Prevalence and the impact of hepatitis E infection in pediatric liver transplanted recipients with hepatitis in Thailand.

BACKGROUND: The hepatitis E virus (HEV) infection typically causes acute and self-limiting hepatitis. However, chronic infection can occur in immunocompromised hosts. This study determined the prevalence and impact of HEV infection in liver transplanted (LT) children who had transaminitis. METHODS: The demographic data, anti-HEV IgM/IgG, serum/stool HEV RNA, and management for LT children with acute or persistent transaminitis from 2003 to 2020 were retrospectively reviewed. HEV serology was tested by ELISA, and HEV RNA was detected by semi-nested PCR. RESULTS: Seventy-two children with LT with persistent transaminitis with a median age of 4.41 (1.32, 9.14) years (55.6% female) and one with acute hepatitis were investigated for HEV infection. Anti-HEV IgM, anti-HEV IgG, serum, or stool HEV RNA was investigated in 95.8% (N = 69), 93.1% (N = 67), 43.1% (N = 31), and 37.5% (N = 27) of patients, respectively. The prevalence of HEV infection was 37.5% (N = 27). There was no significant difference in characteristics between the HEV-infected and HEV-non-infected patients. Moreover, 22.2% (N = 16) and 15.3% (N = 11) of patients had past HEV infection and HEV-related acute or chronic infection, respectively. Most of the patients had primary treatment as the presumed graft rejection without improvement. In two patients, detectable HEV RNA in serum turned undetectable in approximately 2 weeks and 2 months, and liver enzyme levels normalized after reducing immunosuppressive therapy. CONCLUSIONS: The prevalence of HEV infection among pediatric LT recipients with hepatitis was high. Chronic HEV infection was evidenced in two patients. Investigations of HEV infection in pediatric LT recipients with persistent transaminitis should guide proper management.

Spleen and Liver Stiffness to Detect Esophageal Varices in Children with Biliary Atresia.

OBJECTIVES: The aim of the study was to determine the accuracy of noninvasive parameters, such as liver (LS) and spleen stiffness (SS) to detect esophageal varices (EV) in children with biliary atresia (BA). METHODS: Children with BA between 2000 and 2015 were recruited. All underwent esophagogastroduodenoscopy and transient elastography. Demographic data, laboratory investigations, alanine transferase-to-platelet ratio index (APRI), and Varices Prediction Rule (VPR) score were collected. RESULTS: A total of 51 children (mean age 10.63 years, standard deviation (SD) = 6.08 years; 53% boys) were enrolled. There were differences in onset and outcome of portoenterostomy, spleen palpablility, platelet count, albumin, LS, SS, and VPR between the varice and varice-free groups (P < 0.05). In the varice group, the median LS was 18.12 (interquartile ratio, IQR 13.15-19.12) and the median SS was 46.85 (IQR 25.95-54.55) kPa. In the varice-free group, the median LS was 7.85 (IQR 5.88-16.75) and the median SS was 16.54 (IQR 11.75-21.75) kPa. Both LS and SS were higher in the varice than the varice-free group (P < 0001). The area under the receiver operating characteristic curve of LS, SS, spleen palpability, platelet count, APRI, and VPR were 0.734, 0.870, 0.817, 0.810, 0.751, and 0.794, respectively. Using a cut-off value of 12.5 kPa for LS, the sensitivity and specificity were 80 and 70%, respectively. Using a cut-off value of 28.9 kPa for SS, the sensitivity and specificity were 75 and 87%, respectively. Combination of LS and SS to diagnose varices increased the specificity to 93%. CONCLUSIONS: SS as a single marker had the best diagnostic value to predict esophageal varices in children with BA. The combination of SS and LS furthermore, increased the diagnostic yield.

Value of Serum Zinc in Diagnosing and Assessing Severity of Liver Disease in Children With Wilson Disease.

OBJECTIVES: Wilson disease (WD) is a rare inborn error of copper metabolism with diverse manifestations. There has been no study of zinc (Zn), the copper's antagonist, in WD diagnosis and severity so far. Our aims were to evaluate serum Zn in WD and its correlation with the disease severity score (revised WD index). Although the ATP7B mutation analysis is highly accurate for WD diagnosis, it may not be readily available in a resource-limiting setting. We proposed a disease diagnostic score (Proposed WD diagnostic score) which incorporates serum Zn. METHODS: Medical records of WD and non-WD children seen at King's College Hospital from 2005 to 2015 were reviewed for the selected parameters using the Proposed WD diagnostic score. Available serum Zn data in WD children before disease diagnosis and the calculated severity score were statistically analyzed. Diagnostic values of the Proposed WD diagnostic score were evaluated. RESULTS: Serum Zn level was significantly lower in 8 WD-acute liver failure (ALF) (5.8 [4.1-8.3] µmol/L) compared to 18 WD-non-ALF (13.5 [6.1-22.2] µmol/L) and 9 ALF from indeterminate cause (9.8 [7.0-12.1] µmol/L) (P < 0.001). Serum Zn significantly correlated with the revised WD index (r = -0.554, P = 0.004). The Proposed WD diagnostic score that included serum Zn level as 1 of the parameters had sensitivity and specificity of 87% and 99.2%, respectively. CONCLUSIONS: Serum Zn is a novel parameter for diagnosis and correlates with severity of WD. The Proposed WD diagnostic score is useful while awaiting ATP7B mutation analysis.

Wilson's Disease in Thai Children between 2000 and 2012 at King Chulalongkorn Memorial Hospital.

OBJECTIVE: Wilson's disease (WD) is a rare autosomal recessive disorder characterized by copper accumulation. Clinical presentations are extraordinarily diverse, and currently no single diagnostic test can confirm WD with high accuracy. A complete understanding of the presentations and improved diagnostic methods are important for disease management. The authors' aimed to examine disease characteristics, management, and treatment outcome of WD in children, especially when genetic analysis and liver copper measurements were limited. MATERIAL AND METHOD: Data was collected from 21 WD children who were treated at King Chulalongkorn Memorial Hospital between 2000 and 2012. Inclusion criteria followed the WD scoring system, where other liver diseases are ruled out systematically. RESULTS: The mean age at diagnosis was 13.5 ± 3.36 years, with 19 symptomatic patients, and two asymptomatic individuals who were diagnosed through family screening. Presentations varied, jaundice (52%), ascites (52%), edema (52%), Coombs-negative hemolytic anemia (14%), neurological abnormalities (33%), renal involvement (19%), and fulminant hepatic failure (5%). Based on the key parameters in WD scoring system, 14 patients (66%) had Kayser-Fleischer (KF) rings. Seventeen (89%) had low serum ceruloplasmin, and 20 (95%) had increased urinary copper excretion. These positive findings made WD scoring system accurately diagnose 66% of patients. Chelation therapy was the first line of therapy for all patients except one, who underwent liver transplantation. After therapy, liver function test returned to normal in all patients. However, neurological symptoms did not improve with combined drug therapy using chelating and neuropsychiatric agents. CONCLUSION: WD in children mostly affected the liver WD was suspected in seven patients (34%), thus needed further investigation. Therefore, long-term follow-up in those with suspected WD is the appropriate method for diagnosis and management in limited diagnostic tests. We suggest further treatment, and use of clinical response to treatment, as a criterion for confirming the WD diagnosis.

Antibody persistence of standard versus double three-dose hepatitis B vaccine in liver transplant children: a randomized controlled trial.

Rapid hepatitis B (HB) surface antibody (anti-HBs) loss is prevalent after liver transplantation (LT). Herein, we evaluated anti-HBs persistence after HB vaccination using two regimens in LT children. We recruited 66 previously immunized LT children with anti-HBs level of < 100 mIU/mL. Participants were randomly reimmunized with standard-three-dose (SD) and double-three-dose (DD) intramuscular HB vaccination at 0, 1, and 6 months. Anti-HBs were assessed at every outpatient visit. Antibody loss defined as anti-HBs levels < 100 mIU/mL after three-dose vaccination. After three-dose vaccination, 81.8% and 78.7% of participants in the SD and DD groups, had anti-HBs levels > 100 mIU/mL, with a geometric mean titer (GMT) of 601.68 and 668.01 mIU/mL (P = 0.983). After a mean follow-up of 2.31 years, the anti-HBs GMT was 209.81 and 212.61 mIU/mL in the SD and DD groups (P = 0.969). The number of immunosuppressants used and an anti-HBs level < 1 mIU/mL at baseline were independently associated with anti-HB loss. The DD regimen strongly increased the risk of anti-HBs loss (adjusted hazard ratio, 2.97 [1.21-7.31]; P = 0.018). The SD HB reimmunization regimen effectively maintained protective anti-HBs levels in children undergoing LT, making it the preferred regimen for such children with anti-HB loss.Trial registration: TCTR20180723002.

Diseases of bile duct in children.

Several diseases originate from bile duct pathology. Despite studies on these diseases, certain etiologies of some of them still cannot be concluded. The most common disease of the bile duct in newborns is biliary atresia, whose prognosis varies according to the age of surgical correction. Other diseases such as Alagille syndrome, inspissated bile duct syndrome, and choledochal cysts are also time-sensitive because they can cause severe liver damage due to obstruction. The majority of these diseases present with cholestatic jaundice in the newborn or infant period, which is quite difficult to differentiate regarding clinical acumen and initial investigations. Intraoperative cholangiography is potentially necessary to make an accurate diagnosis, and further treatment will be performed synchronously or planned as findings suggest. This article provides a concise review of bile duct diseases, with interesting cases.

Gastroesophageal reflux disease in children: What's new right now?

Gastroesophageal reflux (GER) in children is very common and refers to the involuntary passage of gastric contents into the esophagus. This is often physiological and managed conservatively. In contrast, GER disease (GERD) is a less common pathologic process causing troublesome symptoms, which may need medical management. Apart from abnormal transient relaxations of the lower esophageal sphincter, other factors that play a role in the pathogenesis of GERD include defects in esophageal mucosal defense, impaired esophageal and gastric motility and clearance, as well as anatomical defects of the lower esophageal reflux barrier such as hiatal hernia. The clinical manifestations of GERD in young children are varied and nonspecific prompting the necessity for careful diagnostic evaluation. Management should be targeted to the underlying aetiopathogenesis and to limit complications of GERD. The following review focuses on up-to-date information regarding of the pathogenesis, diagnostic evaluation and management of GERD in children.

Functional constipation in children: What physicians should know.

Functional constipation (FC) is considered the most common functional gastrointestinal disorder in children with a pooled global prevalence of 14.4% (95% confidence interval: 11.2-17.6) when diagnosed based on the Rome IV criteria. Its pathophysiological mechanisms are thought be multifactorial and complicated, resulting in difficult management. Currently, the most effective medication, when used in parallel with toilet training, is osmotic laxatives. Children's adherence to medication and parental concern regarding long-term laxative use are the main contributors to treatment failure. Recently, novel therapies with a high safety profile have been developed, such as probiotics, synbiotics, serotonin 5-hydroxytryptamine 4 receptor agonists, chloride channel activators, and herbal and transitional medicines; nonetheless, well-designed research to support the use of these therapies is needed. This review aims to focus on multiple aspects of FC in children, including global prevalence, pathogenesis, diagnostic criteria, tools, as well as conventional and novel treatment options, such as non-pharmacological management, including adequate fiber and fluid intake, physiotherapy, or neuromodulators. We also report that in very difficult cases, surgical intervention may be required.

Strategies to Prevent Mother-to-child Transmission of Hepatitis B Virus.

Mother-to-child transmission (MTCT) of hepatitis B virus (HBV) is the primary cause of chronic HBV infection worldwide. MTCT prevention and antiviral treatment of infected individuals could eliminate this public health burden. Antiviral treatment of hepatitis B surface antigen (HBsAg)-positive pregnant women and immunoprophylaxis with HBV vaccine and hepatitis B immune globulin are the most effective strategies to interfere with MTCT of HBV. However, for worldwide application of those strategies, feasibility, availability, cost, safety, and effectiveness should be considered. Cesarean section and breastfeeding avoidance in hepatitis B e antigen-positive mothers with a high viral load and without antiviral therapy during pregnancy could be an option, but more supporting evidence is needed. HBsAg screening of all pregnant women is recommended when initiating antiviral therapy and immunoprophylaxis for MTCT prevention, except in areas with limited resources. Timely HBV vaccination series administered soon after birth might be the mainstay of prevention. This review aimed to provide a concise update on the effectiveness of available strategies to prevent MTCT of HBV.

Cohort analysis of pediatric intussusception score to diagnose intussusception.

BACKGROUND: Intussusception is a primary cause of intestinal obstruction in young children. Delayed diagnosis is associated with increased morbidity. Ultrasonography (USG) is the gold standard for diagnosis, but it is operator dependent and often unavailable in limited resource areas. AIM: To study the clinical characteristics of intussusception including management and evaluation of the diagnostic accuracy of abdominal radiography (AR) and the promising parameters found in the pediatric intussusception score (PIS). METHODS: Children with suspected intussusception in our center from 2006 to 2018 were recruited. Clinical manifestations, investigations, and treatment outcomes were recorded. AR images were interpreted by a pediatric radiologist. Diagnosis of intussusception was composed of compatible USG and response with reduction. The diagnostic value of the proposed PIS was evaluated. RESULTS: Ninety-seven children were diagnosed with intussusception (2.06 ± 2.67 years, 62.9% male), of whom 74% were < 2 years old and 37.1% were referrals. The common manifestations of intussusception were irritability or abdominal pain (86.7%) and vomiting (59.2%). Children aged 6 mo to 2 years, pallor, palpable abdominal mass, and positive AR were the parameters that could discriminate intussusception from other mimics (P < 0.05). Referral case was the only significant parameter for failure to reduce intussusception (P < 0.05). AR to diagnose intussusception had a sensitivity of 59.2%. The proposed PIS, a combination of clinical irritability or abdominal pain, children aged 6 mo to 2 years, and compatible AR, had a sensitivity of 85.7%. CONCLUSION: AR alone provides poor screening for intussusception. The proposed PIS in combination with common manifestations and AR data was shown to increase the diagnostic sensitivity, leading to timely clinical management.

Prevalence of gastroesophageal reflux disease in children with extraesophageal manifestations using combined-video, multichannel intraluminal impedance-pH study.

BACKGROUND: Gastroesophageal reflux disease (GERD) might be either a cause or comorbidity in children with extraesophageal problems especially as refractory respiratory symptoms, without any best methods or criterion for diagnosing it in children. AIM: To evaluate the prevalence of extraesophageal GERD using conventional and combined-video, multichannel intraluminal impedance-pH (MII-pH), and to propose novel diagnostic parameters. METHODS: The study was conducted among children suspected of extraesophageal GERD at King Chulalongkorn Memorial Hospital between 2019 and 2022. The children underwent conventional and/or combined-video MII-pH. The potential parameters were assessed and receiver operating characteristic was used for the significant parameters. RESULTS: Of 51 patients (52.9% males), aged 2.24 years were recruited. The common problems were cough, recurrent pneumonia, and hypersecretion. Using MII-pH, 35.3% of the children were diagnosed with GERD by reflux index (31.4%), total reflux events (3.9%), and symptom indices (9.8%) with higher symptom recorded in the GERD group (94 vs 171, P = 0.033). In the video monitoring group (n = 17), there were more symptoms recorded (120 vs 220, P = 0.062) and more GERD (11.8% vs 29.4%, P = 0.398) by symptom indices. Longest reflux time and mean nocturnal baseline impedance were significant parameters for diagnosis with receiver operating characteristic areas of 0.907 (P = 0.001) and 0.726 (P = 0.014). CONCLUSION: The prevalence of extraesophageal GERD in children was not high as expected. The diagnostic yield of symptom indices increased using video monitoring. Long reflux time and mean nocturnal baseline impedance are novel parameters that should be integrated into the GERD diagnostic criteria in children.

Safety and Efficacy of a Third Dose of the BNT162b2 Vaccine in Liver-Transplanted and Healthy Adolescents.

Objectives: According to our previous study, the 2-dose-BNT162b2 vaccination is less effective against the Omicron variant. This study aimed to assess the safety and efficacy of a 3-dose-BNT162b2 vaccination in liver-transplanted (LT) and healthy adolescents. Methods: LT and healthy adolescents who met the inclusion criteria received a third dose of the BNT162b2 vaccine (30 µg). Antireceptor-binding domain immunoglobulin and T-cell-specific responses to severe acute respiratory syndrome coronavirus 2 spike peptides were assessed 3 months before the third dose (Visit -1) and 0 (Visit 0), 1 (Visit 1), and 2 months (Visit 2) after the third dose. Antinucleocapsid immunoglobulin and neutralizing antibodies were assessed at Visits 0 and 1. Adverse events (AEs) were monitored. Results: Eleven LT and 14 healthy adolescents aged 14.64 (13.2, 15.7) years (44.2% male) had antireceptor-binding domain immunoglobulin geometric mean titers of 1412.47 (95% confidence interval [CI], 948.18-2041.11) and 1235.79 (95% CI, 901.07-1705.73) U/mL at Visit -1 but increased to 38 587.76 (95% CI, 24 628.03-60 460.18) and 29 222.38 (95% CI, 16 291.72-52 401.03) U/mL (P < 0.05) at Visit 1, respectively. This was consistent with neutralizing antibodies (42.29% and 95.37% vs 44.65% and 91.68%, P < 0.001) and interferon-γ-secreting cells in LT and healthy adolescents at Visit 0 versus Visit 1, respectively. For serious AEs, an LT girl with autoimmune overlap syndrome died 5 months postvaccination from acute liver failure. Conclusions: In both LT and healthy adolescents, humoral and cellular immune responses were high after the 3-dose-BNT162b2 vaccination. However, serious AEs were suspected in LT adolescents with autoimmune diseases.

Cytomegalovirus infection in liver-transplanted children.

Cytomegalovirus (CMV) infection is a common complication of liver trans-plantation in children. The CMV serostatus of recipients and donors is the primary risk factor, and prophylaxis or pre-emptive strategies are recommended for high-risk patients. Graft rejection, coinfection and Epstein-Bar virus reactivation, which can lead to post-transplant lymphoproliferative disease, are indirect effects of CMV infection. Assessment of CMV infection viral load should be routinely performed upon clinical suspicion. However, tissue-invasive CMV disease is not associated with CMV viraemia and requires confirmation by tissue pathology. Oral valganciclovir and intravenous ganciclovir are equivalent treatments, and the duration of treatment depends on factors including CMV viral load, tissue pathology, and clinical response. Risk stratification by donor and recipient status prior to transplantation and post-transplantation antiviral prophylaxis or pre-emptive therapy are recommended. Adult guidelines have been established but additional study of the effectiveness of the preventive guidelines in children is needed. This review summarizes the burden, risk factors, clinical manifestations, laboratory evaluation, treatment, and prevention of CMV infection in children after liver transplantation.

Eliminating viral hepatitis in children after liver transplants: How to reach the goal by 2030.

Viral hepatitis infections are a great burden in children who have received liver transplant. Hepatotropic viruses can cause liver inflammation that can develop into liver graft fibrosis and cirrhosis over the long term. Immunological reactions due to viral hepatitis infections are associated with or can mimic graft rejection, rendering the condition difficult to manage. Prevention strategies using vaccinations are agreeable to patients, safe, cost-effective and practical. Hence, strategies to eliminate viral hepatitis A and B focus mainly on immunization programmes for children who have received a liver transplant. Although a vaccine has been developed to prevent hepatitis C and E viruses, its use is not licensed worldwide. Consequently, eliminating hepatitis C and E viruses mainly involves early detection in children with suspected cases and effective treatment with antiviral therapy. Good hygiene and sanitation are also important to prevent hepatitis A and E infections. Donor blood products and liver grafts should be screened for hepatitis B, C and E in children who are undergoing liver transplantation. Future research on early detection of viral hepatitis infections should include molecular techniques for detecting hepatitis B and E. Moreover, novel antiviral drugs for eradicating viral hepatitis that are highly effective and safe are needed for children who have undergone liver transplantation.

Safety and Humoral and Cellular Immunogenicity of the BNT162b2 SARS-CoV-2 Vaccine in Liver-Transplanted Adolescents Compared to Healthy Adolescents.

Since BNT162b2 was approved to prevent COVID-19 in children, we aim to compare the safety and immunogenicity of the BNT162b2 vaccine in liver-transplanted (LT) and healthy adolescents. LT and healthy adolescents received two doses of 30 µg of BNT162b2. All were evaluated for total COVID-19 antibodies directed against the receptor-binding domain (RBD) and interferon-γ using the ELISpot at all time points; anti-nucleocapsid immunoglobulin was evaluated at week 8 and the surrogate virus-neutralizing antibody (sVN) to Omicron at day 0 and week 8. Adverse effects were recorded during days 0−7. In total, 16 LT and 27 healthy adolescents were enrolled (aged 14.78 ± 1.70 years). After completion, all LT and healthy adolescents were positive for anti-RBD immunoglobulin, with geometric mean titers of 1511.37 (95% CI 720.22−3171.59) and 6311.90 (95% CI 4955.46−8039.64)) U/mL (p < 0.001). All tested negative for anti-nucleocapsid immunoglobulin, indicating no COVID-19 infection after vaccination. However, the sVNs to Omicron were positive in only nine (33.33%) healthy adolescents and none of the LT adolescents. Interferon-γ-secreting cells were lower in LT adolescents than healthy adolescents. The LT adolescents had a lower immunogenic response to BNT162b2 than the healthy adolescents. Administrating two doses of BNT162b2 was safe, but was less effective against the Omicron variant.

Pediatric liver transplantation outcomes from a single center in Thailand.

BACKGROUND: Liver transplantation (LT) has become an acceptable curative method for children with several liver diseases, especially irreversible acute liver failure and chronic liver diseases. King Chulalongkorn Memorial Hospital is one of Thailand's largest liver transplant centers and is responsible for many pediatric cases. AIM: To report the experience with pediatric LT and evaluate outcomes of living-related vs deceased-donor grafts. METHODS: This evaluation included children who underwent LT between August 2004 and November 2019. Data were retrospectively reviewed, including demographics, diagnoses, laboratory values of donors and recipients, the pediatric end-stage liver disease (PELD) or model for end-stage liver disease (MELD) score, graft source, wait time, perioperative course, postoperative complications, and survival rates. Continuous data were reported using the median and interquartile range. The Mann-Whitney U-test was used to compare the wait time between the living-related and deceased-donor groups. The chi-square or Fisher's exact test were used to compare the frequencies of between-group complications. Survival rates were calculated using the Kaplan-Meier method. RESULTS: Ninety-four operated pediatric liver transplant patients were identified (54% were females). The median age at transplantation was 1.2 (0.8-3.8) years. The median PELD and MELD scores were 20 (13-26.8) and 19.5 (15.8-26.3), respectively. Most grafts (81.9%) were obtained from living-related donors. The median wait time for the living donors was significantly shorter compared with the deceased donors at 1.6 (0.3-3.1) mo vs 11.2 (2.1-33.3) mo (P = 0.01). Most patients were diagnosed with biliary atresia (74.5%), and infection was the most common complication within 30 d post-transplantation (14.9%). Without a desensitization protocol, 9% of transplants were ABO-incompatible. Eight hepatitis B core antibodies (anti-HBc)-negative recipients received positive anti-HBc grafts without different observed complications. The overall survival rate was 93.6% and 90.3% at 1 and 5 years, respectively. No graft loss during follow-up was noted among survivors. CONCLUSION: A significant number of pediatric LT cases were reported in Thailand. Based on relatively comparable outcomes, ABO-incompatible and HBc antibody-positive grafts may be considered in an organ shortage situation.

Safety and Immunogenicity of Standard and Double Doses of Hepatitis B Vaccine in Children after Liver Transplantation: An Open-Label, Randomised Controlled Trial.

A high prevalence of hepatitis B (HepB) antibody loss after liver transplantation (LT) and de novo HepB infection (DNH) was documented, hence revaccination to prevent DNH is crucial. This study aimed to compare the safety and immunogenicity of two HepB vaccine regimens in liver-transplanted children. Liver-transplanted children who were previously immunised but showed HepB surface antibodies (anti-HBs) ≤ 100 mIU/mL were randomised to receive a standard three-dose (SD) and double three-dose (DD) vaccine intramuscularly in months 0-1-6. Anti-HBs and T-cell-specific response to the HepB antigen were assessed. A total of 61 children (54.1% male, aged 1.32 ± 1.02 years) completed the study without any serious adverse reaction. The seroprotective rate was 69.6% vs. 60% (p = 0.368) and 91.3% vs. 85% (p = 0.431) in SD and DD after the first and third 3-dose vaccinations, respectively. The geometric mean titre (95% confidence interval) of anti-HBs in SD and DD were 443.33 (200.75-979.07) vs. 446.17 (155.58-1279.50) mIU/mL, respectively, at completion. Numbers of interferon-γ-secreting cells were higher in hyporesponders/responders than in nonresponders (p = 0.003). The significant factors for the immunologic response to HepB vaccination were anti-HB levels prevaccination, tacrolimus trough levels, and time from LT to revaccination. SD and DD had comparative immunogenicity and were safe for liver-transplanted children who were previously immunised.