Desensitization Protocols in Immunologic High Risk Pediatric Recipients.

Abstract

Renal transplantation (Tx) is the modality of choice for renal replacement in children with ESKD. Sensitized recipients have increased significantly and in this group renal tx rate is extremely low. Currently therapies that modulate antiHLA antibodies such as intravenous inmune globuline (IVIG), plasmapheresis (PP) and rituximab have improved their transplantation's chances. We report our desensitization protocols,the outcome of the sensitized patients after tx, and the immunologic post tx monitoring. We has been used two protocols, IGEV 2gr/kg for 3 months (2/6) and IGEV 2 gr/kg two doses plus one dose of rituximab 375 mg/m2 (4/6). Sensitized patients in waiting list for DD received one of these protocols. After one month they were included in a medical urgency list for tx. After tx they received another dose of IGEV 2 gr/kg and prophylactic PP. Donor specific alloantibody (DSA) was monitorized. Induction therapy was timoglobulin, and maintenance:prednisone, MMF and tacrolimus. Antibody mediated rejection (AMR) or T- cell mediated rejection (ACR) were defined by Banff classification. Between January 2009 and December 2013, 160 patients underwent kidney Tx. Six highly sensitized, with PRA more than 40% went into pretransplant desensitization. After 12 months (3-20) they received a kidney from DD. PRA pre desensitization 89,3% (100-71), post desensitization 79,3% (97-39). All the patients had negative CDCXM pretx and 2/6 had positive CFXM pretx. Rejection incidence 33%: 1 cellular acute rejection (CAR), 1 humoral acute rejection (HAR), 1 mixed rejection. 1/6 had a BK nephritis. Observation period was 26,5 month (6-48). Renal function determined by creatinine was: 1.2, 1.0, 1.3 mg/dl at one, three and twelve month postx. At the end of observation period creatinine was 1.3 mg/dl (0,81-2,62). One patient had proteinuria.Patients survival was 100%, graft survival 83,3%. One patient lost the graft for an AMR. Sensitization to HLA antigens is a significant barrier to renal transplantation. New protocols for desensitization with IVIG, PP and antiCD20 antibodies has become sucessfull to allow tx in this group of patients. The highly sensitized patients should be closely monitorized because they have and increase risk of AMR. The same therapies can be usefull to treat AHR.