**1. Introduction**

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104 Current Issues and Future Direction in Kidney Transplantation

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With the evolution in our understanding of the human leukocyte antigen (HLA) system, there have been substantial improvements in the HLA-typing techniques and the ability to detect anti-HLA antibodies, allowing accurate assessment of immunological risk among potential renal transplant candidates. Specifically, flow cytometry and the solid phase assay such as the enzyme-linked immunosorbent assay (ELISA) and Luminex technology have improved the sensitivity of detecting low levels class I and II donor-specific anti-HLA antibodies (DSA). Although there is now established evidence showing the presence of DSA is associated with a greater risk of antibody-mediated rejection (AMR) and early graft loss, the clinical signifi‐ cance of low levels DSA remains unclear. As a result of prior sensitizing events, there has been an expansion in the number of highly sensitized transplant candidates with multiple anti-HLA antibodies. Management of these candidates for the preparation of transplantation continues to be a subject of intense debate. In this chapter, we will discuss the identification of potential clinically relevant DSA detected by the different assays including the 'acceptable' level of clinically significant DSA and the advantage of C1q-positive DSA in further stratifying the immunological risk of transplant candidates. The association between DSA and non-DSA with graft and patient outcomes following kidney transplantation will be discussed in greater detail. Furthermore, we will examine the transplant outcomes of highly sensitized patients under‐ going desensitization regimens and to determine the optimal desensitization regimens along with their risks and benefits.

© 2013 Dheda et al.; licensee InTech. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2013 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
