Objective To investigate the clinical efficacy and safety of individualized preconditioning in ABO-incompatible living donor kidney transplantation.Methods A series of 36 living donor kidney transplants across a wide range of ABO blood group incompatibilities using individualized preconditioning protocols were performed from September 2014 to June 2017.Preconditioning included oral immunosuppressants with or without the administration of rituximab,PE or DFPP.Medical records and electronic databases were reviewed for isoagglutinin titers,patient and graft survivals,graft function,rejections,infections as well as surgical complications.Results Of 30 ABO blood group incompatibilities,there were 6 cases of AB to A,2 cases of AB to B,4 cases of A to B,3 cases of B to A,13 cases of A to O (13),and 8 cases of B to O.Median initial ABO antibody titers were 1∶32 (1∶2-1∶256) (IgM) and 1 ∶ 8 (0-1∶64) (IgG),respectively.Individualized preconditioning included oral immunosuppressants alone (10 cases),oral immunosuppressants + PE (4 cases),oral immunosuppressants + PE + DFPP (1 case),oral immunosuppressants + rituximab + PE (16 cases),oral immunosuppressants + rituximab + DFPP (2 cases),and oral immunosuppressants + rituximab + PE+ DFPP (3 cases).After individualized preconditioning,an acceptable ABO antibody titer (≤1 ∶ 16) was obtained on the day of transplantation.Median follow-up duration was 12 months (1-33).Graft and patient survival rate was 94.4％ (34/36) and 100％ (36/36) respectively.Median value of serum creatinine at one year posttransplantation was 89 μmol/L,and eGFR was (81.07 mL/min/1.73 m2).In total,there was one episode of urinary tract infection and upper gastrointestinal tract hemorrhage,two cases of hyperacute rejection (leading to graft loss),acutecelluar-mediated rejection,delayed graft function,bone marrow suppression and pneumonia,and 3 cases of acute antibody-mediated rejection and wound fat liquefaction,respectively.Conclusion Our initial experience indicates that individualized preconditioning protocol based on initial ABO antibody titers is safe and technically feasible,and leads to excellent short-term survival of ABOi living donor kidney transplantation.

Objective:To explore the efficacy and safety of pretreating with oral immunosuppressants alone for ABO-incompatible (ABOi) renal transplant recipients with an initial isoagglutinin titer <1: 8.Methods:From September 2014 to October 2019, 16 cases of ABOi renal transplantation pretreated with oral immunosuppressants alone and 32 cases of ABO-compatible (ABOc) renal transplantation were recruited for comparing the inter-group incidence of graft function, acute rejection, infection and recipient and allograft survival.Results:The 16 ABOi renal transplantations were AB-to-A(n=4), AB-to-B(n=3), A-to-B(n=1), B-to-A(n=4), A-to-O(n=2) and B-to-O(n=2). The initial isoagglutinin titer (IgM & IgG) and that on the date of transplantation were both ≤1∶8. The median follow-up period was 495(90-1696) days. One patient in ABOi group underwent allograft nephrectomy due to hyperacute rejection. The graft survival rates were 93.75%(15/16) and 100%(32/32) in ABOi and ABOc groups respectively. No recipient died. No significant inter-group difference existed in postoperative renal function after 6 months (serum creatinine μmol/L: 114.30±28.13 vs. 106.08±23.80, P=0.38; eGFR ml/min/1.73 m 2: 64.93±19.60 vs. 82.34±22.58, P=0.13). In ABOi group, there were 3 episodes of postoperative infection, 2 episodes of acute rejection within 2 weeks (including 1 episode of hyperacute rejection) and 1 episode of acute rejection after 2 weeks; 5 episodes of postoperative infection, no acute rejection within 2 weeks and 5 episodes of acute rejection after 2 weeks in ABOc group. No significant inter-group difference existed in the incidence of infection or rejection ( P>0.05). Conclusions:Using oral immunosuppressant alone is both safe and feasible for ABOi renal transplantation recipients with an initial isoagglutinin titer ≤1∶8. It may greatly simplify the pretreatment scheme for those with a low initial isoagglutinin titer and lower the incidence of complications.