#3880 Outcomes of ABO-incompatible living kidney donor transplantation according to isoagglutinin titers

Abstract Background and Aims ABO-incompatible (ABOi) living kidney donor transplantation (LKDT) has been successfully adopted by transplant centres worldwide. A reduction in isoagglutinin titres < 1:8 is (arbitrary) necessary for ABOi-LKDT and elevated titres prior to desensitization or a rebound after the procedure can potentially impact on the LKDT outcomes. The aim of the study was to analyse the ABOi-LKDT short and mid-term outcomes according to the initial, after desensitization and post-LKDT isoagglutinin titres. Method We retrospectively reviewed the evolution of kidney function (KF) in 32 patients undergoing ABOi-LDKT in Hospital del Mar between June 2014 and December 2024. KF 7 days, 3, 6, 12, 24 and 36 months after LKDT was evaluated according to maximum baseline, after-desensitization and maximum post-LKDT both IgG and IgM isoagglutinin titers, considering also post-LKDT rebound. Desensitization consisted of rituximab administration and apheresis (plasmapheresis, immunoadsorption, or both). Infection rate, graft and patient survival were also assessed. Results We analyzed 32 ABOi-LKDT recipients (28 male) with a mean age of 57.8 ± 13.4 years and a mean follow-up of 36 months [14.8–56.3]. No LKDT recipient had baseline isoagglutinin titres >256 and all of them had ≤8 titres before surgery. A higher number of apheresis sessions was necessary in those cases with higher IgG maximum baseline isoagglutinin titres (<8: 1[1–2]; 64: 3[2.5–4]; 128: 3[2.5–3.5]; 256: 3[3–3]; p< 0.002). Isoagglutinin titres at evaluated time-points or rebound after LKDT had no influence on the ratio of acute rejection (15.6%), infectious complications (cytomegalovirus 18.7%; BK virus 15.6%). We did not observe differences in patient survival or graft survival during follow-up, according to isoagglutinin titres considered or rebound post-LKDT. Conclusion Maximum baseline IgG or IgM isoagglutinin titers, after-desensitization and maximum post-LKDT had no influence on graft survival or rejection ratio. Those recipients who needed a higher number of apheresis sessions to achieve pre-LKDT isoagglutinin target, did not have a higher rate of infections.