Trends in underlying causes of death in solid organ transplant recipients between 2010 and 2020: Using the CLASS method for determining specific causes of death

Vaccination strategies for solid organ transplant candidates and recipients: insights and recommendations

INTRODUCTION

Vaccines save lives. They are integral to reducing the morbidity and mortality of vaccine-preventable infections in solid organ transplant recipients. Pre-transplant vaccination provides a unique opportunity for administration of live, viral vaccines, and enhanced vaccine efficacy, compared to the post-transplant period with decreased vaccine response due to immunosuppression.

AREAS COVERED

We discuss a general approach to pre- and post-transplant vaccination in solid organ transplant candidates and recipients. We then review guideline statements and recent literature related to individual vaccines, including the recently developed respiratory syncytial virus vaccine. Travel and occupation-related vaccines are also discussed.

EXPERT OPINION

The challenge of vaccination for immunocompromised patients expands as the prevalence of immunocompromised adults rises, and immunocompromised patients are frequently excluded from vaccine trials. In an age of vaccine hesitancy and reemerging vaccine-preventable infections, well-powered, prospective studies are needed to evaluate the clinical effectiveness of vaccines in solid organ transplant candidates and recipients.

mRNA-1273 COVID-19 vaccine induces CD4+ T-cell responses among solid organ transplant recipients

Background

Cell-mediated immunity may provide durable protection against severe COVID-19, including among solid organ transplant recipients (SOTRs). This exploratory analysis in the open-label phase 3b trial evaluated cell-mediated immunity of mRNA-1273 in a subset of participants (59 kidney and 33 liver SOTRs; 12 immunocompetent participants).

Methods

In Part A, SOTRs received three 100-µg doses of mRNA-1273; immunocompetent participants received two doses. In Part B, an additional 100-µg dose was offered ≥4 months after the primary series. SARS-CoV-2 spike (S) protein-specific T-cell responses were measured by intracellular cytokine staining and polyfunctionality analyses.

Results

The primary series and additional dose of mRNA-1273 induced S protein-specific CD4+ T-cell responses exhibiting a Th-1-biased profile in both SOTRs and immunocompetent participants; however, response rates and magnitudes were lower among SOTRs. S protein-specific Th-2 CD4+ T-cell responses were below those observed for Th-1; CD8+ T-cell responses were not as robust among SOTRs compared with immunocompetent participants. Kidney SOTRs received multiple immunosuppressants and had lower cell-mediated immunity responses than liver SOTRs. Polyfunctional responses exhibited Th-1 cytokine signatures with ≤5 functional markers reported in SOTRs and immunocompetent participants.

Conclusion

Overall, a three-dose mRNA-1273 primary series elicited Th-1-biased CD4+ T-cell responses among SOTRs that were improved with an additional dose.

Clinical trial registration

https://beta.clinicaltrials.gov/study/NCT04860297?term=NCT04860297%20&rank=1, identifier NCT04860297.

The assesement of the long-term effects of kidney transplantation, including the incidence of malignant tumors, in recipients operated on between 2006 and 2015 - a cohort study and literature review

<b>Introduction:</b> Chronic kidney disease (CKD) is a global public health problem, occurring more frequently in developed countries. In Poland, it affects approximately 4 million people, which constitutes 10.8% of the population. End-stage renal disease (ESRD) requires renal replacement therapy - dialysis therapy or kidney transplantation. Kidney transplantation, supported by immunosuppressive therapy, is the preferred method of treating ESRD, improving the quality and length of life of patients.<b>Aim and Methods:</b> The aim of the study was to determine the long-term effects of kidney transplantation, including proper graft function, the frequency of adverse effects of immunosuppressive therapy, the degree of patient compliance with therapeutic recommendations, and the incidence of malignancies. A survey was conducted in a group of 137 patients who underwent kidney transplantation between 2006 and 2015. Hospitalization data were also analyzed, including age, body weight and blood type of the recipient.<b>Results:</b> Of the 137 patients studied, 61 were women and 76 were men. The mean age of the patients was 45.1 years. The most common etiology of CKD was glomerulonephritis. After kidney transplantation, 86.86% of patients declared normal graft function. Post-transplant weight gain was noted in 75.18% of patients. 11.68% of recipients developed malignancies, with an average time from transplantation to diagnosis of 5.1 years. Of the patients with cancer, 93.75% maintained normal graft function.<b>Conclusions:</b> Long-term effects of kidney transplantation are satisfactory, with a high percentage of patients maintaining normal graft function. Complications associated with immunosuppressive therapy are comparable to literature data. It is necessary to increase patient awareness of modifiable risk factors to improve treatment outcomes. The incidence of malignancy after transplantation is lower than in the literature, but the methodological limitations of the study must be taken into account. Cancer treatment had no significant effect on graft function in most cases.

Improved Outcomes of Liver Transplantation in Patients With Hepatitis C, Following the Introduction of Innovative Antiviral Therapies

Background

The treatment landscape for hepatitis C virus (HCV) underwent a significant shift with the introduction of direct-acting antiviral (DAA) medications in late 2013. This study aimed to evaluate the impact of DAAs on liver transplantation outcomes, examining both the benefits and any potential drawbacks associated with their use.

Methods and materials

A retrospective registry analysis of the United Network for Organ Sharing database was done for liver transplants in patients diagnosed with hepatitis C, that were performed in the United States from January 2000 to May 2020.

Results

The study was divided into two subgroups, based on the timing of the new DAA medication that FDA approved. The only significant difference between the two cohorts is the recipient's age. The data analysis showed a significant overall 5-year graft survival improvement in the 2014-2020 group compared with the 2000-2013 group, from a mean of 64.8% in 2000-2013 to a mean of 76% in 2014-2020 (P < 0.001). Interestingly, when we compared the 5-year graft survivals with recipients who had a donor above age 50, the graft survival rate difference was even more significant (74% vs. 56%, P < 0.001) as some studies have shown a suboptimal graft outcome when the donor age is above 40 years old. Not only has the utilization of donation after circulatory death livers increased significantly after 2014 but the graft survival in this cohort has also been significantly higher (P < 0.001).

Conclusion

The emergence of DAAs in 2013 marked a watershed moment in the management of HCV offering high cure rates, minimal side effects, and shorter treatment durations to a point that the short- and long-term outcomes of liver transplantation for HCV is almost equal to the other causes of liver transplantation.

Compassionate access to virus-specific T cells for adoptive immunotherapy over 15 years

Adoptive T-cell immunotherapy holds great promise for the treatment of viral complications in immunocompromised patients resistant to standard anti-viral strategies. We present a retrospective analysis of 78 patients from 19 hospitals across Australia and New Zealand, treated over the last 15 years with "off-the-shelf" allogeneic T cells directed to a combination of Epstein-Barr virus (EBV), cytomegalovirus (CMV), BK polyomavirus (BKV), John Cunningham virus (JCV) and/or adenovirus (AdV) under the Australian Therapeutic Goods Administration's Special Access Scheme. Most patients had severe post-transplant viral complications, including drug-resistant end-organ CMV disease, BKV-associated haemorrhagic cystitis and EBV-driven post-transplant lymphoproliferative disorder. Adoptive immunotherapy is well tolerated with few adverse effects. Importantly, 46/71 (65%) patients show definitive clinical improvement including reduction in viral load, clinical symptoms and complete resolution of end-organ disease. In addition, seven high-risk patients remain disease free. Based on this long-term encouraging clinical experience, we propose that a dedicated nationally funded centre for anti-viral cellular therapies should be considered to provide T cell therapies for critically ill patients for compassionate use.

Management of Post-transplant Infections in Collaborating Hospitals (MATCH) Programme: a prospective cohort of all transplant recipients at Copenhagen University Hospital-Rigshospitalet, Denmark

PURPOSE

The Management of Post-transplant Infections in Collaborating Hospitals (MATCH) programme, initiated in 2011 and still ongoing, was created to 1) optimise the implementation of existing preventive strategies against viral infections in solid organ transplant (SOT) recipients and allogenic haematopoietic stem-cell transplant (HSCT) recipients and 2) advance research in the field of transplantation by collecting data from a multitude of sources.

PARTICIPANTS

All SOT and HSCT recipients at Copenhagen University Hospital, Rigshospitalet, are followed in MATCH. By February 2021, a total of 1192 HSCT recipients and 2039 SOT recipients have been included. Participants are followed life long. An automated electronic data capture system retrieves prospective data from nationwide registries. Data from the years prior to transplantation are also collected.

FINDINGS TO DATE

Data entries before and after transplantation include the following: biochemistry: 13 995 222 and 26 127 817; microbiology, cultures: 242 023 and 410 558; other microbiological analyses: 265 007 and 566 402; and pathology: 170 884 and 200 394. There are genomic data on 2431 transplant recipients, whole blood biobank samples from 1003 transplant recipients and faeces biobank samples from 207 HSCT recipients. Clinical data collected in MATCH have contributed to 50 scientific papers published in peer-reviewed journals and have demonstrated success in reducing cytomegalovirus disease in SOT recipients. The programme has established international collaborations with the Swiss Transplant Cohort Study and the lung transplant cohort at Toronto General Hospital.

FUTURE PLANS

Enrolment into MATCH is ongoing with no planned end date for enrolment or follow-up. MATCH will continue to provide high-quality data on transplant recipients and expand and strengthen international collaborations.

Safety and Immunogenicity of the mRNA-1273 Coronavirus Disease 2019 Vaccine in Solid Organ Transplant Recipients

BACKGROUND

Solid organ transplant recipients (SOTRs) are at high risk for severe COVID-19.

METHODS

This open-label, phase 3b trial evaluated mRNA-1273 in 137 kidney and 77 liver SOTRs and 20 immunocompetent participants. In part A, SOTRs received three 100-µg doses of mRNA-1273; immunocompetent participants received 2 doses. In part B, an additional 100-µg dose was offered ≥4 months after the primary series. Here, we report interim trial results.

RESULTS

mRNA-1273 was well-tolerated in SOTRs. Four serious adverse events were considered vaccine related by the investigator in 3 SOTRs with preexisting comorbidities. No vaccine-related biopsy-proven organ rejection events or deaths were reported. mRNA-1273 elicited modest neutralizing antibody responses after dose 2 and improved responses after dose 3 in SOTRs. Post-dose 3 responses among liver SOTRs were comparable to post-dose 2 responses in immunocompetent participants. Post-additional dose responses were increased in SOTRs, regardless of primary series vaccination. In liver SOTRs, post-additional dose responses were ∼3-fold higher versus post-dose 2 but lower than immunocompetent participant responses. Most kidney SOTRs received multiple immunosuppressants and had reduced antibody responses versus liver SOTRs.

CONCLUSIONS

mRNA-1273 was well-tolerated, and dose 3 and the additional dose improved antibody responses among SOTRs.

CLINICAL TRIALS REGISTRATION

NCT04860297.

Mechanistic Understanding of EBV+Lymphoproliferative Disease Development After Transplantation

Posttransplant lymphoproliferative disorders (PTLDs) are among the most common malignant complications after transplantation, leading to a drastic reduction in patient survival rates. The majority of PTLDs are tightly linked to Epstein-Barr virus (EBV+PTLDs) and are the result of an uncontrolled proliferation of EBV-infected cells. However, although EBV infections are a common finding in transplant recipients, most patients with high EBV loads will never develop EBV+PTLD. Natural killer cells and EBV-specific CD8+ T lymphocytes are critical for controlling EBV-infected cells, and the impairment of these cytotoxic immune responses facilitates the unfettered proliferation of EBV-infected cells. Recent years have seen a considerable increase in available literature aiming to describe novel risk factors associated with the development of EBV+PTLD, which may critically relate to the strength of EBV-specific natural killer cell and EBV-CD8+ T lymphocyte responses. The accumulation of risk factors and the increased risk of developing EBV+PTLD go hand in hand. On the one hand, most of these risk factors, such as the level of immunosuppression or the EBV donor and recipient serologic mismatch, and distinct genetic risk factors are host related and affect cytotoxic EBV-specific immune responses. On the other hand, there is growing evidence that distinct EBV variants may have an increased malignant potential and are thus more likely to induce EBV+PTLD. Here, we aim to review, from a mechanistic point of view, the risk factors for EBV+PTLD in the host and the infecting EBV variants that may explain why only a minority of transplant recipients develop EBV+PTLD.

Clinical characteristics and outcomes of community-acquired pneumonia in solid organ transplant recipients

BACKGROUND

Pneumonia is a frequent complication of solid organ transplantation that adversely impacts both graft and recipient survival. There is a paucity of data on community-acquired pneumonia (CAP) in transplant recipients, particularly the long term outcomes. We conducted a study to compare the clinical characteristics and outcomes of pneumonia in solid organ transplant (SOT) recipients to those in non-transplant (NT) recipients.

MATERIAL AND METHODS

Clinical characteristics were abstracted from electronic medical records. Outcomes included time to hospital discharge, short and long-term mortality. Inverse-propensity score weights were assigned to account for between-group differences. Adjusted analysis included a weighted logistic regression. Results were reported as odds ratios with a corresponding 95 % confidence interval (CI).

RESULTS

A total of 7449 patients were admitted with CAP. Patients were divided into two groups: SOT recipients 42 (0.56 %) and NT recipients 7396 (99.2 %). SOT recipients were younger, more commonly males, with higher prevalence of comorbidities. After accounting for inverse-propensity score weighting, the odds of mortality were higher in SOT recipients in hospital, at 30 days and at 1 year. The magnitude of increase in mortality for SOT recipients was greatest at 1 year with 1.41 (95 % CI: 1.38-1.44) times higher odds.

CONCLUSION

In patients with CAP, SOT recipients are younger, more commonly male and have more co-morbidities compared with NT recipients. They also have higher 1 year mortality after adjustment. Clinicians must be vigilant toward the pronounced long-term mortality risk among these patients and ensure continued follow-up care for them.

Trends in underlying causes of death in allogeneic hematopoietic cell transplant recipients over the last decade

OBJECTIVES

Improved survival after hematopoietic cell transplantation (HCT) and an increasingly comorbid transplant population may give rise to new trends in the causes of death.

METHODS

This study includes all adult allogeneic HCT recipients transplanted at Rigshospitalet between January 1, 2010 and December 31, 2019. Underlying causes of death were determined using the Classification of Death Causes after Transplantation (CLASS) method.

RESULTS

Among 802 HCT recipients, 289 died during the study period. The main causes of death were relapse (N = 133, 46.0%), graft-versus-host disease (GvHD) (N = 64, 22.1%) and infections (N = 35, 12.1%). Multivariable analyses showed that with increasing transplant calendar year, a decreased risk of all-cause mortality (HR 0.92, 95% CI 0.87-0.97) and death from GvHD (HR 0.87, 95% CI 0.78-0.97) was identified, but not for other specific causes. Standardized mortality ratios (SMRs) for all-cause mortality decreased from 23.8 (95% CI 19.1-28.5) to 18.4 (95% CI 15.0-21.9) for patients transplanted in 2010-2014 versus 2015-2019, while SMR for patients who died from GvHD decreased from 8.19 (95% CI 5.43-10.94) to 3.65 (95% CI 2.13-5.18).

CONCLUSIONS

As risk of all-cause mortality and death from GvHD decreases, death from relapse remains the greatest obstacle in further improvement of survival after HCT.

Do Infectious Diseases After Kidney Retransplantation Differ From Those After First Kidney Transplantation?

Background

Infectious diseases (IDs) are highly relevant after solid organ transplantation in terms of morbidity and mortality, being among the most common causes of death. Patients undergoing kidney retransplantation (re-K-Tx) have been already receiving immunosuppressive therapy over a prolonged period, potentially facilitating subsequent infections. Comparing ID events after re-K-Tx and first kidney transplantation (f-K-Tx) can delineate patterns and risks of ID events associated with prolonged immunosuppression.

Methods

We included adult patients with records on f-K-Tx and re-K-Tx in the Swiss Transplant Cohort Study. We analyzed ID events after f-K-Tx and re-K-Tx within the same patients and compared infection rates, causative pathogens, and infection sites. Recurrent time-to-event analyses were performed for comparison of infection rates.

Results

A total of 59 patients with a median age of 47 years (range, 18-73) were included. Overall, 312 ID events in 52 patients occurred. In multivariable recurrent event modeling, the rate of ID events was significantly lower after re-K-Tx (hazard ratio, 0.70; P = .02). More bacterial (68.9% vs 60.4%) and fungal (4.0% vs 1.1%) infections were observed after f-K-Tx but fewer viral infections (27.0% vs 38.5%) as compared with re-K-Tx (P = .11). After f-K-Tx, urinary and gastrointestinal tract infections were more frequent; after re-K-Tx, respiratory tract and surgical site infections were more frequent (P < .001).

Conclusions

ID events were less frequent after re-K-Tx. Affected sites differed significantly after f-K-Tx vs re-K-Tx.

Mycophenolate mofetil hampers antibody responses to a broad range of vaccinations in kidney transplant recipients: Results from a randomized controlled study

OBJECTIVES

To study the effect of mycophenolate mofetil (MMF) on various vaccination responses in kidney transplant recipients.

METHODS

In a randomized controlled trial (EudraCT nr.: 2014-001372-66), low immunologically risk kidney transplant recipients were randomized to TAC/MMF or TAC-monotherapy (TACmono), six months post-transplantation. One year after transplantation, in a pre-specified sub-study, recipients were vaccinated against pneumococcus, tetanus and influenza. Blood was sampled before and 21 days after vaccination. Adequate vaccination responses were defined by international criteria. A post-hoc analysis was conducted on SARS-CoV-2 vaccination responses within the same cohort.

RESULTS

Seventy-one recipients received pneumococcal and tetanus vaccines (TAC/MMF: n = 37, TACmono: n = 34), with 29 also vaccinated against influenza. When vaccinated, recipients were 60 (54-66) years old, with median eGFR of 54 (44-67) ml/min, tacrolimus trough levels 6.1 (5.4-7.0) ug/L in both groups and TAC/MMF daily MMF dose of 1000 (500-2000) mg. Adequate vaccination responses were: pneumococcal (TAC/MMF 43%, TACmono 74%, p = 0.016), tetanus (TAC/MMF 35%, TACmono 82%, p < 0.0001) and influenza (TAC/MMF 20%, TACmono 71%, p = 0.0092). Only 7% of TAC/MMF responded adequately to all three compared to 36% of TACmono (p = 0.080). Additionally, 40% of TAC/MMF responded inadequately to all three, whereas all TACmono patients responded adequately to at least one vaccination (p = 0.041). Lower SARS-CoV-2 vaccination antibody responses correlated with lower pneumococcal antibody vaccination responses (correlation coefficient: 0.41, p = 0.040).

CONCLUSIONS

MMF on top of tacrolimus severely hampers antibody responses to a broad range of vaccinations.

Survival Outcomes After Double-Lung Transplantation for Refractory Lung-Limited Cancers and Incidence of Post-Transplant Lung Cancer

BACKGROUND To evaluate the role of double-lung transplantation (DLT) for lung cancer, the survival outcomes of patients who underwent DLT for lung cancer and the incidence of de novo lung cancer after DLT were assessed. MATERIAL AND METHODS Data from all cases reported in the literature were pooled for analysis and additional data were collected from the Organ Procurement Transplantation Network (OPTN) registry. Recurrence-free survival (RFS), overall survival (OS), and cancer-specific survival (CSS) of patients who underwent DLT for lung cancer were determined. Moreover, the incidence of de novo lung cancer and associated OS in lung transplant recipients were examined. RESULTS Of the 20 cases series and 15 cases from the OPTN registry, the 5-year RFS was 55.0% and 66.7% and the 5-year OS was 55.0% and 26.7%, respectively, and the median CSS was 48.0 (range, 2.0-144.0) and 27.7 (range, 0.2-66.6) months, respectively. In the OPTN data, the incidence of post-transplant lung cancer in patients who underwent DLT for the non-cancerous disease was 0.8% and the 5-year OS was 47.3%. CONCLUSIONS In conclusion, our integrated analysis of the case series and the OPTN registry demonstrated promising survival outcomes for patients with refractory bilateral lung cancer who underwent DLT. Although there are limitations to consider, the results of this study underscore the potential benefits of DLT in managing refractory lung-limited lung cancer.

Susceptibility to SARS-CoV-2 Infection and Immune Responses to COVID-19 Vaccination Among Recipients of Solid Organ Transplants

Solid organ transplant recipients (SOTRs) are at high risk for infections including SARS-CoV-2, primarily due to use of immunosuppressive therapies that prevent organ rejection. Furthermore, these immunosuppressants are typically associated with suboptimal responses to vaccination. While COVID-19 vaccines have reduced the risk of COVID-19-related morbidity and mortality in SOTRs, breakthrough infection rates and death remain higher in this population compared with immunocompetent individuals. Approaches to enhancing response in SOTRs, such as through administration of additional doses and heterologous vaccination, have resulted in increased seroresponse and antibody levels. In this article, safety and immunogenicity of mRNA COVID-19 vaccines in SOTRs are explored by dose. Key considerations for clinical practice and the current vaccine recommendations for SOTRs are discussed within the context of the dynamic COVID-19 vaccination guideline landscape. A thorough understanding of these topics is essential for determining public health and vaccination strategies to help protect immunocompromised populations, including SOTRs.