Endoscopic treatment in biliary strictures after pediatric liver transplantation.

BACKGROUND AND AIM: The aim of the study was to assess efficacy and safety of endoscopic treatment in BS after pediatric LTx. METHODS: We retrospectively reviewed data of patients with DDA who developed BS and underwent ERCP. RESULTS: Of 189 transplanted patients with DDA, strictures developed in 30 (16%). In this subgroup, the median age at LTx was 14.7 (1.5-17.6) and follow-up period was 3.9 (1.3-11.3). ABS were in 76% and NABS in combination with ABS in 24% of patients. Overall, 95 ERCP sessions (3.0 per patient) were performed with successful outcome in 22 (73%) cases. Duration of treatment was 9.1 (1.8-24.1) months. Five patients underwent surgical revision and three patients retransplantation (10%). Risk factors of endoscopy failure were HCV or HBV infection, prolonged CIT and treatment before 2007. The most common complications after ERCP were cholangitis (8.2%) and pancreatitis (4.2%). There were worse overall prognosis and higher risk of post-ERCP complications in NABS. CONCLUSIONS: ERCP is safe and effective in the majority of patients with post-transplant duct-to-duct BS, and it is currently recommended as the first-line treatment.

The limited prognostic value of liver histology in children with biliary atresia.

UNLABELLED: Background and rationale for the study. The aim of the study was to determine the prognostic value of histopathological findings with special care to the severity of liver fibrosis at the moment of hepatoportoenterostomy (HPE) in children with biliary atresia (BA). We performed analysis of 142 wedge liver biopsies taken at the time of HPE. All patients were operated by the same surgical team between 1995 and 2007. According to the outcome 6 months after HPE patients were divided into prognostic groups: group 1-bilirubin level < 2 mg% (n = 65), group 2-bilirubin level > 2 mg% (n = 77). Liver biopsies were re-evaluated according to the extended histopathological protocol and then were compared between the prognostic groups. Survival with native liver (SNL) estimates were performed in regard to severity of liver fibrosis. RESULTS: Survival with native liver estimates after 2, 5 and 10 years in patients after successful operation were 96%, 91%, 75% vs. 30%, 11%, and 5% if operation failed (p < 0.001). There was no difference between groups in the following variables: fibrosis (p = 0.69), portal inflammation (p = 0.99), lobular inflammation (p = 0.95), cholangiolitis (p = 0.23), accumulation of bile pigments (zone 1:p = 0.49; zone 2:p = 0.51; zone 3:p = 0.48), bile plugs in canaliculi (p = 0.12), bile plugs in ducts (p = 0.32), bilirubinostasis in hepatocytes (p = 0.45), bile ductular proliferation (p = 0.59), ductal plate malformation (p = 0.12), focal necrosis (p = 0.44), giant cell transformation (p = 0.45), haematopoesis (p = 0.52), ductopenia (p = 0.46), microabscesses (p = 0.49), ballooning of hepatocytes (p = 0.08). The actuarial 5/10-year SNL was not dependent on severity of liver fibrosis (log-rank test p = 0.84). The severity of fibrosis corresponded neither with the age at HPE nor with the laboratory findings before operation but increased the risk of portal hypertension. CONCLUSION: Liver histology at the time of HPE is of limited value in prognosis making in BA.

Tissue Expression of Programmed Cell Death 1 Ligand1 (PD-L1) in Biopsies of Transplant Livers of Pediatric Patients as a Possible Marker of Acute Cellular Rejection.

INTRODUCTION: Preclinical models have demonstrated that PD-1 and its ligand programmed death ligand1 (PD-L1) play significant roles in both graft induction and the maintenance of immune tolerance. It has also been suggested that PD-L1 tissue expression may predict graft rejection; however, the available data are sparse and inconclusive. Some studies were conducted on patients with cancer; most of them do not concern the liver, especially within the context of the use of immunohistochemical tests. Therefore, the aim of our study was to assess the relationship between tissue expression of PD-L1 in a unique material, i.e., in the liver biopsies of pediatric patients after transplantation with the presence of acute cellular rejection (ACR). MATERIAL AND METHODS: This retrospective study enrolled 55 biopsies from 55 patients who underwent protocol liver biopsies. The control group consisted of 19 biopsies from 13 patients diagnosed with acute cellular rejection (rejection activity index/RAI/ from 2 to 8). An immunohistochemical (IHC) staining for PD-L1 was performed in all of the liver specimens; its expression was analyzed in different regions of liver tissue (in inflammatory infiltrates and within the endothelium and hepatocytes). The following changes were re-evaluated in each specimen: features of any kind of rejection (acute cellular, antibody-mediated, chronic); the presence and severity of fibrosis (Ishak scale); and the presence of cholestasis and steatosis. Clinical parameters were also evaluated, including tests of liver function (AST, ALT, GGT, bilirubin). RESULTS: The age of patients in the study group ranged from 2.37 to 18.9 years (median 13.87 years), with the time after transplantation being 1-17 years (median 8.36 years). The age of patients in the control group ranged from 1.48 to 17.51 years (median 7.93 years), with their biopsies being taken 0.62-14.39 years (median 1.33 years) after transplantation. We found a statistically significant relationship between PD-L1 expression on inflammatory infiltrates and ACR; however, there was no statistically significant relationship between PD-L1 endothelial expression and ACR. PD-L1 was not positive in the hepatocytes regardless of if it was the study or control group that was under observation. CONCLUSION: PD-L1 appears to be a promising marker to predict graft rejection.

Is M30 staining a reliable marker predicting graft rejection and fibrosis in protocolar liver biopsies in post-liver transplant pediatric patients?

BACKGROUND: Liver transplantation is currently a treatment of choice in patients with end-stage liver disease. Acute cellular rejection (ACR), antibody-mediated rejection (AMR), and chronic rejection (ChR) are major causes of graft injury. Therefore, new markers predicting graft rejection are investigating. Apoptosis has been recently proposed as one of the mechanisms contributing to liver fibrosis in liver grafts. Coarse needle liver biopsy is still a gold standard in monitoring post-transplant pathologies. The aim of this study was to assess the utility of immunohistochemical (IHC) staining for M30 (cytokeratin 18), as a prognostic marker of rejection in pediatric recipients of liver transplant and predicting marker of liver fibrosis and worse follow-up. METHODS: The study enrolled 55 biopsies from 55 patients aged 2.37 to 18.9 years (median 13.87 years) who underwent protocolar liver biopsies taken 1-17 years after liver transplantation (median 8.36 years). The control group (positive control group) consisted of 26 biopsies from 16 patients in whom acute ACR was diagnosed. IHC staining for M30 (cytokeratin 18) and histochemical Azan staining were performed in all liver specimens. The following changes were re-evaluated in each specimen: features of ACR (the severity was assessed using RAI/Rejection Activity Index/Scale, which ranges from 3-9 points and include 3 histopathological changes suggestive of rejection), AMR or ChR; severity of fibrosis (Ishak Scale); presence of cholestasis and steatosis. Clinical parameters including laboratory tests of liver function (AST, ALT, GGTP, bilirubin) were also evaluated. RESULTS: M30 expression correlated with presence of acute cellular rejection. However, no relationship was found between M30 expression and severity of fibrosis. CONCLUSIONS: M30 staining, marker of apoptosis, seems to be a promising marker predicting acute cellular rejection.

Diagnosing Acute Cellular Rejection after Paediatric Liver Transplantation-Is There Room for Interleukin Profiles?

BACKGROUND: The current gold standard to diagnose T-cell-mediated acute rejection (TCMR) requires liver histology. Using data from the ChilSFree study on immune response after paediatric liver transplantation (pLT), we aimed to assess whether soluble cytokines can serve as an alternative diagnostic tool in children suspected to have TCMR. METHODS: A total of n = 53 blood samples obtained on the day of or up to 3 days before liver biopsy performed for suspected TCMR at median 18 days (range 7-427) after pLT in n = 50 children (38% female, age at pLT 1.8 (0.5-17.5) years) were analysed for circulating cytokine levels using Luminex-based Multiplex technology. Diagnostic accuracy of cytokine concentrations was assessed using a multivariable model based on elastic net regression and gradient boosting machine analysis. RESULTS: TCMR was present in 68% of biopsies. There was strong evidence that patients with TCMR had increased levels of soluble CXCL8, CXCL9, CXCL10, IL-16, IL-18, HGF, CCL4, MIF, SCGF-ß, and HGF before biopsy. There was some evidence for increased levels of sCD25, ICAM-1, IL-6, IL-3, and CCL11. Diagnostic value of both single cytokine levels and a combination of cytokines and clinical markers was poor, with AUROCs not exceeding 0.7. CONCLUSION: Patients with TCMR showed raised levels of cytokines and chemokines reflective of T-cell activation and chemotaxis. Despite giving insight into the mechanisms of TCMR, the diagnostic value of soluble cytokines for the confirmation of TCMR in a clinical scenario of suspected TCMR is poor.

Long-term Outcome of Asymptomatic Patients With Graft Fibrosis in Protocol Biopsies After Pediatric Liver Transplantation.

BACKGROUND: The histological prevalence of allograft fibrosis in asymptomatic children after liver transplantation (LT) is well documented. However, long-term graft and patient survival remain unclear. This retrospective multicenter study aims to determine the prevalence of allograft fibrosis and analyze the long-term outcome for patients transplanted in childhood. METHODS: We reviewed clinical data of children who had undergone 10-y protocol liver biopsies. We excluded patients with autoimmune hepatitis, primary sclerosing cholangitis, hepatitis B or C, and retransplantation. In total, 494 patients transplanted in childhood across 12 international transplant centers were included. We evaluated the development of fibrosis by comparing the results with biopsies obtained 5 and 15 y post-LT. Histological findings were correlated with graft and patient survival up to 20 y post-LT. RESULTS: In the 10-y biopsies, periportal or pericentral fibrosis was observed in 253 patients (51%), 87 (18%) had bridging fibrosis, 30 (6%) had cirrhosis, and 124 (25%) had no fibrosis. The prevalence and stage of graft fibrosis significantly progressed from 5 to 10 y. At 10 y, the severity of fibrosis correlated significantly with inflammation. Patients with graft cirrhosis in the 10-y biopsy were more likely to die or require retransplantation subsequently ( P = 0.027). CONCLUSIONS: At 10 y post-LT, most patients transplanted in childhood developed fibrosis, based on the protocol liver biopsies. Although mild-to-moderate graft fibrosis did not largely affect patient or graft survival up to 20 y post-LT, this progressive fibrosis finding has substantial implications for developing cirrhosis and portal hypertension in adult care.

Prevalence, management and efficacy of treatment in portal vein obstruction after paediatric liver transplantation: protocol of the retrospective international multicentre PORTAL registry.

INTRODUCTION: Portal vein obstruction (PVO) consists of anastomotic stenosis and thrombosis, which occurs due to a progression of the former. The aim of this large-scale international study is to assess the prevalence, current management practices and efficacy of treatment in patients with PVO. METHODS AND ANALYSIS: The Portal vein Obstruction Revascularisation Therapy After Liver transplantation registry will facilitate an international, retrospective, multicentre, observational study, with 25 centres around the world already actively involved. Paediatric patients (aged <18 years) with a diagnosed PVO between 1 January 2001 and 1 January 2021 after liver transplantation will be eligible for inclusion. The primary endpoints are the prevalence of PVO, primary and secondary patency after PVO intervention and current management practices. Secondary endpoints are patient and graft survival, severe complications of PVO and technical success of revascularisation techniques. ETHICS AND DISSEMINATION: Medical Ethics Review Board of the University Medical Center Groningen has approved the study (METc 2021/072). The results of this study will be disseminated via peer-reviewed publications and scientific presentations at national and international conferences. TRIAL REGISTRATION NUMBER: Netherlands Trial Register (NL9261).

Liver Histopathology in Late Protocol Biopsies after Pediatric Liver Transplantation.

Liver transplantation has become a routine treatment for children with end stage liver failure. Recently, the long term survival of pediatric patients after liver transplantation has improved, with a life expectancy much longer than that of adult recipients, but also with longer exposition of the graft to various injuries, including immunological, inflammatory and others. Biochemical tests, although important, do not always reflect graft injury. The aim of our study was to analyze the histopathology of the graft in late protocol biopsies and correlate it with the clinical and biochemical status of these patients. We analyzed 61 protocol liver biopsies taken from 61 patients. Biopsies were taken 9.03-17.09 years (mean 12.68, median 11.74 years) after transplantation. Liver specimens were examined particularly for the presence and stage of liver fibrosis, inflammation, steatosis, and acute or chronic cellular and humoral rejection. We did not find any abnormalities in 26 (42.6%) liver specimens. None of the patients had signs of cellular or antibody mediated rejection or chronic rejection. In 23 liver biopsies (37.7%), we found non-specific lymphoid infiltrates. Another problem was fibrosis (equal to or more than three on the Ishak scale)-we found it in 17 patients, including seven liver specimens (11.5%) with severe fibrosis (Ishak 5-6). Conclusions: Various pathomorphological abnormalities were found in more than half of patients with a median 11.74 years post-transplant follow-up. Most of them presented normal laboratory liver tests at the same time, suggesting a slow subclinical process leading to pathomorphological abnormalities. No single factor for the development of these abnormalities was found, but our study supports the need for protocol liver biopsies even in patients with normal/almost normal biochemical liver tests.

Inferior Vena Cava and Venous Outflow Reconstruction in Living Donor Liver Transplantation in Children: A Single-Center Retrospective Study and Literature Review.

BACKGROUND In this report, we present technical problems and solutions used in the reconstruction of the inferior vena cava and graft venous outflow during living donor liver transplantation (LDLT) in children. MATERIAL AND METHODS In 65 grafts out of 379 liver transplantations from living donors, reconstruction of multiple hepatic venous branches and/or IVC was necessary. In 4 cases, cryopreserved deceased donor venous grafts were used for the reconstruction of the IVC and/or HV. RESULTS Follow-up ranged from 2 months to 17.8 years (median 7.2 years). In 4 children, liver re-transplantation was required for a reason not related to venous outflow (biliary complications in 3 patients, graft insufficiency caused by small-for-size syndrome). Two patients died: 1 due to tumor recurrence and 1 due to multi-organ failure. Fifty-nine patients are alive with good liver function. One patient (1.5%) after deceased donor venous graft reconstruction showed symptoms of venous outflow obstruction, which was successfully treated with endovascular balloon angioplasty and stent placement. The remaining 59 transplanted patients do not show any signs of venous outflow obstruction. CONCLUSIONS In most cases, the reconstruction of multiple hepatic veins of living donor allografts can successfully be done with local venoplasty, while using cold-stored vein grafts may be helpful in selected cases of LDLT.

ABO Incompatible Liver Transplantation in Children: A 20 Year Experience from Centres in the TransplantChild European Reference Network.

An increasing number of AB0-incompatible (AB0i) liver transplantations (LT) are being undertaken internationally in recent years due to organ shortages and the need for urgent transplantation. The aim of our study was establish the value of ABOi LT from available retrospective results of AB0i pediatric liver transplantations performed in European reference centers now belonging to the TransplantChild, European Reference Network (ERN). Data from medical records were analyzed, including demographic data, diagnosis, urgency of transplantation, time on the waiting list, PELD/MELD score, desensitization procedures, immunosuppression, selected post-transplant complications, and patient and graft survival. A total of 142 patients (pts) with transplants between 1986 and 2018 in 8 European transplant centers were included in the study. The indications for liver transplantation were: cholestatic diseases in 62 pts, acute liver failure in 42 pts, and other conditions in the remaining 38 pts. Sixty-six patients received grafts from living donors, and seventy-six received grafts from deceased donors. Both patient and graft survival were significantly affected by deceased donor type, urgent transplantation, and the development of vascular complications. In the multivariate analysis, vascular complications had a negative impact on patient and graft survival, while a longer time from the first AB0i LT in the study showed better results, suggesting an international learning experience. In conclusion, we believe that AB0i LT in children is now a safe procedure that may be adopted more readily in children.

Hemodynamic failure as an indication to urgent liver transplantation in infants with giant hepatic hemangiomas or vascular malformations--report of four cases.

The aim of this study was to present acute hemodynamic failure as a rare indication for liver transplantation in neonates and infants with liver hemangiomatosis. We report four patients aged one to six months with giant liver hemangiomas, with huge arterio-venous shunting within these malformations. In three, many skin hemangiomas were found. All children developed right ventricular failure. In two, a trial of pharmacological reduction was attempted with corticosteroids and cyclophosphamide. In one patient, the arterio-venous fistulas were embolized without any improvement in hemodynamic status. Two children underwent rescue hepatic artery surgical ligation, which did not prevent heart and then multiorgan failure including liver failure. After unsuccessful conventional therapy, all infants were considered for urgent liver transplantation; in three cases, it was performed with a living-related donor, and in one case with a deceased donor. All patients are alive and well with the follow-up between nine and 37 months after transplantation. Liver transplantation should be considered as a rescue treatment in children with hepatic vascular malformations leading to hemodynamic insufficiency when conventional therapy is unsuccessful and multiorgan failure develops.

Pathogenesis of chronic constipation in a Polish group of paediatric patients - an attempt to create the optimal histopathological diagnostic protocol.

INTRODUCTION: Histopathological diagnosis of chronic constipation in children is difficult and time-consuming because the aetiology of the problem is heterogenous. AIM: To create the optimal immunohistochemical (IHC) and histological diagnostic protocol using novel antibodies and assessing precisely their patterns. MATERIAL AND METHODS: Twenty-eight paediatric patients were enrolled to the study. The study group consisted of the following: 9 patients with confirmed Hirschsprung's disease (HD), 11 patients with desmosis of the colon (DC) (3) or with chronic constipation of unknown aetiology (3), and eight children operated on due to other problems. Retrospective analysis of full-thickness material from the large intestine was performed. In each specimen the number of ganglion cells was estimated per square millimetre as well as the number of submucosal and intramuscular ganglion cells per ganglion. The following IHC and histological stains were also performed: calretinin, CD117, picrosirius, and trichrome gomori. Patterns (nuclear vs. cytoplasmic vs. membranous) and intensity (strong vs. faint) of the stainings were analysed. RESULTS: There was no statistically significant difference between groups while comparing the intensity and pattern of each staining, except HD (no staining due to lack of ganglion cells), p > 0.001. Calretinin was positive in each patient with ganglion cells; however, it did not unequivocally stain all cells identified in routine haematoxylin and eosin staining. CONCLUSIONS: Calretinin is helpful in identifying ganglion cells; however, it cannot replace an experienced paediatric pathologist. In children with chronic constipation it is worth obtaining a full thickness intestinal biopsy in order to perform additional histological and immunohistochemical stains starting with picrosirius red.

Liver transplantation for fulminant Wilson's disease in children.

BACKGROUND: Fulminant Wilson's disease (FWD) is rare and fatal condition in children unless liver transplantation is performed, however introduction of new technologies could change this poor prognosis. The aim of our study was retrospective analysis of clinical course, treatment and outcome of children with FWD treated in our institution. MATERIAL/METHODS: Between 1999-2007 we've treated in our hospital 13 patients with mean age of 15.5 yrs with FWD. We performed retrospective analysis of clinical course, biochemical parameters, MELD/PELD score, Wilson score and Kings'-College criteria for LTx in acute liver failure in all these patients. Type of treatment and final outcome were analyzed, as well as qualification for transplantation was reevaluated in each case in accordance to pathological examination of explanted during transplantation livers. RESULTS: The initial symptoms of FWD were typically weakness, abdominal pain and developing later after 5-60 days (mean 20 days), jaundice. Eleven patients developed neurological symptoms with coma lasting for 2-11 days before transplantation or death. Maximal serum bilirubin concentration ranged between 4.5-71.6 mg% (mean 42.24 mg%), INR 2.9-10.0 (mean 5.4). MELD/PELD score was between 21-58 (mean 38), 10 patients fulfilled general King's-College criteria for transplantation in acute liver failure. Wilson's index ranged between 11 and 17 points (mean 13 points). In 11 children urgent liver transplantation (LTx) was performed, 1 child recovered on albumin dialysis and chelating treatment, 1 child died shortly after very late referral to our center. Actual follow-up of living patients is 0.36-7.43 years (mean 2.57 yrs), all are doing well with good liver function. CONCLUSIONS: FWD lead to death in almost all pediatric patients if LTx can not be performed, however early introduction of albumin dialysis (MARS) and chelating therapy allowed for survival without transplantation in single patient. It seems also that MARS therapy allows for at least prolongation of waiting time for LTx. Wilson's was slightly better predictor of need for LTx in our patients than classical King's-College criteria.

Non-resectable hepatic tumors in children - role of liver transplantation.

BACKGROUND: There is a group of children with primary hepatic tumors which can not be resected by conventional partial liver resection. Total hepatectomy followed by liver transplantation may be the only solution in such cases. Authors reviewed own experience with the liver transplantation for unresectable tumors in children and assessed the possible indications and role of transplantation in these patients. MATERIAL AND METHODS: Liver transplantation was performed in 17 children with unresectable hepatic tumors out of total number of 350 children transplanted. Hepatocarcinoma was present in 8 children, hepatoblastoma in 6 and benign giant hemangioma in 3. There was no other option for the treatment which would lead to the oncological cure of children with malignant tumors. All patients with giant hemangiomas were infants transplanted urgently due to circulatory and then multiorgan failure. RESULTS: Survival within whole group is 75.5% (13 of 17 pts), 3 children died of malignant tumor recurrence, one of other causes. All 3 children with benign tumors are alive and well. Actual follow-up is from 3 months to 7 years. CONCLUSIONS: Liver transplantation should be considered as option in the treatment of all children with unresectable hepatic tumors. With the careful and individual patient selection significant chances for survival can be achieved in this group of patients which would otherwise not survive with the conventional treatment.

Percutaneous Treatment of Biliary Strictures After Pediatric Liver Transplantation.

BACKGROUND Biliary strictures (BS) are frequent after pediatric liver transplantation (LTx) and in spite of ongoing progress, they remain a significant cause of morbidity. In children, the majority of reconstruction is hepatico-jejunal anastomosis (HJA). The aim of this study was to analyze our experience in percutaneous transhepatic treatment of BS. MATERIAL AND METHODS Between 1998 and 2014, 589 (269 living donor) pediatric LTx were performed in our institution. We retrospectively reviewed clinical data of patients with HJA who developed BS and who underwent percutaneous transhepatic biliary drainage (PTBD). RESULTS Out of 400 patients with HJA, 35 patients developed BS. There were 27 cases (77%) of anastomotic BS (ABS) and 8 cases (23%) of multilevel BS (MBS). Ninety-two PTBD sessions (2.5 per patient) were performed, with successful outcomes in 20 cases (57%). Fifteen patients, after failed PTBD, underwent surgery which was successful in 11 cases. Overall good outcomes were achieved in 31 cases (88.5%). The most common complication of PTBD was cholangitis which occurred in 5.4% of the cases. We did not find any risk factors for PTBD failure, except for treatment occurring before 2007. CONCLUSIONS Percutaneous treatment is effective and safe in BS and is recommended as a first-line approach. The majority of patients in our study required multiple interventions, however, the overall risk of complications was low. Surgery is essential in selected cases and always should be considered if PTBD fails.

Acute liver failure in children-Is living donor liver transplantation justified?

OBJECTIVES: Living donor liver transplantation (LDLT) in patients with acute liver failure (ALF) has become an acceptable alternative to transplantation from deceased donors (DDLT). The aim of this study was to analyze outcomes of LDLT in pediatric patients with ALF based on our center's experience. MATERIAL AND METHODS: We enrolled 63 children (at our institution) with ALF who underwent liver transplantation between 1997 and 2016. Among them 24 (38%) underwent a LDLT and 39 (62%) received a DDLT. Retrospectively analyzed patient clinical data included: time lapse between qualification for transplantation and transplant surgery, graft characteristics, postoperative complications, long-term results post-transplantation, and living donor morbidity. Overall, we have made a comparison of clinical results between LDLT and DDLT groups. RESULTS: Follow-up periods ranged from 12 to 182 months (median 109 months) for LDLT patients and 12 to 183 months (median 72 months) for DDLT patients. The median waiting time for a transplant was shorter in LDLT group than in DDLT group. There was not a single case of primary non-function (PNF) in the LDLT group and 20 out of 24 patients (83.3%) had good early graft function; 3 patients (12.5%) in the LDLT group died within 2 months of transplantation but there was no late mortality. In comparison, 4 out of 39 patients (10.2%) had PNF in DDLT group while 20 patients (51.2%) had good early graft function; 8 patients (20.5%) died early within 2 months and 2 patients (5.1%) died late after transplantation. The LDLT group had a shorter cold ischemia time (CIT) of 4 hours in comparison to 9.2 hours in the DDLT group (p<0.0001). CONCLUSIONS: LDLT is a lifesaving procedure for pediatric patients with ALF. Our experience showed that it may be performed with very good results, and with very low morbidity and no mortality among living donors when performed by experienced teams following strict procedures.

Diagnostic Approach in Biliary Strictures After Pediatric Liver Transplantation.

BACKGROUND The diagnosis of post-liver transplant biliary strictures (BS) requires a high degree of clinical suspicion because of the diversity of symptoms and usually mild clinical presentation. If quickly treated, successful outcome is achieved most cases. The aim of our study was to analyze the value of diagnostic methods in BS after pediatric LTx. MATERIAL AND METHODS We retrospectively reviewed clinical data of children with BS after liver transplantation, with the main focus on diagnostic methods, including imaging studies and histology. All patients underwent endoscopic, transhepatic, or surgical treatment of the stricture. RESULTS Sixty-seven patients after LTx performed at the median age of 9.1 years (0.4-18) developed BS, mostly within the first 12 months (40%). Laboratory findings at diagnosis were: bilirubin 4.65 (5.8±SD), GGTP 434 (382.9±SD), and ALT 126.5 (116.8±SD); 16 patients presented with bilirubin level <1 mg% and 4 with GGTP below 100 IU. Ultrasound scan (USS) visualized dilatation of the bile ducts in 53 (79%) patients. Overall sensitivity of hepatobiliary scintigraphy (HBS) was 93%, with dilatation of bile ducts in 69% and impaired excretion in 68% of patients. MRCP showed 100% accuracy in detecting biliary dilatation and a stricture was visualized in 39%. Liver histology was consistent with biliary obstruction in 66%. Treatment of BS was successful in the majority of cases, with 89% graft survival. CONCLUSIONS Non-invasive investigations are highly sensitive in post-transplant BS and should play the key role in diagnostic algorithms.

Metastases of pancreatic neuroendocrine tumor to the liver as extremely rare indication for liver transplantation in children. Case report and review of the literature.

Neuroendocrine tumors (NET) are extremely rare in children (0.75 cases per 100,000 children and adolescents a year) and the majority of these tumors are benign or present low grade of malignancy. According to the American registry Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute, less than 2% of all neuroendocrine tumors in children occur in the pancreas, making it a rare site for these tumors. The majority of them are found in children over 10years of age, especially those with malignant potential. Treatment of NET consists of different methods: surgery, somatostatin analogues and chemotherapy. Radical surgical resection remains the standard of treatment; however, it is not always feasible because of distant metastases. The authors present a case report of pancreatic NET with multiple metastases to the liver. The patient was treated with pancreatic resection and liver transplantation for liver metastases. Prior to liver transplantation, the patient was treated with somatostatin analogues, sunitinib and chemotherapy. Management of liver metastases with liver transplantation is discussed.

Immunological factors and liver fibrosis in pediatric liver transplant recipients.

BACKGROUND: The aim of our study was to retrospectively assess any correlation between graft fibrosis and selected immunological factors in pediatric liver transplant recipients. MATERIAL AND METHODS: The study was performed on 33 patients after living related donor transplantation, divided into 2 groups depending on history of acute rejection episodes after transplantation. We assessed liver biopsies for presence of fibrosis, signs of antibody-mediated rejection, inflammatory infiltrations, and changes in bile ducts. We correlated these findings with assessment of anti-HLA antibodies. RESULTS: Among 14 patients with ACR, a history fibrosis was found in 8 patients (57%). In 19 patients without a history of ACR, fibrosis was found in 9 patients (47%). Anti-HLA antibodies were found in 47% of patients with fibrosis and in only 18.75% of patients without fibrosis. Among 3 patients with signs of antibody-mediated rejection, all had fibrosis in the graft 2 years after transplantation. We did not find any patient with chronic rejection or ductopenia. CONCLUSIONS: We suggest that there is a correlation between ACR and development of graft fibrosis present in liver grafts from recipients with normal liver biochemistry. Anti-HLA antibodies class II seems to be most important in development of fibrosis.

Antibody-mediated rejection in pediatric liver transplant recipients.

BACKGROUND: Antibody-mediated rejection (AMR), associated with the presence of C4d deposits, is well-defined in kidney transplantation but much less documented in liver transplantation (LTx). The aim of our study was to retrospectively analyze a group of pediatric liver transplant recipients who experienced episodes of acute rejection in the past, for the signs of AMR and its impact on liver histology. MATERIAL/METHODS: Our study population consisted of 18 patients after living related donor liver transplantation with a history of acute cellular rejection (1-5/patient). In all of them, actual liver function was good at almost 2-year median follow-up after transplantation. We reassessed all liver biopsies taken from these children between 5 days to 5.7 years after transplantation for signs of acute cellular rejection and antibody-mediated rejection. In all patients, anti-HLA antibodies were also assessed at least 2 years after transplantation (2.18-12.27 years, median 6.795 years). RESULTS: There were 27 episodes of acute rejection proved by liver biopsy. Signs of AMR were found in 6 of 18 patients (33.3%). In 5 of these patients, donor-specific (DSA) and non-specific anti-HLA antibodies were also identified. In the group of 12 patients with acute rejection without histochemical signs of AMR, anti-HLA antibodies were found in sera of only 5 of 12 patients after transplantation. CONCLUSIONS: Our study shows some correlation between C4d-positive reaction in liver biopsies with acute cellular rejection and presence of anti-HLA antibodies, particularly against HLA class II. We did not find any difference in the late graft function, which could be correlated with the presence of AMR. Further studies on larger groups of patients are necessary.