnight the liver in one of the tissues primarily involved in the modulation of immune responses. Summary: Data summarized herein underline the intricacies of cytokine networks. The concept of modulating the immune response using single cytokines is unlikely to succeed. Future therapeutic uses of cytokines will not be effective unless a 'cytokinomics' approach to the study of these important immune modulators is employed. Systematic analyses of cytokine production and of their effects in a biological system will be required.