Prospective evaluation of the prevalence and clinical significance of positive autoantibodies after pediatric liver transplantation

Positive autoantibodies in living liver donors

BACKGROUND

There is a nationwide shortage of organs available for liver transplantation. Living donors help meet this growing demand. Not uncommonly, donors will have positive autoantibodies. However, it is unclear whether donor positive autoantibodies are correlated with worse outcomes following living liver donor transplantations.

AIM

To analyze the significance of positive autoantibodies in donors on post-transplant outcomes in recipients.

METHODS

We performed a retrospective review of living liver donors who had undergone liver transplantation between January 1, 2012 and August 31, 2021. Demographic characteristics and pre-transplant data including antinuclear antibodies (ANA) and anti-smooth muscle antibody titers were collected in donors. Outcomes of interest were post-transplantation complications including mortality, biliary strictures, biliary leaks, infection, and rejection. Pediatric recipients and donors without measured pre-transplant autoantibody serologies were excluded from this study.

RESULTS

172 living donor liver transplantations were performed during the study period, of which 115 patients met inclusion criteria. 37 (32%) living donors were autoantibody-positive with a median ANA titer of 1:160 (range 1:80 to 1:1280) and median anti-SMA titer of 1:40 (range 1:20 to 1:160). There were no significant differences in baseline demographics between the autoantibody positive and negative donors. Post-transplantation rates of death (P value = 1), infections (P value = 0.66), and overall rates of complications (P value = 0.52) were similar between the autoantibody positive and negative groups. Higher incidences of anastomotic strictures and rejection were observed in the autoantibody positive group; however, these differences were not statistically significant (P value = 0.07 and P value = 0.30 respectively).

CONCLUSION

Isolated pre-transplant autoantibody positivity is not correlated to worse post-transplant outcomes in living liver donor transplants.

Cold Ischemia Time and Graft Fibrosis Are Associated with Autoantibodies after Pediatric Liver Transplantation: A Retrospective Cohort Study of the European Reference Network TransplantChild

The reported prevalence of autoantibodies (AAB) (ANA, SMA, LKM, SLA) after pediatric liver transplantation (pLTX) varies considerably from 26-75%, but their clinical impact on outcome is uncertain. We aimed to study the prevalence of AAB after pLTX, their association with donor-, transplant-, and recipient-characteristics, and their relation to outcome. In our multicenter retrospective study, we aimed to clarify conflicting results from earlier studies. Six ERN TransplantChild centers reported data on 242 patients, of whom 61% were AAB positive. Prevalence varied across these centers. Independent of the interval between pLTX and AAB analysis, a one-hour increase in CIT resulted in an odds ratio (OR) of 1.37 (95% CI 1.11-1.69) for SMA positivity and an OR of 1.42 (95%CI 1.18-1.72) for ANA positivity. Steroid-free immunosuppression (IS) versus steroid-including IS (OR 5.28; 95% CI 1.45-19.28) was a risk factor for SMA positivity. Liver enzymes were not associated with ANA or SMA positivity. We did not observe an association of rejection activity index with ANA or SMA. However, the liver fibrosis score in follow-up biopsies was associated with ANA titer and donor age. In conclusion, this first multicenter study on AAB after pLTX showed high AAB prevalence and varied widely between centers. Longer CIT and prednisolone-free-IS were associated with AAB positivity, whereas AAB were not indicative of rejection, but instead were associated with graft fibrosis. The detection of AAB may be a marker of liver fibrosis and may be taken into consideration when indications for liver biopsy and immunosuppressive regimes, or reduction of immunosuppression in long-term follow-up, are being discussed. Prospective immunological profiling of pLTX patients, including AAB, is important to further improve our understanding of transplant immunology and silent graft fibrosis.

De novo lupus-like glomerulonephritis after pediatric non-kidney organ transplantation

BACKGROUND

We propose a novel clinically significant finding, de novo lupus-like glomerulonephritis (DNLLGN), in patients with autoantibodies and kidney abnormalities in pediatric liver transplant (LT) and intestinal inclusive transplants (ITx).

METHODS

We describe the clinical, serologic, and histopathologic presentation and kidney outcomes in eight patients from our center found to have DNLLGN on kidney biopsy.

RESULTS

Pediatric recipients of non-kidney solid organ transplants developed an unusual de novo immune complex glomerulonephritis with morphologic similarity to lupus nephritis. Six had isolated LT (0.9% of all pediatric LT at our center) and two had ITx (2.1% of all ITx). Five (63%) presented with nephrotic syndrome. Five patients had autoantibodies. Patients underwent kidney biopsy at a mean of 11.5 years in LT and 2.8 years in ITx after the index transplant. Biopsies demonstrated changes similar to focal or diffuse active lupus. Follow-up eGFR at a mean of 6 years after biopsy showed a mean decrease of 30 ml/min/1.73 m² in all patients (p = 0.11).

CONCLUSIONS

DNLLGN has not been previously recognized in this clinical setting, yet 8 kidney biopsies from pediatric recipients of LT and ITx at our center in 25 years demonstrated this finding. DNLLGN appears to be an under-reported phenomenon of clinical significance. A higher resolution version of the Graphical abstract is available as Supplementary information.

Autoantibodies and Donor-specific Antibodies are Associated With Graft Dysfunction in Pediatric Liver Transplantation

OBJECTIVES

Autoantibodies (AAb) and donor-specific HLA antibodies (DSA) are frequently present in pediatric liver transplant (LT) recipients. Their clinical significance remains incompletely understood. We aimed to investigate the prevalence of serum AAb and DSA in pediatric LT recipients and its correlation with patient characteristics and histological and biochemical parameters.

METHODS

We retrospectively reviewed the data from 62 pediatric LT patients in follow-up at Ghent University Hospital between January 2007 and February 2018. Blood samples with AAb measurement were taken systematically, liver biopsies (LB) were performed on clinical indication.

RESULTS

AAb were detected in 27 (43.3%) patients, with antinuclear antibodies (ANA) being the most frequently (24%) encountered AAb. There was an association between AAb positivity and female gender (P = 0,032) and deceased donor LT (P = 0,006). Patients with positive AAb underwent a higher number of LB during their follow-up (P < 0,001), and an association was found with the presence of nonspecific histologic alterations (P = 0,032) in the absence of de novo autoimmune hepatitis. Positive AAb were also associated with higher alkaline phosphatase (P < 0,001), ALT (P < 0,001), AST (P < 0,001), γ-GT (P = 0,001), IgG (P = 0,011) and lower albumin (P = 0,029). Fourteen out of 50 (28%) patients were DSA-positive, mostly anti-HLA class II. DSA positivity was associated with T-cell-mediated rejection (P = 0,019), higher total (P = 0,033), and direct (P = 0,012) bilirubin and γ-GT (P < 0,001).

CONCLUSIONS

The presence of AAb and DSA is associated with histological and biochemical parameters of graft dysfunction. Larger prospective studies are warranted to investigate the causal relationships between AAb and DSA development and outcome parameters post pediatric LT.

Incidence of de novo autoimmune hepatitis in children and adolescents with increased autoantibodies after liver transplantation: a meta-analysis

The objective of this meta-analysis was to assess the incidence of de novo autoimmune hepatitis (AIH) in children and adolescents with increased autoantibodies after liver transplantation. We systematically retrieved studies from PubMed, Embase, Central, CNKI, VIP and Wanfang published before February 1, 2020. All analyses were conducted using R-4.0.1 statistical package (Meta). Seven studies with high quality were pooled in our final analysis (N = 251 participants). The incidence of de novo AIH was 9% [95% confidence interval (CI) 1-23%, I²  = 86%]. Subgroup analysis suggested that publications not using the International Autoimmune Hepatitis Group (IAIHG) criteria have marginally significantly higher incidence of de novo AIH than those using IAIHG criteria (P for interaction = 0.08). The incidence of chronic rejection was 8% (95% CI 2-17%, I²  = 72%). Meta-regression indicated significant correlation (P = 0.04; estimate: 1.51) between the incidence of de novo AIH and the rate of increase of antibodies to liver/kidney microsome (anti-LKM). It is still challenging to distinguish de novo AIH and chronic rejection in children and adolescents with increased autoantibodies after liver transplantation. The diagnostic criteria for de novo AIH in children and adolescents and the role of anti-LKM in the development of de novo AIH deserve future investigation.

High Frequency of Concomitant Food Allergy Development and Autoantibody Formation in Children Who Have Undergone Liver Transplantation

BACKGROUND

Allergy and other immune-mediated diseases are more frequently reported in children who have undergone liver transplantation. Furthermore, autoantibodies are also prevalent, suggesting a state of immune dysregulation in these patients. Whether or not these processes occur simultaneously in the same individual has not been studied previously.

METHODS

A cohort of 43 children who had undergone liver transplantation for nonautoimmune liver disease at median age of 1.3 years was investigated for allergy and autoimmune disease. Sensitization to food and inhalant allergens was assessed, and autoantibodies were measured.

RESULTS

The prevalence of food allergy was 26% and that of respiratory allergy was 23%, whereas 33% and 26% of the subjects were sensitized to food and inhalant allergens, respectively. Autoimmune disease (ie, autoimmune hepatitis) occurred in a single individual (2%), whereas autoantibodies were present in 44% of the children. Food allergy and autoantibodies occurred concomitantly in 19% of the children, which was almost twice the frequency expected by chance (11%, P = 0.04). Respiratory allergy and the presence of autoantibodies were unrelated (12% concurrence versus the expected 10%, P = 0.73). In the logistic regression analysis, autoantibody formation was associated with discontinued immunosuppression and food allergy, with odds ratios of 13 (P = 0.01) and 7.1 (P = 0.03), respectively.

CONCLUSIONS

In contrast to respiratory allergy, food allergy and autoantibody formation occurred together in the same children who underwent liver transplantation at a frequency higher than would be expected by chance. This may reflect an underlying immune dysregulation that impairs immune tolerance to both food allergens and autoantigens.

Impact of Antibodies That React With Liver Tissue and Donor-Specific Anti-HLA Antibodies in Pediatric Idiopathic Posttransplantation Hepatitis

Background

The cause of late graft dysfunction has not been elucidated. Although an antibody-mediated reaction is suspected as a potential mechanism, the target antigens have not been clarified.

Methods

To clarify the etiology of idiopathic posttransplantation hepatitis (IPTH), we simultaneously examined the presence of antibodies that react with liver tissue (ARLT) by means of indirect immunofluorescence staining, as well as the presence of donor-specific anti-human leukocyte antigen antibodies (HLA-DSA). A subanalysis of the IPTH group was also performed. Within the IPTH group, the correlation between ARLT titer and clinical data were analyzed.

Results

In the sera of patients with IPTH (30 patients), ARLT were found at a significantly higher frequency than in patients without IPTH (42 patients; P < 0.001). Moreover, the ARLT titer appeared to be correlated with the severity of hepatitis or hepatic injury. In contrast, the frequency of HLA-DSA was significantly lower in patients with IPTH than in patients without IPTH (P = 0.001).

Conclusion

Our findings indicate that ARLT, and not HLA-DSA, profoundly influence the etiology of IPTH.

The authors show that antibodies that react with liver tissue and not donor-specific anti-human leukocyte antigen antibodies, profoundly influence the etiology of idiopathic posttransplantation hepatitis in children providing a rationale for therapy.

Autoimmune Hepatitis in the Liver Transplant Graft

Recurrent autoimmune hepatitis (AIH) and de novo AIH are 2 important causes of late graft failure after liver transplantation (LT). Recurrent AIH occurs in patients who undergo LT for AIH. De novo AIH occurs in patients who are transplanted for etiologies other than AIH. Although typically treated with standard treatment for AIH, including corticosteroids and azathioprine, both recurrent and de novo AIH may progress to end-stage liver disease requiring retransplantation.

Lack of Clinical Relevance of ANA and ASMA Positivity in Patients with Liver Transplantation without a History of Autoimmune Diseases

The relevance of isolated autoimmunity elevation in orthotopic liver transplantation (OLT) patients is unknown. Our aim was to analyse how serum autoantibodies change in time and to evaluate their clinical relevance in OLT patients. Patients were invited to provide samples to evaluate ANA, AMA, ASMA, and LKM at the time of enrolment (T0), after 6 months (T6), and after 12 months (T12). We included 114 patients in the study (76% males, median age 62.5 years), finding isolated elevation of at least one serum antibody in up to 80% of them. We described fluctuating positive autoantibodies in the one year of observation, with only 45.6% of patients positive for ANA and less than 2% positive for ASMA, at all three times. Isolated elevation of tissue antibodies was not related to gender, age, HCC at transplant, early rejection, cause of transplantation, immunotherapy taken, and age at the time of the study. We did not detect a higher prevalence of positive autoimmunity in patients with signs of liver injury. ANA and ASMA evaluation in patients with liver transplantation and no history of autoimmune disease has no clinical relevance, since it varies in time and is not related to any risk factors or liver injury. Routine autoimmunity evaluation should be avoided.

Autoimmune Liver Disease Post-Liver Transplantation: A Summary and Proposed Areas for Future Research

Autoimmune liver diseases (AILD) are rare diseases with a reported prevalence of less than 50 per 100 000 population. As the research landscape and our understanding of AILDs and liver transplantation evolves, there remain areas of unmet needs. One of these areas of unmet needs is prevention of disease recurrence after liver transplantation. Disease recurrence is not an insignificant event because allograft loss with the need for retransplantation can occur. Patients transplanted for AILD are more likely to experience acute rejection compared to those transplanted for non-AILD, and the reason(s) behind this observation is unclear. Tasks for the future include a better understanding of the pathogenesis of AILD, definition of the precise pathogenetic mechanisms of recurrent AILD, and development of strategies that can identify recipients at risk for disease recurrence. Importantly, the role of crosstalk between alloimmune responses and autoimmune responses in AILD is an important area that needs further study.

This article reviews the relevant literature of de novo autoimmune hepatitis, recurrent autoimmune hepatitis, recurrent primary sclerosing cholangitis, and recurrent primary biliary cirrhosis in terms of the clinical entity, the scientific advancements, and future scientific goals to enhance our understanding of these diseases.

A review of the relevant literature of de novo autoimmune hepatitis, recurrent autoimmune hepatitis, recurrent primary sclerosing cholangitis, and recurrent primary biliary cirrhosis in terms of the clinical entity, the scientific advancements and future scientific goals to enhance our understanding of these diseases.

Autoimmunity after liver transplantation: a frequent event but a rare clinical problem

Autoantibodies are frequently detected after liver transplantation (LT), but their role is unclear. This study was designed to address three points: autoantibody prevalence pre-LT and over time up to five yr after LT, identification of possible predictors of autoantibody formation, and correlation between autoantibodies and graft dysfunction. To these aims, we retrospectively evaluated 92 consecutive LT recipients for whom prospectively stored frozen sera were available for autoantibodies assessment by immunofluorescence. The overall autoantibody prevalence resulted significantly higher after LT than before LT (64% vs. 27%, p < 0.001 and 35.9% vs. 8.7%, p < 0.001 considering cutoff titer of ≥ 1:80 and ≥ 1:160, respectively). Recipient gender, donor age and gender, and indication for LT and main immunosuppressant (cyclosporine vs. tacrolimus) were not associated with the presence of autoantibodies. Patients with graft dysfunction had a significantly higher autoantibody prevalence irrespective of the etiology of liver injury as compared to those patients with persistently normal liver biochemistry, but only for cutoff titers ≥ 1:160 (p = 0.004). No cases of de novo autoimmune hepatitis were observed. In conclusion, autoantibodies are very frequently detected after LT also at high titers and their association with graft dysfunction likely represents an aspecific indicator of liver injury.

Histologic findings predictive of a diagnosis of de novo autoimmune hepatitis after liver transplantation in adults

BACKGROUND

Autoimmune hepatitis (AIH) after liver transplantation has been defined histologically as a "hepatitic" pattern of injury, characterized by lymphoplasmacytic inflammation with necroinflammatory activity (NIA), comparable with findings seen in native livers. This definition, however, is difficult to apply in practice because specific histologic criteria are not clearly delineated. This study aimed to determine which histologic features correlated best with clinical and serologic features of dAIH.

METHODS

Index liver biopsies from patients with autoimmune-like hepatitis transplanted for non-AIH in two centers (n=35 and 20) were reviewed. Histologic features were correlated with the clinical diagnosis of AIH based on a retrospective review of clinical and serologic data, including therapeutic response.

RESULTS

A clinical diagnosis of AIH was retrospectively assigned to 24 of 35 (68%) and 18 of 20 (90%) patients, respectively (P=0.10). In multivariate analysis, centrilobular NIA and centrilobular plasma cell (PC) ratio of 30% to 50% were independently discriminating for a clinical diagnosis of AIH (P=0.04 and 0.05, respectively). The best level of predictability (99.6%) was mathematically achieved when severe centrilobular NIA and centrilobular PC ratio of 30% to 50% were both present.

CONCLUSION

A histologic pattern of centrilobular injury including increased NIA and increased PC infiltration correlates with measurements of autoimmunity in liver recipients. It could be used to segregate cases for further study and introduced into the AIH scoring systems when applied in the context of liver transplantation.

Development of autoantibodies after pediatric liver transplantation

Dn-AIH is a long-term complication after LT. The aim of this study was to analyze the occurrence of autoantibodies in pediatric recipients and the clinical significance. From 1992 to 2008, 96 pediatric LT for non-autoimmune liver diseases were performed in 94 children in our institution. Serum autoantibodies were checked in 68 subjects (73.9%). A positive autoantibody was defined as titers ≥1:40 for ANA, or ≥1:20 for ASMA, anti-LKM, and AMA. Autoantibodies were detectable in 51 of 68 patients (75.0%). There was positivity for ANA in 30 patients, ASMA in 32, and AMA in three, while anti-LKM was all negative. Immunosuppressive treatment with CsA, more than one episode of rejection, and abnormal ALT were risk factors for the development of autoantibodies. The incidence of the development of autoantibodies was 75.0% in pediatric LT cases in this study. ASMA was the most commonly found autoantibody. Autoantibodies may not play a sentinel role for dn-AIH after LT.

Importance of liver biopsy findings in immunosuppression management: biopsy monitoring and working criteria for patients with operational tolerance

Obstacles to morbidity-free long-term survival after liver transplantation (LT) include complications of immunosuppression (IS), recurrence of the original disease and malignancies, and unexplained chronic hepatitis and graft fibrosis. Many programs attempt to minimize chronic exposure to IS by reducing dosages and stopping steroids. A few programs have successfully weaned a highly select group of recipients from all IS without apparent adverse consequences, but long-term follow-up is limited. Patients subjected to adjustments in IS are usually followed by serial liver chemistry tests, which are relatively insensitive methods for detecting allograft damage. Protocol biopsy has largely been abandoned for hepatitis C virus-negative recipients, at least in part because of the inability to integrate routine histopathological findings into a rational clinical management algorithm. Recognizing a need to more precisely categorize and determine the clinical significance of findings in long-term biopsy samples, the Banff Working Group on Liver Allograft Pathology has reviewed the literature, pooled the experience of its members, and proposed working definitions for biopsy changes that (1) are conducive to lowering IS and are compatible with operational tolerance (OT) and (2) raise concern for closer follow-up and perhaps increased IS during or after IS weaning. The establishment of guidelines should help us to standardize analyses of the effects of various treatments and/or weaning protocols and more rigorously categorize patients who are assumed to show OT. Long-term follow-up using standardized criteria will help us to determine the consequences of lowering IS and to define and determine the incidence and robustness of OT in liver allografts.

Diagnosis, pathogenesis, and treatment of autoimmune hepatitis after liver transplantation

Autoimmune hepatitis can recur or appear de novo after liver transplantation, and it can result in hepatic fibrosis, graft loss, and re-transplantation. The goals of this review are to describe the prevalence, manifestations, putative pathogenic mechanisms, outcomes, and management of these occurrences. Autoimmune hepatitis recurs in 8-12 % of transplanted patients at 1 year and 36-68 % at 5 years. Recurrence may be asymptomatic and detected only by surveillance liver test abnormalities or protocol liver tissue examination. Autoantibodies that characterized the original disease, hypergammaglobulinemia, increased serum immunoglobulin G level, and histological findings of interface hepatitis, lymphoplasmacytic infiltration, perivenular hepatocyte necrosis, pseudo-rosetting, and acidophil bodies typify recurrence. Premature corticosteroid withdrawal and pre-transplant severity of the original disease are possible risk factors. De novo autoimmune hepatitis occurs in 1-7 % of patients 0.1-9 years after transplantation, especially in children. The appearance of autoantibodies may herald its emergence, and antibodies to glutathione-S-transferase T1 have been predictive of the disease. Recurrent disease may reflect recruitment of residual memory T lymphocytes and host-specific genetic predispositions, whereas de novo disease may reflect an allo-antigenic immune response and molecular mimicries that override self-tolerance. Treatment should be appropriate for autoimmune hepatitis and not based on anti-rejection drugs. Corticosteroid therapy alone or combined with azathioprine is the essential treatment. The substitution of mycophenolate mofetil for azathioprine and switch of the calcineurin inhibitor or its replacement with rapamycin have also been used for refractory disease. Re-transplantation has been necessary in 8-23 %.

Immunohistochemical phenotyping of the inflammatory infiltrate in de novo autoimmune hepatitis after liver transplantation in children

We have investigated the inflammatory infiltrate in post-transplant dn-AIH, a form of late insidious graft rejection, focusing on transcription factors defining effector and T-regs, using an antigen retrieval immunohistochemical method on archived liver tissue, and compared it with ACR and classical AIH. Paraffin-embedded liver biopsies from pediatric patients with dn-AIH (n = 10), ACR (n = 10), and AIH (n = 13) were selected randomly and stained using antibodies directed to CD4, CD8, T-bet (marker of Th1 polarization), GATA-3 (marker of Th2 polarization), FOXP3 (marker for T regulatory cells), IL-17, CD56 (NK cells), and perforin. Portal and lobular lymphocytic infiltrate was assessed semi-quantitatively. Prominent CD4, CD8, and T-bet positivity were present in both the lobular and portal infiltrate of all three conditions. Overall T-bet score of lobular inflammation in the dn-AIH group was lower than in the ACR and AIH groups (p = 0.02). In contrast, most samples showed absent or minimal GATA-3 positivity. FOXP3, CD56, IL-17, and perforin staining of mild to moderate severity were present in all three groups in both the portal and lobular infiltrate. A Th1 polarization of the inflammatory infiltrate characterizes dn-AIH, but also ACR and AIH.

What is the long-term outcome of the liver allograft?

With improved long-term survival following liver transplantation (LT), issues relating to the assessment of the liver allograft in long-term survivors are becoming increasingly relevant. Histological abnormalities are commonly present in late post-transplant biopsies, including protocol biopsies from patients who appear to be well with good graft function. Recurrent disease is the commonest recognised cause of abnormal graft histology, but may be modified by the effects of immunosuppression or interactions with other graft complications, resulting in complex or atypical changes. Other abnormalities seen in late post-transplant biopsies include rejection (which often has different appearances to those seen in the post-transplant period), de novo disease, "idiopathic" post-transplant hepatitis (IPTH) and nodular regenerative hyperplasia. In many cases graft dysfunction has more than one cause and liver biopsy may help to identify the predominant cause of graft damage. Problems exist with the terminology used to describe less well understood patterns of graft injury, but there is emerging evidence to suggest that late rejection, de novo autoimmune hepatitis and IPTH may all be part of an overlapping spectrum of immune-mediated injury occurring in the late post-transplant liver allograft. Careful clinico-pathological correlation is very important and the wording of the biopsy report should take into account therapeutic implications, particularly whether changes in immunosuppression may be indicated. This article will provide an overview of the main histological changes occurring in long-term survivors post-LT, focusing on areas where the assessment of late post-transplant biopsies is most relevant clinically.

Current views on rejection pathology in liver transplantation

Histological assessments continue to play an important role in the diagnosis and management of liver allograft rejection. The changes occurring in acute and chronic rejection are well recognized and liver biopsy remains the 'gold standard' for diagnosing these two conditions. Recent interest has focused on the diagnosis of late cellular rejection, which may have different histological appearances to early acute rejection and instead has features that overlap with so-called 'de novo autoimmune hepatitis' and 'idiopathic post-transplant chronic hepatitis'. There is increasing evidence to suggest that 'central perivenulitis' may be an important manifestation of late rejection, although other causes of centrilobular necro-inflammation need to be considered in the differential diagnosis. There are also important areas of overlap between rejection and recurrent hepatitis C infection and the distinction between these two conditions continues to be a problem in the assessment of liver allograft biopsies. Studies using immunohistochemical staining for C4d as a marker for antibody-mediated damage have found evidence of C4d deposition in liver allograft rejection, but the functional significance of these observations is currently uncertain. This review will focus on these difficult and controversial areas in the pathology of rejection, documenting what is currently known and identifying areas where further clarification is required.

Autoimmune hepatitis: new paradigms in the pathogenesis, diagnosis, and management

Autoimmune hepatitis (AIH), primary biliary cirrhosis, and primary sclerosing cholangitis are the three major autoimmune diseases affecting the liver, and of these three, AIH is the most typical autoimmune disease being characterized by a T-cell-rich infiltrate, raised circulating γ-globulins, autoantibodies, HLA associations, and links with other autoimmune diseases. It is the only one, of the three diseases, that responds well to immunosuppressive therapy. AIH is caused by dysregulation of immunoregulatory networks and the consequent emergence of autoreactive T cells that orchestrate a progressive destruction of hepatocytes leading untreated to liver failure. T cells play a major role in the immunopathogenesis, and both CD4(+) and CD8(+) T cells are involved together with effector responses mediated by NK cells, γδ T cells, and macrophages. A number of triggering factors have been proposed including viruses, xenobiotics, and drugs, but none have been conclusively shown to be involved in pathogenesis.

Indirect immunohistochemical evaluation of graft fibrosis and interface hepatitis after pediatric liver transplantation

Fibrosis or IH following pediatric liver transplantation is recognized as major causes of graft loss, but the etiology remains unclear. To determine this issue, we used an indirect immunohistochemistry technique with post-transplant serum samples from recipients and normal human liver tissues from living liver donors, and the association between occult antibody reaction to the liver and the occurrence of fibrosis or IH was evaluated. Forty-three recipients were evaluated, and both hepatocytes and biliary epithelial cells were evaluated for staining intensity. Fibrosis and IH occurred in 13 and six patients, respectively. According to staining results for the hepatocytes and biliary epithelial cells, 18 and 11 patients, respectively, were classified into the positive group. According to log-rank analysis, positive reaction for hepatocytes was associated with increased rates of fibrosis and IH (p = 0.002 and 0.048, respectively), while positive reaction for biliary epithelial cells was associated with an increased rate of fibrosis (p = 0.014). Multivariate analysis revealed that positive reaction for hepatocytes and biliary epithelial cells was independently associated with fibrosis occurrence (p = 0.020 and 0.047, respectively). In conclusion, immune-mediated reactions by occult antibodies may underlie the pathogeneses of fibrosis and IH.

What does the long-term liver allograft look like for the pediatric recipient?

1. Histological abnormalities are commonly present in late posttransplant biopsies from pediatric liver allograft recipients. 2. Many of the changes are seen in children who appear to be clinically well with good graft function. 3. In comparison with adults, children may be more prone to developing late rejection (possibly related to noncompliance with immunosuppression) and biliary/vascular complications, but they are much less likely to suffer problems with disease recurrence. 4. De novo autoimmune hepatitis occurs in 5% to 10% of children after transplantation and may represent a hepatitic form of late cellular rejection. Most cases respond to treatment with increased immunosuppression. 5. Recent studies have shown a high frequency of unexplained (idiopathic) chronic hepatitis in late posttransplant biopsies from children. This is associated with the development of graft fibrosis and cirrhosis. 6. Further studies are required to investigate the role of protocol liver biopsies in determining therapeutic strategies in children who appear to have good graft function according to noninvasive investigations.

De novo bile salt transporter antibodies as a possible cause of recurrent graft failure after liver transplantation: a novel mechanism of cholestasis

Progressive familial intrahepatic cholestasis type 2 (PFIC-2) is caused by mutations of the bile salt export pump (BSEP [ABCB11]), an ATP-binding cassette (ABC)-transporter exclusively expressed at the canalicular membrane of hepatocytes. An absence of BSEP from the canalicular membrane causes cholestasis and leads to liver cirrhosis, which may necessitate liver transplantation in early childhood. We report on the first case of a child with PFIC-2 suffering from repeated posttransplant recurrence of progressive intrahepatic cholestasis due to autoantibodies against BSEP. These antibodies occurred after transplantation and were detected in the patient's serum and at the canalicular membrane of two consecutive liver transplants. The antibodies were reactive toward the first extracellular loop of BSEP, were of high affinity, and inhibited transport activity of BSEP, thus causing severe cholestasis. The patient had three homozygous, missense changes in the BSEP gene. Their combination resulted in the complete absence of BSEP, which explains the lack of tolerance, a prerequisite of autoantibody formation toward BSEP. The findings illustrate a novel disease mechanism due to a new class of functionally relevant autoantibodies resulting in cholestasis and subsequent liver failure.

Immune-mediated liver dysfunction after antiviral treatment in liver transplanted patients with hepatitis C: allo or autoimmune de novo hepatitis?

BACKGROUND

The recurrence of hepatitis C after liver transplantation is extremely frequent. Antiviral therapy combining pegylated-interferon with ribavirin is therefore increasingly used in these patients. It has been recently reported, however, that during antiviral treatment a hepatic immune-mediated liver dysfunction, similar to "de novo" autoimmune hepatitis, may develop in a few transplanted patients.

PATIENTS AND METHODS

Three patients, treated with pegylated-interferon alpha-2a and ribavirin for recurrent hepatitis C after liver transplantation, developed an aggressive hepatitis with clinical, biochemical, and histological features similar to those of autoimmune hepatitis.

RESULTS

In all three patients, a liver enzymes increase was evident after hepatitis C virus-RNA had become undetectable. Diagnosis of "de novo" autoimmune hepatitis was proposed, based on the presence of high-titre circulating autoantibodies and liver histology features. Following the introduction of a steroid therapy, clinical and biochemical parameters progressively improved. Hepatitis C virus infection, however, relapsed after a few months in all the patients.

CONCLUSIONS

Following liver transplantation, antiviral therapy with pegylated-interferon alpha-2a and ribavirin for recurrent hepatitis C may be associated, in a few patients, with severe immune-mediated graft dysfunction similar to autoimmune hepatitis.

Idiopathic post-transplantation hepatitis following living donor liver transplantation, and significance of autoantibody titre for outcome

Idiopathic post-transplantation hepatitis (IPTH) is a common histology occurring late after liver transplantation. Its natural history and the effect of treatment have not been determined. This study is a matched case-control study that evaluates predictors, outcome and response to treatment for IPTH. Patients were divided by autoantibodies into high-titre (> or = 1:160) and low-titre (<1:160) groups, so as to evaluate clinicopathological differences between the two groups. IPTH was identified in 42 of 944 recipients (4.4%) with tacrolimus-based immunosuppression. They comprised 10 males and 32 females, having median age 6.0 (0-50) years. IPTH presented at a median duration of 5.2 (0.7-10.8) years after transplantation. Particular risk of IPTH was associated with acute rejection, late-onset acute rejection occurring later than 6 month post-transplant, and autoantibody positivity. IPTH was associated with dependence on steroids and frequent adverse outcomes: retransplantation in five (12%); relapse in four (9.5%); and progression of fibrosis in eight (19%). The high-titre group and low-titre group did not differ in their clinicopathological features, response to treatment or outcome. To prevent the development of IPTH, appropriate adjustment of immunosuppression and close follow-up is necessary for patients who suffer repeated episodes of rejection.

Interface hepatitis is associated with a high incidence of late graft fibrosis in a group of tightly monitored pediatric orthotopic liver transplantation patients

Chronic graft dysfunction, manifesting with elevated liver enzymes and histological features of interface hepatitis (IH), is being increasingly recognized as a long-term problem after liver transplantation. The aim of this study was to characterize our group of post-orthotopic liver transplantation (OLT) patients with respect to clinical, laboratory, and histological signs of IH. A retrospective study of charts and liver biopsy specimens from patients transplanted between 1986 and 1999 was used. Histological features of IH were found in 29/119 patients at a median interval of 23.9 months (95% confidence interval -28.2 to 52.6) after OLT. All patients with IH had risk factors for chronic rejection, such as steroid-resistant rejection, acute rejection later than 3 months post-OLT, female receiver of male graft, or pretransplant cytomegalovirus (CMV)-positive serology with a CMV-negative donor liver. None of the 29 had features favoring a diagnosis of de novo autoimmune hepatitis, but 4 had isolated hypergammaglobulinemia, and 4 had non-organ-specific autoantibodies without hyperimmunoglobulin G. Sixteen of 29 patients also had features of chronic rejection, such as foam cell arteriopathy, loss of bile ducts, or pericentral fibrosis. After abnormal biopsy, all but 1 patient were switched to tacrolimus. During a median follow-up of 12 years, death occurred in 5, retransplantation occurred in 7, and definite cirrhosis occurred in 4. In conclusion, IH was detected in 24.4% of our patients and was associated with a high degree of fibrosis development. Most likely, IH represents a form of chronic rejection directed against periportal hepatocytes.