Primary Biliary Cholangitis Guidance Update: Implications for Liver Transplantation

[Liver transplantation in viral and autoimmune liver diseases]

BACKGROUND

Despite substantial progress in the management of viral and autoimmune liver diseases, these entities remain relevant indications for liver transplantation.

AIMS

To provide an overview of the current knowledge regarding the management of viral and autoimmune liver diseases before and after liver transplantation.

MATERIALS AND METHODS

Selective literature search, including current guidelines and abstracts of key scientific meetings.

RESULTS AND DISCUSSION

Viral and autoimmune liver disease can be effectively treated in most cases, which has resulted in an overall decline in liver transplantations for this indication group. However, hepatitis D infection and primary sclerosing cholangitis remain difficult-to-treat liver diseases in some patients and may progress to end-stage liver disease despite best possible management. Viral or autoimmune hepatitis can lead to fulminant liver failure requiring emergency liver transplantation. In patients who are transplanted due to viral or autoimmune liver disease, specific measures to prevent recurrence of these diseases after transplantation are mandatory. In view of effective treatment modalities for chronic hepatitis B and C, even liver grafts from donors infected with these viruses can be considered for liver transplantation under certain circumstances.

Two Decades of Liver Transplants for Primary Biliary Cholangitis: A Comparative Study of Living Donors vs. Deceased Donor Liver Transplantations

Primary biliary cholangitis (PBC) prompts liver transplantation (LT) due to cholestasis, cirrhosis, and liver failure. Despite lower MELD scores, recent studies highlight higher PBC waitlist mortality, intensifying the need for alternative transplantation strategies. Living donor liver transplant (LDLT) has emerged as a solution to the organ shortage. This study compares LDLT and deceased donor liver transplant (DDLT) outcomes in PBC patients via retrospective analysis of the UNOS database (2002-2021). Patient survival, graft failure, and predictors were evaluated through Kaplan-Meier and Cox-proportional analyses. Among 3482 DDLTs and 468 LDLTs, LDLT showed superior patient survival (92.3%, 89.1%, 87.6%, 85.0%, 77.2% vs. 91.5%, 88.3%, 86.3%, 82.2%, 71.0%; respectively; p = 0.02) with no significant graft survival difference at 1-, 2-, 3-, 5-, and 10-years post-LT (91.0%, 88.0%, 85.7%, 83.0%, 75.4% vs. 90.5%, 87.4%, 85.3%, 81.3%, 70.0%; respectively; p = 0.06). Compared to DCD, LDLT showed superior patient and graft survival (p < 0.05). Younger male PBC recipients with a high BMI, diabetes, and dialysis history were associated with mortality and graft failure (p < 0.05). Our study showed that LDLT had superior patient survival to DDLT. Predictors of poor post-LT outcomes require further validation studies.

Clinical Management of Primary Biliary Cholangitis-Strategies and Evolving Trends

PBC is a chronic progressive autoimmune disorder involving the destruction of intrahepatic small bile ducts, cholestasis, fibrosis, and ultimately cirrhosis if left untreated. It is largely driven by the autoimmune response, but bile acids and the intestinal microbiota are implicated in disease progression as well. The only drugs licensed for PBC are UDCA and OCA. UDCA as a first-line and OCA as a second-line therapy are safe and effective, but the lack of response in a significant portion of patients and inadequate control of symptoms such as fatigue and pruritus remain as concerns. Liver transplantation is an end-stage therapy for many patients refractory to UDCA, which gives excellent survival rates but also moderate to high recurrence rates. The limited options for FDA-approved PBC therapies necessitate the development of alternative approaches. Currently, a wide variety of experimental drugs exist targeting immunological and physiological aspects of PBC to suppress inflammation. Immunological therapies include drugs targeting immune molecules in the B cell and T cell response, and specific cytokines and chemokines implicated in inflammation. Drugs targeting bile acids are also noteworthy as bile acids can perpetuate hepatic inflammation and lead to fibrosis over time. These include FXR agonists, ASBT inhibitors, and PPAR agonists such as bezafibrate and fenofibrate. Nonetheless, many of these drugs can only delay disease progression and fail to enhance patients' quality of life. Nanomedicine shows great potential for treatment of autoimmune diseases, as it provides a new approach that focuses on tolerance induction rather than immunosuppression. Tolerogenic nanoparticles carrying immune-modifying agents can be engineered to safely and effectively target the antigen-specific immune response in autoimmune diseases. These may work well with PBC especially, given the anatomical features and immunological specificity of the disease. Nanobiological therapy is thus an area of highly promising research for future treatment of PBC.

Outcomes of Liver Transplant Candidates with Primary Biliary Cholangitis: The Data from the Scientific Registry of Transplant Recipients

BACKGROUND

Primary biliary cholangitis (PBC) is progressive and can cause end-stage liver disease necessitating a liver transplant (LT). PBC patients may be disadvantaged on LT waitlist due to MELD-based priority listing or other factors.

AIM

The aim was to assess waitlist duration, waitlist mortality, and post-LT outcomes of PBC patients.

METHODS

The Scientific Registry of Transplant Recipients data for 1994-2016 was utilized. Adult patients with PBC without hepatocellular carcinoma (HCC) were selected. Their clinico-demographic parameters and waitlist and post-transplant outcomes were compared to those of patients with hepatitis C (HCV) without HCC.

RESULTS

Out of 223,391 listings for LT in 1994-2016, 8133 (3.6%) was for PBC without HCC. Mean age was 55.5 years, 76.9% white, 86.2% female, mean MELD score 21, 6.6% retransplants. There were 52,017 patients with hepatitis C included for comparison. The mean waitlist mortality was 17.9% for PBC and 17.6% for HCV (p > 0.05). The average transplantation rate was 57.7% for PBC and 53.3% for HCV (p < 0.0001), while waitlist dropout (death or removal due to deterioration) rate was 25.0% for PBC and 25.4% for HCV (p > 0.05). There was no significant difference in median waiting duration till transplantation between PBC patients and HCV after 2002 (103 vs. 95 days, p > 0.05). Post-LT mortality and graft loss rates were significantly lower in PBC than in HCV patients (all p < 0.02).

CONCLUSIONS

Despite no evidence of impaired waitlist outcomes and favorable post-transplant survival in patients with PBC, there is still a high waitlist dropout rate suggesting the presence of an unmet need for effective treatment.

Recurrence of disease following organ transplantation in autoimmune liver disease and systemic lupus erythematosus

Disease recurrence after organ transplantation associated with graft failure is a major clinical challenge in autoimmune diseases. Primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC) and autoimmune Hepatitis (AIH) are the three most common (autoimmune liver diseases) ALD for which liver transplantation (LT) is the most effective treatment option for patients with end-stage diseases. Although the 5- and 10-year survival rates of post-LT patients are remarkable (80-84% and 71-79% in PBC, 73-87% and 58-83% in PSC, 76-79% and 67-77% respectively in AIH patients), post-LT disease recurrence is not uncommon. Here, we summarize literature findings on disease recurrence of these ALD with emphasis on the incidence, risk factors and impact on long-term outcome. We noted that the incidence of disease recurrence varies between studies, which ranges from 53% to 10.9% in PBC, 8.2% to 44.7% in PSC and 7% to 42% in AIH. The variations are likely due to differences in study design, such as sample size, duration of studies and follow up time. This is further compounded by the lack of precise clinical diagnosis criteria and biomarkers of disease recurrence in these ALD, variation in post-LT treatment protocols to prevent disease recurrence and a multitude of risk factors associated with these ALD. While recurrence of PBC and AIH does not significantly impact long term outcome including overall survival, recurrent PSC patients often require another LT. Renal transplantation, like LT, is the treatment of choice in patients with end-stage lupus nephritis. While calcineurin inhibitor (CNI) and immunosuppressive drugs have improved the survival rate, post-transplant recurrence of lupus nephritis from surveillance-biopsy proven lupus nephritis range from 30% to 44%. On the other hand, recurrence of post-transplant lupus nephritis from registry survey analysis were only 1.1% to 2.4%. In general, risk factors associated with an increased frequency of post-transplant recurrence of autoimmune diseases are not clearly defined. Large scale multi-center studies are needed to further define guidelines for the diagnosis and clinical management to minimize disease recurrence and improve outcomes of post-transplant patients.