Bootcongres

Introduction: Peri-transplant removal of anti-blood group ABO antibodies is the cornerstone of all current ABO-incompatible (ABOi) transplantation programs. Protocols differ substantially between centers and have been evolved over the last decade. After observing persistently low anti-ABO titers after transplantation (IgG < 1:8), our center has abandoned post-operative immunoadsorption (IA) as part of the Swedish protocol. Patients and Methods: We studied all 65 consecutive ABOi kidney transplant recipients in our center between March 2006 and October 2013. The pre-operative regimen consisted of rituximab, tacrolimus, mycophenolate mofetil, prednisone, immunoglobulins and IA (median 4 sessions). The first 30 patients received also post-operative IA per protocol (median 3 sessions). After the first 10 patients, the pre-operative anti-ABO titer threshold was changed from 1:8 to < 1:8. We analysed the differences in biopsy-proven acute antibody-mediated (AMR) and mixed cellular and humoral rejections (MAR) at three months in the group with and without post-operative IA. Renal function after one year was analysed in all 51 patients who had completed one year follow-up. Results: In patients with post-operative IA blood group O was overrepresented (87% vs. 43%, p=0.001) and recipients were younger (mean age 49 vs. 57 years, p=0.02). The incidence of rejection was higher in the group with post-operative IA: AMR 6 vs. 3, p=0.19; MAR: 3 vs. 0, p=0.06; AMR or MAR: 9 vs. 3, p=0.03. Median serum creatinine concentration at one year was comparable between patients with post-operative IA (n=26) and those without (n=25): 146 µmol/L versus142 µmol/L, p=0.29. Blood group O, number of HLA mismatches, maximal panel reactive antibodies and age and sex of recipient and donor did not correlate with rejection. In multivariate analysis only the number of HLA mismatches on A, B and DR loci demonstrated a non-significant correlation with rejection (OR 1.58, p=0.08). Conclusion: A modified protocol without routine IA after ABOi kidney transplantation, does not lead to an increase in the incidence of antibody-mediated rejections. Withholding post-operative IA is a safe and more patient-friendly ABOi regimen with lower costs.