Immunosuppressive Drugs in Liver Transplant: An Insight

Latin American association for the study of the liver (ALEH) guidance on postoperative care after liver transplantation

Liver transplantation (LT) is a well-established therapy for patients with decompensated cirrhosis and early-stage hepatocellular carcinoma. Liver transplantation activity varies sharply across Latin American (LATAM) countries due to differences in resources, expertise, and funding and local attitudes toward organ donation and transplantation. This current guidance of postoperative care after LT is the first position paper of the Latin American Association for the Study of the Liver (ALEH) Special Interest Group (SIG), drawing evidence-based recommendations regarding immediate and long-term postoperative care of LT recipients, taking into consideration their applicability in Latin America.

Cytopenias in Autoimmune Liver Diseases-A Review

Autoimmune liver diseases (AiLDs), including autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), and primary sclerosing cholangitis (PSC), are immune-mediated conditions associated with significant hepatic and systemic manifestations. Among these, cytopenias-defined as reductions in blood cell counts affecting single or multiple lineages-represent a clinically important, though often under-recognized, complication. Cytopenias in AiLDs arise from diverse mechanisms, including immune-mediated destruction, hypersplenism due to portal hypertension, bone marrow suppression, and nutritional deficiencies. These abnormalities can exacerbate bleeding, infections, or fatigue, complicating the disease course and impacting therapeutic strategies. Immune-mediated cytopenias, such as autoimmune hemolytic anemia (AIHA), immune thrombocytopenic purpura (ITP), and autoimmune neutropenia (AIN), are more frequently associated with AIH, whereas cytopenias in PBC and PSC are largely attributed to hypersplenism. Diagnostic evaluation involves a systematic approach combining clinical history, laboratory testing (e.g., complete blood counts, Coombs tests, and nutritional assessments), imaging studies, and bone marrow evaluation in complex cases. Treatment strategies aim to address the underlying cause of cytopenias, including immunosuppressive therapy for autoimmune mechanisms, beta-blockers or splenectomy for hypersplenism, and supplementation for nutritional deficiencies. Challenges include distinguishing between immune- and hypersplenism-related cytopenias, managing drug-induced cytopenias, and optimizing care in transplant candidates. The recently recognized IgG4-related disease, often mimicking cholestatic AiLDs, adds another layer of complexity, given its association with autoimmune cytopenias and hypersplenism. This review aims to act as a guide for the clinician dealing with patients with AiLDs with respect to the occurrence of cytopenias, with a specific focus on pathophysiology and management of these cytopenias. Furthermore, there need to be enhanced multidisciplinary discussions about those patients between the hematologists and hepatologists, with a maintenance of a high index of suspicion for the rarer causes of cytopenias in AiLDs on the part of the treating physician, and there is a need for further studies to elucidate the mechanisms behind the occurrence of cytopenias in AiLDs.

Side Effects of Immunosuppressant Drugs After Liver Transplant

Liver transplantation (LT) is the standard of care for both end-stage liver failure and hepatocellular carcinoma (HCC). Side effects of the main used immunosuppressive drugs have a noteworthy impact on the long-term outcome of LT recipients. Consequently, to achieve a balance between optimal immunosuppression and minimal side effects is a cornerstone of the post-LT period. Today, there are no validated markers for overimmunosuppression and underimmunosuppression, only a few drugs have therapeutic drug monitoring, and immunosuppression regimens vary from center to center and from country to country. Currently, there are many drugs with different efficacy and safety profiles. Using different agents permits a decrease in the dosage and minimizes the toxicities. A small subset of recipients achieves immunotolerance with the chance to stop immunosuppressive therapy. This article focuses on the side effects of immunosuppressive drugs, which significantly impact long-term outcomes for LT recipients. The primary aim is to highlight the balance between achieving effective immunosuppression and minimizing adverse effects, emphasizing the role of personalized therapeutic strategies. Moreover, this review evaluates the mechanisms of action and specific complications associated with immunosuppressive agents. Finally, special attention is given to strategies for reducing immunosuppressive burdens, improving patient quality of life, and identifying immunotolerant individuals.

Update on the Complications and Management of Liver Cirrhosis

Liver cirrhosis represents the advanced pathological stage of chronic liver disease, characterized by the progressive destruction and regeneration of the hepatic parenchyma over years, culminating in fibrosis and disruption of the vascular architecture. As a leading global cause of morbidity and mortality, it continues to affect millions worldwide, imposing a substantial burden on healthcare systems. Alcoholic/nonalcoholic fatty liver disease and chronic viral hepatitis infection, hepatitis C (HCV) in particular, remain leading causes of cirrhosis. Despite significant advances in understanding the pathogenesis of cirrhosis, its management is still complex due to the multifaceted complications, including ascites, hepatic encephalopathy, variceal bleeding, and hepatocellular carcinoma, all of which severely compromise the patient outcomes and quality of life. This review aims at filling a critical gap by providing a comprehensive summary of the latest evidence on the complications and management of liver cirrhosis. Evidence-based therapies targeting both the etiologies and complications of cirrhosis are essential for improving outcomes. While liver transplantation is considered a definitive cure, advancements in pharmacological therapies offer promising avenues for halting and potentially reversing disease progression. This review summarizes the latest management strategies for cirrhosis and its associated complications, emphasizing the importance of early intervention and novel therapeutic options for improving outcomes and quality of life in affected individuals.

Bibliometric and LDA analysis of acute rejection in liver transplantation: Emerging trends, immunotherapy challenges, and the role of artificial intelligence

With the rising demand for liver transplantation (LT), research on acute rejection (AR) has become increasingly diverse, yet no consensus has been reached. This study presents a bibliometric and latent Dirichlet allocation (LDA) topic modeling analysis of AR research in LT, encompassing 1399 articles. The United States, Zhejiang University, and the University of California, San Francisco emerged as leading contributors, while Levitsky J and Uemoto SJ were key researchers. The most influential journals included the American Journal of Transplantation, Journal of Hepatology, and Transplantation. The analysis reveals a transition from traditional histological assessments to molecular diagnostics, genetic and epigenetic profiling, and noninvasive biomarkers such as donor-derived cell-free DNA (dd-cfDNA) and microRNAs. Advances in immune checkpoint inhibitors (ICIs), cell-based therapies (Tregs, mesenchymal stem cells (MSCs)), AI-guided immunosuppression, and nanoparticle-mediated drug delivery systems reflect a growing emphasis on precision medicine. In addition, recent exploration of microbiome-based therapies and regenerative medicine, including MSCs and their extracellular vesicles, offers promising new avenues for reducing long-term immunosuppressive drug dependency and enhancing graft survival. These developments not only improve early AR detection and personalized treatment but also reduce toxicity, foster immune tolerance, and expand the scope of individualized therapeutic options. Global collaboration, supported by cutting-edge research and AI-driven decision-making, remains essential for refining AR strategies, improving graft survival, and achieving better long-term patient outcomes.

Targeting T helper 17 cells: emerging strategies for overcoming transplant rejection

Solid organ transplantation has significantly improved the survival rate of patients with terminal organ failure. However, its success is often compromised by allograft rejection, a process in which T helper 17 (Th17) cells play a crucial role. These cells facilitate rejection by enhancing neutrophil infiltration into the graft and by activating endothelial cells and fibroblasts. Additionally, Th17 cells can trigger the activation of other T cell types, including Th1, Th2, and CD8+ T cells, further contributing to rejection. An imbalance between Th17 and regulatory T cells (Tregs) is known to promote rejection. To counteract this, immunosuppressive drugs have been developed to inhibit T cell activity and foster transplant tolerance. Another approach involves the adoptive transfer of regulatory cells, such as Tregs and myeloid-derived suppressor cells, to dampen T cell functions. This review primarily focuses on the roles of Th17 cells in rejection and their interactions with other T cell subsets. We also explore various strategies aimed at suppressing T cells to induce tolerance.

Fumagillin Shortage: How to Treat Enterocytozoon bieneusi Microsporidiosis in Solid Organ Transplant Recipients in 2024?

Intestinal microsporidiosis caused by Enterocytozoon bieneusi is an opportunistic infection that especially affects solid organ transplant (SOT) recipients. Management revolves around tapering the immunosuppressive regimen and/or using a specific anti-microsporidia treatment, but only fumagillin has demonstrated efficacy for treatment of this infection. Since fumagillin has been commercially discontinued, nitazoxanide is increasingly being used in this indication. We aimed to describe therapeutic management of E. bieneusi infections in this context. We conducted a French nationwide observational retrospective study on reported cases of E. bieneusi infections in SOT recipients. We identified 154 cases: 64 (41.6%) were managed by simply modifying the immunosuppressive regimen, 54 (35.1%) were given fumagillin, and 36 (23.4%) were given nitazoxanide. Clinical remission rate ranged from 77.8% to 90.7% and was not significantly different between therapeutic strategies but tended to be lower with nitazoxanide. Stool negativization rate was highest with fumagillin (91.7%) and lowest with nitazoxanide (28.6%). Relapses occurred in 6.9% of cases and were more frequent with nitazoxanide (14.3%). This study shows that tapering immunosuppression can result in a satisfactory remission rate but is sometimes accompanied by relapses. Nitazoxanide had limited effectiveness, whereas fumagillin had good results that provide a solid rationale for bringing fumagillin back to market.

Trial Registration Number

ClinicalTrials.gov ID: NCT05417815.

A cross-sectional study on the prevalence of eating disorders in liver transplanted patients with type 2 diabetes and/or overweight/obesity

Liver transplantation (LT) associates with weight gain and metabolic complications. However, risk of eating disorders post-transplantation and factors influencing their onset remain poorly understood. This study aimed to fill this knowledge gap by characterizing the risk of having eating disorders or Orthorexia Nervosa (ON) according to the EAT-26, BES and Bratman screening questionnaires in 104 liver transplant recipients (mean age 62.5 years; median time from LT 6 years) with type 2 diabetes and/or overweight/obesity. Eighty-two patients (78.9 %) had diabetes; mean BMI was 30.1 ± 5.9 kg/m2. Risk of eating disorders was observed in 6.9 %-10.8 % and the risk of orthorexia (Bratman test score > 4) was observed in 60.5 % of patients. A significant association was found between BMI and the likelihood of having eating disorders considering EAT-26 (OR = 0.17, p = .009). The absence of a direct link between diabetes and the risk of having eating disorders suggest multifactorial influences on post-transplant eating behaviors. The study highlights the importance of proactive screening to evaluate eating behaviors in liver transplant recipients to define tailored interventions and optimize post-transplant outcomes. Limitations refer to the observational nature of the study and the absence of pre-transplant data. Further research is warranted to validate these findings, elucidate temporal relationship between transplantation and the onset of eating disorders, and explore potential mechanisms underlying these associations. Such insights are crucial for developing effective strategies to mitigate the impact of eating disorders on post-transplant health and well-being.

Maintenance immunosuppressive therapy in liver transplantation: results from CESIT study, an Italian retrospective cohort study

OBJECTIVES

To investigate the use of maintenance immunosuppressive treatments following liver transplantation and to compare their risk-benefit profiles in clinical practice.

DESIGN

Retrospective multicentrer cohort study.

SETTING

Four Italian regions (Lombardy, Veneto, Lazio, Sardinia).

METHODS

Data were integrated from the national transplant information system and administrative claims data from four Italian regions. All adults who underwent incident liver transplantation between 2009 and 2019 were identified and categorised into two groups: cirrhosis or hepatocellular carcinoma (HCC). The trend of immunosuppressive treatment over years was analysed, and their effectiveness/safety profiles were compared using multivariate Cox models (HR; 95% CI).

MAIN OUTCOME MEASURES

Mortality, transplant reject/graft failure, incidence of severe infections, cancer, diabetes, major adverse cardiovascular events and lipid-modifying agents use.

RESULTS

The study comprised 750 subjects in the cirrhosis cohort and 1159 in the HCC cohort. Over the study years, there was a decline in the use of cyclosporine-CsA, while combination therapy involving tacrolimus with other drugs increased compared with monotherapy. Overall, tacrolimus monotherapy use was slightly over 40% in both groups, followed by tacrolimus+mycophenolate (39.5%-cirrhosis; 30.6%-HCC) and tacrolimus+molecular target of rapamycin inhibitors (mTORi) (8.5%-cirrhosis; 13.3%-HCC). No significant differences emerged in risk-benefit profile of different tacrolimus-based therapies, except for a higher risk of mortality in cirrhosis subjects under tacrolimus monotherapy compared with tacrolimus+mycophenolate (HR: 2.07; 1.17 to 3.65).

CONCLUSIONS

The study highlights a shift over time in postliver transplant therapeutic patterns, favouring the use of tacrolimus in combination with mycophenolate or mTORi, rather than monotherapy. Moreover, a potential association between tacrolimus monotherapy and increased mortality in the cirrhosis cohort was identified. Further research is warranted to investigate these findings more deeply and to optimise treatment strategies for liver transplant recipients.

Seroconversion in liver and intestine transplant patients after one, two or three doses of adenoviral vector vaccines against SARS-CoV-2. Single center experience in Argentina

BACKGROUND

The capacity of different anti-SARS-CoV-2 vaccines to elicit immune response is not equivalent in the healthy population compared to chronically immunosuppressed patients. Most of the reports available to assess the effects of anti-SARS-CoV-2 vaccines on solid organ transplant recipients (SOTR) were performed using mRNA-based vaccines.

OBJECTIVE

This study aims to assess the seroconversion rate in a cohort of liver and liver- intestinal transplant patients after vaccination with the non-replicative vector-based vaccines after transplantation used in our country, Argentina (rAd26-rAd5 (Sputnik V) and ChAdOx11 nCoV-19 (AZD1222) (Astra Zeneca-Oxford).

METHODS

One hundred and three (103) liver and liver-intestinal transplant recipients were enrolled. Patients with previous PCR-confirmed COVID19 were excluded, therefore 77 were finally included for analysis; 75 were liver transplant recipients, 1 was a combined liver-intestine and 1 a multivisceral transplant. All received their first vaccine dose between March and June 2021; 66,2% males, and the mean age was 56,3 years. All patients have a post-transplant follow up longer than 1 year (mean 6.6 years, median 5 years, range 1-23 years). Immune response after first, second and third doses were determined using three different spike (S)-S commercial ELISA kits and an in-house made anti nucleocapsid-protein (N) ELISA.

RESULTS

Following the three doses, 57.1 % (44/77) of the patients seroconverted, while 33/77 (42.9 %) did not present anti-SARS-CoV-2 antibodies. The seroconversion rate was different for each dose. We found that 5/27 (18.5 %) of transplant patients seroconverted after a single dose; 18/29 pts (62.0 %) had anti-SARS-Cov-2 antibodies after the second doses; and 18/21 pts (85.7 %) reached the seroconversion after the third doses. The proportion of seroconversion was significantly increased in the second doses regardless the response observed after the first doses (p = 0.012, Fisher's exact test), particularly when two doses of ChAdOx11 vaccine was administrated (p = 0.040, Chi-square). However, the comparisons of seroconversion rate between Sputnik V and ChAdOx11 vaccines showed no differences after the different vaccination doses. No significant statistical difference in patient́s gender, age, comorbidities, type of vaccine, post-transplant, or maintenance immunosuppressive therapy was found between responders and non-responders.

CONCLUSION

Despite having a lower seroconversion rate compared to the general population, viral-vector vaccines benefit SOTR patients increasing the seroconversion rate using at least two doses of vaccine. These results support the concept of developing tailor-made vaccination guidelines for this specific population. This analysis provides further support to safety and efficacy of viral-vector vaccines in liver and liver-intestine transplant patients.

Plasma immune signatures can predict rejection-free survival in the first year after pediatric liver transplantation

BACKGROUND & AIMS

After pediatric liver transplantation (pLT), children undergo life-long immunosuppression since reliable biomarkers for the assessment of rejection probability are scarce. In the multicenter (n = 7) prospective clinical cohort "ChilSFree" study, we aimed to characterize longitudinal dynamics of soluble and cellular immune mediators during the first year after pLT and identify early biomarkers associated with outcome.

METHODS

Using a Luminex-based multiplex technique paired with flow cytometry, we characterized longitudinal dynamics of soluble immune mediators (SIMs, n = 50) and immune cells in the blood of 244 patients at eight visits over 1 year: before, and 7/14/21/28 days and 3/6/12 months after pLT.

RESULTS

The unsupervised clustering of patients based on SIM profiles revealed six unique SIM signatures associated with clinical outcome. From three signatures linked to improved outcome, one was associated with 1-year-long rejection-free survival and stable graft function and was characterized by low levels of pro-inflammatory SIMs (CXCL8/9/10/12, CCL7, SCGF-β, sICAM-1), and high levels of regenerative (SCF, TNF-β) and pro-apoptotic (TRAIL) SIMs (all, p <0.001, fold change >100). Of note, this SIM signature appeared 2 weeks after pLT and remained stable over the entire year, pointing towards its potential as a novel early biomarker for minimizing or weaning immunosuppression. In the blood of these patients, a higher frequency of CD56bright natural killer cells (p <0.01), a known hallmark also associated with operationally tolerant pLT patients, was detected. The concordance of the model for prediction of rejection based on identified SIM signatures was 0.715, and 0.795, in combination with living-related transplantation as a covariate, respectively.

CONCLUSIONS

SIM blood signatures may enable the non-invasive and early assessment of rejection risks in the first year after pLT, paving the way for improved clinical management.

IMPACT AND IMPLICATIONS

ChilSFree represents the largest pediatric liver transplant (pLT) cohort with paired longitudinal data on soluble immune mediators (SIMs) and immune phenotyping in the first year after pLT. SIM signatures allow for the selection of rejection-free patients 2 weeks after pLT independently of patient diagnosis, sex, or age. The SIM signatures may enable the non-invasive and early assessment of rejection risks, paving the way for minimization or withdrawal of immunosuppression after pLT.

Role of sonography in detection and evaluation of post liver transplant complications

OBJECTIVES

To evaluate the role of sonography in revealing and characterizing liver transplant complications based on gray scale and color Doppler, describe the normal Doppler findings, and discuss the significance of distinguishing normal transient changes in the spectral waveform from findings that may suggests ominous complications.

METHODS

We carried out a retrospective cross-sectional study at Prince Sultan Military Medical City, Riyadh, Saudi Arabia. The medical records and imaging studies of a total of 122 candidates who underwent transplantation between January 2016 to February 2022 were reviewed.

RESULTS

Our results showed that most patients were males with the most frequent age group being those between 54-71 years. Hepatitis B virus and hepatic cellular carcinoma were the most common indications for transplants. A total of 95 patients received a graft from a living related donor. Regarding complications, biliary issues (including leaks and ducts dilation) were the second most frequent complication after collections. Vascular complications represented 7.4% of all complications and was the leading cause of death in 4.8% of cases. Among all vascular issues encountered during liver transplant, portal vein thrombosis was the most predominant. In respect to Doppler findings, portal vein velocities and resistive index of hepatic artery had re-averaged within 7-10 post-operative days in most patients.

CONCLUSION

Ultrasound plays crucial role in the post-operative management of compilations, facilitating early detection, which is substantial for the graft survival.

Assessing Frailty, Rational Use of Medications, and Adherence to Immunosuppressive Therapy in Liver Transplant Recipients

AIM

The study was conducted to determine the level of frailty, rational medication use, and adherence to immunosuppressive therapy in liver transplant patients and to examine the relationships among them.

MATERIALS AND METHODS

The data of the descriptive cross-sectional study were collected between January 2023 and September 2023. Our study included 200 liver transplant recipients. In addition to demographic and medical characteristics, frailty status, rational drug use, and compliance with immunosuppressive therapy were measured in a 15-20 minute questionnaire administration period.

RESULTS

The frailty scores of liver transplant patients were 2.11 ± 1.34, rational drug use scores were 82.88 ± 13.11, and compliance with immunosuppressive therapy scores were 11.12 ± 1.07. The scores for rational drug use and adherence to immunosuppressive therapy were not affected by frailty status, and patients used drugs rationally and adhered to immunosuppressive therapy even when they were frail. It was found that the vulnerability status of the participants was affected by gender and occupational variables, most patients were in the vulnerable group in women and men, and those who did not work were more vulnerable than the other groups.

CONCLUSION

It was found that liver transplant patients were frail, and frailty did not affect the level of rational drug use and compliance with immunosuppressive therapy.

Evaluation of THP-1 and Jurkat Cell Lines Coculture for the In Vitro Assessment of the Effects of Immunosuppressive Substances

The strong appeal to reduce animal testing calls for the development and validation of in vitro, in chemico and in silico models that would replace the need for in vivo testing and ex vivo materials. A category that requires such new approach methods is the assessment of immunosuppression that can be induced by chemicals including environmental pollutants. To assess the immunosuppressive action on monocytes and lymphocytes, we mimicked the whole-blood cytokine-release assay by preparing an in vitro coculture of THP-1 and Jurkat cell lines. We optimised its activation and investigated the effects of known immunosuppressive drugs with different mechanisms of action on the release of proinflammatory cytokines. Decreased secretion of IL-8 was achieved by several immunosuppressive mechanisms and was therefore selected as an appropriate marker of immunosuppression. A set of environmentally occurring bisphenols, BPA, BPAP, BPP, BPZ, BPE, TCBPA and BPS-MAE, were then applied to the model and BPP and BPZ were found to act as potent immunosuppressants at micromolar concentrations.

Herbal and Non-Herbal Dietary Supplements for Psychiatric Indications: Considerations in Liver Transplantation

PURPOSE OF REVIEW

Traditional, complementary, and integrative medicine (TCIM) modalities are widely employed. However, TCIM, specifically herbal and non-herbal dietary supplements, can pose challenges in the context of organ transplantation. In this review, we discuss common supplements used for psychiatric purposes and highlight important considerations for candidates and recipients of liver transplants.

RECENT FINDINGS

Ashwagandha, kava kava, green tea extract, skullcap, turmeric, and valerian have known idiosyncratic hepatotoxic potential and may complicate the liver transplantation course. Multiple supplements reportedly carry a lower risk of hepatotoxicity, though evidence for widespread use in those at risk for or with hepatic impairment is limited. Psychiatrists caring for candidates and recipients of liver transplants must recognize that patients may find supplements helpful in alleviating psychiatric symptoms, despite an overall limited evidence base. Evaluating benefit versus risk ratios and reviewing drug-drug interactions is essential to promote transplant candidacy and mitigate the possibility of native or graft liver dysfunction.

Immunosuppressive Induction Therapy Using the Antithymocyteglobulin Grafalon: A Single-Center Non-Interventional Study

Background: Induction therapy with depleting antibodies in the setting of liver transplantation (LT) is discussed controversially to this day. The rabbit antithymocyteglobulin (ATG) Thymoglobulin (rATG) was introduced as early as 1984 and was frequently used as a standard regime for induction therapy after LT. There are no public reports characterizing Grafalon (ATG-F), a novel ATG, as an induction agent after LT. Objectives: The aim of this observational non-interventional study was to investigate the safety and efficacy of Grafalon induction therapy and characterize its clinical effects in the setting of LT. Methods: A cohort of 80 patients undergoing deceased donor LT at the Medical University of Vienna and receiving Grafalon as part of the clinical standard immunosuppressive regimen was prospectively included between March 2021 and November 2022. Patients were monitored closely for leukocytopenia and thrombocytopenia during the first postoperative week and followed up for incidence and severity of biopsy-proven acute rejection (BPAR), overall survival, and bacterial infections in the first year after LT. Results: The incidences of thrombocytopenia and leukocytopenia following Grafalon treatment peaked on postoperative day four, with 64% and 31%, respectively. However, there were no cases of severe leukocytopenia after the first postoperative week. Induction therapy with Grafalon resulted in a rate of localized bacterial infections and bacteremia of 28% and 21%, respectively. The rate of BPAR was 12.5% in the first year after LT; the one-year survival rate in this cohort was 90%. Conclusions: Overall, this study provides evidence of the safety and efficacy of Grafalon as an induction agent. Further studies investigating the potential long-term effects of Grafalon, as well as comparison studies with different immunosuppressive regimens, are needed in order to draw further conclusions.

Basics and Art of Immunosuppression in Liver Transplantation

Liver transplantation is one of the most challenging areas in the medical field. Despite that, it has already been established as a standard treatment option, especially in decompensated cirrhosis and selected cases of hepatocellular carcinoma and acute liver failure. Complications due to graft rejection, including mortality and morbidity, have greatly improved over time due to better immunosuppressive agents and management protocols. Currently, immunosuppression in liver transplant patients makes use of the best possible combinations of effective agents to achieve optimal immunosuppression for long-term graft survival. Induction agents are no longer used routinely, and the aim is to provide minimal immunosuppression in the maintenance phase. Currently available immunosuppressive agents are mainly classified as biological and pharmacological agents. Though the protocols may vary among the centers and over time, the basics of effective use usually remain similar. Most protocols use the combination of multiple agents with different mechanisms of action to reduce the dose and minimize the side effects. Along with the improvement in operative and perioperative techniques, this art of immunosuppression has contributed to the recent progress made in the outcomes of liver transplants. In this review, we will discuss the various types of immunosuppressive agents currently in use, the different protocols of immunosuppression used, and the art of optimal use for achieving maximum immunosuppression without increasing toxicity. We will also discuss the practical aspects of various immunosuppression regimens, including drug monitoring, and briefly discuss the concepts of immunosuppression minimization and withdrawal.

Infections After Liver Transplant -Timeline, Management and Prevention

Liver transplantation (LT) is the standard treatment for end- stage liver disease. Patient and graft survival have improved significantly in the last three decades owing to improvement in surgical technique, better perioperative management and better immunosuppressive regimens. However, LT recipients are at increased risk of infections, particularly in the first year after transplantation. The risk of infection is directly proportional to immunosuppressive regimen and graft function. In this review, we will briefly discuss the timeline of infections after liver transplant, preventive strategies and management of infectious complications.

Relative carcinogenicity of tacrolimus vs mycophenolate after solid organ transplantation and its implications for liver transplant care

BACKGROUND

De novo malignancy is a leading cause of late morbidity and mortality in liver transplant recipients. Cumulative immunosuppression has been shown to contribute to post-transplant malignancy (PTM) risk. There is emerging evidence on the differential carcinogenic risk profile of individual immunosuppressive drugs, independent of the net effect of immunosuppression. Calcineurin inhibitors such as tacrolimus may promote tumourigenesis, whereas mycophenolic acid (MPA), the active metabolite of mycophenolate mofetil, may limit tumour progression. Liver transplantation (LT) is relatively unique among solid organ transplantation in that immunosuppression monotherapy with either tacrolimus or MPA is often achievable, which makes careful consideration of the risk-benefit profile of these immunosuppression agents particularly relevant for this cohort. However, there is limited clinical data on this subject in both LT and other solid organ transplant recipients.

AIM

To investigate the relative carcinogenicity of tacrolimus and MPA in solid organ transplantation.

METHODS

A literature search was conducted using MEDLINE and Embase databases using the key terms "solid organ transplantation", "tacrolimus", "mycophenolic acid", and "carcinogenicity", in order to identify relevant articles published in English between 1st January 2002 to 11th August 2022. Related terms, synonyms and explosion of MeSH terms, Boolean operators and truncations were also utilised in the search. Reference lists of retrieved articles were also reviewed to identify any additional articles. Excluding duplicates, abstracts from 1230 records were screened by a single reviewer, whereby 31 records were reviewed in detail. Full-text articles were assessed for eligibility based on pre-specified inclusion and exclusion criteria.

RESULTS

A total of 6 studies were included in this review. All studies were large population registries or cohort studies, which varied in transplant era, type of organ transplanted and immunosuppression protocol used. Overall, there was no clear difference demonstrated between tacrolimus and MPA in de novo PTM risk following solid organ transplantation. Furthermore, no study provided a direct comparison of carcinogenic risk between tacrolimus and MPA monotherapy in solid organ transplantation recipients.

CONCLUSION

The contrasting carcinogenic risk profiles of tacrolimus and MPA demonstrated in previous experimental studies, and its application in solid organ transplantation, is yet to be confirmed in clinical studies. Thus, the optimal choice of immunosuppression drug to use as maintenance monotherapy in LT recipients is not supported by a strong evidence base and remains unclear.

Successful use of tacrolimus for treatment-refractory neuroblastoma-associated opsoclonus-myoclonus-ataxia syndrome: A case series

Opsoclonus-myoclonus-ataxia syndrome (OMAS) is an autoimmune central nervous system disorder, primarily manifesting as a paraneoplastic sequalae to neuroblastoma, and characterized by motor disorders and behavioral disturbances. OMAS is typified by aberrant B-cell and T-cell activation. Current treatment involves immunosuppression using corticosteroids, intravenous immunoglobulin, and rituximab. However, these approaches often lead to treatment-related toxicities and symptomatic recurrences with chronic neurocognitive impairment. We treated three children with refractory neuroblastoma-associated OMAS with tacrolimus, a T-cell-targeting calcineurin inhibitor, effectively controlling symptoms within a month and enabling the discontinuation of immunosuppression with minimal side effects. Tacrolimus shows promise as a therapeutic option for refractory OMAS.

Exploring Costimulatory Blockade-Based Immunologic Strategies in Transplantation: Are They a Promising Immunomodulatory Approach for Organ and Vascularized Composite Allotransplantation?

The field of transplantation, including the specialized area of vascularized composite allotransplantation (VCA), has been transformed since the first hand transplant in 1998. The major challenge in VCA comes from the need for life-long immunosuppressive therapy due to its non-vital nature and a high rate of systemic complications. Ongoing research is focused on immunosuppressive therapeutic strategies to avoid toxicity and promote donor-specific tolerance. This includes studying the balance between tolerance and effector mechanisms in immune modulation, particularly the role of costimulatory signals in T lymphocyte activation. Costimulatory signals during T cell activation can have either stimulatory or inhibitory effects. Interfering with T cell activation through costimulation blockade strategies shows potential in avoiding rejection and prolonging the survival of transplanted organs. This review paper aims to summarize current data on the immunologic role of costimulatory blockade in the field of transplantation. It focuses on strategies that can be applied in vascularized composite allotransplantation, offering insights into novel methods for enhancing the success and safety of these procedures.

Post Liver Transplant Renal Dysfunction-Evaluation, Management and Immunosuppressive Practice

Liver transplantation (LT) is an effective and lifesaving treatment for patients with end-stage liver disease and hepatocellular carcinoma. Significant improvement in intermediate and long-term survival has been possible due to advancements in immunosuppressive therapy, perioperative care, and surgical techniques. Despite these advances, metabolic complications, including diabetes mellitus, cardiovascular diseases, malignancies, and renal dysfunction, are challenging issues after LT. Acute kidney injury (AKI) and chronic kidney disease (CKD) after LT are common and result in significant morbidity and mortality. Early diagnosis of kidney injury after LT is challenging, and no technique has yet proven effective in prediction of renal dysfunction. The methods for assessing renal function range from formulas that predict glomerular filtration rate to non-invasive biomarkers. The universal adoption of the model for end-stage liver disease has a direct impact on the incidence of peri-transplant AKI and development of CKD in the long-term. Post-LT renal dysfunction is multifactorial and is usually a result of pre-transplantation comorbidities, occurrence of renal dysfunction on the waiting list, perioperative events, and post-transplant nephrotoxic immunosuppressive medication use. Early identification of patients at risk for renal dysfunction and adoption of preventive measures are crucial in the pre-transplant period. No data are currently available to suggest a surgical technique that reliably demonstrates renal protection. Nephroprotective strategies during LT follow accepted surgical practice guidelines, such as maintenance of intravascular volume and mean arterial pressure. The management of kidney disease following LT is challenging, as by the time the serum creatinine is significantly elevated, few interventions impact the course of progression. Early nephroprotective measures are strongly advised and they mostly center on delaying the administration of calcineurin inhibitors (CNIs) during the initial postoperative period, lowering CNI dosage and combining CNI with mycophenolate mofetil and everolimus. The reasons for renal failure following LT, the techniques used to diagnose it, and the therapies designed to preserve renal function both immediately and late after LT are all critically evaluated in this review.

Adequate cumulative exposure to tacrolimus and low tacrolimus variability decrease the incidence of biliary complications after liver transplantation

BACKGROUND

Nonearly biliary complications (BCs) after liver transplantation (LT) are highly associated with immunological status. Tacrolimus is the main immunosuppressant. Whether and how tacrolimus bioavailability affects BCs is unclear.

METHODS

LT recipients receiving tacrolimus-free immunosuppressants or developing BCs within 3 months after LT were excluded. Tacrolimus-related variables included trough concentration (C0), variability and cumulative exposure to tacrolimus (CET). Receiver operating characteristic (ROC) curves defined cutoff values of CET and variability. The values divided patients into adequate and low CET groups, also high and low-variability groups. Inverse probability of treatment weighting (IPTW) was used to reduce bias. Logistic regression identified risk factors. Kaplan-Meier curves were generated for survival comparison.

RESULTS

409 patients were enrolled, and 39 (9.5 %) suffered from BCs. The mean C0 values were 6.9 and 7.2 ng/mL in the BCs and BCs-free groups, respectively. CET within 3 postoperative months was 550.0 and 608.6 ng.day/mL, while the tacrolimus variability was 0.4 and 0.3, respectively. The cutoff values for CET within 3 months and variability predicting BCs were 660.5 and 0.54, respectively. Multivariable logistic regression revealed that low CET within 3 months (p = 0.005, p = 0.002) and high variability (p < 0.001, p < 0.001) were associated with BCs before and after IPTW. Appropriate CET and low variability were associated with better overall survival (p = 0.009 and 0.029). Subgroup analysis indicated that long cold ischemia time (CIT), high bilirubin and low CET had a higher relative risk and raised the incidence of BCs.

CONCLUSIONS

Adequate CET and low variability of tacrolimus ameliorated nonearly BCs incidence and improved survival.

Live-attenuated vaccination for measles, mumps, and rubella in pediatric liver transplantation

BACKGROUND

Infections are a serious short- and long-term problem after pediatric organ transplantation. In immunocompromised patients, they can lead to transplant rejection or a severe course with a sometimes fatal outcome. Vaccination is an appropriate means of reducing morbidity and mortality caused by vaccine-preventable diseases. Unfortunately, due to the disease or its course, it is not always possible to establish adequate vaccine protection against live-attenuated viral vaccines (LAVVs) prior to transplantation. LAVVs such as measles, mumps, and rubella (MMR) are still contraindicated in solid organ transplant recipients receiving immunosuppressive therapy (IST), thus creating a dilemma.

AIM

This review discusses whether, when, and how live-attenuated MMR vaccines can be administered effectively and safely to pediatric liver transplant recipients based on the available data.

MATERIAL AND METHODS

We searched PubMed for literature on live-attenuated MMR vaccination in pediatric liver transplantation (LT).

RESULTS

Nine prospective observational studies and three retrospective case series were identified in which at least 833 doses of measles vaccine were administered to 716 liver transplant children receiving IST. In these selected patients, MMR vaccination was well tolerated and no serious adverse reactions to the vaccine were observed. In addition, an immune response to the vaccine was demonstrated in patients receiving IST.

CONCLUSION

Due to inadequate vaccine protection in this high-risk group, maximum efforts must be made to ensure full immunization. MMR vaccination could also be considered for unprotected patients after LT receiving IST following an individual risk assessment, as severe harm from live vaccines after liver transplantation has been reported only very rarely. To this end, it is important to establish standardized and simple criteria for the selection of suitable patients and the administration of the MMR vaccine to ensure safe use.

Insights into the history and tendency of liver transplantation for liver cancer: a bibliometric-based visual analysis

Research on liver transplantation (LT) for liver cancer has gained increasing attention. This paper has comprehensively described the current status, hotspots and trends in this field. A total of 2991 relevant articles from 1 January 1963 to 28 February 2023 were obtained from the Web of Science Core Collection. VOSviewer and CiteSpace software were utilized as bibliometric tools to analyze and visualize knowledge mapping. Between 1963 and 2023, the number of papers in the area of LT for liver cancer increased continuously. A total of 70 countries/regions, 2303 institutions and 14 840 researchers have published research articles, with the United States and China being the two most productive countries. Our bibliometric-based visual analysis revealed the expansion of LT indications for liver cancer and the prevention/treatment of cancer recurrence as ongoing research hotspots over the past decades. Meanwhile, emerging studies also focus on downstaging/bridging treatments before LT and the long-term survival of LT recipient, in particular the precise application of immunosuppressants.

Immunologic barriers in liver transplantation: a single-cell analysis of the role of mesenchymal stem cells

Background

This study aimed to analyze the biomarkers that may reliably indicate rejection or tolerance and the mechanism that underlie the induction and maintenance of liver transplantation (LT) tolerance related to immunosuppressant or mesenchymal stem cells (MSCs).

Methods

LT models of Lewis-Lewis and F344-Lewis rats were established. Lewis-Lewis rats model served as a control (Syn). F344-Lewis rats were treated with immunosuppressant alone (Allo+IS) or in combination with MSCs (Allo+IS+MSCs). Intrahepatic cell composition particularly immune cells was compared between the groups by single-cell sequencing. Analysis of subclusters, KEGG pathway analysis, and pseudotime trajectory analysis were performed to explore the potential immunoregulatory mechanisms of immunosuppressant alone or combined with MSCs.

Results

Immunosuppressants alone or combined with MSCs increases the liver tolerance, to a certain extent. Single-cell sequencing identified intrahepatic cell composition signature, including cell subpopulations of B cells, cholangiocytes, endothelial cells, erythrocytes, hepatic stellate cells, hepatocytes, mononuclear phagocytes, neutrophils, T cells, and plasmacytoid dendritic cells. Immunosuppressant particularly its combination with MSCs altered the landscape of intrahepatic cells in transplanted livers, as well as gene expression patterns in immune cells. MSCs may be included in the differentiation of T cells, classical monocytes, and non-classical monocytes.

Conclusion

These findings provided novel insights for better understanding the heterogeneity and biological functions of intrahepatic immune cells after LT treated by IS alone or in combination with MSCs. The identified markers of immune cells may serve as the immunotherapeutic targets for MSC treatment of liver transplant rejection.

Liver transplantation in Latin America: reality and challenges

Healthcare systems in Latin America are broadly heterogeneous, but all of them are burdened by a dramatic rise in liver disease. Some challenges that these countries face include an increase in patients requiring a transplant, insufficient rates of organ donation, delayed referral, and inequitable or suboptimal access to liver transplant programs and post-transplant care. This could be improved by expanding the donor pool through the implementation of education programs for citizens and referring physicians, as well as the inclusion of extended criteria donors, living donors and split liver transplantation. Addressing these shortcomings will require national shifts aimed at improving infrastructure, increasing awareness of organ donation, training medical personnel, and providing equitable access to care for all patients.

The Expression of Activation Markers CD25 and CD69 Increases during Biologic Treatment of Psoriasis

CD (cluster of differentiation) 69 and CD25 are considered early and late markers of the activation of lymphocytes, respectively. CD25 is a part of the IL-2 receptor and is present on the surface of immune and non-immune cells, with high amounts on activated lymphocytes and regulatory T cells. CD69 is expressed on various types of white blood cells, including newly activated lymphocytes, lymphocytes infiltrating tissues isolated from subjects with chronic auto-inflammatory diseases, several subtypes of memory T cells and regulatory T cells. Primarily, CD69 was considered to be an early marker of the activation of lymphocytes, but, right now, data derived from in vitro and in vivo studies have revealed the immunomodulatory role of this surface antigen. In 84 patients with psoriasis, of whom 28 were treated with different biologic drugs, as well as in 29 healthy control subjects, the expression of CD25 and CD69 on different subtypes of peripheral blood mononuclear cells (PBMCs) was studied with the use of flow cytometry. Significantly higher levels of CD3/CD69-, CD8/CD69- and CD19/CD69-positive PBMCs as well as within CD3+ cells were present in subjects suffering from psoriasis when compared to healthy controls. In patients with psoriasis who were treated with biologic drugs, the levels of CD3/CD69-, CD4/CD69- and CD19/CD69-positive PBMCs, and CD3/CD69 within CD3+ cells, CD4/CD69 within CD4+ cells, CD4/CD25 within CD4+ cells and CD19/CD69 within CD19+ cells were significantly higher than before therapy. Our results support a role for activation markers, especially CD69, in psoriasis. Further research is warranted to fully clarify their significance in this common dermatosis, especially during biologic treatment.

Long-term normalization of calcineurin activity in model mice rescues Pin1 and attenuates Alzheimer's phenotypes without blocking peripheral T cell IL-2 response

BACKGROUND

Current treatments for Alzheimer's disease (AD) have largely failed to yield significant therapeutic benefits. Novel approaches are desperately needed to help address this immense public health issue. Data suggests that early intervention at the first stages of mild cognitive impairment may have a greater chance for success. The calcineurin (CN)-Pin1 signaling cascade can be selectively targeted with tacrolimus (FK506), a highly specific, FDA-approved CN inhibitor used safely for > 20 years in solid organ transplant recipients. AD prevalence was significantly reduced in solid organ recipients treated with FK506.

METHODS

Time release pellets were used to deliver constant FK506 dosage to APP/PS1 mice without deleterious manipulation or handling. Immunofluorescence, histology, molecular biology, and behavior were used to evaluate changes in AD pathology.

RESULTS

FK506 can be safely and consistently delivered into juvenile APP/PS1 mice via time-release pellets to levels roughly seen in transplant patients, leading to the normalization of CN activity and reduction or elimination of AD pathologies including synapse loss, neuroinflammation, and cognitive impairment. Pin1 activity and function were rescued despite the continuing presence of high levels of transgenic Aβ42. Indicators of neuroinflammation including Iba1 positivity and IL-6 production were also reduced to normal levels. Peripheral blood mononuclear cells (PBMC) obtained during treatment or splenocytes isolated at euthanasia activated normally after mitogens.

CONCLUSIONS

Low-dose, constant FK506 can normalize CNS CN and Pin1 activity, suppress neuroinflammation, and attenuate AD-associated pathology without blocking peripheral IL-2 responses making repurposed FK506 a viable option for early, therapeutic intervention in AD.

Immunomodulatory Role of Mesenchymal Stem Cells in Liver Transplantation: Status and Prospects

BACKGROUND

Liver transplantation (LT) is the only effective therapy for end-stage liver diseases, but some patients usually present with serious infection and immune rejection. Those with immune rejection require long-term administration of immunosuppressants, leading to serious adverse effects. Mesenchymal stem cells (MSCs) have various advantages in immune regulation and are promising drugs most likely to replace immunosuppressants.

SUMMARY

This study summarized the application of MSCs monotherapy, its combination with immunosuppressants, MSCs genetic modification, and MSCs derivative therapy (cell-free therapy) in LT. This may deepen the understanding of immunomodulatory role of MSCs and promote the application of MSCs in immune rejection treatment after LT.

KEY MESSAGES

MSCs could attenuate ischemia-reperfusion injury and immune rejection. There is no consensus on the effects of types and concentrations of immunosuppressants on MSCs. Although genetically modified MSCs have contributed to better outcomes to some extent, the best modification is still unclear. Besides, multiple clinical complications developed frequently after LT. Unfortunately, there are still few studies on the polygenic modification of MSCs for the simultaneous treatment of these complications. Therefore, more studies should be performed to investigate the potency of multi-gene modified MSCs in treating complications after LT. Additionally, MSC derivatives mainly include exosomes, extracellular vesicles, and conditioned medium. Despite therapeutic effects, these three therapies still have some limitations such as heterogeneity between generations and that they cannot be quantified accurately.

The Long Scientific Journey of Sirolimus (Rapamycin): From the Soil of Easter Island (Rapa Nui) to Applied Research and Clinical Trials on β-Thalassemia and Other Hemoglobinopathies

In this review article, we present the fascinating story of rapamycin (sirolimus), a drug able to induce γ-globin gene expression and increased production of fetal hemoglobin (HbF) in erythroid cells, including primary erythroid precursor cells (ErPCs) isolated from β-thalassemia patients. For this reason, rapamycin is considered of great interest for the treatment of β-thalassemia. In fact, high levels of HbF are known to be highly beneficial for β-thalassemia patients. The story of rapamycin discovery began in 1964, with METEI, the Medical Expedition to Easter Island (Rapa Nui). During this expedition, samples of the soil from different parts of the island were collected and, from this material, an antibiotic-producing microorganism (Streptomyces hygroscopicus) was identified. Rapamycin was extracted from the mycelium with organic solvents, isolated, and demonstrated to be very active as an anti-bacterial and anti-fungal agent. Later, rapamycin was demonstrated to inhibit the in vitro cell growth of tumor cell lines. More importantly, rapamycin was found to be an immunosuppressive agent applicable to prevent kidney rejection after transplantation. More recently, rapamycin was found to be a potent inducer of HbF both in vitro using ErPCs isolated from β-thalassemia patients, in vivo using experimental mice, and in patients treated with this compound. These studies were the basis for proposing clinical trials on β-thalassemia patients.

T-cell specific antibody induction versus corticosteroid induction immunosuppression for liver transplant recipients: a meta-analysis

Corticosteroids remain the mainstay of immunosuppression for liver transplant recipients despite several serious complications including infection, hepatitis C virus (HCV) recurrence, diabetes mellitus (DM), and hypertension. We attempted to compare the safety and efficacy of T-cell specific antibody induction with complete corticosteroid avoidance. We searched MEDLINE, EMBASE, and Cochrane central library. Randomized controlled trials comparing T-cell specific antibody induction with corticosteroid induction immunosuppression were included. Our primary outcome was the incidence of biopsy-proven acute rejection. Eleven trials involving 1683 patients were included. The incidence of acute rejection was not significantly different between the antibody and steroid induction groups (risk ratio [RR] 0.85, 95% confidence interval [CI] 0.72, 1.01, P = 0.06, I2 = 0%). However, T-cell specific antibody induction significantly reduced the risk of cytomegalovirus infection (RR 0.48, 95% CI 0.33, 0.70, P = 0.0002, I2 = 3%), HCV recurrence (RR 0.89, 95% CI 0.80, 0.99, P = 0.03, I2 = 0%), DM (RR 0.41, 95% CI 0.32, 0.54, P < 0.0001, I2 = 0%) and hypertension (RR 0.71, 95% CI 0.55, 0.90, P = 0.005, I2 = 35%). Trial sequential analysis for acute rejection showed that the cumulative z-curve did not cross the Trial sequential boundary and the required information size was not reached. T-cell specific antibody induction compared to corticosteroid induction seems to significantly reduce opportunistic infections including cytomegalovirus infection and HCV recurrence and metabolic complications including DM and hypertension. However, given the insufficient study power, low quality of evidence, and heterogeneous immunosuppressive regimens, our results should be cautiously appreciated.

Infections after organ transplantation and immune response

Organ transplantation has provided another chance of survival for end-stage organ failure patients. Yet, transplant rejection is still a main challenging factor. Immunosuppressive drugs have been used to avoid rejection and suppress the immune response against allografts. Thus, immunosuppressants increase the risk of infection in immunocompromised organ transplant recipients. The infection risk reflects the relationship between the nature and severity of immunosuppression and infectious diseases. Furthermore, immunosuppressants show an immunological impact on the genetics of innate and adaptive immune responses. This effect usually reactivates the post-transplant infection in the donor and recipient tissues since T-cell activation has a substantial role in allograft rejection. Meanwhile, different infections have been found to activate the T-cells into CD₄⁺ helper T-cell subset and CD₈⁺ cytotoxic T-lymphocyte that affect the infection and the allograft. Therefore, the best management and preventive strategies of immunosuppression, antimicrobial prophylaxis, and intensive medical care are required for successful organ transplantation. This review addresses the activation of immune responses against different infections in immunocompromised individuals after organ transplantation.

CuBTC metal organic framework-based dispersive solid phase extraction of cyclosporine and tacrolimus from plasma samples prior to determination by high performance liquid chromatography-tandem mass spectrometry

Immunosuppressive drugs are prescribed to reduce the immune system of persons who are undergoing organ transplants. The concentration of these drugs in blood and plasma samples must be accurately and precisely determined during immunosuppressive therapy due to their significant side effects. In this study, a metal organic framework-based dispersive solid phase extraction method was developed for the extraction of tacrolimus and cyclosporine from plasma samples before their determination by high performance liquid chromatography-tandem mass spectrometry. For this purpose, CuBTC metal organic framework nanoparticles were prepared by a hydrothermal approach and they were used as the sorbent in the extraction procedure. The adsorbed analytes were eluted by a suitable organic solvent and then more concentrated by evaporation of the eluate. All of the effective parameters of the method including sorbent amount, adsorption time, eluent type, desorption time, eluent volume, and sample solution pH were studied and optimized. They were obtained 5 mg, 5 min, acetone, 5 min, 300 μL, and 5, respectively. Under optimal conditions, the developed method was validated and the data showed that the linear range, the limit of detection, the limit of quantification, the coefficient of determination, the enrichment factor, and relative standard deviation values were 1-1000 ng mL^-1, 0.30 ng mL^-1, 0.5 ng mL^-1, 0.99, 15.6, and 5.8 % for tacrolimus and 0.8-500 ng mL^-1, 0.25 ng mL^-1, 0.4 ng mL^-1, 0.99, 17, and 5.6 % for cyclosporine, respectively. Finally, the method was successfully used in the determination of the studied drugs in plasma samples.