A review of the role of immune cells in acute kidney injury.

Acute kidney injury (AKI) is a systemic disease occurring commonly in patients who are critically ill. Etiologies of AKI can be septic or aseptic (nephrotoxic, or ischemia-reperfusion injury). Recent evidence reveals that innate and adaptive immune responses are involved in mediating damage to renal tubular cells and in recovery from AKI. Dendritic cells, monocytes/macrophages, neutrophils, T lymphocytes, and B lymphocytes all contribute to kidney injury. Conversely, M2 macrophages and regulatory T cells are essential in suppressing inflammation, tissue remodeling and repair following kidney injury. AKI itself confers an increased risk for developing infection owing to increased production and decreased clearance of cytokines, in addition to dysfunction of immune cells themselves. Neutrophils are the predominant cell type rendered dysfunctional by AKI. In this review, we describe the bi-directional interplay between the immune system and AKI and summarize recent developments in this field of research.