LATE BREAKING II

S.J. Cohney¹, R.G. Walker¹, A.J. Robertson¹, N. Suh¹, P. Hughes¹, R. Masterson¹, S. Flint¹, E. Vanhardeveld¹, R. Millar¹, B. Bennett¹, C. Hogan², M. Haeusler^2
1Nephrology, Royal Melbourne Hospital, Parkville/AUSTRALIA, ²Haematology, Royal Melbourne Hospital, Parkville/AUSTRALIA

Body: INTRODUCTION: We & others have reported successful ABO incompatible renal transplantation (ABOi) using conventional immunosuppression and removal of anti-blood group antibodies (without splenectomy or Rituximab). Here we report outcomes of 17 patients undergoing ABOi using conventional immunosuppression without antibody removal. While this has previously been reported with A2 donors, this is the first series reporting successful ABOi without antibody removal involving other donor/recipient incompatibilities including A1 to O. METHODS: Patients with low anti-blood group titres were selected: diamed gelcard ≤ 8 (median 4), orthomed ≤ 32 (median 8), tube ≤ 128 (median 32). Titres were evaluated by all 3 methods at baseline; clinical decisions were predominantly based on “orthomed”. Immunosuppression was identical to that administered to concurrent ABO compatible transplant recipients at our centre, except Mycophenolate Mofetil (MMF) was commenced 7 to 10 days earlier. All received Basiliximab induction, commencing Tacrolimus & Prednisolone just prior to transplantation. Tacrolimus targets were: 8ng/ml to 12ng/ml for 2 wks, 8ng/ml to 10ng/ml to 1mth, 5 ng/ml to 8 ng/ml to 3mths, 4 ng/ml to 6 ng/ml from mth 3 to 12, and 2ng/ml to 4ng/ml thereafter. RESULTS: 17 patients met the criteria, constituting ~ 25% of ABOi patients evaluated at our centre. Incompatibilities were B to A (7 patients), A₁ to O (3), B to O (2), A1 to B (2), A₂ to O (1), AB to A (1), A2B to A (1). Median Tacrolimus levels were 7ng/ml at 1mth, 6ng/ml at 3mths and 4.1ng/ml at 12mths. Prednisolone was tapered to 5mg by 8 to 12 weeks, and MMF doses ranged from 1g to 1.5g per day (divided doses) at 3 months. Ten Patients have had their transplants beyond 12mths, and at a median follow up of 18 months (1wk to 33mths), patient & graft survival are 100% with stable renal function in all recipients median creatinine 98umol/l (80 umol/l to 132 umol/l), median GFR 66mls/min (48mls/min to 91mls/min). Allowing for differences in body habitus, recipient and donor renal function are similar in all cases. There have been no episodes of antibody mediated rejection, and one episode of subclinical borderline cellular rejection on a 3mth protocol biopsy; the latter was treated with oral steroid, with no rejection on a 12 month biopsy. Protocol biopsies have been performed on 14 patients at 3 and 12 months respectively. All biopsies are C4d negative, contrasting with the positive C4d staining seen in many otherwise histologically normal biopsies of patients with higher titre undergoing ABOi. No patient has Transplant Glomerulopathy. There have been no opportunistic infections and one patient with preexisting glucose intolerance has developed Diabetes Mellitus CONCLUSION: Patients with low levels of anti-blood group antibodies can safely undergo ABOi renal transplantation without antibody removal, splenectomy or Rituximab, reducing morbidity, inconvenience, & cost, for some patients. This may increase the applicability of ABOi & has implications for (i) Paired Kidney Donation, (ii) Deceased donor programmes with disparate waiting times according to blood group, & (iii) ABOi transplantation of non-renal solid organs from deceased donors

Disclosure: All authors have declared no conflicts of interest.