Antibody responses in postsplenectomy trauma patients receiving the 23-valent pneumococcal polysaccharide vaccine at 14 versus 28 days postoperatively

BACKGROUND: We have previously demonstrated, using functional antibody assays, that patients undergoing splenectomy for trauma exhibit a better response to pneumococcal immunization when vaccinated at 14 days postoperatively versus 1 or 7 days. However, patients immunized at 14 days failed to reach the response of normal controls. This study was conducted to determine whether even later immunization would improve the antibody response. METHODS: Forty surviving patients undergoing emergent splenectomy were randomized to receive Pneumovax at 14 or 28 days after splenectomy. Blood samples were drawn at the time of vaccination (prevaccination) and 4 weeks later (postvaccination). A control group of 24 healthy adults was used for comparison. Antibody titers to four of the most common serotypes were determined by enzyme-linked immunosorbent assay and opsonophagocytic assay (OPA). RESULTS: Samples from 38 patient were analyzed. Each serotype and each group tested demonstrated a statistically significant increase in geometric mean enzyme-linked immunosorbent assay immunoglobulin G antibody concentration (microg/mL) and OPA titer (1/dilution) after vaccination. There were no statistically significant differences (p >or= 0.07) in the immunoglobulin G antibody concentrations and OPA titers between the 14-day or the 28-day study groups when compared with normal healthy adults regardless of the serotype tested. In addition, there were no differences in the antibody responses between the 14-day and the 28-day study groups. CONCLUSION: Despite our previous study suggesting that delay in vaccination after emergent splenectomy resulted in improved antibody response, antibody response was not improved any further by delaying vaccination to 28 days.     

Acquired Downregulation of Donor‐Specific Antibody Production After ABO‐Incompatible Kidney Transplantation

The mechanism of long‐term B cell immunity against donor blood group antigens in recipients who undergo ABO‐incompatible (ABOi) living‐donor kidney transplantation (LKTx) is unknown. To address this question, we evaluated serial anti‐A and anti‐B antibody titers in 50 adult recipients. Donor‐specific antibody titers remained low (≤1:4) in 42 recipients (84%). However, antibodies against nondonor blood group antigens were continuously produced in recipients with blood type O. We stimulated recipients' peripheral blood mononuclear cells in vitro to investigate whether B cells produced antibodies against donor blood group antigens in the absence of graft adsorption in vivo. Antibodies in cell culture supernatant were measured using specific enzyme‐linked immunosorbent assays (ELISAs). Thirty‐five healthy volunteers and 57 recipients who underwent ABO‐compatible LKTx served as controls. Antibody production in vitro against donor blood group antigens by cells from ABOi LKTx patients was lower than in the control groups. Immunoglobulin deposits were undetectable in biopsies of grafts of eight recipients with low antibody titers (≤1:4) after ABOi LKTx. One patient with blood type A1 who received a second ABOi LKTx from a type B donor did not produce B‐specific antibodies. These findings suggest diminished donor‐specific antibody production function in the setting of adult ABOi LKTx.     

Persistence of Yellow Fever Vaccine–Induced Antibodies After Solid Organ Transplantation

Immunization using live attenuated vaccines represents a contra‐indication after solid organ transplantation (SOT): consequently, transplant candidates planning to travel in countries where yellow fever is endemic should be vaccinated prior to transplantation. The persistence of yellow fever vaccine‐induced antibodies after transplantation has not been studied yet. We measured yellow‐fever neutralizing antibodies in 53 SOT recipients vaccinated prior to transplantation (including 29 kidney recipients and 18 liver recipients). All but one (98%) had protective titers of antibodies after a median duration of 3 years (min.: 0.8, max.: 21) after transplantation. The median antibody level was 40 U/L (interquartile range: 40–80). For the 46 patients with a known or estimated date of vaccination, yellow‐fever antibodies were still detectable after a median time of 13 years (range: 2–32 years) post‐immunization. Our data suggest there is long‐term persistence of antibodies to yellow fever in SOT recipients who have been vaccinated prior to transplantation.     

The double‐antigen ELISA concept for early detection of Erns‐specific classical swine fever virus antibodies and application as an accompanying test for differentiation of infected from marker vaccinated animals

Emergency vaccination with live marker vaccines represents a promising control strategy for future classical swine fever (CSF) outbreaks, and the first live marker vaccine is available in Europe. Successful implementation is dependent on a reliable accompanying diagnostic assay that allows differentiation of infected from vaccinated animals (DIVA). As induction of a protective immune response relies on virus‐neutralizing antibodies against E2 protein of CSF virus (CSFV), the most promising DIVA strategy is based on detection of E^rns‐specific antibodies in infected swine. The aim of this study was to develop and to evaluate a novel E^rns‐specific prototype ELISA (pigtype CSFV E^rns Ab), which may be used for CSF diagnosis including application as an accompanying discriminatory test for CSFV marker vaccines. The concept of a double‐antigen ELISA was shown to be a solid strategy to detect E^rns‐specific antibodies against CSFV isolates of different genotypes (sensitivity: 93.5%; specificity: 99.7%). Furthermore, detection of early seroconversion is advantageous compared with a frequently used CSFV E2 antibody ELISA. Clear differences in reactivity between sera taken from infected animals and animals vaccinated with various marker vaccines were observed. In combination with the marker vaccine CP7_E2alf, the novel ELISA represents a sensitivity of 90.2% and a specificity of 93.8%. However, cross‐reactivity with antibodies against ruminant pestiviruses was observed. Interestingly, the majority of samples tested false‐positive in other E^rns‐based antibody ELISAs were identified correctly by the novel prototype E^rns ELISA and vice versa. In conclusion, the pigtype CSFV E^rns Ab ELISA can contribute to an improvement in routine CSFV antibody screening, particularly for analysis of sera taken at an early time point after infection and is applicable as a DIVA assay. An additional E^rns antibody assay is recommended for identification of false‐positive results in a pig herd immunized with the licensed CP7_E2alf marker vaccine.     

Analysis of Acquisition of COVID-2019 Neutralizing Antibodies in Organ Transplant Recipients

BackgroundThis study confirmed the kinetics of antibodies acquired by SARS-CoV-2 vaccination in solid-organ transplant recipients and examined their association with the development of COVID-19 and immunosuppressive status in organ transplant recipients.MethodsWe measured COVID-19 neutralizing antibody titer in 21 organ transplant recipients vaccinated with the COVID-19 vaccine and 14 nontransplant recipients (control group) 3 times before and at 1 and 6 months after the third dose of vaccine. By confirming the kinetics of the acquired antibodies, we examined the relevance of the background characteristics of organ transplant recipients, such as the development of infectious diseases and immunosuppressive status.ResultsThe proportion of patients with neutralizing antibodies was significantly higher in the nontransplant group than in the transplant group. Neutralizing antibody titers were significantly lower in transplant recipients when they were compared before the third dose and 1 month later. In the transplant recipient group, 11 patients were positive, and 10 were negative for neutralizing antibodies. When the causal relationship between the neutralizing antibody titer and background was examined, a positive correlation was found between the antibody titer and the number of years since transplantation, and a negative correlation was found between the tacrolimus trough values, amount of mycophenolate mofetil or steroids taken internally, and antibody titer.ConclusionThis study suggests that the effectiveness of vaccination in transplant recipients is associated with the post-transplant period before vaccination and the dose of immunosuppressive agents.     

Lack of serologic immunity against vaccine‐preventable diseases in children after thoracic transplantation

We investigated whether children after heart‐ (HTx) or heart–lung transplantation (HLTx) show protective antibody levels against recommended vaccinations, whether vaccination schedules are completed and which factors influence serologic immunity. We performed a cross sectional ELISA – quantification of specific antibodies in 46 patients after pediatric thoracic Tx. Findings were correlated to vaccination history, age at Tx, clinical course and immunosuppressive regimen. We found protective antibody levels against diphtheria in 74% of patients, against tetanus in 22%, against Haemophilus influenzae type b in 30% and against Streptococcus pneumoniae in 59%. Antibody concentrations against live attenuated vaccines were significantly lower in children transplanted in the first 2 years of life. Antibodies were absent for measles in 55% of late – and 81% of early transplanted children, for mumps in 66%/94%, for rubella in 30%/56% and for Varicella in 34%/63%. We found significant correlation of low antibody concentrations and age at Tx. Patients without protective antibody concentrations had significantly longer use of steroids. Vaccination schedules were incomplete or delayed in the majority of patients associated with more days in hospital pre‐Tx. Our study shows that closer adherence to pretransplantation vaccination schedules and also post‐transplantation monitoring of antibody levels are required in transplant patients.     

Humoral response to natural influenza infection in solid organ transplant recipients

The humoral immune response of transplant recipients to influenza vaccination has been studied in detail. In contrast, the hemagglutinin inhibiting (HI) antibody response evoked by natural influenza infection and its impact on viral kinetics is unknown. In this prospective, multicenter, cohort study of natural influenza infection in transplant recipients, we measured HI antibody titers at presentation and 4 weeks later. Serial nasopharyngeal viral loads were determined using a quantitative influenza A polymerase chain reaction (PCR). We analyzed 196 transplant recipients with influenza infection. In the cohort of organ transplant patients with influenza A (n = 116), seropositivity rates for strain‐specific antibodies were 44.0% (95% confidence interval [CI] 31.5‐53.2%) at diagnosis and 64.7% (95% CI 55.4‐72.9%) 4 weeks postinfection. Seroconversion was observed in 32.8% (95% CI 24.7‐41.9%) of the cases. Lung transplant recipients were more likely to seroconvert (P = .002) and vaccine recipients were less likely to seroconvert (P = .024). A subset of patients (n = 30) who were unresponsive to prior vaccination were also unresponsive to natural infection. There was no correlation between viral kinetics and antibody response. This study provides novel data on the seroresponse to influenza infection in transplant patients and its relationship to a number of parameters including a prior vaccination status, virologic measures, and clinical variables.     

Reduced specificity of Erns antibody ELISAs for samples from piglets with maternally derived antibodies induced by vaccination of sows with classical swine fever marker vaccine CP7_E2alf

Successful implementation of marker vaccines against classical swine fever virus is dependent on a reliable accompanying diagnostic assay that allows differentiation of infected from vaccinated animals (DIVA ) as well as the development of a testing scheme during emergency vaccination. In this context, special attention needs to be paid to breeding farms, because the offspring of marker vaccinated sows possess maternally derived antibodies (MDA s). So far, limited information is available on the influence of MDA s on serological testing in the context of a DIVA strategy. Therefore, two commercially available E^rns antibody ELISA s were compared, using serum samples of piglets with a high‐to‐moderate titre of MDA s against marker vaccine CP 7_E2alf. False‐positive results were detected by both E^rns antibody ELISA s for serum samples of piglets with an age of up to 4 weeks. Interestingly, most samples tested false‐positive in the first E^rns antibody ELISA were identified correctly by the other E^rns antibody ELISA and vice versa. In conclusion, in case of emergency vaccination of sows, the specificity of both ELISA s in newborn piglets younger than 4 weeks may be relatively low. This could be addressed in a testing strategy by either not sampling piglets up to the age of 4 weeks or using both ELISA s in a screening‐confirmation set‐up.     

Desensitization for renal transplantation: depletion of donor‐specific anti‐HLA antibodies,preservation of memory antibodies,and clinical risks

Desensitization protocols reduce donor‐specific anti‐HLA antibodies (DSA) and enable renal transplantation in patients with a positive complement‐dependent cytotoxic cross‐match (CDC‐CXM). The effect of this treatment on protective antibody and immunoglobulin levels is unknown. Thirteen patients with end‐stage renal disease, DSA and positive CDC‐CXM underwent desensitization. Sera collected pre‐ and post‐transplantation were analysed for anti‐tetanus and anti‐pneumococcal antibodies, total immunoglobulin (Ig) levels and IgG subclasses and were compared to healthy controls and contemporaneous renal transplant recipients treated with standard immunosuppression alone. Ten patients developed negative CDC‐CXM and enzyme‐linked immunosorbent assay (ELISA) and underwent successful transplantation. Eight recipients achieved good graft function without antibody‐mediated or late rejection, BK virus or cytomegalovirus infection. One patient had primary non‐function due to recurrent oxalosis, and one patient with immediate graft function died from septicaemia. Seven recipients required post‐operative transfusion and three developed septicaemia. DSA remained negative by ELISA at 12 months, but were detectable by Luminex^®. Anti‐tetanus and anti‐pneumococcal antibodies, total Ig and IgG subclasses were below the normal range but comparable to levels in renal transplant recipients who had not undergone desensitization. Desensitization protocols effectively reduce DSA and allow successful transplantation. Post‐operative bleeding and short‐term infectious risk is increased. Protective antibody and serum immunoglobulin levels are relatively preserved.     

Durability of the hepatitis B vaccination in pediatric renal transplant recipients

Since hepatitis B virus (HBV) vaccine implementation, HBV infection has significantly decreased. However, adult renal transplant recipients show a higher rate of seroreversion compared to the general population, leading to HBV infection risk. Data are limited in pediatric renal transplant recipients. Retrospective data were collected to determine the seroprotection and durability of HBV vaccination in pediatric renal transplant patients from 2004 to 2014. One hundred subjects were categorized based on pre‐ and post‐transplant hepatitis B surface antibody (HBsAb). Pretransplant, 85 recipients (85%) had a positive HBsAb compared to 15 (15%) with negative HBsAb. In univariable analyses, other than age (P < .05) no significant differences existed pretransplant by demographics, pretransplantation dialysis, or number of vaccinations. Of the 85 pretransplantation responders, 53 (62%) remained HBsAb positive post‐transplantation, 28 (32%) seroreverted, and 4 developed indeterminate titers. All seroreversions occurred within 5 years post‐transplant. Receipt of a living donor organ had higher risk of reversion (P = .005). No significant differences were found in demographics, pretransplantation dialysis, vaccination number, or acute rejection. Despite vaccination, 15% of pediatric renal transplant candidates were seronegative, and an additional 32% lost seroprotection within 5 years post‐transplantation leaving nearly half of transplant recipients at risk for HBV infection.     

Panel Reactive Antibody Responses Against Influenza Vaccination in Kidney Transplant Recipients

IntroductionSeasonal influenza is an important cause of morbidity and mortality in the post-transplant period; therefore, the influenza vaccination has been recommended for all kidney transplant recipients before the influenza season. However, at least theoretically, the introduction of antigens via vaccines may trigger rejection attacks by causing an antibody response. In this study, we examined the development of de novo panel reactive antibody (PRA) development against the influenza vaccine in kidney transplant recipients.Materials and MethodsOverall, 41 kidney transplant recipients who received the influenza vaccination and 50 kidney transplant recipients (study group) who refused to receive the influenza vaccination (control group) were enrolled in the study. Following basal biochemistry examination, the inactivated trivalent influenza vaccine was administered intramuscularly. Panel reactive antibodies were screened in all patients before and after vaccination on days 30 and 180. The primary outcome variable was development of de novo panel reactive antibodies.ResultsOne patient in the study group developed de novo class I and II PRA at 6 months after vaccination (P > .05), while no antibody development was noted in the control group. Graft dysfunction or biopsy-confirmed rejection was not observed during the follow-up period in both groups.ConclusionThe influenza vaccination is generally effective and safe in solid organ transplant recipients. The vaccination procedure has the potential to trigger antibody development and occurrence of rejection. Therefore, vaccinated kidney transplant recipients should be monitored more carefully with regard to PRA; if the graft deteriorates, a rapid transplant biopsy should be performed.     

De Novo Anti‐HLA Antibody After Pandemic H1N1 and Seasonal Influenza Immunization in Kidney Transplant Recipients

In solid organ transplanted patients, annual influenza immunization is strongly recommended because of morbidity and mortality of influenza infections. In 2009, the rapid spread of a novel H1N1 influenza A virus led to the accelerated development of novel pandemic influenza vaccines. In Switzerland, the recipients received one dose of seasonal influenza and two doses of AS03‐adjuvanted H1N1 vaccines. This situation provided a unique opportunity to analyze the influence of novel adjuvanted influenza vaccines on the production of de novo anti‐HLA antibodies. We prospectively followed two independent cohorts including 92 and 59 kidney‐transplanted patients, assessing their anti‐HLA antibodies before, 6 weeks and 6 months after vaccination. Sixteen of 92 (17.3%) and 7 of 59 (11.9%) patients developed anti‐HLA antibodies. These antibodies, detected using the single antigen beads technology, were mostly at low levels and included both donor‐specific and non‐donor‐specific antibodies. In 2 of the 20 patients who were followed at 6 months, clinical events possibly related to de novo anti‐HLA antibodies were observed. In conclusion, multiple doses of influenza vaccine may lead to the production of anti‐HLA antibodies in a significant proportion of kidney transplant recipients. The long‐term clinical significance of these results remains to be addressed.     

Safety and efficacy of influenza vaccination in renal transplant recipients

This Practice Point commentary discusses Scharpé et al.'s single-center, nonrandomized, prospective trial of influenza vaccination in renal transplant recipients. In total, 165 transplant recipients and 41 healthy volunteers were vaccinated with a standard inactivated trivalent influenza vaccine (containing strains of the A/H1N1, A/H3N2 and B viruses). No rejection episodes or other adverse events were reported in either group. Influenza-specific antibody titers increased in renal transplant recipients following vaccination, as measured by comparison of pre-vaccination and post-vaccination seroprotection and seroresponse rates. This commentary discusses the limitations of the trial, and urges caution in extending the conclusions drawn by Scharpé et al. regarding the safety of the trivalent, non-adjuvant-containing influenza vaccine to newer adjuvant-assisted vaccines. Annual vaccination for influenza by use of the trivalent vaccine strategy without adjuvant should, however, be standard of care for all stable renal transplant recipients who do not have clinical contraindications.     

Comparison of Humoral Response in Kidney Transplant Recipients and Donors and Healthy Volunteers Following Second Dose of SARS-CoV-2 mRNA Vaccine

PurposeTo investigate the kinetics and durability of anti-spike glycoprotein (S) immunoglobulin G (IgG) after the second dose of mRNA-based SARS-CoV-2 vaccine in kidney transplant recipients (recipients) compared with those in kidney donors (donors) and healthy volunteers (HVs) and identify factors negatively associated with SARS-CoV-2 vaccine effectiveness in recipients.MethodsWe enrolled 378 recipients with no history of COVID-19 and no anti-S-IgG before the first vaccine and who received a second mRNA-based vaccine dose. Antibodies were detected using an immunoassay more than 4 weeks after the second vaccine dose. Anti-S-IgG <0.8, ≥0.8 to 15, and ≥15 U/mL were considered negative, weak positive, and strongly positive, respectively, whereas anti–nucleocapsid protein IgG was negative. Anti-S-IgG titer was determined in 990 HVs and 102 donors.ResultsAnti-S-IgG titers were 154, 2475, and 1181 U/mL in the recipient, HV, and donor groups, respectively, with values significantly lower in recipients. The anti-S-IgG-positivity rate of recipients gradually increased following the second vaccination, suggesting that recipients had a delayed response compared with the HV and donor groups, who had a 100% positivity rate at an earlier time point. Anti-S-IgG titers decreased in donors and HVs, whereas they remained stable in recipients, although at a significantly lower level. Independent negative factors associated with anti-S-IgG titers in recipients were age >60 years and lymphocytopenia (odds ratio: 2.35 and 2.44, respectively).ConclusionsKidney transplant recipients demonstrate delayed and attenuated responses, with lower SARS-CoV-2 antibody titers after the second dose of the mRNA-based COVID-19 vaccine.     

Serum antibody activity to glomerular endothelial cells is a prospective indicator of renal allograft rejection

Background. Vascular endothelial ells (ECs) are considered to be a primary target for injury in allograft rejection. However, the relationship between serum antibody activity to ECs and rejection episodes has not been extensively examined in renal transplantation. Methods. Twenty-two renal transplant recipients were included in this study. Serum levels of anti-endothelial cell antibody (AECA) were measured using a cellular enzyme-linked immunosorbent assay (ELISA) in which human umbilical vein endothelial cells (HUVEC), human glomerular endothelial cells (HGEC), and human dermal microvascular endothelial cells (MvE) were used as target cells. Serum samples were obtained just before transplantation and once a week during the immediate 1- to 3-month posttransplantation period. Results. There was a significant correlation between the the presence of AECA against HGEC and rejection episodes (P < 0.05). Patients with multiple episodes of rejection showed significantly higher frequencies of AECA than patients with a single episode of rejection (P < 0.001). It should be noted that patients suffering from multiple episodes of rejection had higher AECA titers than those without a rejection episode before transplantation. Conclusions. These findings imply that the HGEC-ELISA could be used as a prospective, informative test to identify patients at a high risk of acute rejection in renal transplantation. Received: December 10, 2001 / Accepted: March 22, 2002     

Influenza Vaccination in Orthotopic Liver Transplant Recipients: Absence of Post Administration ALT Elevation

Influenza vaccination has reduced life-threatening complications from influenza virus infection in adult liver transplant recipients. We evaluated changes in aminotransferase level and immunogenicity of influenza vaccination in liver transplant recipients. Fifty-one liver transplant recipients were administered a standard dose of the 2002-2003 inactivated trivalent influenza vaccine. ALT values were measured at baseline, 1 week and 4-6 weeks postvaccination. Antibody responses to each component of the vaccine were measured at baseline and after 4-6 weeks by a hemagglutination inhibition (HAI) assay. Response was defined as an HAI titer > or = 1: 40 and/or a 4-fold increase in antibody titers from baseline. An ALT elevation was defined as a rise of > or = 50% from baseline. There was no difference in the median rise in ALT value between seroconverters and nonseroconverters. A significant number of recipients developed potentially protective antibody titers (p-value < 0.0001). At less than 4 months post transplantation, 1/7 (14%), at 4-12 months, 6/9 (67%), and after 12 months, 30/35 (86%) subjects responded to the H1 strain. Of 51 recipients, one HCV (-) recipients vaccinated within 3 months of transplantation developed acute cellular rejection. Influenza virus vaccination is not associated with allograft rejection or ALT flares in liver transplant recipients.     

SARS-CoV-2 Infection After Vaccination: Kidney Transplant Recipient Profile and Disease Evolution in a Single Center

BackgroundSARS-CoV-2 infection has had a major impact on kidney transplant patients. Recent evidence suggests that solid organ transplant recipients who received mRNA vaccines reach low immunization rates. There are only few reports about the risk factors and severity of COVID-19 in these patients. Our single center experience describes the patient profile and disease evolution observed in this vulnerable group after inoculation.Material and MethodsRetrospective cohort study with kidney transplant patients who received a COVID-19 vaccine before testing positive for SARS-CoV-19 using polymerase chain reaction. Demographic characteristics and clinical information are described and compared with our previous series of patients who were infected before the initiation of the vaccination rollout.ResultsSixteen kidney transplant recipients diagnosed with COVID-19 after being vaccinated were included and compared with our previous series of 76 unvaccinated patients who were positive for COVID-19. No differences were found among risk factors such as age, time after transplant, hypertension, and obesity between groups (P value > .05). After COVID-19 diagnosis among inoculated patients, 10 patients were hospitalized, and 4 of who met the criteria for admission to the intensive care unit. Three patients died of COVID-19 complications. Despite this, the incidence of infections has decreased after vaccination rollout (P value < .05).ConclusionsPatients’ risk profiles remain constant among recipients who were positive for COVID-19 between waves. We did not find significant differences in hospitalization and severity rates in this reduced group of patients. However, the overall incidence in our kidney transplant population has decreased.     

Hepatitis B virus vaccination of recipients and donors of allogeneic peripheral blood stem cell transplantation

Abstract: Background: The aim of this study was to determine the role of hepatitis B virus (HBV) vaccination as defined by the seroconversion to hepatitis B surface antibody (anti‐HBs) positivity in peripheral blood stem cell transplants. Methods: A total of 65 recipients and their donors were enrolled in this study. Recipients were divided into four distinct groups. Group 1 consisted of individuals who were vaccinated, group 2 consisted of individuals who were naturally immunized, group 3 consisted of individuals who were HBs‐Ag positive, and group 4 consisted of individuals who were HBV naïve and not vaccinated. Results: Eighty‐eight percent of the HBV‐vaccinated recipients (14 of 16), who had vaccinated‐donors, seroconverted to anti‐HBs positivity. Eighty‐three percent of HBV‐naïve recipients (five of six), who received stem cells from HBV‐immune donors, seroconverted to anti‐HBs positivity. Two of the four HBs‐Ag positive recipients with HBV‐immune donors seroconverted to anti‐HBs positivity after transplantation. Fifty‐seven percent of previously vaccinated‐recipients (eight of 14) lost detectable anti‐HBs antibody following transplantation. Finally, 31% of HBV‐naïve recipients with HBV‐naïve donors acquired a de novo HBV infection. Conclusions: (i) Hepatitis B virus immunization of recipients of allogeneic hematopoietic cell transplantation results in an effective antibody response. (ii) The HBV‐immune status of the donor plays an important role in post‐transplantation HBs‐Ab on seroconversion. (iii) Systematic re‐immunization of recipients will be necessary to maintain HBV immunity in long‐term serving recipients.