Acute cellular rejection following liver transplantation: clinical pathologic features and effect on outcome

Defining the T cell transcriptional landscape in pediatric liver transplant rejection at single cell resolution

Acute cellular rejection (ACR) affects >80% of pediatric liver transplant recipients within 5 years, and late ACR is associated with graft failure. Traditional anti-rejection therapy for late ACR is ineffective and has remained unchanged for six decades. Although CD8+ T cells promote late ACR, little has been done to define their specificity and gene expression. Here, we used single-cell sequencing and immune repertoire profiling (10X Genomics) on 30 cryopreserved 16G liver biopsies from 14 patients (5 pre-transplant or with no ACR, 9 with ACR). We identified expanded intragraft CD8+ T cell clonotypes (CD8EXP) and their gene expression profiles in response to anti-rejection treatment. Notably, we found that expanded CD8+ clonotypes (CD8EXP) bore markers of effector and CD56hiCD161- 'NK-like' T cells, retaining their clonotype identity and phenotype in subsequent biopsies from the same patients despite histologic ACR resolution. CD8EXP clonotypes localized to portal infiltrates during active ACR, and persisted in the lobule after histologic ACR resolution. CellPhoneDB analysis revealed differential crosstalk between KC and CD8EXP during late ACR, with activation of the LTB-LTBR pathway and downregulation of TGFß signaling. Therefore, persistently-detected intragraft CD8EXP clones remain active despite ACR treatment and may contribute to long-term allograft fibrosis and failure of operational tolerance.

Presence of KIR2DL2/S2, KIR2DL5, and KIR3DL1 Molecules in Liver Transplant Recipients with Alcoholic Cirrhosis Could Be Implicated in Death by Graft Failure

Background: The second-most frequent diagnosis among patients receiving liver transplants (LTs) is alcoholic liver disease. The multifactorial pathophysiology of alcoholic liver disease depends on the innate immune system and the inflammatory cascade. According to recent studies on these receptors, killer-cell immunoglobulin-like receptors (KIRs) may be involved in sepsis, liver rejection, and virus relapse. We aimed to investigate the impact of preclinical issues like ascites and encephalopathy and KIR genetic traits on death from sepsis, multiorgan failure (MF), and graft failure (GF) in AC patients undergoing LTs. Methods: We retrospectively reviewed 164 consecutive and deceased Caucasian AC patients who underwent LTs. Pre-transplant complications, cause of death, and patient survival were analyzed. Genomic DNA was taken from peripheral blood, and PCR-SSO was used for genotyping KIR. Results: Compared to GF patients, there was a statistically significant increase in the frequency of KIR2DL2+ (75.8% vs. 51.2%; p = 0.047). Another increase in frequency was also observed in KIR2DS2+ in sepsis compared to the GF group (51.2% vs. 43.7%; p = 0.018). In patients who passed away from MF, a decrease in KIR2DL5+ was observed in AC patients with and without encephalopathy (p = 0.018). The frequency of KIR3DL1+ in the AC patients significantly increased the mortality from sepsis (p = 0.045), which was confirmed by multivariate logistic regression. The frequency of KIR3DL1+ in the AC patients significantly increased the mortality from sepsis (p = 0.012) and was confirmed by multivariate logistic regression. KIR2DS1+ and KIR2DS4+ showed increased mortality due to GF compared to patients without these genes (p = 0.011 and 0.012, respectively). However, this fact was confirmed only for KIR2DS1+ by multivariate logistic Cox regression. Conclusions: The presence of the KIR2DL2/S2+, KIR2DL5+, and KIR3DL1+ genes increases the frequency of death from multiple organ failure or graft failure. Our findings highlight the AC patient’s vulnerability to a LT during hospitalization. Following the transplant and outside of it, we adopt essential preventive measures to create a routine healthcare screening to enhance and modify treatments to increase survival.

Identification of High-Mobility Group Box 1 (HMGB1) Expression as a Potential Predictor of Rejection and Poor Prognosis After Liver Transplantation

BACKGROUND Acute cellular rejection (ACR) frequently occurs after liver transplantation (LT) and can result in permanent damage of the liver allograft. Specific and sensitive biomarkers for predicting and monitoring ACR are vital for guiding post-transplantation care. In the present study, we aimed to investigate the function of high-mobility group box 1 (HMGB1) in predicting ACR and prognosis after LT. MATERIAL AND METHODS A total of 113 LT recipients were enrolled in the study, including 62 patients in an ACR group and 51 patients in a non-rejection group. Using tissues from the 113 patients, HMGB1 expression was examined by immunohistochemistry, and the total score for HMGB1 expression was calculated by multiplying the percentage of immunoreactive cells score and the staining intensity score. We then analyzed the association between HMGB1 expression and clinical features. Finally, the function of HMGB1 in predicting the prognosis of LT was determined using Kaplan-Meier (K-M) survival and Cox multivariate analyses. RESULTS Immunohistochemical staining results demonstrated that the expression of HMGB1 was significantly increased in the ACR group, compared with that in the non-rejection group (P<0.05). Clinical characteristic analysis revealed that high HMGB1 levels were related to ACR (P<0.05). Moreover, K-M survival analysis showed that patients with high HMGB1 expression displayed poorer prognosis (P<0.05). Cox multivariate analysis demonstrated that HMGB1 was an independent prognostic predictor for post-LT survival (odds ratio, 3.283; P=0.008). CONCLUSIONS LT recipients' HMGB1 levels may be a useful and noninvasive biomarker for the prediction of ACR and prognosis after LT.

Identification of peripheral CD154+ T cells and HLA-DRB1 as biomarkers of acute cellular rejection in adult liver transplant recipients

Decreasing graft rejection and increasing graft and patient survival are great challenges facing liver transplantation (LT). Different T cell subsets participate in the acute cellular rejection (ACR) of the allograft. Cell-mediated immunity markers of the recipient could help to understand the mechanisms underlying acute rejection. This study aimed to analyse different surface antigens on T cells in a cohort of adult liver patients undergoing LT to determine the influence on ACR using multi-parametric flow cytometry functional assay. Thirty patients were monitored at baseline and during 1 year post-transplant. Two groups were established, with (ACR) and without (NACR) acute cellular rejection. Leukocyte, total lymphocyte, percentages of CD4+ CD154+ and CD8+ CD154+ T cells, human leukocyte antigen (HLA) mismatch between recipient-donor and their relation with ACR as well as the acute rejection frequencies were analysed. T cells were stimulated with concanavalin A (Con-A) and surface antigens were analysed by fluorescence activated cell sorter (FACS) analysis. A high percentage of CD4+ CD154+ T cells (P = 0·001) and a low percentage of CD8+ CD154+ T cells (P = 0·002) at baseline were statistically significant in ACR. A receiver operating characteristic analysis determined the cut-off values capable to stratify patients at high risk of ACR with high sensitivity and specificity for CD4+ CD154+ (P = 0·001) and CD8+ CD154+ T cells (P = 0·002). In logistic regression analysis, CD4+ CD154+ , CD8+ CD154+ and HLA mismatch were confirmed as independent risk factors to ACR. Post-transplant percentages of both T cell subsets were significantly higher in ACR, despite variations compared to pretransplant. These findings support the selection of candidates for LT based on the pretransplant percentages of CD4+ CD154+ and CD8+ CD154+ T cells in parallel with other transplant factors.

Paraphenylenediamine and related chemicals as allergens responsible for allergic contact dermatitis

INTRODUCTION

Paraphenylenediamine (PPDA) is a chemical with strong sensitizing properties used for dyeing of hair and textiles. Paraphenylenediamine can cross-react, resulting in allergy to other related compounds. The prevalence of PPDA sensitization varies widely. The objectives were to assess the frequency of positive patch test reactions to PPDA and related chemicals among patients with allergic contact dermatitis (ACD) and to analyze them regarding their clinical pattern, occupation and cross-reactions.

MATERIAL AND METHODS

The sociodemographic and clinical data of patients with positive patch tests to PPDA, N-isopropyl-N-phenyl-4-phenylenediamine (IPPD), ethylenediamine (EDA), triethylenetetramine (TETA) and toluene-2,5-diamine (TDA) were analyzed. The frequency, strength and cross-reactions with other chemicals were assessed.

RESULTS

Of 4087 ACD patients patch-tested between 2006 and 2015, positive reactions to PPDA and other amines were found in 166 (4.1%). The occupational character of PPDA allergy was established in 34.3% of patients. Personal history of atopy was reported by 36.7% of patients. In 98% of those examined, allergy presented as ACD, most frequently affecting hands. Hypersensitivity to PPDA was diagnosed in 77.1%, to IPPD in 20.5%, to TDA in 6%, to TETA in 1.2%, and to EDA in 0.6% of cases. The patients with an extremely strong PPDA reaction significantly more frequently showed reactions to other para group chemicals, especially to benzocaine.

CONCLUSIONS

Paraphenylenediamine was a major cause of contact allergy of diverse clinical picture more often affecting women, especially with atopy. Every fifth PPDA-allergic person exhibited hypersensitivity to other related compounds. Strong reactions to PPDA increased the risk of cross-reactions.

Pretransplant ascites and encephalopathy and their influence on survival and liver graft rejection in alcoholic cirrhosis disease

INTRODUCTION

The Child-Pugh and model for end-stage liver disease (MELD) scores are widely used to predict the outcomes of liver transplant (LT). Both have similar prognostic values in most cases, although their benefits might differ in some specific conditions. The aim of our study was to analyze the influence of pre-transplant ascites and encephalopathy in post-transplant liver rejection development and survival in alcohol cirrhosis (AC) patients undergoing LT to determine the usefulness of the Child-Pugh score for the assessment of prognosis in such patients.

MATERIAL AND METHODS

Two hundred and eighty-one AC patients, classified according to viral infections and pre-transplant complications, were analyzed. Acute (AR) and chronic (CR) liver rejections and Child-Pugh, MELD and albumin-bilirubin (ALBI) scores were studied in all cases.

RESULTS

Similar AC rejection percentages were observed in ascites or encephalopathy groups (18.5% and 16.5%, p = 0.735), although a higher but not statistically significant AC rate was observed in patients with grade III ascites (p = 0.777) and with grade II encephalopathy (p = 0.089). Chronic rejection was only developed by 9.1% of AC patients, regardless of the presence of ascites (6.2%) or encephalopathy (5.5%). The presence of ascites and encephalopathy complications did not seem to influence post-transplant survival. Neither the Child-Pugh nor the ALBI score can be considered the best for predicting patient survival in the short or long term.

CONCLUSIONS

Ascites and encephalopathy do not seem to influence AC or CR in patient survival, regardless of the presence of viral infections, so in our study neither the Child-Pugh nor ALBI score seems to be the best score to predict the outcomes of these patients.

Influence of Preformed Antibodies in Liver Transplantation

The significance of human leukocyte antigen (HLA) matching and preformed donor-specific antibodies (DSAs) in liver transplantation remains unclear. The aim of this study was to analyze the presence of DSAs in a large cohort of 810 liver recipients undergoing liver transplant to determine the influence on acute (AR) or chronic liver rejection (CR), graft loss and allograft survival. DSAs were identified using complement dependent cytotoxicity crossmatch (CDC-CM) and multiplexed solid-phase-based flow cytometry assay (Luminex). CDC-CM showed that a 3.2% of liver transplants were positive (+CDC-CM) with an AR frequency of 19.2% which was not different from that observed in negative patients (-CDC-CM, 22.3%). Only two patients transplanted with +CDC-CM (7.6%) developed CR and suffered re-transplant. +CDC-CM patients showed a significantly lower survival rate compared to -CDC-CM patients (23.1% vs. 59.1%, p = 0.0003), developing allograft failure within the first three months (p < 0.00001). In conclusion, we have demonstrated a relationship between the presence of preformed DSAs and the low graft liver survival, indicating the important role and the potential interest of performing this analysis before liver transplantation. Our results could help to detect patients with an increased risk of graft loss, a better choice of liver receptors as well as the establishment of individualized immunosuppressive regimens.

Mechanisms of tumor necrosis factor-alpha and interleukin-6 induction during human liver transplantation

In human orthotopic liver transplantation (LTX) intraoperative elevations of TNF-α (> 100 pg/ml) and IL-6 (>800 pg/ml) have been found to correlate with early post-operative rejections and infections respectively. In this study the possible mechanism responsible for the induction of these cytokines has been investigated during liver allografting in 38 recipients. Intraoperative elevations of TNF-α (> 100 pg/ml) were detected in the majority of pre-transplant endotoxin positive recipients (8/12, > 10 endotoxin units/ml), the patients turning endotoxin positive until the end of grafting (3/5), and in a subgroup (6/21 patients), apparently endotoxin negative for the whole operation. Therefore endotoxin (ET) seems to stimulate release of TNF-α in approximately 50% of the patients, whereas sensitized Kupffer graft cells or immediate allograft reactivity of the host are likely to account for the remaining TNF-α positive cases. Elevations of IL-6 > 800 pg/ml) were found in approximately 50% of the TNF-α positive cases, indicating partially independent regulatory pathways for IL-6 induction in the TNF-α negative patients. In agreement with a previous study, 11/13 (85%) of the intraoperative TNF-α positive recipients rejected their grafts within the first 10 days post-operatively. These data demonstrate that ET/infection associated as well as ET independent/reperfusion associated intraoperative TNF-α elevations, promote the initiation of allograft rejection in human liver transplantation. The transient and low endotoxaemia caused by the liver grafting procedure performed without veno-venous bypass seems to be of minor importance in the intraoperative induction of TNF-α.

Evolution of soluble forms of CD86, CD95 and CD95L molecules in liver transplant recipients

Co-stimulatory factors such as CD86 and apoptotic molecules such as CD95 and CD95L required to start and to turn off the allogenic immune response may also be present as soluble proteins. To determine the role of the soluble forms of CD86 (sCD86), CD95 (sCD95) and CD95L (sCD95L) in the outcome of liver transplants, we analyzed the circulating levels of these molecules in patients subjected to liver transplantation in the pre-operative period and during the first month post-transplantation. Serum samples were obtained from sixty-nine first orthotopic liver transplants (OLT). The patients were classified into acute rejection (AR=24) and not acute rejection (NAR=45), or considering the presence of chronic active hepatitis B or C (VP=30) or other primary liver diseases (VN=39). The levels of sCD86, sCD95 and sCD95L were analyzed by solid phase sandwich enzyme-linked immunoabsorbent assays. Our results first showed that the pre-transplantation serum levels of sCD86 in the AR group were significantly higher than in the NAR group (1007±82U/mL vs. 739±46U/mL, p=0.006), and in the post-transplantation period these levels decreased sharply. Second, the levels of sCD95L and sCD95 in the pre-transplantation period did not point to statistically significant differences between the AR and NAR groups. Considering primary liver disease, the pre-transplantation levels of sCD86 and sCD95L in the VP group were significantly higher than those of the VN group (VP, 977±69U/mL vs. VN, 722±51U/mL, p<0.002, and VP, 482±78pg/mL vs. VN, 221±31pg/mL, p=0.002, respectively). Multivariate analysis revealed that only the pre-transplantation levels of sCD86 were independently associated with the development of episodes of acute rejection (p=0.005, OR=2.1, IC 95%=1.27-3.47). In conclusion, the present work shows that primary liver disease could influence the pre-transplantation levels of sCD86 and sCD95L. High pre-transplantation serum levels of sCD86 could favor the development of episodes of acute rejection.

CD28 and KIR2D receptors as sensors of the immune status in heart and liver transplantation

Viral infections and cellular acute rejection (AR) condition immunosuppressive therapy and compromise the evolution of allografts. Immune monitoring can be useful for ascertaining rejection and for differentiating allo-reaction from activation induced by infections. This work analyzes the usefulness of monitoring the expression of CD28 and KIR2D receptors in peripheral blood T lymphocytes by flow cytometry, to ascertain the immune response in heart and liver transplant recipients. In both types of transplant, the up-regulation of CD28 in CD4(+) lymphocytes in the periods of greatest AR frequency indicates an effective allo-response, whereas the post-transplantation emergence of circulating CD8(+)CD28(-) and CD8(+)CD28(-)KIR2D(+) T cells correlates with better early clinical results. Cytomegalovirus (CMV) infection, but not hepatitis C virus (HCV) or other infections, abrogated both CD28 up-regulation and CD8(+)CD28(-)KIR2D(+) T-cell expansion. Our results show that monitoring the expression of CD28 and KIR2D receptors on T lymphocytes might be considered as sensors of the immune status of heart and liver recipients.

Chronic rejection of the liver: the role of immunosuppression

Liver transplantation is now widely recognised as an effective treatment option for patients with advanced liver disease. Many units now achieve greater than 85% survival at 1 year, with the majority of patients having a high quality of life. The maintenance of a high quality of life requires careful clinical management to ensure that the continued maintenance of excellent liver graft function is not achieved at the expense of immunosuppressive drug complications or morbidity. Acute liver rejection will occur in between 30 to 45% of patients, although with modern immunosuppressive protocols, usually combining one of the calcineurin agents, either cyclosporin or tacrolimus, with both azathioprine and corticosteroids (prednisolone) ensures that relatively few grafts are lost from severe acute rejection. While the incidence and severity of acute rejection may be one factor in raising the risk of chronic rejection, it may not be the principal one in many patients. It is important to recognise that the frequency of rejection also varies with the primary underlying liver disease, with patients with hepatitis B or alcoholic liver disease having relatively low rejection rates, compared with patients with primary biliary cirrhosis (PBC) or primary sclerosing cholangitis (PSC), which range between 20 to 70%. Chronic rejection will account for some 5% of grafts lost in the first 3 to 5 years. Indeed, there is some evidence that the incidence of chronic rejection is actually declining over the past few years. While the reason for this apparent decline is uncertain, and it could relate to better immunosuppression management, or more likely to the growing recognition that chronic graft dysfunction may be due to recurrent liver disease, such as autoimmune hepatitis, PBC, PSC, or recurrent hepatitis C. The differentiation of recurrent primary liver disease from chronic rejection can prove to be very difficult in clinical practice. Thus, the clinician must carefully monitor liver and graft function, evaluate any biochemical changes, and try to reach a clear diagnosis before considering any modification of immunosuppressive schedules.

Tissue factor expression demonstrates severe sinusoidal endothelial cell damage during rejection after living-donor liver transplantation

BACKGROUND/PURPOSE

Since it is well known that endothelial cells may be important targets during rejection after living-donor liver transplantation, in this study we investigated liver sinusoidal endothelial cell (SEC) damage during rejection by focusing on thrombomodulin (TM) and hyaluronic acid (HA) as plasma markers of SEC damage. We also examined tissue factor (TF) expression in SECs, because damage to endothelial cells leads to immediate activation of the coagulation system, with the damage being triggered mainly by TF.

METHODS

Living-donor liver transplantation was performed at Mie University Hospital between March 2002 and December 2007; there were 8 patients with rejection (4 with acute cellular rejection and 4 with chronic rejection) and 32 patients without rejection. Liver biopsy tissue was immunostained with an anti-TF antibody, and assessed for SEC damage. In addition, total RNA was extracted from liver biopsy tissue and tested for TF mRNA expression by reverse-transcription polymerase chain reaction (RT-PCR).

RESULTS

The plasma TM level was significantly higher in the rejection group than in the non-rejection group. TF expression was observed in SECs, in infiltrating inflammatory cells, and in the vascular endothelium in the rejection group. TF mRNA expression was significantly higher in the rejection group than in the non-rejection group.

CONCLUSIONS

We demonstrated that TF expression revealed severe SEC damage in grafted liver during both acute cellular rejection and chronic rejection.

Impact of recipient HLA-C in liver transplant: a protective effect of HLA-Cw*07 on acute rejection

The involvement of the human leukocyte antigen (HLA) in liver graft acceptance is controversial, but the frequency of acute rejection (AR) remains high in spite of the use of the modern immunosuppressive agents. The present study was aimed at determining whether an association exists between liver recipient HLA-C polymorphism and AR development that could influence graft acceptance. Four hundred and forty-six liver recipients and 473 controls were studied within the framework of a collaborative study carried out by the Spanish Transplant Immunotolerance Group (RED-GIT). HLA-A and -B were typed by the standard microlymphocytotoxicity technique, and HLA-C by polymerase chain reaction-sequence-specific oligonucleotide probes (PCR-SSOP). A statistically significant decrease in the HLA-Cw*07 allele frequency was found in liver recipients suffering AR episodes compared to those without AR (NAR). Studies regarding the possible influence of the Asn80 and Lys80 epitopes showed that the Asn80 epitope also could be associated with AR. However, further analysis considering Asn80 alleles others than HLA-Cw*07, confirmed that the apparent protective effect of the Asn80 epitope was actually from the HLA-Cw*07 allele. In conclusion, the HLA-Cw*07 allele carried by the liver recipient is negatively associated with AR development, and could be considered a predictive factor for liver graft acceptance.

Pediatric liver transplantation

Liver transplantation has become the accepted standard of care in the treatment of a child with a failing liver. Advances in the management of critical care and immunosuppression along with the development of innovative operative procedures have improved outcome such that 5-year survival rates of 80% to 90% are expected following liver transplantation. Organ allocation schemes have evolved in an effort to better stratify recipient risk thereby more appropriately distributing deceased donor grafts. A persistent shortage of appropriate donors continues to contribute to patient mortality. The consequences of long-term immunosuppression have become increasingly apparent such that health care providers need to be aware of the side effects of chronic immunosuppression. New strategies need to be defined to minimize the need of continuous immunosuppression. The continued success of pediatric liver transplantation will require multi-disciplinary health care teams comprised of general pediatricians, pediatric hepatologists, transplant surgeons, and transplant coordinators who focus on the complex needs of the transplant recipient.

Pediatric liver transplantation

In the past two decades, pediatric liver transplantation has become the state-of-the-art operation with anticipated success and limited mortality. The future success of pediatric liver transplantation will require thoughtful solutions to the delicate balance of risk to donors and recipients, the complex needs of the acute postoperative patient, and the long-term challenges of chronic immunosuppression in these previously unsalvageable patients.

Study of Fas (CD95) and FasL (CD178) polymorphisms in liver transplant recipients

The Fas receptor is capable of transducing apoptotic cell death upon interaction with their ligand (FasL). Recent studies suggest that the Fas/FasL system is involved both in graft rejection and in transplantation tolerance. In this study, we analyzed the effect of Fas and FasL polymorphisms in liver allograft outcome. Fas and FasL polymorphisms were analyzed in 151 primary liver graft recipients. The Fas (-670 A/G) and the FasL (IVS2nt -124 A/G and IVS3nt 169 T/delT) polymorphisms were analyzed by polymerase chain reaction-restriction fragment length polymorphism. Fas -1377 G/A polymorphism was determined by allele-specific amplification. Fas and FasL polymorphisms were not associated with acute and chronic rejection in liver transplant. In contrast, those recipients bearing the AA -670 Fas genotype showed significantly lower graft survival rate (S = 40%) than those bearing the GA genotype (S = 63.1%). These differences were detected from the first year post-transplant. Multivariate analysis confirmed that the AA genotype increased the risk of liver graft loss. This work suggests for the first time a possible harmful effect of Fas -670 AA genotype on liver graft survival, whereas the Fas and FasL polymorphisms are not associated with acute or chronic rejection in liver graft recipients.

Evaluation of CD86 gene polymorphism at +1057 position in liver transplant recipients

BACKGROUND

Efficient T cell-APC interaction requires the participation of primary and co-stimulatory signals. The main co-stimulatory pathway involves the interaction of CD80 and CD86, expressed on the APCs, with their T cell counter-receptor, CD28 and CTLA-4. Recently, a G to A transition has been described at position +1057 of the CD86 gene, located in their cytoplasmic tail.

METHODS

CD86 polymorphism was analyzed by sequence based typing in DNA samples obtained from 205 liver transplant recipients. Acute rejection and chronic rejection were diagnosed based upon conventional clinical, biochemical and histological criteria.

RESULTS

The study of CD86 +1057 (G/A) polymorphism revealed that recipients bearing the A allele or the AA genotype have a reduced risk of acute rejection. In fact, the AA genotype was absent in the group of patients showing acute rejection episodes, whereas its frequency in those patients without acute rejection episodes was 8.8% (P=0.009, OR=0.07). This polymorphism did not reveal any association with the incidence of chronic rejection, but patients bearing the AA genotype showed a higher graft survival rate (83.3%) than those bearing the GA genotype (49.3%) or GG genotype (56.5%).

CONCLUSIONS

The results of the present report suggest that the CD86 AA genotype at +1057 position could be involved in liver transplant acceptance, given that its presence is related to a decrease of acute rejection frequency and to a graft survival increase.

Liver transplantation in children: part 1--peri-operative issues

This two-part review provides a comprehensive summary of clinical and research literature on paediatric liver transplantation. Part 1 outlines the peri-operative issues of liver transplantation, covers a brief history, discusses the indications and methods of transplantation and outlines the physical complications which can occur either as a result of the surgery or the subsequent immunosuppressive therapy required to maintain graft integrity. Post-liver transplantation care may require prolonged admission in hospital due to the complications that can occur during surgery and as a result of immunosuppression. This can have a further impact on the emotional status of the child and family. Health care professionals in all settings require greater knowledge about paediatric liver transplantation, its associated complications and long-term health implications.

Biliary epithelial cell antibodies induce expression of toll-like receptors 2 and 3: a mechanism for post-liver transplantation cholangitis?

Studies to determine the role of preformed antibodies to biliary epithelial cells (BECs) in liver transplant rejections have been initiated. However, the clinical importance of these antibodies in the posttransplantation period still remains to be elucidated. Reactivity to BECs isolated from a normal healthy liver was investigated in sera of 56 patients before and after liver transplantation (LTX) using flow cytometry. Functional capacity of BEC antibodies was determined by the ability to induce expression of Toll-like receptors (TLRs) on BECs. Cytokine and chemokine production induced by BEC antibodies was determined by enzyme-linked immunosorbent assay. In all, 7 patients (13%) had BEC antibodies only pre-LTX, 14 (25%) only after LTX, 18 (32%) both before and after LTX, and 17 (30%) had no detectable antibodies. Presence of preformed BEC antibodies correlated with acute rejections (P < 0.03). Deposition of immunoglobulins in bile ducts was detected in biopsies of patients during rejections. Significantly higher numbers of patients with post-LTX antibodies (9 of 32) developed cholangitis, compared with 0 of 17 without antibodies (P < 0.02). Specificity studies indicated that these antibodies were both non-HLA- and HLA-specific. Normal BECs expressed mRNA but not the proteins for the TLRs. However, treatment with F(ab')2 fragments of BEC antibodies induced protein expression of TLRs 2 and 3 and significantly high production of interleukin (IL)-6, monocyte chemoattractant protein (MCP)-1, macrophage inflammatory protein (MIP)-1alpha, epithelial neutrophil activating peptide (ENA)-78, and IL-8. In conclusion, BEC antibodies via induction of TLR2 and TLR3 expression, as well as inflammatory cytokine and chemokine production may induce epithelial cell inflammatory responses to bacterial components and contribute to posttransplantation cholangitis.

Acute Liver Rejection: Accuracy and Predictive Values of Doppler US Measurements—Initial Experience

PURPOSE

To prospectively evaluate accuracy and predictive values of Doppler ultrasonographic (US) measurement of portal blood velocity (PBV) and splenic pulsatility index (SPI) in diagnosis of clinically relevant acute rejection in patients with clinicobiochemical hepatic dysfunction after orthotopic liver transplantation (OLT).

MATERIALS AND METHODS

Study was approved by the institutional review board, and protocol conformed to ethical guidelines of Declaration of Helsinki. Patient informed consent was obtained. In 27 patients with OLT (23 men, four women; mean age, 48 years; range, 27-64 years), PBV and SPI were measured at Doppler US within 48 hours before or after liver biopsy for clinically suspected acute rejection. Biopsy specimens were assigned scores according to Banff method, and rejection activity index (RAI) was calculated. RAI score of 4 or greater was considered clinically relevant acute rejection. Doppler US parameters were analyzed as absolute values and as percentage point changes with respect to values obtained at last examination before rejection was suspected. Information from two Doppler US parameters was combined; Doppler US composite index was calculated. Statistical tests were conducted to assess accuracy, sensitivity, specificity, and predictive values of Doppler US parameters in diagnosis of graft rejection.

RESULTS

Clinically relevant acute rejection was diagnosed in nine patients. Median time from OLT until histologic diagnosis of acute rejection was 8 days (range, 5-20 days). Rejection was associated with a marked reduction in mean PBV (-43% +/- 5 [standard error of the mean]) and a slight increase in SPI (+12% +/- 16). The calculated Doppler US composite index was strictly related to severity of rejection (P < .001). When applied retrospectively, this index had good accuracy (88%) for prediction of rejection (specificity, 89%; sensitivity, 86%; negative predictive value, 94%).

CONCLUSION

During the first weeks after OLT, a marked decrease in PBV associated with increased SPI supports suspicion of clinically relevant acute rejection.

Acute liver transplant rejection: incidence and the role of high-doses steroids

The aim of this study was to assess the incidence of acute rejection (AR), and the efficacy of high doses of steroids during induction of immunosuppression for AR treatment. Fifty-five patients (33.5%) experienced AR episodes in our series; but, there were no deaths or retransplantations related to AR. The median time from liver transplantation to AR was 18.5 days (range, 2-351 days). In the group with the initial dose of methylprednisolone (MP) </=0.75 g, AR occurred in 32.9% of patients; and in the group with higher dose of MP, 43.6% (P > 0.05). After 1-year observation, liver function tests were similar in both AR and non-AR groups. The only biochemical parameter that was significantly lower in the non-AR group was the aspartate aminotransferase (AST). Liver function tests determined after 1-year follow-up were not significantly different between the groups with AR treated with doses of MP lower versus higher than 1.25 g. However, liver function tests in the group treated for AR with higher doses of MP were slightly better than in the remaining subjects. Recurrence of AR occurred in 5 cases in the group with lower doses of MP (</=1.25 g), and in 2 cases in the group with higher doses of MP (>1.25 g). A relatively low dose of MP was effective to treat AR. The tendency of AR patients treated with higher dose of MP to display better liver function needs further investigation. However, AR does not seem to affect later liver function.

Outcomes of acute rejection after interferon therapy in liver transplant recipients

Interferon alfa has been increasingly used against recurrent hepatitis C (HCV) disease in post-liver transplant (LT) recipients. A serious potential adverse effect is acute rejection. We reviewed our experience using interferon-based therapy (interferon or pegylated interferon with or without ribavirin) for treating recurrent HCV in LT recipients. Forty-four LT recipients were treated with interferon for recurrent HCV. Five of the 44 patients developed acute rejection during interferon-based therapy. These 5 patients started treatment of 42.4 +/- 33.89 months (mean +/- SD) after LT. Mean (+/- SD) histological activity index and fibrosis scores before initiating antiviral therapy were 8.8 (+/- 1.92) and 2.6 (+/- 0.55), respectively. Patients were treated for 3.3 +/- 2.28 months (mean +/- SD) prior to rejection. At the time of rejection, HCV load was not detectable in 4 of the 5 recipients. All 5 patients had tolerated interferon therapy, and none had stopped therapy because of adverse effects. The rejection was successfully treated in 3 patients. In 2 of those 3 patients, cirrhosis eventually developed. In the 2 patients who did not respond to rejection treatment, immediate graft failure occurred, leading to re-LT in 1 patient and death from sepsis in the other. In conclusion, the results indicate that further studies are needed to assess the safety of interferon in LT recipients. Interferon-based therapy may lead to acute rejection and subsequent graft loss and should therefore be used with caution. Treated recipients may also develop progressive cirrhosis despite achieving a sustained virological response.

Overview of pediatric liver transplantation

Liver transplantation is a successful and useful therapy for children with chronic or end-stage liver disease and those with a variety of extrahepatic metabolic diseases that can be corrected by liver replacement. Major developments in medical management, donor availability and procurement, operative techniques, and post-operative management all contributed to the dramatic improvement in outcome and growth of liver transplantation from its inception in 1963 [1,7,21]. The excellent long-term outcomes that have been achieved are the product of the coordinated efforts of liver transplant surgeons, specialists in pediatric hepatology and other medical areas, nurses, local practitioners, and the patients and their families. Future advances in transplant immunobiology, organ availability and infection control are likely to lead to still greater improvements in short and long-term outcome [34].

Impact of HLA-C on acute rejection in liver transplantation

Although liver transplants show a special tolerogenic behaviour, rejection remains an important problem that involves several immunological mechanisms, some of which are unknown. Our study sought to analyze the influence of HLA-C polymorphism on short-term liver graft acceptance by HLA-C genotyping of 100 orthotopic liver transplant recipient-donor pairs. Recipients were statified according to the occurrence of acute rejection. HLA-Cw*06 allele appeared to be underrepresented among recipients without versus those with acute rejection or those in control groups. With regard to HLA-C allelic compatibility, the frequency of acute rejection or those in episodes decreased with fewer HLA-C mismatches. These findings suggest the participation of HLA-C molecules in liver graft alloresponses, involving HLA-C genotyping, as well as compatibility.

Human leukocyte antigen-C in short- and long-term liver graft acceptance

In liver transplantation, rejection is still an important problem, and the role of human leukocyte antigens (HLA) has not been clearly established. At present, the possible involvement of HLA-C antigen in liver transplantation is still unexplored. The aim of this work was to analyze the influence of HLA-C polymorphism on the outcome of liver transplantation. For this purpose, genotyping of 100 orthotopic liver transplant recipient-donor pairs for HLA-C was performed with polymerase chain reaction-sequence-specific primers (PCR-SSPs). Liver recipients were stratified according to the occurrence of acute rejection. Patients without acute rejection were found to have a lower frequency of the HLA-Cw*06 allele compared with those with acute rejection or the control group. Moreover, when the role of HLA-C dimorphism was analyzed, natural killer (NK)1-alloantigens were found to be predominant in recipients without acute rejection. When the match of HLA-C single alleles and NK-alloantigens between donor and recipient was analyzed, it appeared that the frequency of acute rejection gradually decreased with decrease of the number of allele mismatches. Graft survival was increased when the number of mismatches in both HLA-C or NK-alloantigens was lower. In conclusion, the HLA-C locus may play a role in liver graft alloreactivity or allotolerance and, therefore, may be useful to avoid acute rejection and to achieve graft acceptance, resulting in a better final outcome in liver transplantation.

Late acute rejection after liver transplantation: the Western Canada experience

Acute rejection usually occurs within 3 months posttransplantation. Most centers reduce immunosuppression over 6 to 12 months to minimize opportunistic infection, malignancy, and drug toxicity. Pretransplant disease and low immunosuppression have been reported in association with late acute rejection (LAR). The objective of this study was to determine the incidence, predictive factors, and outcomes of LAR via retrospective review of adult liver transplant recipients in Western Canada from 1989 to 2000. LAR was defined as biopsy-proven acute rejection occurring more than 180 days posttransplantation. Patient characteristics, immunosuppression, and outcome were determined. Both a univariate and multiple logistic regression analysis were performed. LAR occurred in 97 (23%) of 415 patients more than 180 days posttransplantation. Median follow-up was 402 days (range, 180 to 3137 days); 79% of LAR episodes were graded mild. At the time of LAR, 33% were on a steroid taper. A total of 73% of LAR episodes were treated with pulse intravenous steroids, and 5% were steroid-resistant. In the univariate analysis, patients undergoing transplantation for viral etiologies and older age were associated with less LAR. Immunosuppression was significant in a multiple logistic regression model, but not with a proportional hazards model. On multivariate analysis, only patients undergoing transplantation for viral etiologies remained resistant to LAR (hazard ratio, 0.52; range, 0.34 to 0.93, P = .02). There was a trend toward increased chronic rejection in patients who developed LAR (P = .04). LAR is common and occurs after more than 1 year posttransplantation. Patients undergoing transplantation for viral etiologies seem to have a lower risk of LAR. There may be an increased risk of chronic rejection in those developing LAR.

Acute cellular rejection in liver transplant recipients under cyclosporine immunosuppression: predictive factors of response to antirejection therapy

BACKGROUND

Predictive factors of response to antirejection therapy in acute cellular rejection (ACR) in liver transplantation are not well established.

METHODS

To investigate the possible existence of these factors, we reviewed 111 consecutive episodes of ACR fulfilling the following criteria: histologically confirmed ACR; cyclosporine-based immunosuppression; initial antirejection treatment with high-dose steroid boluses; minimum follow-up of 2 weeks after treatment; and no other graft complication interfering with evaluation of therapeutic response. ACR episodes not responding to initial steroid therapy were given additional treatment (OKT3 and/or repeated steroid boluses). We analyzed the association of the response to the antirejection treatment with different clinical, laboratory, histological, and donor-recipient compatibility variables at two times: after the initial antirejection therapy, and after all the antirejection therapy administered.

RESULTS

Eighty episodes of ACR (72%) resolved after the initial therapy with high-dose steroid boluses, and another 18 (16%), initially steroid-resistant, resolved with additional antirejection treatment. Thirteen episodes (12%) were refractory to all antirejection treatment administered. Variables with independent predictive value of nonresponse to initial therapy with steroid boluses were late-onset ACR (>2 months after transplantation), high serum bilirubin and alanine aminotransferase, low blood cyclosporine concentration in the week before antirejection treatment, and severe histological endothelialitis. Late-onset ACR and high serum bilirubin were also independent predictors of refractoriness to all the treatment administered.

CONCLUSIONS

Response to antirejection treatment in ACR in liver transplantation can be predicted by several clinical and laboratory data. ACR episodes with factors predictive of therapeutic unresponsiveness could benefit from more aggressive antirejection treatment.

A randomized double-blind comparative study of mycophenolate mofetil and azathioprine in combination with cyclosporine and corticosteroids in primary liver transplant recipients

Acute hepatic allograft rejection occurs in approximately 50% to 60% of the patients undergoing liver transplantation. In this study, we compared the rate of acute rejection in liver transplant recipients randomized in a double-blind comparative study to treatment with mycophenolate mofetil (MMF) or azathioprine (AZA), both in combination with cyclosporine and corticosteroids. Five hundred sixty-five primary liver transplant recipients were randomly assigned to treatment with MMF, 1 g twice daily intravenously followed by 1.5 g twice daily orally (n = 278), or AZA, 1.0 to 2.0 mg/kg/d intravenously followed by oral administration (n = 287), in combination with cyclosporine and corticosteroids. Patients were followed up for at least 1 year, and efficacy analysis was based on intent-to-treat methods. Acute rejection was defined according to the Banff histological criteria. The two study groups were balanced for demographic and clinical baseline characteristics. The incidence of acute rejection or graft loss was 47.7% in the AZA patients and 38.5% in the MMF patients (P <.03). The incidence of biopsy-proven and treated rejection censoring for graft loss was 40.0% in the AZA group versus 31.0% in the MMF group (P <.06). Steroid-resistant rejection requiring treatment with either OKT3 or antithymocyte globulin occurred in 8.2% of AZA patients versus 3.8% in MMF patients (P <.02). Patient and graft survival rates at 1 year posttransplantation were 85.4% in the AZA group and 85.3% in the MMF group (P = not significant). MMF was superior to AZA in preventing acute rejection in the first 6 months posttransplantation. MMF and AZA were equivalent in preventing graft loss at 1 year, and the safety profiles between the two immunosuppressive agents were similar.

Prognostic model for early acute rejection after liver transplantation

Hepatic graft rejection is a common complication after liver transplantation (LT), with a maximum incidence within the first weeks. The identification of high-risk patients for early acute rejection (EAR) might be useful for clinicians. A series of 133 liver graft recipients treated with calcineurin inhibitors was retrospectively assessed to identify predisposing factors for EAR and develop a mathematical model to predict the individual risk of each patient. The incidence of EAR (< or =45 days after LT) was 35.3%. Multivariate analysis showed that recipient age, underlying liver disease, and Child's class before LT were independently associated with the development of EAR. Combining these 3 variables, the following risk score for the development of EAR was obtained: EAR score [F(x)] = 2.44 + (1.14 x hepatitis C virus cirrhosis) + (2.78 x immunologic cirrhosis) + (2.51 x metabolic cirrhosis)--(0.08 x recipient age in years) + (1.65 x Child's class A) [corrected]. Risk for rejection = e(F(x))/1 + e(F(x)). The combination of age, cause of liver disease, and Child's class may allow us to predict the risk for EAR.

CD28/CTLA-4 and CD80/CD86 costimulatory molecules are mainly involved in acceptance or rejection of human liver transplant

CD28/CTLA-4 interactions with their specific B7-ligands (CD80 and CD86) have decisive roles in antigenic and allogenic responses. Recently, experimental transplant studies demonstrated that donor-specific tolerance is achieved by blocking these interactions. The present study analyzes the expression of these co-stimulatory molecules in peripheral blood cells from 74 liver recipients and in 16 liver biopsies, which were classified into acute-rejection (AR, n = 27) and nonacute-rejection (NAR, n = 47) groups, as well as their influence on the in vitro response of in vivo allosensitized cells. The results clearly indicate that in human liver transplant too, B7 and CD28/CTLA-4 expression on B and CD4(+) peripheral lymphocytes respectively, contributes to graft acceptance or rejection, and appears to be of crucial importance in modulating the host alloresponse and specific-CTL generation. In the NAR-group, costimulatory molecule expression remained at basal levels after transplant, whereas in the AR-group these molecules were significantly upregulated on days of AR. CTLA-4 was observed in the infiltrating lymphocytes in most of the biopsies, but CD80 or CD86 were not. Moreover, specific cytotoxicity from the in vivo primed cells was clearly suppressed in the NAR-patients with low co-stimulatory molecule expression, whereas this activity was not modified but rather stimulated in the AR-group. Together, these findings indicate that intervention of CD28/CTLA-4/B7 signaling could be therapeutically useful in clinical transplantation.

Clinical utility of monitoring sialyl Lewis(X) (CD15S) antigen on peripheral lymphocytes for the diagnosis and treatment of rejection after renal transplantation

BACKGROUND

In organ transplantation, the grafts must be carefully monitored, but it is often difficult to make a quick and accurate diagnosis of unusual changes. Extensive research has failed to identify a useful marker for rejection. We investigated the clinical utility of sialyl Lewis(X) (CD15s) monitoring in 17 renal transplant patients with acute rejection.

METHODS

The expression of CD15s on peripheral lymphocytes was examined using flow cytometry in renal transplant recipients with rejection (n=17), without rejection (n=23), recipients infected with cytomegalovirus (n=7), recipients with other diseases (n=7), and healthy volunteers (n=18). CD15s expression was compared with histological findings, and was also examined before and after steroid pulse therapy to investigate the effects of steroids on CD15s antigen expression on the surface of the peripheral lymphocytes.

RESULTS

CD15s was strongly expressed in all patients with rejection, but was not expressed in any of the patients without rejection or in any healthy volunteers. Histologically, cell infiltration into the rejected graft was moderate or severe in all patients with strong expression of CD15s. In contrast, no or only mild infiltration was observed in patients with weak expression of CD15s. In addition, 14 of 17 patients (14/17, 82%) with strong CD15s expression improved upon administration of steroid pulse therapy, although there was no benefit from steroids in any of the patients with weak expression of CD15s.

CONCLUSIONS

The CD15s antigen is expressed strongly on the peripheral lymphocytes at the time of rejection. It is interesting that the efficacy of steroid therapy in the patients with elevated creatinine could be predicted by CD15s expression on the peripheral lymphocytes before graft biopsy. There have been only few reports showing the relationship between CD markers and the efficacy of the treatment in patients with elevated creatinine. We report that the detection of CD15s on the peripheral lymphocytes by flow cytometry was an easy, helpful, and noninvasive means for the diagnosis and treatment of patients with elevated creatinine after renal transplantation.

Living related liver transplantation: histopathologic analysis of graft dysfunction in 304 patients

Between June 1990 and August 1997, 304 mainly pediatric patients underwent a total of 311 orthotopic living related liver transplantations (LRLTs) under tacrolimus immunosuppression at Kyoto University Hospital. Congenital biliary atresia was the most common underlying disease. The donor was a parent, and the left lateral segments were used as grafts in most cases. The average number of loci of HLA-A, -B, and -DR mismatches between the donor and the recipient were 2.1. Forty-three transplants were ABO-incompatible. Liver histology at the time of abnormal liver function after transplantation was analyzed. Preservation injury was rare and mild. Acute cellular rejection (ACR) occurred in 36% of transplants during the first 6 months. Average rejection activity index (the Banff schema) was 4.2 and severe rejection was rarely seen. The number of mismatching HLA loci and immunosuppression regimens affected the incidence of ACR. Chronic rejection (CR) occurred in 2% of transplants. Concerning humoral rejection, no hyperacute rejection was seen. However, hepatic artery thrombosis (delayed hyperacute rejection) was seen in an ABO-incompatible transplant. Acute hepatitis, including those related to cytomegalovirus and Epstein-Barr virus, occurred in 17% of transplants. Chronic hepatitis, including hepatitis B and C, developed in 3%. Acute or chronic cholangitis occurred in 16%, and a significantly higher incidence of cholangitis was found in ABO-incompatible transplants. Posttransplantation lymphoproliferative disease developed in 2%. In LRLT, milder preservation injury and less frequent ACR and CR were suggested, probably because of the short cold-ischemia time and the advantages of HLA histocompatibility, respectively.

Implication of soluble and membrane HLA class I and serum IL-10 in liver graft acceptance

Membrane HLA class-I expression (mHLA-I), soluble HLA class-I antigens (sHLA-I) and interleukin (IL)-10 are different factors implicated in the special acceptance of liver allograft. In this study, pre- and post-operative levels of mHLA-I in peripheral blood lymphocytes (PBL) and serum sHLA-I were analyzed in 86 liver transplants, immunosuppressed with Cyclosporine-A, methylprednisolone and azathioprine, and classified into acute-rejection (AR, n = 28) and non-acute-rejection (NAR, n = 58) groups. Serum IL-10 was studied in 47 recipients (AR-group, n = 16 and NAR-group, n = 31). Pre-transplant values of mHLA-I and sHLA-I showed a bimodal distribution (high/low) in NAR-recipients, but in AR-patients were mainly included in the low expression/secretion zone (mHLA-I, p < 0.02 and sHLA-I, p < 0.05). Consequently, average pre-transplant mHLA-I (868 +/- 109 versus 998 +/- 123, p < 0.05) and sHLA-I (1.3 +/- 0.4 versus 2.02 +/- 0.7 microg/ml, p < 0.01) was lower in the AR- than in the NAR-group. After transplant both parameters decreased in the NAR-group, but increased in AR-recipients previous to and on rejection diagnosis day. Additionally, serum IL-10 levels were significantly higher (p < 0.01) in the NAR than in the AR-group during the first 24 h post-transplant. In conclusion, low pre-transplant mHLA-I and sHLA-I levels pre-dispose liver recipients to acute rejection, whereas early post-transplant increases of serum IL-10 appear to be related to a good liver allograft acceptance.

Increased expression of interleukin-4 during liver allograft rejection

BACKGROUND/AIMS

To investigate the respective roles of interleukin-2 (IL-2) and IL-4 during rejection, we evaluated the expression of IL-2, IL-2 receptor and IL-4 in human liver allografts.

METHODS

Immunohistochemistry and RT-PCR were performed in liver biopsies. To determine the effects of immunosuppression and cholestasis in IL-4 production, in vitro experiments were also designed.

RESULTS

IL-2 protein and its mRNA were absent in the liver, with minimal expression of IL-2 receptor, during rejection. In contrast, IL-4 protein and its mRNA were highly expressed during acute and chronic rejection, whereas this expression was absent in stable liver transplant recipients. In vitro, cyclosporine potently inhibited IL-2 and IL-2 receptor expression of activated mononuclear blood cells, but poorly inhibited IL-4 expression. Chenodeoxycholic acid decreased IL-2 and IL-2 receptor expression, but increased IL-4 expression.

CONCLUSIONS

During liver allograft rejection, IL-2 pathway is down-regulated, while IL-4 expression is increased by cholestasis and poorly inhibited by cyclosporine. These data suggest that IL-4 is involved in the mechanisms of liver allograft rejection in patients treated with cyclosporine.

Is acute rejection deleterious to long-term liver allograft function?

BACKGROUND/AIMS

The decreasing incidence of chronic rejection after liver transplantation emphasizes the need for an alternative end-point to assess the long-term consequences of acute rejection. The purpose of this study was to determine the effects of resolved episodes of acute rejection on late liver allograft function.

METHODS

Parameters of hepatic function (liver biochemistry, indocyanine green and sulfobromophthalein clearances, histology) were analyzed in 170 consecutive adult recipients, who were followed prospectively on the basis of repeat annual work-up. Mean follow-up was 3.7+/-0.2 years.

RESULTS

The rates of acute and chronic rejection were 51% and 4.1%, respectively. At the last follow-up, there was no significant difference in graft function between patients with a single episode of acute rejection (n=56) and those without rejection (n=84). Among patients treated for a single episode of acute rejection, late hepatic function was not influenced by the severity of acute rejection and the response to corticosteroids. In contrast, patients with recurrent acute rejection (n=30) had significant impairment of liver function tests (aspartate aminotransferase, p<0.05; alanine aminotransferase, p<0.01; alkaline phosphatase, p<0.01; gamma-glutamyl transpeptidase, p<0.001), lower dye clearances (indocyanine green, p<0.01; sulfobromophthalein, p<0.01) and more severe histologic damage (p<0.001).

CONCLUSIONS

Single episodes of acute rejection do not impair the long-term hepatic function, whereas recurrent episodes leave sequellar damage to the liver allograft. These results provide a rationale for converting patients with rejection to a heavier immunosuppressive regimen, while leaving nearly half the recipients on a lifelong light immunosuppressive regimen.

Effect of partial HLA class I match on acute rejection in viral pre-infected human liver allograft recipients

BACKGROUND

Acute rejection in liver transplants is one of the commonest causes of liver dysfunction in the early postoperative period. However, the factors involved in liver graft rejection are still unknown. Our study was aimed at ascertaining whether the degree of HLA class I and class II compatibility or pretransplant viral infection have any influence on early acute liver graft rejection.

METHODS

We reviewed clinical and laboratory data in 190 consecutive patients who underwent a liver transplant. HLA-A, HLA-B, and HLA-DR typing for the establishment of an HLA match score was performed by a standard microcytotoxicity method. The existence of pretransplant viral infection was investigated in sera and biopsy tissue by serologic (hepatitis B virus, hepatitis C virus) and polymerase chain reaction (cytomegalovirus) techniques, respectively. The influence of these two factors in acute rejection and the interaction between them was also analyzed.

RESULTS

A strong association between viral infection and acute rejection in the group with partial class I matching was found (odds ratio=7.75; P<0.0009), whereas no correlation was observed in the group with zero class I matching (odds ratio=0.98; P=0.81). The rejection percentage in the group in which partial class I match and viral infections coexisted was 60%, whereas in the partially class I-matched group without pretransplant viral presence it was 16%.

CONCLUSIONS

These findings suggest a participation of partial HLA class I compatibility in triggering acute rejection in recipients suffering preoperative viral infections and support the idea that HLA class I antigen matching could play a role as a linking element between the MHC-restricted T cell-mediated response to viral infection and the allogenic response in liver transplantation.

De novo malignancies after liver transplantation using tacrolimus-based protocols or cyclosporine-based quadruple immunosuppression with an interleukin-2 receptor antibody or antithymocyte globulin

BACKGROUND

Although conventional immunosuppression after liver transplantation consists of cyclosporine A (CsA), steroids, and azathioprine, recently introduced protocols entail CsA-based quadruple induction protocols or tacrolimus-based combinations. These protocols aim to reduce the rejection rate and the considerable morbidity related to the side effects of additional immunosuppressive treatment, but have not yet been analyzed regarding their long term de novo neoplastic risk.

METHODS

From September 1988 to May 1994, 500 liver transplantations were performed in 458 patients. The median follow-up was 50 months (range, 0.3-97 months) for all patients. Conventional triple therapy was implemented in 25 patients, CsA-based quadruple induction therapy using an antilymphocyte globulin preparation (ATG) in 190 patients, an interleukin-2 receptor antibody (BT563) in 141 patients, and tacrolimus-based dual or triple immunosuppression in 102 patients. The different protocols were evaluated in four randomized and two nonrandomized prospective trials.

RESULTS

De novo neoplasias were detected in 33 patients (7.2%) and were comprised of lymphomas (n = 7), skin malignancies (n = 8 lesions in 7 patients), intraepithelial neoplasias of the cervix uteri (n = 7), breast carcinoma (n = 3), lung carcinoma (n = 3), and other malignancies (n = 6). The incidence of de novo neoplasias did not differ in the different trial arms. Only a positive T-crossmatch and a low CD4+/CD8+ ratio in patients receiving CsA-based immunosuppression demonstrated a significant correlation with the development of a de novo tumor in a multivariant logistic regression analysis.

CONCLUSIONS

The development of de novo neoplastic diseases after liver transplantation with the use of CsA-based quadruple induction protocols or tacrolimus-based regimens for immunosuppresion was assessed over the long term. Recently introduced immunosuppressive protocols did not alter the posttransplant de novo tumor rate. Patients with a low CD4+/CD8+ ratio during CsA-based therapy or a positive T-crossmatch were identified to be at an increased risk for the development of a de novo malignancy.

HLA-DRB1 and -DQB1 polymorphism in liver recipients: relationship between HLA-DQB1*0302 allele frequency and acute rejection

Polymorphism of HLA-DRB1 and HLA-DQB1 loci was performed in fifty-three orthotopic liver graft recipients as well as in 108 unrelated healthy controls. Nonradioactive SSOPs were used to study PCR-amplified DNA from peripheral blood lymphocytes and biopsied material. The comparison frequency for DQB1 alleles did not reveal any significant differences between the total group of liver recipients and controls. However, when the liver recipients were subgrouped according to their rejection episode manifestations, increased and significant frequencies were observed for HLA-DQB1*0302 allele in patients showing acute rejection episodes compared to healthy controls or patients without acute rejection. This relationship did not appear influenced by the amino acid beta alanine residue in the 57th position. On the other hand, the study of the DRB1 allele frequencies did not show significant differences in any study. These results suggest that HLA-DQB1 genes could be important in the liver graft alloresponses, opening a way to a better understanding of the special tolerance state, normally observed in this type of transplant, leading us to consider the possible HLA-DQB1*0302 allele effect on tolerance rupture.

Posttransplant lymphoproliferative disorder in liver allograft biopsies: a comparison of three methods for the demonstration of Epstein-Barr virus

Posttransplant lymphoproliferative disorder (PTLD) is associated with Epstein-Barr virus (EBV), and may clinically resemble acute allograft rejection. Three methods to show EBV in tissue were evaluated in 15 liver allograft biopsies from 12 patients including four with PTLD: (1) semiquantitative polymerase chain reaction (PCR) for EBV DNA; (2) in situ hybridization for EBV RNA (EBER); and (3) immunoperoxidase for EBV latent membrane protein (LMP). Index cases had a PCR dot blot result of "positive" or "weak positive." Findings were correlated with histology, clinical data, therapy, and outcome. All four PTLD patients had a clinical diagnosis of acute rejection. All four showed EBV: PCR 4, EBER 4, LMP 3, Liver function tests were elevated in three, but EBV viral capsid antigen (VCA) IgM was not increased in three, but EBV viral capsid antigen (VCA) IgM was not increased in three. Immunosuppression was withdrawn and all four patients underwent a second transplantation. One died 4 days posttransplant with disseminated PTLD, two died of sepsis at 1.5 and 14 months, and one is well at 3 years without PTLD. Eleven biopsies without PTLD showed: acute rejection 7, acute rejection and hepatitis 1, hepatitis B 1, and non-inflammatory changes 2. In this group, EBV results included: PCR weak positive in 10 and 1+ in one, EBER negative in ten and rare positive cells in one, LMP negative in 11. Liver function tests were elevated in 10, whereas VCA IgM was not increased in three and increased in one. Patients with acute rejection were treated with increased immunosuppression: none developed PTLD, with follow-up of at least 6 months in nine cases. Two patients died within 4 months of biopsy. One patient with PTLD in tonsils had a liver biopsy showing both acute rejection and EBV (PCR 1+, rare EBER + small cells). Histological studies combined with special EBV detection methods, can be useful to evaluate atypical lymphoid infiltrates in liver allograft biopsies and confirmation of a diagnosis of PTLD. All three methods are useful; EBER and PCR are the most sensitive. EBER and LMP can use paraffin sections.

Risk factors for liver rejection: evidence to suggest enhanced allograft tolerance in infancy

After liver transplantation, a relatively low intensity immunosuppressive regimen is employed in our unit: after initial triple therapy (prednisolone, azathioprine, cyclosporin), prednisolone is discontinued at three months and azathioprine at one year. A retrospective study was therefore performed to determine the incidence of rejection, and to identify risk factors for rejection in our patient population. Over a 10 year period, 135 transplants were performed on 109 children. Thirty four (25%) were on infants less than 1 year old. Incidences of acute rejection and irreversible chronic rejection were calculated for grafts surviving more than one and four weeks respectively. Acute rejection occurred in 51 of 101 allografts (50%), and irreversible chronic rejection in 11 of 91 allografts (12%). The immunosuppression strategy was not associated with an increased incidence of rejection. Acute rejection occurred in only eight of 28 allografts (29%) in those transplanted during their first year, compared with 43 of 73 (59%) in older children. Logistic and Cox regression analysis supported age at transplantation as a significant risk factor for acute rejection. Irreversible chronic rejection did not occur in any of 24 grafts in patients transplanted before one year, compared with 11 of 67 (16%) in older recipients. This suggests possible enhanced allograft tolerance with transplantation during the first year of life. This unexpected and potentially important finding now requires confirmation in other large patient series, with blind interpretation of post-transplant liver biopsies.