Acute antibody mediated rejection (AMR) used to be a major problem in ABO-incompatible KidneyTransplantation (ABOi-KTx), and currently rituximab has been accepted to reduce the prevalence of AMR. Furthermore, we have tested to reduce and exclude rituximab in ABOi-RTx. Patients and Methods: One hundred adult patients, 62 females and 38 males with a mean age of 50 years (21-75), underwent ABOi-KTx between January 2007 and February 2012. All patients received 2 weeks of mycophenolate mofetile and predonisolone before transplant, followed by calcineurin inhibitor (cyclosporine in 80 or tacrolimus in 20 cases) and basiliximab after transplant. The patients with starting titer of 32x or more (SD group: n=77) received low dose rituximab (100 or 200mg/body x2) and 4 times of pre-transplant plasmapheresis (PP). SD group included 7 patients with pre-existing donor specific antibody (DSA). For the patients with starting titer below 16x (LR group: n=23), rituximab was exclude from desensitization therapy and pre-transplant PP was reduced to 2 times.Results: With a mean observation period of 32 (9-70) months, 3 and 5 years patient and graft survival are 98% in SD group and 100% in LR group. 9%(7/77) of SD group and 13 %( 3/23) of LD group were treated for clinical and subclinical T cell mediated rejection. Clinical AMR were observed in 3.9%(3/77) of SD group, and successfully treated with additional PP/IVIG and steroid pulse therapy. By stepwise regression analysis, pretransplant IgG titer more than 64x revealed significant predictive factor for clinical AMR. Subclinical AMR was observed 3.9%(3/38) of SD group, 2 of them had pre-existing DSA. None of LR group developed clinical or subclinical AMR. Cytomegalovirus infection was observed 31%(24/77) of SD group and 13%(3/23) of LR group under pre-emptive therapy principle. Conclusions: This study suggests that rituximab can safely be excluded from the desensitization protocol of ABOi-KTx in low risk patient population. The amount of rituximab can be reduced in standard and high risk patients without significant increase in prevalence of AMR. Furthermore, reduction of pretransplant IgG titer to less than 32x may reduce the prevalence of AMR.
To cite this abstract in AMA style:Narumi S, Watarai Y, Yamamoto T, Tsujita M, Hiramitsu T, Nanmoku K, Goto N, Katayama A, Ueki T, Takeda A, Morozumi K, Uchida K, Kobayashi T. Minimization of Immunosuppression for ABO-Incompatible Kidney Transplantation Based on the Strength of Pretreatment Anti A/B Antibody Titer [abstract]. Am J Transplant. 2013; 13 (suppl 5). https://atcmeetingabstracts.com/abstract/minimization-of-immunosuppression-for-abo-incompatible-kidney-transplantation-based-on-the-strength-of-pretreatment-anti-ab-antibody-titer/. Accessed April 18, 2021.
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