Our laboratory research is focused on kidney ischemia reperfusion injury (IRI), the leading cause of acute kidney injury in native kidneys and allografts. We study microvascular events during the early initiation period of IRI, as well as repair, with lymphocytes being our mediator of interest. We found that CD4 cells, as well as other lymphocytes, have an important role in modulating injury and repair after IRI. We are exploring mechanisms of lymphocyte trafficking to injured kidney, interplay between lymphocytes and other leukocytes in IRI, the role of infiltrating vs. resident lymphocytes, antigenic determinants of lymphocyte activation, and effects of IRI on immune memory and alloreactivity. Emphasis is on experimental approaches on the bench that will lead to new diagnostics and therapeutics translatable to humans. Furthermore, given that kidney IRI is associated with increased mortality in native kidneys via effects on distant organs, we are studying mechanisms of cross talk between injured kidney and distant organs that ultimately leads to patient demise. For these studies we are using integrative physiologic, molecular and functional assays to simplify complex signals during inter-organ communication. Finally, we are involved in clinical trials in kidney transplant patients to validate findings in the lab as well as improve outcomes in both transplant recipients and live donors. Our research program is also a major training vehicle for students, post-doctoral fellows and faculty interested in acute kidney injury and transplantation. Our work is supported by the NIDDK, NHLBI, National Kidney Foundation and industry.