Immunosuppressed Recipients Research Articles

Rescue Everolimus Post Lung Transplantation is Not Associated With an Increased Incidence of CLAD or CLAD-Related Mortality.

Everolimus (EVE) has been used as a calcineurin inhibitor (CNI) minimization/ elimination agent or to augment immunosuppression in lung transplant recipients (LTR) with CNI-induced nephrotoxicity or neurotoxicity. The long-term evidence for survival and progression to chronic lung allograft dysfunction (CLAD) is lacking. The primary aim was to compare survival outcomes of LTR starting EVE-based immunosuppression with those remaining on CNI-based regimens. The secondary outcomes being time to CLAD, incidence of CLAD and the emergence of obstructive (BOS) or restrictive (RAS) phenotypes. Single center retrospective study of 91 LTR starting EVE-based immunosuppression matched 1:1 with LTR remaining on CNI-based immunosuppression. On multivariate analysis, compared to those remaining on CNI-based immunosuppression, starting EVE was not associated with poorer survival [HR 1.04, 95% CI: 0.67-1.61, p = 0.853], or a statistically significant faster time to CLAD [HR 1.34, 95% CI: 0.87-2.04, p = 0.182]. There was no difference in the emergence of CLAD (EVE, [n = 57, 62.6%] vs. CNI-based [n = 52, 57.1%], p = 0.41), or the incidence of BOS (p = 0.60) or RAS (p = 0.16) between the two groups. Introduction of EVE-based immunosuppression does not increase the risk of death or accelerate the progression to CLAD compared to CNI-based immunosuppression.

Relationship of Post-Transplant Lymphoproliferative Disorders (PTLD) Subtypes and Clinical Outcome in Pediatric Heart Transplant Recipients: A Retrospective Single Institutional Analysis/Experience of 558 Patients.

Post-transplant lymphoproliferative disorders (PTLD) are heterogenous lymphoproliferative disorders that develop as a consequence of immunosuppression in transplant recipients. We sought to determine if subtypes of PTLD correlated with different outcomes. We performed a retrospective review of PTLD occurring in pediatric heart transplant recipients. A total of 558 children and infants underwent cardiac transplantation at our institution between 1985 and 2019 and were followed until March 2021. Forty-nine of 558 patients developed PTLD (8.8%). As compared to older children (>one year of age), infant recipients (<three months of age) were less likely to develop PTLD. Monomorphic PTLDs (M-PTLD, 61%) was the most common subtype at initial diagnosis, followed by non-destructive (21%), polymorphic (14%), and classic Hodgkin lymphoma (cHL, 4%). Patients who underwent transplantation at a young age (<three months) had significantly lower rates of M-PTLD or cHL and a longer time from transplant to PTLD diagnosis as compared to children older than one year at transplant (p = 0.04). Although not reaching statistical significance, patients with a shorter time to PTLD diagnosis showed a trend toward higher rates of M-PTLD or cHL. As expected, the overall survival (OS) of patients with M-PTLD or cHL was significantly lower than patients with non-destructive or polymorphic PTLD.

Association Between Perioperative Costs and Induction Immunosuppression in Pediatric Liver Transplant Recipients.

The objectives of this study was to describe variation in induction regimen, identify predictors of induction immunosuppression (IS) choice, and examine the impact of induction IS regimen on length of stay (LOS) and total perioperative costs in pediatric liver transplant recipients. We analyzed liver transplant utilization data in the Pediatric Health Information System database. Patients were divided into 3 induction IS groups: (1) steroids only, (2) T-cell depleting antibody (TDA), and (3) non-TDA. We identified predictors of induction IS regimen and examined associations between each outcome and choice of induction IS. We analyzed 4905 liver transplant recipients (50% female, 80% under age 13 years, 42% non-Hispanic White). Most patients (3162, 64%) received steroids only induction, and about twice as many patients received a non-TDA regimen (1093, 22%) versus a TDA regimen (650, 13%). Median total perioperative costs were highest for the TDA group [$146,438 (interquartile range $113,461-$195,575)] versus the non-TDA group [$129,307 ($102,632-$173,953)] and the steroids only group ($127,049 ($98,814-$181,053)]. Compared to steroids only induction, TDA was associated with increased LOS (+2 days, P = 0.017) with no difference in cost. Non-TDA induction was associated with a decreased LOS (-3 days, P < 0.001) and increased cost (+$42,542; P < 0.001) independent of LOS. Compared to a steroids only induction IS regimen, non-TDA induction was associated with increased total perioperative costs, even after adjustments for LOS. Future work will combine cost and outcome data to provide decision-making support in pediatric liver transplant recipients.

SARS-CoV-2 infection in adult liver transplantation recipients: a systematic review of risk factors for mortality and immunosuppression role.

Data on mortality, immunosuppression, and vaccination role regarding liver transplant (LT) recipients affected by COVID-19 are still under debate. This study aims to identify risk factors for mortality and the role of immunosuppression in COVID-19 LT recipients. A systematic review of SARS-CoV-2 infection in LT recipients was performed. The primary outcomes were risk factors for mortality, the role of immunosuppression and vaccination. A meta-analysis was not performed as there was a different metric of the same outcome (mortality) and a lack of a control group in most studies. Overall, 1,343 LT recipients of 1,810 SOT were included, and data on mortality were available for 1,110 liver transplant recipients with SARS-CoV-2 infection. Mortality ranged between 0-37%. Risk factors of mortality were age >60 years, Mofetil (MMF) use, extra-hepatic solid tumour, Charlson Comorbidity Index, male sex, dyspnoea at diagnosis, higher baseline serum creatinine, congestive heart failure, chronic lung disease, chronic kidney disease, diabetes, BMI >30. Only 51% of 233 LT patients presented a positive response after vaccination, and older age (>65y) and MMF use were associated with lower antibodies. Tacrolimus (TAC) was identified as a protective factor for mortality. Liver transplant patients present additional risk factors of mortality related to immunosuppression. Immunosuppression role in the progression to severe infection and mortality may correlate with different drugs. Moreover, fully vaccinated patients have a lower risk of developing severe COVID-19. The present research suggests safely using TAC and reducing MMF use during the COVID-19 pandemic.

Delta-Omicron recombinant escapes therapeutic antibody neutralization

The emergence of recombinant viruses is a threat to public health, as recombination may integrate variant-specific features that together result in escape from treatment or immunity. The selective advantages of recombinant SARS-CoV-2 isolates over their parental lineages remain unknown. We identified a Delta-Omicron (AY.45-BA.1) recombinant in an immunosuppressed transplant recipient treated with monoclonal antibody Sotrovimab. The single recombination breakpoint is located in the spike N-terminal domain adjacent to the Sotrovimab binding site. While Delta and BA.1 are sensitive to Sotrovimab neutralization, the Delta-Omicron recombinant is highly resistant. To our knowledge, this is the first described instance of recombination between circulating SARS-CoV-2 variants as a functional mechanism of resistance to treatment and immune escape.

Clinical adoptive regulatory T Cell therapy: State of the art, challenges, and prospective.

Rejection of solid organ transplant and graft versus host disease (GvHD) continue to be challenging in post transplantation management. The introduction of calcineurin inhibitors dramatically improved recipients' short-term prognosis. However, long-term clinical outlook remains poor, moreover, the lifelong dependency on these toxic drugs leads to chronic deterioration of graft function, in particular the renal function, infections and de-novo malignancies. These observations led investigators to identify alternative therapeutic options to promote long-term graft survival, which could be used concomitantly, but preferably, replace pharmacologic immunosuppression as standard of care. Adoptive T cell (ATC) therapy has evolved as one of the most promising approaches in regenerative medicine in the recent years. A range of cell types with disparate immunoregulatory and regenerative properties are actively being investigated as potential therapeutic agents for specific transplant rejection, autoimmunity or injury-related indications. A significant body of data from preclinical models pointed to efficacy of cellular therapies. Significantly, early clinical trial observations have confirmed safety and tolerability, and yielded promising data in support of efficacy of the cellular therapeutics. The first class of these therapeutic agents commonly referred to as advanced therapy medicinal products have been approved and are now available for clinical use. Specifically, clinical trials have supported the utility of CD4+CD25+FOXP3+ regulatory T cells (Tregs) to minimize unwanted or overshooting immune responses and reduce the level of pharmacological immunosuppression in transplant recipients. Tregs are recognized as the principal orchestrators of maintaining peripheral tolerance, thereby blocking excessive immune responses and prevent autoimmunity. Here, we summarize rationale for the adoptive Treg therapy, challenges in manufacturing and clinical experiences with this novel living drug and outline future perspectives of its use in transplantation.

Vaccine Effectiveness Against the SARS-CoV-2 B.1.1.529 Omicron Variant in Solid Organ and Islet Transplant Recipients in England: A National Retrospective Cohort Study.

The effectiveness of vaccines against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) B.1.1.529 Omicron variant in immunosuppressed solid organ and islet transplant (SOT) recipients is unclear. National registries in England were linked to identify SARS-CoV-2 positive tests, noninjury hospitalization within 14 d, and deaths within 28 d between December 7, 2020, and March 31, 2022 in adult SOT recipients. Incidence rate ratios (IRRs) for infection, and hospitalization or death, were adjusted for recipient demographics and calendar month for the Omicron-dominant period (December 20, 2021, to March 31, 2022). Mortality risk following SARS-CoV-2 infection was adjusted for recipient demographics and dominant variant using a Cox proportional-hazards model for the entire time period. During the Omicron-dominant period, infection IRRs (95% confidence intervals) were higher in those receiving 2, 3, and 4 vaccine doses than in unvaccinated patients (1.25 [1.08-1.45], 1.46 [1.28-1.67], and 1.79 [1.54-2.06], respectively). However, hospitalization or death IRRs during this period were lower in those receiving 3 or 4 vaccine doses than in unvaccinated patients (0.62 [0.45-0.86] and 0.39 [0.26-0.58], respectively). Risk-adjusted analyses for deaths after SARS-CoV-2 infection between December 7, 2020, and March 31, 2022, found hazard ratios (95% confidence intervals) of 0.67 (0.46-0.98), 0.46 (0.30-0.69), and 0.18 (0.09-0.35) for those with 2, 3, and 4 vaccine doses, respectively, when compared with the unvaccinated group. In immunosuppressed SOT recipients, vaccination is associated with incremental, dose-dependent protection against hospitalization or death after SARS-CoV-2 infection, including against the Omicron variant.

Impact of immunosuppression regimen on COVID-19 mortality in kidney transplant recipients: Analysis from a Colombian transplantation centers registry

BackgroundThe impact of immunosuppression in solid organ transplant recipients with SARS-CoV-2 infection is unknown. The knowledge about the behavior of different immunosuppression schemes in clinical outcomes is scarce. This study aimed to determine the risk of death in kidney transplant recipients with COVID-19 under two different schemes of immunosuppression. MethodsWe describe our experience in kidney transplant recipients with SARS-CoV-2 infection in seven transplant centers during the first year of the pandemic before starting the vaccination programs in the city of Bogotá. Demographic characteristics, clinical presentation, immunosuppression schemes at presentation, and global treatment strategies were compared between recovered and dead patients; survival analysis was carried out between calcineurin inhibitors based regimen and free calcineurin inhibitors regimen. ResultsAmong 165 confirmed cases, 28 died (17%); the risk factors for mortality identified in univariate analysis were age older than 60 years (p=.003) diabetes (p=.001), immunosuppression based on calcineurin inhibitors (CNI) (p=.025) and patients receiving steroids (p=.041). In multivariable analysis, hypoxemia (p=.000) and calcineurin inhibitors regimen (p=.002) were predictors of death. Survival analysis showed increased mortality risk in patients receiving CNI based immunosuppression regimen vs. CNI free regimens mortality rates were, respectively, 21.7% and 8.5% (p=.036). ConclusionsOur results suggest that the calcineurin inhibitors probably do not provide greater protection compared to calcineurin inhibitor free schemes being necessary to carry out analyzes that allow us to evaluate the outcomes with different immunosuppression schemes in solid organ transplant recipients with SARS-CoV-2 infection.

Hematopoietic stem cell donor vaccination with cytomegalovirus triplex augments frequencies of functional and durable cytomegalovirus-specific T cells in the recipient: A novel strategy to limit antiviral prophylaxis.

To enhance protective cytomegalovirus (CMV)-specific T cells in immunosuppressed recipients of an allogeneic hematopoietic cell transplant (HCT), we evaluated post-HCT impact of vaccinating healthy HCT donors with Triplex. Triplex is a viral vectored recombinant vaccine expressing three immunodominant CMV antigens. The vector is modified vaccinia Ankara (MVA), an attenuated, non-replicating poxvirus derived from the vaccinia virus strain Ankara. It demonstrated tolerability and immunogenicity in healthy adults and HCT recipients, in whom it also reduced CMV reactivation. Here, we report feasibility, safety, and immunological outcomes of a pilot phase 1 trial (NCT03560752 at ClinicalTrials.gov) including 17 CMV-seropositive recipients who received an HCT from a matched related donor (MRD) vaccinated with 5.1× 108 pfu/ml of Triplex before cell harvest (median 15, range 11-28 days). Donor and recipient pairs who committed to participation in the trial resulted in exceptional adherence to the protocol. Triplex was well-tolerated with limited adverse events in donors and recipients, who all engrafted with full donor chimerism. On day 28 post-HCT, levels of functional vaccinia- and CMV-specific CD137+ CD8+ T cells were significantly higher (p< .0001 and p= .0174, respectively) in recipients of Triplex vaccinated MRD than unvaccinated MRD (control cohort). Predominantly, central and effector memory CMV-specific T-cell responses continued to steadily expand through 1-year follow-up. CMV viremia requiring antivirals developed in three recipients (18%). In summary, this novel approach represents a promising strategy applicable to different HCT settings for limiting the use of antiviral prophylaxis, which can impair and delay CMV-specific immunity, leading to CMV reactivation requiring treatment.

Improved Medication Adherence with the Use of Extended-Release Tacrolimus in Liver Transplant Recipients: A Pilot Randomized Controlled Trial.

Nonadherence to immunosuppression in liver transplant recipients (LTRs) leads to deterioration in health outcomes. Once-dailyextended-release tacrolimus (TAC-ER) may improve adherence when compared to twice-dailyimmediate-release tacrolimus (TAC-IR). We conducted a randomized controlled study to evaluate medication adherence, clinical efficacy, and safety of TAC-ER in stable LTR. All patients >18 years who underwent liver transplantation before 6 months were eligible. Patients were randomized 1 : 1 to continued TAC-IR or conversion to TAC-ER. The primary outcome was change in medication adherence from baseline to 9 months, assessed using BAASIS. Secondary outcomes were tacrolimus trough levels, safety, and quality of life. Thirty-one patients were consented and randomized to either of the two groups: conversion to TAC-ER (n = 15) or continued TAC-IR (n = 16). Six patients in the TAC-ER group withdrew after randomization due to apprehension about switching medication (n = 2), unwillingness to travel (n = 2), and increased liver tests after conversion (n = 2, both were acute rejections despite therapeutic tacrolimus levels and were considered unrelated to TAC-ER). We compared the results of nine patients in the TAC-ER group that completed the study with those of sixteen in the TAC-IR group. At baseline, there was no difference in tacrolimus trough levels between groups. Improved adherence was observed in the TAC-ER group as 100% of patients reported at least one period of full adherence during the study period (100% vs. 62.6%, p = 0.035). Tacrolimus trough levels and liver tests were comparable between groups throughout the study. There were no differences in eGFR, HbA1c, or QoL between the groups. TAC-ER improved medication adherence while maintaining comparable trough levels, liver function, and QoL as TAC-IR in LTR.

Impaired Cellular and Antibody immunity after COVID-19 in Chronically Immunosuppressed Transplant Recipients.

Assessment of cellular immunity to the SARS-CoV-2 coronavirus is of great interest in chronically immunosuppressed transplant recipients (Tr), who are predisposed to infections and vaccination failures. We evaluated CD154-expressing T-cells induced by spike (S) antigenic peptides in 204 subjects-103 COVID-19 patients and 101 healthy unexposed subjects. S-reactive CD154+T-cell frequencies were a) higher in 42 healthy unexposed Tr who were sampled pre-pandemic, compared with healthy NT (p=0.02), b) lower in Tr COVID-19 patients compared with healthy Tr (p<0.0001) and were accompanied by lower S-reactive B-cell frequencies (p<0.05), c) lower in Tr with severe COVID-19 (p<0.0001), or COVID-19 requiring hospitalization (p<0.05), compared with healthy Tr. Among Tr with COVID-19, cytomegalovirus co-infection occurred in 34%; further, incidence of anti-receptor-binding-domain IgG (p=0.011) was lower compared with NT COVID-19 patients. Healthy unexposed Tr exhibit pre-existing T-cell immunity to SARS-CoV-2. COVID-19 impairs anti-S T-cell and antibody and predisposes to CMV co-infection in transplant recipients.

The Clinical Manifestation of Immunosuppressive Therapy as a Tool to Improve Immune Monitoring in Renal Transplant Recipients

Introduction: Metrics for posttransplant immune monitoring to prevent over or under immunosuppression in renal transplant recipients (RTRs) are lacking. Methods: We surveyed 132 RTRs, 38 in the first year posttransplant and 94 >1-year posttransplant, to study the clinical expression of immunosuppressive therapy. A questionnaire administered to these RTRs was divided into physical (Q physical) and mental (Q mental) symptoms. Results: In multivariable models for the association between the calculated Q physical and Q mental scores and different clinical and biochemical variables in the 38 RTRs who filled out the questionnaire 130 times during the first year posttransplant, it was found that mycophenolic acid (MPA) and prednisone use increased the mean Q physical score by 0.59 (95% CI: 0.21–0.98, p = 0.002) and 0.53 (95% CI: 0.26–0.81, p = 0.00), respectively, while MPA use increased the mean Q mental score by 0.72 (95% CI: 0.31–1.12, p = 0.001). Among the 94 RTRs who each completed the questionnaire only once, the odds for the mean Q mental score to be above the median value were more than 3 times higher for RTRs treated versus non-treated with MPA (OR 3.38, 95% CI: 1.1–10.3, p = 0.03). MPA-treated RTRs had higher mean scores for questions related to sleep disorders (1.83 ± 1.06 vs. 1.32 ± 0.67 for not treated, p = 0.037), to difficulty falling asleep (1.72 ± 1.11 vs. 1.16 ± 0.5, p = 0.02), and to depression and anxiety. Conclusion: We concluded that prednisone and MPA use are associated with an increased Q physical and Q mental scores in RTRs. Routine monitoring of physical and mental status of RTRs should be implemented to improve the diagnosis of overimmunosuppression. Dose reduction or discontinuation of MPA should be considered in RTRs who report sleep disorders, depression, and anxiety.

Reduction in Maintenance Immunosuppression in Kidney Transplant Recipients With Stable Donor-Derived Cell-Free DNA Measurements: A Case Series

Personalization of maintenance immunosuppression in kidney transplant recipients has long remained a goal in the transplant community. The recent addition of donor-derived cell-free DNA assays to detect allograft rejection and monitor allograft health may permit for reductions in maintenance immunosuppression in recipients with stable levels. Herein, we described 5 patients with stable donor-derived cell-free DNA levels who underwent reduction in maintenance immunosuppression without precipitation of clinical rejection, proteinuria, or de novo donor specific antibody formation.

COVID-19 mortality may be reduced among fully vaccinated solid organ transplant recipients.

Solid organ transplant (SOT) recipients are at increased risk for morbidity and mortality from COVID-19 due to their immunosuppressed state and reduced immunogenicity from COVID-19 mRNA vaccines. This investigation examined the association between COVID-19 mRNA vaccination status and mortality among SOT recipients diagnosed with COVID-19. A retrospective, registry-based chart review was conducted investigating COVID-19 mortality among immunosuppressed solid organ transplant (SOT) recipients in a large metropolitan healthcare system in Houston, Texas, USA. Electronic health record data was collected from consecutive SOT recipients who received a diagnostic SARS-CoV-2 test between March 1, 2020, and October 1, 2021. The primary exposure was COVID-19 vaccination status at time of COVID-19 diagnosis. Patients were considered 'fully vaccinated' at fourteen days after completing their vaccine course. COVID-19 mortality within 60 days and intensive care unit admission within 30 days were primary and secondary endpoints, respectively. Among 646 SOT recipients who were diagnosed with COVID-19 at Houston Methodist Hospital between March 2020, and October 2021, 70 (10.8%) expired from COVID-19 within 60 days. Transplanted organs included 63 (9.8%) heart, 355 (55.0%) kidney, 108 (16.7%) liver, 70 (10.8%) lung, and 50 (7.7%) multi-organ. Increasing age was a risk factor for COVID-19 mortality, while vaccination within 180 days of COVID-19 diagnosis was protective in Cox proportional hazard models with hazard ratio 1.04 (95% CI: 1.01-1.06) and 0.31 (0.11-0.90), respectively). These findings were confirmed in the propensity score matched cohort between vaccinated and unvaccinated patients. This investigation found COVID-19 mortality may be significantly reduced among immunosuppressed SOT recipients within 6 months following vaccination. These findings can inform vaccination policies targeting immunosuppressed populations worldwide.

Complications of rabbit anti-thymocyte globulin induction immunosuppression in HIV-infected kidney transplant recipients.

Kidney transplantation in HIV-infected individuals with end-stage kidney disease is associated with improved survival compared to dialysis. Rabbit anti-thymocyte globulin (rATG) induction in HIV-infected kidney transplant recipients has been associated with a lower risk of acute rejection, but data on the rates of de novo malignancy and BK viremia in these patients is lacking. We performed a single-center retrospective cohort study of adult HIV-infected individuals who underwent kidney transplantation with rATG induction between January 2006 and December 2016. The primary outcome was the development of de novo malignancy. Secondary outcomes included the development of BK viremia, infections requiring hospitalization, HIV progression, biopsy-proven acute rejection, and patient and allograft survival. Twenty-seven HIV-infected individuals with end-stage kidney disease received deceased (n=23) or living (n=4) donor kidney transplants. The cumulative rate of malignancy at five years was 29%, of whom 29% died because of advanced malignancy. BK viremia was detected in six participants (22%), of whom one had biopsy-proven BK virus-associated nephropathy and all of whom cleared the BK viremia. Five-year acute rejection rates, patient survival and death-censored allograft survival were 17%, 85% and 80% respectively. rATG induction in HIV-infected kidney transplant recipients was associated with a low risk of acute rejection, but a potentially higher risk of de novo malignancies and BK viremia in this cohort. Screening strategies to closely monitor for BK virus infection and malignancy post-transplantation may improve outcomes in HIV-infected kidney transplant recipients receiving rATG induction.

Antineoplastic chemotherapy and immunosuppression in liver transplant recipients: Squaring the circle?

Malignancies are a major cause of late death after liver transplantation (LT). In LT recipients presenting a malignancy, antineoplastic chemotherapy is central part of the therapeutic arsenal, but management of both immunosuppressive and antineoplastic chemotherapy can be very challenging. The aim of the present retrospective study was to describe a recent single center cohort of LT recipients treated with antineoplastic cytotoxic chemotherapy. All LT recipients who received antineoplastic chemotherapy in our center between 2005 and 2021 were included. The study population included 72 antineoplastic chemotherapy courses in 69 patients. There was a majority of men (81.9%); median age at LT was 54.9 (range 1-68) and was 63.0 (18-79) at the diagnosis of malignancy. Lung carcinomas (23.6%), head and neck carcinomas (20.8%), lymphomas (16.7%), and recurrent hepatocellular carcinoma (HCC) (8.3%) were the most frequent malignancies. Neoadjuvant (30.6%), adjuvant (12.5%) or palliative (54.2%) chemotherapy was performed. Immunosuppressive regimen was modified from a calcineurin inhibitor (CNI)-based to an everolimus-based regimen (63.5% of CNI discontinuation). Median survival after diagnosis of malignancy was 22.5 months and 5-year survival was 30.1%. Chemotherapy regimen was considered optimal in 81.9% of the cases. Multivariate analysis disclosed that non-PTLD N+ stage malignancy (HR=5.52 95%CI [1.40;21.69], p=.014), non-PTLD M+ stage malignancy (HR=10.55 95%CI [3.20;34.73], p=.0001), and suboptimal chemotherapy (HR=2.73 95%CI [1.34;5.56], p=.005) were significantly associated with poorer prognosis. No rejection episode occurred during chemotherapy. The present study is the first one focused on antineoplastic chemotherapy in LT recipients. Our results suggest that immunosuppressive drugs and antineoplastic chemotherapy can be managed satisfactorily in most cases but this needs confirmation from larger cohorts.

Monkeypox a Concern for Donor-derived Infection?

Monkeypox a Concern for Donor-derived Infection?

Humoral and cellular immune responses to Pfizer-BioNTech BNT162b2 SARS-CoV-2 vaccine in adolescents with liver transplantation: Single center experience.

Immune responses to vaccines against severe acute respiratory syndrome (SARS)-coronavirus (CoV)-2 are variable. In the absence of disease, youngsters are expected to better react to vaccines than adults. Nevertheless, chronic immunosuppression in transplant recipients may impair their capability to generate protection. We aim to explore immune responses after BNT162b2 SARS-CoV-2 vaccination in our cohort of young liver-transplanted patients. A prospective study of adolescent liver-transplanted patients (n=33) in the long-term follow-up was performed. Immune responses after receiving Pfizer-BioNTech BNT162b2 vaccine were analyzed at two time-points: baseline and 30 days after the second dose. Humoral responses were measured by fluoroenzyme-immunoassay and T-cell responses by interferon-γ-release assay. Post-vaccine coronavirus disease (COVID-19) events were recorded by a survey. Pre-vaccine SARS-CoV-2-specific antibodies were undetectable in 27/32 (84.4%), negative/indeterminate in 3/32 (9.4%) and positive in 2/32 (6.3%) patients. Cellular responses at baseline were negative in 12/18 (66.6%), positive in 3/18 (16.6%) and indeterminate in 3/18 (16.6%) recipients. None of the baseline positives recalled any symptoms. Post-vaccine antibodies were detected in all patients and 92.6% showed levels >816 BAU/mL. Twenty (71.4%) recipients had positive T-cell responses. Regarding post-vaccine SARS-Cov-2 infection, 10 (30.3%) patients reported COVID-19 without hospitalization and 21 (63.6%) did not notify any infection. Negative and positive cell-response groups after vaccination showed statistically significant differences regarding COVID-19 cases (62.5% vs 22.2%, respectively; p=0.046). Adolescents and young adults with liver transplantation responded to SARS-Cov-2 vaccine, generating both humoral and cellular responses. Recipients developing cellular responses after vaccination had a lower incidence of COVID-19.

Gram-negative bacteremia in solid organ transplant recipients: Clinical characteristics and outcomes as compared to immunocompetent non-transplant recipients.

Outcomes from Gram-negative bacteremia (GNB) in solid organ transplant (SOT) recipients are poorly understood. This is a single center prospective cohort study comparing the clinical characteristics and outcomes of SOT recipients with GNB to immunocompetent non-SOT patients with GNB between 1/1/2002 through 12/31/2018. Outcomes of interest included incidence of septic shock, respiratory failure, and time to death. A multivariable logistic regression model was used to determine factors associated with incidence of septic shock and respiratory failure. Time to death was evaluated using Cox proportional hazard models. A total of 297 SOT and 1245 immunocompetent non-SOT patients were included. Incidence of septic shock did not significantly differ between the groups (SOT 25.3% vs. non-SOT 24.6%, p = .8225). Overall survival did not significantly differ by transplant status (30-day survival: SOT 76%, 95% confidence interval [CI] 70, 92, non-SOT 74%, 95% CI 71, 77: log rank: p = .76). SOT recipients taking three immunosuppressive medications had significantly lower odds of developing septic shock or respiratory failure requiring intubation and mechanical ventilation than those taking ≤1 agent (shock: adjusted odds ratio [aOR] 0.29, 95% CI 0.09, 0.90, p = .0316; respiratory failure: aOR 0.14, 95% CI: 0.04, 0.49, p = .0020). SOT recipients with GNB do not experience higher rates of septic shock, respiratory failure, or mortality than immnon-SOT recipients with GNB. Among SOT recipients, a greater number of immunosuppressive medications may be associated with improved outcomes during GNB. Future studies are needed to understand the potential relationship between levels of immunosuppression and clinical outcome in SOT recipients with GNB.

Basiliximab as maintenance immunosuppression in heart transplant recipients: A single pediatric center experience.

Pediatric heart transplant recipients are at risk for complications from prolonged exposure to immunosuppressive drugs, pharmacokinetic challenges in maintaining consistent immunosuppression, and medication non-adherence. Basiliximab (BAS), an interleukin-2 receptor antagonist, is used for induction therapy across many pediatric heart transplant centers, but use as maintenance immunosuppression has not been well described. This was a retrospective, single pediatric center cohort study of heart transplant recipients who received BAS for maintenance immunosuppression (defined as >2 monthly doses) from January 1, 2011, to December 31, 2021. Ten patients met study criteria with a median age of 17.5 (5-22)years and median 9.6 (1.2-18.9)years since transplant at time of BAS initiation. The primary indications for BAS use were recurrent rejection (n=4), fluctuating immunosuppression levels (n=3), and renal dysfunction (n=3). A median of 5.5 (3-32) monthly BAS doses were received. Three patients had a rejection event while on BAS. Calcineurin inhibitor exposure was reduced in 70% of patients. Three of the 10 patients were alive at last follow-up. There was one documented infection during BAS use, and no hypersensitivity reactions. Monthly BAS infusions were well tolerated and allowed for reduced calcineurin inhibitor exposure in most patients. Mortality commonly occurred despite BAS use, potentially reflecting the acuity of this patient cohort. BAS can be considered for maintenance immunosuppression in pediatric patients with fluctuating immunosuppressive levels and/or renal dysfunction. More studies are needed to determine long-term outcomes and explore expanded use of BAS in the pediatric heart transplant population.