Liver Recipients Research Articles

US Liver Transplant Outcomes After Normothermic Regional Perfusion vs Standard Super Rapid Recovery

Normothermic regional perfusion (NRP) is an emerging recovery modality for transplantable allografts from controlled donation after circulatory death (cDCD) donors. In the US, only 11.4% of liver recipients who are transplanted from a deceased donor receive a cDCD liver. NRP has the potential to safely expand the US donor pool with improved transplant outcomes as compared with standard super rapid recovery (SRR). To assess outcomes of US liver transplants using controlled donation after circulatory death livers recovered with normothermic regional perfusion vs standard super rapid recovery. This was a retrospective, observational cohort study comparing liver transplant outcomes from cDCD donors recovered by NRP vs SRR. Outcomes of cDCD liver transplant from January 2017 to May 2023 were collated from 17 US transplant centers and included livers recovered by SRR and NRP (thoracoabdominal NRP [TA-NRP] and abdominal NRP [A-NRP]). Seven transplant centers used NRP, allowing for liver allografts to be transplanted at 17 centers; 10 centers imported livers recovered via NRP from other centers. cDCD livers were recovered by either NRP or SRR. The primary outcome was ischemic cholangiopathy (IC). Secondary end points included primary nonfunction (PNF), early allograft dysfunction (EAD), biliary anastomotic strictures, posttransplant length of stay (LOS), and patient and graft survival. A total of 242 cDCD livers were included in this study: 136 recovered by SRR and 106 recovered by NRP (TA-NRP, 79 and A-NRP, 27). Median (IQR) NRP and SRR donor age was 30.5 (22-44) years and 36 (27-49) years, respectively. Median (IQR) posttransplant LOS was significantly shorter in the NRP cohort (7 [5-11] days vs 10 [7-16] days; P < .001). PNF occurred only in the SRR allografts group (n = 2). EAD was more common in the SRR cohort (123 of 136 [56.1%] vs 77 of 106 [36.4%]; P = .007). Biliary anastomotic strictures were increased 2.8-fold in SRR recipients (7 of 105 [6.7%] vs 30 of 134 [22.4%]; P = .001). Only SRR recipients had IC (0 vs 12 of 133 [9.0%]; P = .002); IC-free survival by Kaplan-Meier was significantly improved in NRP recipients. Patient and graft survival were comparable between cohorts. There was comparable patient and graft survival in liver transplant recipients of cDCD donors recovered by NRP vs SRR, with reduced rates of IC, biliary complications, and EAD in NRP recipients. The feasibility of A-NRP and TA-NRP implementation across multiple US transplant centers supports increasing adoption of NRP to improve organ use, access to transplant, and risk of wait-list mortality.

Insights from Seoul National University Hospital's experience: a systematic review of pure laparoscopic donor hepatectomy progression.

Following its initial execution in November 2015, pure laparoscopic donor hepatectomy (PLDH) has gained acceptance as a conventional practice at Seoul National University Hospital (SNUH). It is noteworthy that a significant proportion of cases entail full right hepatectomies, which are acknowledged to be technically demanding. As expertise and knowledge have been accrued, the pure laparoscopic technique has been extended to encompass liver recipients as a viable option in SNUH. The aim of this review is to present the developmental progression of PLDH, with a focus on pure laparoscopic donor right hepatectomy (PLDRH), at SNUH. This includes the standardization process, which can be achieved by sharing the hospital's accumulated experience and previous reports. Various types of graft, including full right, left, left lateral section, and monosegment, were procured by pure laparoscopic technique. The criteria for selection were expanded to include donors with variations in the anatomy of the portal vein and bile duct. Additionally, the procedure of PLDRH was determined to be safe and viable for donors with high body mass index and larger graft weight. In conclusion, this review demonstrates the alterations implemented throughout our evolution from restricted to inclusive criteria for donor selection, leading to a complete shift from open surgery to pure laparoscopic procedures in donor hepatectomy and eventually pure laparoscopic living donor liver transplantation (LDLT) in recipient.

Impact of Back-to-Base Normothermic Machine Perfusion on Complications and Costs: A Multicenter, Real-World Risk-Matched Analysis.

Assess cost and complication outcomes after liver transplantation (LT) using normothermic machine perfusion (NMP). End-ischemic NMP is often used to aid logistics, yet its impact on outcomes after LT remains unclear, as does its true impact on costs associated with transplantation. Deceased donor liver recipients at 2 centers (January 1, 2019, to June 30, 2023) were included. Retransplants, splits, and combined grafts were excluded. End-ischemic NMP (OrganOx-Metra) was implemented in October 2022 for extended-criteria donation after brain death (DBDs), all donations after circulatory deaths (DCDs), and logistics. NMP cases were matched 1:2 with static cold storage controls (SCS) using the Balance-of-Risk [donation after brain death (DBD)-grafts] and UK-DCD Score (DCD-grafts). Overall, 803 transplantations were included, 174 (21.7%) receiving NMP. Matching was achieved between 118 NMP-DBDs with 236 SCS; and 37 NMP-DCD with 74 corresponding SCS. For both graft types, median inpatient comprehensive complications index values were comparable between groups. DCD-NMP grafts experienced reduced cumulative 90-day comprehensive complications index (27.6 vs 41.9, P =0.028). NMP also reduced the need for early relaparotomy and renal replacement therapy, with subsequently less frequent major complications (Clavien-Dindo ≥IVa). This effect was more pronounced in DCD transplants. NMP had no protective effect on early biliary complications. Organ acquisition/preservation costs were higher with NMP, yet NMP-treated grafts had lower 90-day pretransplant costs in the context of shorter waiting list times. Overall costs were comparable for both cohorts. This is the first risk-adjusted outcome and cost analysis comparing NMP and SCS. In addition to logistical benefits, NMP was associated with a reduction in relaparotomy and bleeding in DBD grafts, and overall complications and post-LT renal replacement for DCDs. While organ acquisition/preservation was more costly with NMP, overall 90-day health care costs-per-transplantation were comparable.

Stepwise development and expansion of an abdominal normothermic regional perfusion program for donation after circulatory determination of death organ procurement.

Normothermic regional perfusion (NRP) represents an innovative technology that improves the outcomes for liver and kidney recipients of donation after circulatory determination of death (DCD) organs but protocols for abdominal-only NRP (A-NRP) DCD are lacking in the US. We describe the implementation and expansion strategies of a transplant-center-based A-NRP DCD program that has grown in volume, geographical reach, and donor acceptance parameters, presented as four eras. In the implementation era, two donors were attempted, and one liver graft was transplanted. In the local expansion era, 33% of attempted donors resulted in transplantation and 42% of liver grafts from donors who died within the functional warm ischemic time (fWIT) limit were transplanted. In the Regional Expansion era, 25% of attempted donors resulted in transplantation and 50% of liver grafts from donors who died within the fWIT limit were transplanted. In the Donor Acceptance Expansion era, 46% of attempted donors resulted in transplantation and 72% of liver grafts from donors who died within the fWIT limit were transplanted. Eight discarded grafts demonstrated a potential opportunity for utilization. The stepwise approach to building an A-NRP program described here can serve as a model for other transplant centers.

Endoscopic full-thickness resection of sigmoid colon cancer in a liver recipient

Compared with the general population, solid organ transplant recipients have a higher cancer risk. This is mainly due to the use of immunosuppressive therapy. Colorectal cancer is one of the most common cancers in recipients. This paper presents the experience of endoscopic full-thickness resection (EFTR) of a sigmoid colon cancer in a liver recipient.

De Novo Metabolic Syndrome 1 Year after Liver Transplantation and Its Association with Mid- and Long-Term Morbidity and Mortality in Liver Recipients.

Background: Metabolic syndrome (MS) constitutes an important source of cardiovascular- and cancer-related morbidity and mortality in the general population. Limited information is available on whether these findings can be directly extrapolated to liver recipients. This study aimed to investigate the impact of post-transplant MS present 1 year after liver transplantation on survival rates, risk of major cardiovascular events (CVEs), and de novo malignancies. Methods: Adult deceased-liver-donor recipients who underwent transplantation in our centre between 2010 and 2019 and reached at least 1 year of post-transplantation follow-up were eligible. Results: Of 259 enrolled patients, 20% developed post-transplant MS 1 year after the procedure. The presence of post-transplant MS at 1 year did not affect all-cause mortality (p = 0.144) and risk of de novo malignancies (p = 0.198) in liver recipients. However, it was associated with an overall and time-dependent increase in the risk of major CVEs (p < 0.001). MASH aetiology of liver disease, pre-existing major CVEs, and development of de novo malignancy were independent predictors of all-cause mortality in liver recipients. Conclusions: New onset MS exerts a wide-ranging effect on the post-transplant prognosis of liver recipients. Obtaining optimal control over all modifiable metabolic risk factors is central to improving long-term outcomes in this population.

Pioneering fully robotic donor hepatectomy and robotic recipient liver graft implantation - a new horizon in liver transplantation.

Pioneering fully robotic donor hepatectomy and robotic recipient liver graft implantation - a new horizon in liver transplantation.

Invasive Fungal Infections in Inpatient Solid Organ Transplant Recipients With COVID-19: A Multicenter Retrospective Cohort.

The prevalence and outcomes of COVID-19-associated invasive fungal infections (CAIFIs) in solid organ transplant recipients (SOTRs) remain poorly understood. A retrospective cohort study of SOTRs with COVID-19 admitted to 5 hospitals within Johns Hopkins Medicine was performed between March 2020 and March 2022. Cox regression multilevel mixed-effects ordinal logistic regression was used. In the cohort of 276 SOTRs, 22 (8%) developed IFIs. The prevalence of CAIFIs was highest in lung transplant recipients (20%), followed by recipients of heart (2/28; 7.1%), liver (3/46; 6.5%), and kidney (7/149; 4.7%) transplants. In the overall cohort, only 42 of 276 SOTRs (15.2%) required mechanical ventilation; these included 11 of 22 SOTRs (50%) of the CAIFI group and 31 of 254 SOTRs (12.2%) of the no-CAIFI group. Compared with those without IFIs, SOTs with IFIs had worse outcomes and required more advanced life support (high-flow oxygen, vasopressor, and dialysis). SOTRs with CAIFIs had higher 1-y death-censored allograft failure (hazard ratio 1.6 5.1 16.4 , P = 0.006) and 1-y mortality adjusting for oxygen requirement (adjusted hazard ratio 1.1 2.4 5.1 , P < 0.001), compared with SOTRs without CAIFIs. The prevalence of CAIFIs in inpatient SOTRs with COVID-19 is substantial. Clinicians should be alert to the possibility of CAIFIs in SOTRs with COVID-19, particularly those requiring supplemental oxygen, regardless of their intubation status.

The role of donor sex on the post-liver transplant outcomes in patients with primary sclerosing cholangitis.

Primary sclerosing cholangitis (PSC) can result in hepatic decompensation and require liver transplantation (LT). This study investigates the effect of the sex of the donor and recipient as a prognostic risk factor for adverse outcomes after LT in patients with PSC. UNOS registry was used to select LT patients with PSC from 1987 to 2019. The study cohort was stratified based on the sex of the recipient and further subdivided based on the sex of the donor. The primary endpoints of this study were all-cause mortality and graft failure, which were evaluated using a sequential Cox regression analysis. This study included 2829 patients; 906 female recipients were transplanted from 441 male donors and 465 female donors. 1923 male recipients were transplanted from 1194 male donors and 729 female donors. Within the mismatch analyses, the male-to-male recipients also had a significantly reduced hazard ratio of graft failure compared to female-to-male transplants [aHR 0.51, 95% confidence interval (CI) 0.33-0.79, P = 0.003]. No difference in graft failure was observed in the mismatched female recipient subgroup. The mismatched male recipient group also showed a decreased hazard ratio of mortality from graft rejection and respiratory causes. No differences in specific mortality causes were identified in the mismatched female recipient group. This study demonstrated an increase in the risk of graft failure and mortality secondary to graft failure in male recipients of female donor livers. No differences in mortality or graft failure were identified in female recipients of male livers.

MASH Continues as a Significant Burden on Metabolic Health of Liver Recipients

BackgroundMetabolic complications are a recognized health concern in liver transplant recipients that result in inferior patient-reported outcomes. Patients with MASH are known to be disproportionately affected by metabolic diseases compared to other indications for transplantation. PurposeThe aim of this study was to investigate the incidence of metabolic abnormalities in liver recipients with specific focus on differences between patients transplanted for MASH and non-MASH-causes. Patients and methodsAn observational, monocentric, and retrospective analysis was performed. Patients who received a cadaveric-donor-liver transplant between 2010 and 2019 were eligible. Results282 patients were enrolled with a median age of 52 years (66.7% males). Metabolic dysfunction-associated steatohepatitis (MASH) led to liver transplant in 8.2% of cases. De-novo metabolic syndrome was diagnosed in 36% of the study population. Patients that underwent transplant owing to MASH showed significantly higher incidence of metabolic complications in both pre- and post-transplant period. Considerable differences were noted in the pattern of weight gain between patients transplanted for MASH and non-MASH patients. The MASH etiology (OR: 5.5; 95% CI: 1.624-22.868; P = .010), higher BMI at 1-year post-transplant (OR: 1.321; 95% CI: 1.214-1.449; P = <.001), and older age at transplant (OR: 1.038; 95% CI: 1.006-1.074; P = .022) were independently associated with new-onset metabolic syndrome in liver recipients. ConclusionMetabolic complications were prevalent in liver recipients. Liver recipients with underlying MASH significantly surpassed patients transplanted for other indications in terms of metabolic complications incidence and demonstrated an unfavorable trajectory of weight gain post-transplant.

Steatotic liver in renal transplant recipients does not correlate with CVD, a retrospective cohort study

Steatotic liver in renal transplant recipients does not correlate with CVD, a retrospective cohort study

Hepatitis B surface antigen positive donors for liver recipients with hepatocellular carcinoma: a single centre experience

Hepatitis B surface antigen positive donors for liver recipients with hepatocellular carcinoma: a single centre experience

The role of cold ischemia time and hypothermic perfusion in predicting early hepatocellular carcinoma recurrences after liver transplantation.

The aim of the study was to identify predictors of early tumor recurrence in patients with hepatocellular carcinoma (HCC) after liver transplantation (LT). Retrospective cohort study in 237 consecutive liver recipients with HCC between 2016 and 2021. Multivariate logistic analysis was performed to identify predictors of early HCC recurrences. The impact of hypothermic-oxygenated perfusion (HOPE) on outcome was analyzed after propensity score weighting. Early recurrences were observed in 15 cases. Microvascular invasion (OR 3.737, 95% CI 1.246-11.206, p = 0.019) and cold ischemia time (OR 1.155, 95% CI 1.001-1.333, p = 0.049) were independently associated with a lower risk of HCC recurrences. After balancing for relevant variables, patients in the HOPE group had lower rates of tumor recurrence (weighted OR 0.126, 95% CI 0.016-0.989, p = 0.049) and higher recurrence free survival (weighted HR 0.132, 95% CI 0.017-0.999, p = 0.050). Reducing cold ischemia time and graft perfusion with HOPE can lead to lower rates of early HCC recurrences and higher recurrence-free survival.

The COVID-19 infection in liver transplant recipients: A Cohort Study

The immunosuppressed state of liver transplant recipients makes them vulnerable to infections after surgery. These infections are directly correlated with the net state of immunosuppression. Higher levels of immunosuppression mean a higher risk of infection, with rates of infection typically highest in the early post-transplant period. Coronavirus disease 2019 (COVID‐19) vaccines have shown efficacy in generating specific immune responses. This study aims to describe the COVID-19 infection before and after vaccination in liver recipients. This was a cohort study including 77 liver transplant recipients with laboratory radiological confirmed COVID-19. COVID-19 infection was present before vaccination in 30 patients. The most frequent COVID-19 clinical presentations before vaccination were cough in 32 patients and myalgia in 21 patients; 27 cases had oxygen depletion and required supplemental oxygen. Of the 30 COVID-19 patients, 4 patients re-experienced the disease about three months after complete vaccination. 33 liver transplant patients had not experienced COVID-19 before vaccination, of which 32 patients received vaccination. In conclusion, liver transplant patients infected with SARS-CoV-2 are at greater risk of severe infection and death compared with immunocompetent individuals. Thus, COVID-19 vaccination for all liver recipients is of paramount importance.

Comparison of Lipid Profiles Between Pediatric Living- and Deceased-Donor Liver Recipients

Background: It has been shown that hyperlipidemia occurs in 71% of patients following liver transplantation. Multiple risk factors, including obesity, diabetes mellitus, and diet, as well as the immunosuppressive medications used, influence the lipid profiles that are seen in these individuals, contributing to the multifactorial etiology of lipid problems. Objectives: The aim of the present study is to compare the lipid profile in liver transplant recipients from living-related (LR) and deceased donors (DDs). Methods: This is a retrospective cross-sectional study performed at Shiraz University of Medical Science between 2005 and 2018. Patients under 18 years old who received liver transplants were included in the study and divided into 2 groups who received from LR and DDs, and lipid profiles were compared between the 2 groups. Results: A total of 397 patients were included in the study; in the first group, 234 received a liver from a DD, and in the second group, 161 from an LR donor. The mean body mass index (BMI) was 17.51 ± 5.49 in the first group and 16.25 ± 3.29 in the second group. The most common underlying diseases were biliary atresia (22%) and autoimmune hepatitis (15%). The mean triglyceride (TG) and high-density lipoprotein (HDL) levels were 133 and 46 mg/dL in the first group and 118 and 54 mg/dL in the second group, while the differences were statistically significant. As age increased, there was a significant difference in the mean values of fasting blood sugar (FBS) and HDL, with FBS increasing and HDL decreasing. There was no significant difference in the use of immunosuppressant drugs between the 2 groups. Conclusions: Patients who received a liver from an LR donor have a significantly lower TG, higher HDL, and a lower cardiovascular risk.

Descriptive study on risk of increased morbidity of schistosomiasis and graft loss after liver transplantation.

Solid-organ transplantation procedures have witnessed a surge in frequency. Consequently, increased attention to associated infections and their impact on graft success is warranted. The liver is the principal target for infection by the flatworm Schistosoma mansoni. Hence, rigorous screening protocols for this parasite should be implemented for liver transplantation donors and recipients. This study investigated the risks posed by schistosomiasis-infected liver tissues for successful liver transplantation (LT), considering donors and recipients, by analyzing reported cases. Among the 43 patients undergoing LT (donors = 19; recipients = 24), 32 were infected with S. mansoni, five were infected with other Schistosoma species, and no identification was made in four patients. Reported follow-up periods ranged from 1 to 132 months, and all patients achieved successful recovery. As these helminths do not replicate in their vertebrate hosts, immunosuppressive treatment is not expected to promote increased morbidity or reactivation. Moreover, suspected or confirmed schistosomiasis infections often have a benign course, and generally, should not prevent LT. The available literature was reviewed and a provisional screening protocol has been proposed.

A Qualitative Study on Nutritional Awareness Among Parents of Pediatric Recipients of Liver or Kidney Transplants.

The primary aim of this study was to examine the extent of nutritional awareness concerning dietary requisites within a cohort comprising pediatric recipients of liver and kidney transplants, along with their respective caregivers. The overarching goal was to establish a foundation for enhancing the dietary nutrition of this specific population. This was a qualitative research study, involving in-depth interviews and subsequent qualitative data analysis. Our sample included pediatric patients in a specific age range who had undergone a liver or kidney transplant, as well as their parents. The data analysis technique we used was content analysis. The survey focused on knowledge of dietary requirements and restrictions, nutritional needs, and adherence to daily dietary requirements among pediatric patients and their respective caregivers. Approximately 30% of the parents lacked relevant nutritional awareness, 30% relied on a single source for acquiring nutritional knowledge, and 40% expressed a considerable need for nutritional guidance. Our findings revealed a deficiency in the understanding of nutritional and dietary requirements for children who have undergone a liver or kidney transplant. Their nutrient intake was unbalanced, and their dietary habits were irregular, highlighting the need for better nutritional guidance and monitoring. The nutritional awareness and knowledge of dietary requirements among pediatric liver and kidney transplant recipients and their care providers are inadequate. Medical professionals are urged to tackle this concern by imparting comprehensive education to parents regarding the nutritional prerequisites essential for their children post-transplant. This approach empowers parents to implement requisite dietary modifications effectively. Furthermore, healthcare institutions should augment the nutritional proficiency of their medical staff through meticulously structured training initiatives.

Utilization of older deceased donors for pediatric liver transplant may negatively impact long-term survival.

Multiple adult studies have investigated the role of older donors (ODs) in expanding the donor pool. However, the impact of donor age on pediatric liver transplantation (LT)has not been fully elucidated. UNOS database was used to identify pediatric (≤18 years) LTs performed in the United States during 2002-22. Donors ≥40 years at donation were classified as older donors (ODs). Propensity analysis was performed with 1:1 matching for potentially confounding variables. A total of 10,024 pediatric liver transplantation (PLT) patients met inclusion criteria; 669 received liver grafts from ODs. Candidates receiving OD liver grafts were more likely to be transplanted for acute liver failure, have higher Model End-Stage Liver Disease/Pediatric End-Stage Liver Disease (MELD/PELD) scores at LT, listed as Status 1/1A at LT, and be in the intensive care unit(ICU) at time of LT (all p < 0.001). Kaplan-Meier (KM) analyses showed that recipients of OD grafts had worse patient and graft survival (p < 0.001)compared to recipients of younger donor (YD)grafts. KM analyses performed on candidates matched for acuity at LT revealed inferior patient and graft survival in recipients of deceased donor grafts (p < 0.001), but not living donor grafts (p > 0.1)from ODs. Cox regression analysis demonstrated that living donor LT, diagnosis of biliary atresia and first liver transplant were favorable predictors of recipient outcomes, whereas ICU stay before LT and transplantation during 2002-12 were unfavorable. Livers from ODs were used for candidates with higher acuity. Pediatric recipients of livers from ODs had worse outcome compared to YDs; however, living donor LT from ODs had the least negative impact on recipient outcomes.

Invigorating human MSCs for transplantation therapy via Nrf2/DKK1 co-stimulation in an acute-on-chronic liver failure mouse model.

Since boosting stem cell resilience in stressful environments is critical for the therapeutic efficacy of stem cell-based transplantations in liver disease, this study aimed to establish the efficacy of a transient plasmid-based preconditioning strategy for boosting the capability of mesenchymal stromal cells (MSCs) for anti-inflammation/antioxidant defenses and paracrine actions in recipient hepatocytes. Human adipose mesenchymal stem cells (hADMSCs) were subjected to transfer, either with or without the nuclear factor erythroid 2-related factor 2 (Nrf2)/Dickkopf1 (DKK1) genes, followed by exposure to TNF-α/H2O2. Mouse models were subjected to acute chronic liver failure (ACLF) and subsequently injected with either transfected or untransfected MSCs. These hADMSCs and ACLF mouse models were used to investigate the interaction between Nrf2/DKK1 and the hepatocyte receptor cytoskeleton-associated protein 4 (CKAP4). Activation of Nrf2 and DKK1 enhanced the anti-stress capacity of MSCs in vitro. In a murine model of ACLF, transient co-overexpression of Nrf2 and DKK1 via plasmid transfection improved MSC resilience against inflammatory and oxidative assaults, boosted MSC transplantation efficacy, and promoted recipient liver regeneration due to a shift from the activation of the anti-regenerative IFN-γ/STAT1 pathway to the pro-regenerative IL-6/STAT3 pathway in the liver. Importantly, the therapeutic benefits of MSC transplantation were nullified when the receptor CKAP4, which interacts with DKK1, was specifically removed from recipient hepatocytes. However, the removal of the another receptor low-density lipoprotein receptor-related protein 6 (LRP6) had no impact on the effectiveness of MSC transplantation. Moreover, in long-term observations, no tumorigenicity was detected in mice following transplantation of transiently preconditioned MSCs. Co-stimulation with Nrf2/DKK1 safely improved the efficacy of human MSC-based therapies in murine models of ACLF through CKAP4-dependent paracrine mechanisms.

B and T Cell Responses to SARS-CoV-2 Vaccination in Kidney and Liver Transplant Recipients with and without Previous COVID-19.

(1) Background: Vulnerable populations including transplant recipients are jeopardised by COVID-19. Herein, we report on B and T cell responses among liver and kidney organ recipients at our centre. (2) Methods: 23 liver and 45 kidney (14 thereof combined kidney/pancreas) transplanted patients were vaccinated with two doses of BNT162b2 followed by a booster dose of mRNA-1273 in 28 non-responders 4 months thereafter. Anti-SARS-CoV-2-Ig was measured by specific ELISA and virus neutralisation assay; T cell responses were measured by a spike protein-specific IFN-γ release assay. (3) Results: Compared to controls, B and T cell responses were weak in transplant recipients, particularly in those without prior exposure to SARS-CoV-2. Within this group, only 15% after the first and 58.3% after the second vaccination achieved seroconversion. A total of 14 out of 28 vaccination non-responders achieved a seroconversion after a third dose. Vaccination side effects were more frequent in healthy controls. The use of mycophenolate was associated with reduced anti-SARS-CoV-2-Ig production. (4) Conclusions: Our data confirm that vaccination responses are insufficient after standard vaccination in liver and kidney transplant recipients and are affected to a variable degree by specific immunosuppressants, particularly mycophenolate. Monitoring vaccination success and re-vaccinating those who are unresponsive seems prudent to achieve sufficient titres. Overall, prospective large-scale, multinational, multicentre studies or high-quality meta-analyses will be needed to generate personalised vaccination strategies in order to achieve protective immunity in high-risk, hard-to-immunize populations.