How, why, and when does primary biliary cirrhosis recur after liver transplantation?

B cell depletion in treating primary biliary cirrhosis: Pros and cons

Primary biliary cirrhosis (PBC) is a progressive autoimmune liver disease of unknown etiology that affects almost exclusively women. Ursodeoxycholic acid (UDCA) is currently the only approved drug by Food and Drug Administration for patients with PBC. Although the precise pathogenesis of PBC remains unclear, it has been postulated that many cell populations, including B cells, are involved in the ongoing inflammatory process, which implicates, not surprisingly, a potential therapeutic target of depleting B cell to treat this disorder. Rituximab is a chimeric anti-CD20 monoclonal antibody that has been approved for the treatment of lymphoma and some autoimmune diseases such as rheumatoid arthritis. Whether it is effective in the treatment of PBC has not been evaluated. Recently, Tsuda et al^[1] demonstrated that B cell depletion with rituximab significantly reduced the number of anti-mitochondrial antibodies (AMA)-producing B cells, AMA titers, the plasma levels of immunoglobulins (IgA, IgM and IgG) as well as serum alkaline phosphatase, and it was well tolerated by all the treated patients with no serious adverse events. This observation provides a novel treatment option for the patients with PBC who have incomplete response to UDCA.

Long-term outcome of living donor liver transplantation for primary biliary cirrhosis

In living donor liver transplantation (LDLT) for primary biliary cirrhosis (PBC), the majority of donors are genetically related to their recipients, leading to concerns of an earlier recurrence of PBC and a poorer prognosis due to genetic susceptibility. Totally 81 patients who underwent LDLT for PBC were the subjects of the present study. Immunosuppressive agents consisted of tacrolimus and methylprednisolone. In the outpatient clinic, when the aspartate and alanine aminotransferase level exceeded the upper limit of the normal range, the dose of methylprednisolone was increased from 4 to 6 mg/day for several months. Blood was examined every 2 weeks for 3 months and a liver biopsy was performed when aminotransferase levels did not decrease to the upper limit of the normal range after more than 3 months. Five-year survival and recurrence rates were estimated and the prognostic factors were analyzed. The mean observation period was 6.2 years. Five years after LDLT for PBC, the biopsy-proven PBC recurrence rate was 1%. The 5-year patient survival rate was 80%. The nonrelated or blood-related donor factor and number of human leukocyte antigen matches did not correlate with prognosis. PBC recurrence rate after LDLT in our series was lower than that in previous studies.

Liver transplantation for primary biliary cirrhosis: results of aggressive corticosteroid withdrawal

INTRODUCTION

A subset of patients with primary biliary cirrhosis (PBC) may require long-term corticosteroid (CS) therapy following liver transplantation (OLT) due to concern over the possibility of recurrence. Our center has attempted to minimize CS use in all of our OLT recipients. In this study, we review our experience in this cohort to determine (1) patient outcome including PBC recurrence following transplantation and (2) the long-term requirement for CS use in PBC patients.

METHODS

From 1988 to 2006, 1102 OLTs were performed in 1032 adults at the University of Colorado, of which 70 patients (6.8%) with PBC received 74 allografts. Bivariate and multivariate analyses were used to evaluate predictors of CS withdrawal. Thirteen potential predictors of CS discontinuation were considered: age, gender, body mass index (BMI), race, type of graft (cadaveric or living donor [LD]), recurrence of PBC, warm ischemia time, and immunosuppressant.

RESULTS

Overall survival at 5 years was 85%. The 1-, 5-, and 10-year recurrence-free survivals were 90%, 72%, and 54%, respectively. PBC recurred in 18 patients (25.7%). Of these, none received a second transplant due to disease recurrence. At the time of last follow-up, 73% of recipients were steroid free. Independent predictors of CS discontinuation are age (>54; P = .0059) and LD graft type (P = .0008). Conversely, cyclosporine (P = .0007), female gender (P = .0216), and BMI > 31 (P = .0306) were negatively associated with CS withdraw. Importantly, steroid discontinuation did not influence PBC recurrence.

CONCLUSIONS

While long-term outcomes in PBC patients are favorable, disease recurrence can generally be managed medically without the need for a second transplant. Using an aggressive CS minimization approach, nearly three-quarters of the patients were CS free at the time of last follow-up. Increasing age and LD grafts were associated with successful CS withdraw. Conversely, cyclosporine use, female gender, and increasing BMI were associated with unsuccessful steroid discontinuation.

The unfinished business of primary biliary cirrhosis

In nearly every multifactorial human disease, there are three periods that characterize our understanding and definition. First, there is a period in which there is rapid accumulation of descriptive data. Second, there is a longer and slower period as information is obtained that redefines and expands basic and clinical knowledge that lacks the final and important area of understanding aetiology and therapeutic intervention. Third, which is much less common for most diseases, is the vigorous definition of pathobiology and treatment. These phases are well illustrated by our current understanding of primary biliary cirrhosis (PBC). The term PBC was first used nearly 60 years ago and for the first 40 or so years, the primary research efforts were directed at clinical definitions and pathology. Subsequently, with the advent of molecular biology, there began a rigorous dissection of the immune response and, in particular, a better understanding of anti-mitochondrial antibodies. These efforts have greatly helped in our understanding of not only the effector mechanisms of disease, but also the uniqueness of the primary target tissue, biliary epithelium. However, this research has still not led to successful translation for specific therapy.

Biliary epithelial cells and primary biliary cirrhosis: the role of liver-infiltrating mononuclear cells

Primary biliary cirrhosis (PBC) is characterized by the highly selective autoimmune injury of small intrahepatic bile ducts, despite widespread distribution of mitochondrial autoantigens. On this basis, it has been suggested that the targeted biliary epithelial cells (BECs) play an active role in the perpetuation of autoimmunity by attracting immune cells via chemokine secretion. To address this issue, we challenged BECs from patients with PBC and controls using multiple Toll-like receptor (TLR) ligands as well as autologous liver-infiltrating mononuclear cells (LMNCs) with subsequent measurement of BEC phenotype and chemokine production and LMNC chemotaxis by quantifying specific chemokines. Our data reflect that BECs from PBC patients and controls express similar levels of TLR subtypes, CD40, and human leukocyte antigen DRalpha (HLA-DRalpha) and produce equivalent amounts of chemokines in our experimental conditions. Interestingly, however, BEC-expressed chemokines elicit enhanced transmigration of PBC LMNCs compared with controls. Furthermore, the addition of autologous LMNCs to PBC BECs led to the production of higher levels of chemokines and enhanced the expression of CD40 and HLA-DRalpha.

CONCLUSION

We submit that the proinflammatory activity of BECs in PBC is secondary to the intervention of LMNCs and is not determined per se. These data support the hypothesis that BECs are in fact "innocent victims" of autoimmune injury and that the adaptive immune response is critical in PBC.