KIDNEY - SENSITIZED PATIENTS

A. Asderakis, M.A. Ilham, F. Edwards, E. Burrows, S. Lloyd, M. Stephens
Transplant Unit, University Hospital of Wales, 4XW/UNITED KINGDOM

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Introduction In the last few years desensitisation protocols have found widespread application in the setting of live donation. We have shown previously, that re-transplanting patients who have developed donor specific antibodies (DSA), in the setting of cadaveric donation, is possible with good outcome in the presence of cytotoxic negative crossmatch. Aim Review the outcome of all cadaveric re-transplants that were performed with negative cross-match but possessed DSA according to traditional solid phase or flow cytometry methods, and associate the results with the Luminex measured levels of DSA. Method and results From 1998 to 2003 there were 55 retransplants from cadaver donors. As all these patients were transplanted with the knowledge of a negative Cytotoxic crossmatch (CDCXM), no specific changes were made in their immunosuppression management. On retrospective analysis using solid phase assay and then flow cytometry-based techniques we identified 10 patients with DSA. On flow cytometry (FC) cross matching (with donor samples) there were three patients who were T-cell positive and B-cell positive, three were T-cell positive and B-cell negative and four were T and B-cell negative. We conducted retrospectively Luminex single bead assays, on the last available pre-transplant sample, to define the type and level of DSA’s. DSA against either class II [DQ2 (MFI values 4235-9348), DQ6 (88-2224), DQ7 (3073-7014), DQ8 (772-4883)] or in 1 patient class I were identified [A11 (3700-3900), CW 3175]. Median follow up was 6 years. Two kidneys were lost early postoperatively, one due to renal vein thrombosis (on biopsy had no sign of rejection) and one due to recurrent FSGS respectively. No graft was lost due to an acute rejection and no humoral rejection occurred in the 1^st year post transplant. One patient died at 6 years with a functioning graft. Two grafts failed at 6 and 8 years, and 4 grafts are still functioning at 6 to 8 years post transplant giving 5-year graft survival of 80%. Functioning grafts have a mean creatinine of 175 and median of 155 mmol/l. There was no association of the kidney function and the graft survival with the MFI level of DSA on the last pre-transplant sample. ConclusionDSA detection in the presence of negative CDCXM does not always predict an adverse outcome or need for desensitisation even in the presence ofpositive FC crossmatch. Even relatively high levels of DQ DSA might be associated with long- term survival in the absence of pre-transplant desensitisation. Better ways are required to define whichpatients require intensive desensitisation protocols.

Disclosure: All authors have declared no conflicts of interest.