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#166
SUCCESSFUL RENAL TRANSPLANTATION BY UTILIZATION OF A THREE WAY PAIRED KIDNEY EXCHANGE.
Julie A. Graziani, CHS, Laura Schenfelder, CHT, Robert A. Montgomery, MD, PhD, Janet Hiller, MSN, Andrea A. Zachary, PhD and Mary S. Leffell, PhD. Baltimore MD, USA, Johns Hopkins School of Medicine, 21205, Medicine and Surgery.

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Three patients (S2, K1, M4) were referred to our center for consideration in a desensitization protocol for highly sensitized patients awaiting renal transplantation. Each patient had at least one potential living donor. AHG (T cells) or one wash-CDC (B cells) crossmatches (XM) with potential living donors were positive with titers > 1024 for each patient. S2, K1, and M4 had well defined HLA antibody to multiple class I and class II antigens with class I and/or class II PRAs of 82, 98 and 100, respectively, by solid phase immunoassay. Based on ABO and unacceptable antigens, the probability of finding a suitable donor in the deceased donor pool was .008, .033, and .029 for S2, K1 and M4 respectively. Our center considers paired kidney exchange (PKE) as an alternative to desensitization for patients with titers >256. The traditional PKE involves swapping the donors of two live donor pairs to achieve ABO compatibility. This case involved exchanges to overcome sensitization to HLA. Because of the broad sensitization, a three-way swap was necessary. S2 and K1 achieved a negative flow cytometric crossmatch (FCXM). M4 achieved a significantly lower titer (4) considered amenable to treatment using plasmapheresis/low dose CMVIg. M4 had a negative AHG XM at the time of transplant and post transplant became negative by FCXM. All three patients maintain excellent renal function. Using a PKE program to overcome sensitization to HLA provides an opportunity for transplantation of patients who might otherwise experience lengthy waiting times, avoids the cost associated with prolonged waiting times and desensitization, and reduces the drain on the already insufficient deceased donor pool.