Introduction: It is known that renal transplant recipients with preformed donor specific antibodies (DSA) have poorer outcomes associated with episodes of acute rejection (AR) and suboptimal allograft function compared to their counterparts without sensitization. In contrast, simultaneous liver and kidney (SLK) transplantation can be performed with a positive cross match and significant preformed DSA with no notable decrease in graft function and survival. In a study of 86 patients who underwent SLK at our institution, our objective was to determine if the presence of class I or class II DSA had any adverse effect on renal allograft function and survival at one year.
Methods: We retrospectively analyzed 86 SLK recipients in our institution from 2009-19. We measured DSA by single antigen assays looking at Class I HLA and Class II HLA with a positive threshold to be 2000 MFI. We categorized patients on whether they were positive for Class I or Class II DSA and evaluated for allograft outcomes and episodes of liver or kidney rejection. Patients received tacrolimus, mycophenolic acid, and steroids without antibody induction. Renal biopsies were performed for cause, not per protocol.
Data: Our preliminary data show the mean patient age was 55 years, and 60% were male.  The mean MELD score was 34. The etiology of cirrhosis was HCV in 24%, NASH 16%, Alcoholic Liver disease 10% and HCC 10.5%. Post SLK, 28% of the patients’ required continuous renal replacement therapy within 24 hours. 40.6% of patients have DSA. 11.6% had class I and 29% had class II.  Patient survival 1 year post SLK is 92% and 87.3% at 3 years.  No difference in survival was found between patients with and without preformed DSA. Four patients experienced an episode of acute liver rejection, and three patient had an episode of acute kidney rejection. There were no differences in the incidence of AR between patients with and without DSA. We found there was no significant difference in eGFR at 6 months, 1 year, 3 years and at the completion of the study in patients with DSA class I HLA or class II or both versus no DSA.  
Conclusion: The presence of either Class I or Class II DSA in patients undergoing combined liver and kidney transplantation is not associated with the incidence of rejection, worse renal function and long term survival.