P111 Analysis of hla antibodies after native nephrectomy in renal allograft recipients

Aim Many centers avoid nephrectomy of chronically rejected kidneys because of fear of sensitization to HLA antibodies. It is not clear if the rise in antibodies is from an overall immune sensitizing event or specific to the removal of the donor organ. We analyzed anti-HLA antibodies following native nephrectomy as a control event to the allograft nephrectomy. Methods Twelve kidney allograft recipients who underwent native nephrectomy for cause had serum samples obtained before the nephrectomy and 1–32 weeks after nephrectomy. All patients remained on clinically indicated immunosuppression. The study was approved as an exempt study by the IRB. The serum samples were tested on a Luminex platform with Single Antigen Class I and Class II beads specific for HLA antibodies. Changes in calculated panel reactive antibody (cPRA) and peak mean fluorescence intensity (MFI) were measured by paired t-test. Results Three of twelve patients (25%) showed an increase in HLA antibodies. One of the sensitized and one of the non-sensitized patients required a blood transfusion during the procedure. Nine patients had no class l or class ll antibody before or after native nephrectomy. The 3 patients who had sensitization to HLA prior to the native nephrectomy all had an increase in antibody post-nephrectomy: pre cPRA = 65 and post cPRA 74, p = 0.02. Two of the 3 sensitized patients showed an increase of MFI in their highest antibody specificity class I MFI (7933 pre and 13733 post) and class II MFI (6200 pre and 8067 post), but this was not significant in this small group. One subject showed increased donor specific antibody, with no significant class I before native nephrectomy, but MFI of A3 of 14800 and B44 of 17600 after native nephrectomy; and class II DR1 MFI of 3300 before (no DR4) and DR1 MFI of 18,200 and DR4 MFI of 15500 after native nephrectomy. There was no incidence of allograft loss. Conclusions HLA antibodies may rise following a native nephrectomy in sensitized patients. Monitoring of HLA antibodies after native nephrectomy may be prudent.