Impact of Induction Immunosuppression Strategies in Simultaneous Liver/Kidney Transplantation

Therapeutic Effects of Anti-PD1 Immunotherapy on Hepatocellular Carcinoma Under Administration of Tacrolimus

BACKGROUND

Liver transplantation (LT) is the treatment of choice for patients with hepatocellular carcinoma (HCC). Recurrence of HCC after LT occurs in 10% to 20% of cases. Preclinical studies to evaluate immune checkpoint inhibitors in conjunction with immunosuppressant treatment in transplant recipients have been lacking. Here, we evaluated the efficacy, safety, and mechanism of programmed cell death-1 (PD1) blockade under tacrolimus treatment in transplant recipients.

METHODS

We used a murine allogeneic skin transplantation model and murine syngeneic subcutaneous and orthotopic HCC models and measured the tumor volume and the change in tumor-infiltrating lymphocytes under PD1 blockade and tacrolimus treatment.

RESULTS

Tacrolimus treatment prolonged allograft survival in the allogeneic transplantation model and enhanced tumor growth in both subcutaneous and orthotopic HCC models. PD1 blockade suppressed tumor growth and lung metastasis in correlation with the number of infiltrating CD8 + T cells. Under tacrolimus treatment, PD1 blockade still resulted in an antitumor effect accompanied by a significant increase in tumor-infiltrating CD8 + T cells, natural killer cells, dendritic cells, and natural killer T cells. Tacrolimus treatment rescued the acceleration of transplant rejection induced by PD1 blockade in the allogeneic transplantation model.

CONCLUSIONS

Our data suggest that treatment with high-dose tacrolimus in conjunction with PD1 blockade has an antitumor effect and reduces transplant rejection in mouse models of allograft skin transplantation and HCC. Thus, these results suggest that a clinical trial of PD1 inhibitors for HCC in LT merits consideration.

Impact of Steroid Only Induction on Rejection in Simultaneous Liver-Kidney Transplantation

Introduction: The occurrence of simultaneous liver kidney transplantation has greatly increased; however, the ideal induction and maintenance immunosuppression remains unknown. Question: This evaluation aimed to determine if corticosteroid only induction in simultaneous liver kidney transplant recipients provided adequate prophylaxis against rejection when compared to basiliximab. Design: This was a single center, retrospective, cohort study of adult simultaneous liver kidney transplant recipients from June 2010 to June 2019 receiving corticosteroid only (N = 41) or basiliximab (N = 42) induction. Results: Liver or kidney biopsy proven acute rejection at 3 months was comparable between the corticosteroid only and basiliximab groups (10% vs 7%, P = .67), which persisted through 12 months posttransplant (15% vs 21%, P = .42). The occurrence of any infection at 3 months was increased in the corticosteroid only group relative to the basiliximab group (41% vs 21%, P = .049). Graft and patient survival at 12 months were similar between groups. Maintenance immunosuppression was overall minimized with a tacrolimus goal of 6-8 ng/mL, mycophenolate mofetil dose reduction to 1000 mg/day by 3 months, and early steroid withdrawal in both groups. Conclusion: Our findings suggested that corticosteroid only induction was an effective strategy for preventing rejection in simultaneous liver kidney transplant recipients, even in combination with reduced maintenance immunosuppression.

Immunology of simultaneous liver and kidney transplants with identification and prevention of rejection

Simultaneous liver and kidney (SLK) transplantation is considered the best treatment modality among selected patients with both chronic kidney disease (CKD) and end-stage liver disease (ESLD). Since the first SLK transplant in 1983, the number of SLK transplants has increased worldwide, and particularly in the United States since the implementation of the MELD system in 2002. SLK transplants are considered a relatively low immunological risk procedure evidenced by multiple studies displaying the immunomodulatory properties of the liver on the immune system of SLK recipients. SLK recipients demonstrate lower rates of both cellular and antibody-mediated rejection on the kidney allograft when compared to kidney transplant-alone recipients. Therefore, SLK transplants in the setting of preformed donor-specific HLA antibodies (DSA) are a common practice, at many centers. Acceptance and transplantation of SLKs are based solely on ABO compatibility without much consideration of crossmatch results or DSA levels. However, some studies suggest an increased risk for rejection for SLK recipients transplanted across high levels of pre-formed HLA DSA. Despite this, there is no consensus regarding acceptable levels of pre-formed DSA, the role of pre-transplant desensitization, splenectomy, or immunosuppressive management in this unique population. Also, the impact of post-transplant DSA monitoring on long-term outcomes is not well-studied in SLK recipients. In this article, we review recent and relevant past articles in this field with a focus on the immunological risk factors among SLK recipients, and strategies to mitigate the negative outcomes among them.

Crossmatch, Donor-specific Antibody Testing, and Immunosuppression in Simultaneous Liver and Kidney Transplantation: A Review

Since the introduction of simultaneous liver-kidney transplantation (SLKT) in the 1960s, the potential for immunological protection from the liver allograft to a simultaneously transplanted kidney has been recognized. Due to expanded indications and changes in allocation policies, there has been increased utilization of SLKT. Despite growing experience, a lack of consensus exists regarding the extent of the immunological privilege of the liver the role for donor-specific HLA antibody (DSA) and crossmatch testing, and appropriateness of modern immunosuppression protocols in SLKT recipients. This review provides a detailed analysis of SLKT outcomes in the context of these factors, suggesting that although the liver can reduce the incidence of antibody-mediated rejection, attention should be given to liver allograft function, previous failed transplants, and other risk factors in pretransplant risk assessment. Current methods of DSA and crossmatch testing in SLKT are also discussed, and the role of specific DSA (high mean fluorescence intensity antibody, C1q+ binding) and their potential importance in posttransplant risk assessment are examined. Finally, trends in SLKT immunosuppression are discussed, including the use of nondepleting agents for induction and de-escalating use of steroids for maintenance immunosuppression. Ongoing research, including multicenter or randomized trials, will be necessary to optimize immune-related outcomes in SLKT recipients.

Immunosuppression considerations in simultaneous organ transplant

Solid organ transplantation is a life-saving procedure for patients in the end stage of heart, lung, kidney, and liver failure. For patients with more than one failing organ, simultaneous organ transplantation has emerged as a viable treatment option. Immunosuppression strategies and outcomes for simultaneous organ transplant recipients have been reported, but often involve limited populations. Transplanting dual organs poses challenges in terms of balancing immunosuppression with immunologic risk and allograft damage from surgical complications. Furthermore, transplanting certain organs can impose considerations on the management of immunosuppression. For example, liver allografts may confer immunologic privilege and lower rates of rejection of other allografts. This review article evaluates immunosuppression strategies for simultaneous kidney-pancreas, liver-kidney, heart-kidney, heart-liver, heart-lung, lung-liver, and lung-kidney transplants. To date, no comprehensive review exists to address immunosuppressive strategies in simultaneous organ transplant populations. Our review summarizes the available literature and provides evidence-based recommendations regarding immunosuppression strategies in simultaneous organ transplant recipients.

Intra-operative kinetics of anti-HLA antibody in simultaneous liver-kidney transplantation

During simultaneous liver-kidney transplantation (SLK) in highly sensitized patients, donor specific anti-human leukocyte antigen antibodies (DSA, HLA) can be present prior to transplant leading to positive crossmatch, yet these recipients have relatively low incidences of acute rejection. The mechanisms and timing underlying immunologic changes that occur intra-operatively remain largely unknown. Therefore, we measured the intra- and peri-operative kinetics of anti-HLA antibodies in highly sensitized SLK recipients. In this study, pre- and post-operative blood samples were obtained from sensitized SLK candidates with documented DSA. Intra-operative samples were obtained from a sub-group of SLK recipients. Pretransplant anti-HLA antibody profiles were created and flow cytometry and anti-human globulin complement-dependent cytotoxic crossmatches were performed. Significant reductions in anti-HLA class I and II DSA were seen intra-operatively shortly after reperfusion of the liver allograft. This effect was most pronounced for anti-HLA class I DSA (mean change, −85%, p < 0.05); changes to anti-HLA class II DSA were less robust (mean change, −47%, p = 0.15). Importantly, non-DSA anti-HLA antibodies remained unchanged throughout the perioperative period, suggesting the mechanism(s) by which the liver lowers DSA levels are specific to the DSA. These data demonstrate the immunologic benefit of performing SLK is lasting and occurs very shortly after liver reperfusion.

Combined Liver-Kidney Transplantation With Preformed Anti-human Leukocyte Antigen Donor-Specific Antibodies

Introduction

The impact of preformed donor-specific anti–human leukocyte antigen (HLA) antibodies (pDSAs) after combined liver-kidney transplantation (CLKT) is still uncertain.

Methods

We conducted a retrospective study in 8 European high-volume transplant centers and investigated the outcome of 166 consecutive CLKTs, including 46 patients with pDSAs.

Results

Patient survival was lower in those with pDSAs (5-year patient survival rate of 63% and 78% with or without pDSA, respectively; P = 0.04). The presence of pDSAs with a mean fluorescence intensity (MFI) ≥ 5000 (hazard ratio 4.96; 95% confidence interval: 2.3–10.9; P < 0.001) and the presence of 3 or more pDSAs (hazard ratio 6.5; 95% confidence interval: 2.5–18.8; P = 0.05) were independently associated with death. The death-censored liver graft survival was similar in patients with or without pDSAs. Kidney graft survival was comparable in both groups. (The 1- and 5-year death-censored graft survival rates were 91.6% and 79.5%, respectively, in patients with pDSAs and 93% and 88%, respectively, in the donor-specific antibody [DSA]-negative group, P = not significant). Despite a higher rate of kidney graft rejection in patients with pDSAs (5-year kidney graft survival rate without rejection of 87% and 97% with or without pDSAs, respectively; P = 0.04), kidney function did not statistically differ between both groups at 5 years post-transplantation (estimated glomerular filtration rate 45 ± 17 vs. 57 ± 29 ml/min per 1.73 m², respectively, in patients with and without pDSAs). Five recipients with pDSAs (11.0%) experienced an antibody-mediated kidney rejection that led to graft loss in 1 patient.

Conclusion

Our results suggest that CLKT with pDSAs is associated with a lower patients’ survival despite good recipients’, liver and kidney grafts’ outcome.