Fax +41 61 306 12 34 E-Mail karger@karger.ch www.karger.com Minireview Nephron Clin Pract 2011;118:c173–c181 DOI: 10.1159/000321381 Urinary Biomarkers in Acute Kidney Transplant Dysfunction Nada Alachkar   a Hamid Rabb   a Bernard G. Jaar   a–c   a  Division of Nephrology, Department of Medicine, The Johns Hopkins University, b  Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, and c  Nephrology Center of Maryland, Baltimore, Md., USA Introduction Kidney transplant remains the treatment of choice for end-stage renal disease (ESRD) patients; it extends their survival and improves their quality of life. Recent data showed that there are 89,707 patients registered on the kidney transplant waiting list at the United Network for Organ Sharing (UNOS) for kidney and 2,274 for kidney- pancreas transplants; kidney transplants performed dur- ing the year of 2009 were: 16,830 kidneys – 10,442 from deceased donors, and 6,388 from living donors [1]. Early diagnosis of renal allograft dysfunction is cru- cial for the management and long-term survival of the transplanted kidney. Acute kidney injury (AKI) of the allograft can result from different etiologies. Early after transplantation, acute tubular necrosis (ATN) manifest- ing as delay graft function (DGF) or slow graft function; acute rejection (AR) or drug toxicity (e.g. calcineurin in- hibitor) are the leading causes of AKI. AR, ATN, and cal- cineurin inhibitor toxicity continue to be major causes of renal allograft dysfunction along with other causes like infections (e.g. BK and CMV viruses, pyelonephritis), ob- struction, and recurrence of the original disease. Clini- cians have been searching for non-invasive tools that Key Words Kidney transplant  Urinary biomarker  Acute rejection  Acute kidney injury Abstract Background: Acute kidney injury (AKI) is a common medical problem among kidney transplant recipients, which may cause a significant impact on patient and allograft survival. Currently, an allograft biopsy remains the ‘gold standard’ for assessing the cause of impaired kidney function. Limitations of the allograft biopsy include the risk of bleeding, injury to the adjacent viscera, and the possibility of sampling error leading to an inadequate diagnosis. Methods: We conduct- ed a comprehensive review of the literature and main pub- lished data that discussed the most relevant biomarkers in acute allograft dysfunction, along with their clinical signifi- cance. Results: There have been significant discoveries of several important biomarkers that correlated with biopsy findings, clinical outcomes and possibly graft survival. Con- clusion: The discovery of surrogate biomarkers in kidney transplantation is an evolving field of crucial importance that mandates further collaborative efforts. Copyright © 2010 S. Karger AG, Basel Published online: December 16, 2010 Nada Alachkar, MD The Johns Hopkins University School of Medicine 720 Rutland Ave., Ross 971 Baltimore, MD 21205 (USA) Tel. +1 410 614 9225, Fax +1 410 614 1643, E-Mail nalachk1  @  jhmi.edu © 2010 S. Karger AG, Basel 1660–2110/11/1182–0173$38.00/0 Accessible online at: www.karger.com/nec