T-cell Contribution to Injury and Regenerative Processes in Kidney Diseases: Focus on Regulatory T Cells

This chapter discusses the diverse role of T cells in immune responses that occur in several kidney diseases and focuses on the regulatory effect of T-cell subsets contributing to the regenerative processes. Kidney diseases in which T cells are implicated in the pathophysiology can be categorized into three different diseases: glomerulonephritis, acute kidney injury (AKI), and transplantation. The role of Tcells is discussed in more detail for each disease. T cells are key participants in immune responses occurring in many different kidney diseases. The injured kidney not only is the target of the immune system but also actively participates in aggravating or suppressing intrarenal immune responses. Ischemic acute kidney injury (AKI) is often simulated by animal models of ischemia-reperfusion injury (IRI). Postischemic kidneys contribute to immune responses by recruiting inflammatory cells including T cells and other leukocyte subsets, and generating proinflammatory cytokines and chemokines. Postischemic kidneys also recruit leukocytes by upregulating the quantity and avidity of adhesion molecules, and a series of steps occur which in turn increase microvascular permeability. Anti-intercellular adhesion molecule-1 (ICAM-1) antibody is shown to protect normal mice from renal IRI, and many studies have demonstrated similar findings in different experimental models. Recently, regulatory T cells (Tregs) are under active investigation in several kidney diseases.