P1758TOCILIZUMAB TREATMENT IN DSA POSITIVE ANTIBODY MEDIATED REJECTION AMONG KIDNEY TRANSPLANT RECIPIENTS

Abstract Background and Aims Pretransplant or de novo donor specific antibodies (DSA) may lead to active or chronic active antibody mediated rejection (a and cABMR) as leading cause of graft loss after kidney transplantation. There is no treatment protocol approved for ABMR. Anti Il-6 tocilizumab (TCZ), inhibitor of DSA production, is a potential approach to stabilize kidney allograft function, however, evidence based results are not available. In our retrospective case series analysis, we assessed the changes in DSA and eGFR during and at the end of treatment with TCZ. Method In our single center case series analysis, 10 kidney transplant patients with biopsy proven ABMR (aABMR 6, cABMR 4, age 43±10.5ys, 6 males, time since transplantation 18(2-119)months, 7 first transplant, serum creatinine 224±80 umol/L at baseline) were studied between January 2017 – June 2019. Total plasma exchange (PE) (5x) was followed by TCZ (8 mg/kg, 1x monthly for 6 months) in case of a and cABMR. Intravenous immunoglobulin (IVIG, 1gr/kg) was added in case of aABMR. Routine laboratory parameters and DSA were reported retrospectively. Results 6 aABMR patients completed the treatment protocol. Class I DSA decreased significantly (MFI 4457(635-14084) vs. 877(595-5678); p=0.007), but Class II DSA remained the same during the treatment (MFI 4725 (586-17615) vs. 8097 (671-14636) p=NS). eGFR of aABMR patients and 1 cABMR patient were stabilized. 3 cABMR patients returned to dialysis. Reversible elevation of liver transaminases were detected in three patients. There was no any serious adverse event recorded. Conclusion The opportunely timed TCZ seems to be effective in reducing Class I DSA and stabilize graft function in patients with aABMR. Further studies are needed to prove the long-term efficacy and the exact role of TCZ in cABMR among kidney transplant patients.