RNA respiratory viruses in solid organ transplantation

Opportunistic Infections Post-Lung Transplantation: Viral, Fungal, and Mycobacterial

Opportunistic infections are a leading cause of lung transplant recipient morbidity and mortality. Risk factors for infection include continuous exposure of the lung allograft to the external environment, high levels of immunosuppression, impaired mucociliary clearance and decreased cough reflex, and impact of the native lung microbiome in single lung transplant recipients. Infection risk is mitigated through careful pretransplant screening of recipients and donors, implementation of antimicrobial prophylaxis strategies, and routine surveillance posttransplant. This review describes common viral, fungal, and mycobacterial infectious after lung transplant and provides recommendations on prevention and treatment.

Respiratory viral infections including COVID-19 in solid organ transplantation

PURPOSE OF REVIEW

Respiratory viral infections are prevalent and contribute to significant morbidity and mortality among solid organ transplant (SOT) recipients. We review updates from literature on respiratory viruses, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), in the SOT recipient.

RECENT FINDINGS

With the wider availability and use of molecular diagnostic tests, our understanding of the epidemiology and impact of respiratory viruses in the SOT population continues to expand. While considerable attention has been given to the coronavirus disease 2019 (COVID-19) pandemic, the advances in prevention and treatment strategies of SARS-CoV-2 offered valuable insights into the development of new therapeutic options for managing other respiratory viruses in both the general and SOT population.

SUMMARY

Respiratory viruses can present with a diverse range of symptoms in SOT recipients, with potentially associated acute rejection and chronic lung allograft dysfunction in lung transplant recipients. The epidemiology, clinical presentations, diagnostic approaches, and treatment and preventive strategies for clinically significant RNA and DNA respiratory viruses in SOT recipients are reviewed. This review also covers novel antivirals, immunologic therapies, and vaccines in development for various community-acquired respiratory viruses.

Systemic corticosteroids for outpatient respiratory viral infections in lung transplant recipients

INTRODUCTION

Respiratory viral infections (RVI) in lung transplant recipients (LTR) have variably been associated with rejection and chronic lung allograft dysfunction. Our center has used systemic corticosteroids to treat outpatient RVI in some cases, but evidence is limited. We reviewed all adult LTR diagnosed with outpatient RVI January 2017 to December 2019. The primary outcome was recovery of lung function (forced expiratory volume in 1 s [FEV1]) at next stable visit between 1 and 12 months postinfection, expressed as a ratio over stable preinfection FEV1 (FEV1 recovery ratio).

METHODS

We identified 100 adult LTR with outpatient RVI diagnoses eligible for study, 36% of whom received corticosteroids. We modelled the adjusted association between corticosteroid use and FEV1 recovery ratio using linear regression.

RESULTS

Steroid-treated patients had a lower FEV1 presentation ratio (0.92 vs. 1.04, p = .0070) and were more likely to have chronic lung allograft dysfunction at time of infection (25% vs. 5%, p = .0077). Mean FEV1 recovery ratio was 1.02 (SD 0.19) with no association with corticosteroid therapy via multivariable linear regression (p = .5888).

CONCLUSIONS

Steroid treatment was not associated with FEV1 recovery. This suggests corticosteroids may not have a role in the management of RVI in this population.

Diagnosis, treatment protocols, and outcomes of liver transplant recipients infected with COVID-19

Several cases of fatal pneumonia during November 2019 were linked initially to severe acute respiratory syndrome coronavirus 2, which the World Health Organization later designated as coronavirus disease 2019 (COVID-19). The World Health Organization declared COVID-19 as a pandemic on March 11, 2020. In the general population, COVID-19 severity can range from asymptomatic/mild symptoms to seriously ill. Its mortality rate could be as high as 49%. The Centers for Disease Control and Prevention have acknowledged that people with specific underlying medical conditions, among those who need immunosuppression after solid organ transplantation (SOT), are at an increased risk of developing severe illness from COVID-19. Liver transplantation is the second most prevalent SOT globally. Due to their immunosuppressed state, liver transplant (LT) recipients are more susceptible to serious infections. Therefore, comorbidities and prolonged immunosuppression among SOT recipients enhance the likelihood of severe COVID-19. It is crucial to comprehend the clinical picture, immunosuppressive management, prognosis, and prophylaxis of COVID-19 infection because it may pose a danger to transplant recipients. This review described the clinical and laboratory findings of COVID-19 in LT recipients and the risk factors for severe disease in this population group. In the following sections, we discussed current COVID-19 therapy choices, reviewed standard practice in modifying immunosuppressant regimens, and outlined the safety and efficacy of currently licensed drugs for inpatient and outpatient management. Additionally, we explored the clinical outcomes of COVID-19 in LT recipients and mentioned the efficacy and safety of vaccination use.

Opportunistic Infections Post-Lung Transplantation: Viral, Fungal, and Mycobacterial

Opportunistic infections are a leading cause of lung transplant recipient morbidity and mortality. Risk factors for infection include continuous exposure of the lung allograft to the external environment, high levels of immunosuppression, impaired mucociliary clearance and decreased cough reflex, and impact of the native lung microbiome in single lung transplant recipients. Infection risk is mitigated through careful pretransplant screening of recipients and donors, implementation of antimicrobial prophylaxis strategies, and routine surveillance posttransplant. This review describes common viral, fungal, and mycobacterial infectious after lung transplant and provides recommendations on prevention and treatment.

Corticosteroids and Outcomes in Solid Organ Transplant Recipients Infected With Severe Acute Respiratory Syndrome Coronavirus 2

Objective

To examine outcomes in organ transplant and nontransplant patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection during the initial 22 months of the pandemic.

Patients and Methods

We used Optum electronic health records to compare outcomes between an adult transplant group and a propensity-matched nontransplant group that tested positive for SARS-CoV-2 from February 1, 2020, to December 15, 2021. Baseline characteristics, hospitalization, intensive care unit admission, mechanical ventilation, renal replacement therapy, inpatient, and 90-day mortality were compared between the transplant and nontransplant groups and among specific transplant recipients. Cox proportional analysis was used to examine hospitalization and mortality by organ transplant, medical therapy, sex, and the period of the pandemic.

Results

We identified 876,959 patients with SARS-CoV-2 infection, of whom 3548 were organ transplant recipients. The transplant recipients had a higher risk of hospitalization (30.6% vs 25%, respectively; P<.001), greater use of mechanical ventilation (7.8% vs 5.6%, respectively; P<.001), and increased inpatient mortality (6.7% vs 4.7%, respectively; P<.001) compared with the nontransplant patients. The initiation of mechanical ventilation was significantly more frequent in the transplant group. After adjustment for baseline characteristics and comorbidities, the transplant group had a higher risk of hospitalization (odds ratio, 1.38; 95% confidence interval, 1.19-1.59), without a difference in mortality. In the transplant group, lung transplant recipients had the highest inpatient mortality (11.6%).

Conclusion

Among patients with SARS-CoV-2 infection, the transplant recipients were at a higher risk of hospitalization and inpatient mortality; however, mortality was mainly driven by advanced age and comorbidities rather than by transplant status or immunosuppressive medications. Lung transplant recipients had the greatest inpatient and 90-day mortality.

Effect of Remdesivir on COVID-19 PCR Positivity and Cycle Threshold in Kidney Transplant Recipients

Information regarding Coronavirus disease 2019 in the transplant population is lacking. Recently it has been suggested that cycle threshold values obtained on polymerase chain reaction tests may serve as a marker of disease severity with lower values (i.e., higher viral load) being associated with higher mortality. This study was done to assess the impact of remdesivir use on the time to a negative COVID-19 PCR as well as the degree of change between two Ct’s based on treatment. A total of 30 kidney transplant patients with a new diagnosis of COVID-19 were assessed. Serial PCR results were followed from the time of diagnosis then every 2–4 weeks until negative. In patients who received remdesivir immediately after COVID-19 confirmation compared to no remdesivir, time to negative PCR was not statistically different with a median duration of 57 days in both groups (p = 0.369). The change in the Ct between the first and the second PCR test was also not statistically different between groups with a median change of 18.4 cycles in the remdesivir group and 15.7 cycles without remdesivir (p = 0.516). The results of this small single-center analysis suggest that remdesivir may not be beneficial in shortening time to a negative COVID-19 PCR.

COVID-19 in liver transplant recipients

Coronavirus disease 2019 (COVID-19), an infection caused by severe acute respiratory syndrome coronavirus-type 2 (SARS-CoV-2), has emerged as a serious threat to public health. Liver transplant (LT) recipients may be at increased risk of acquisition of SARS-CoV-2 infection and higher morbidity and mortality due to constant contact with health-care services, the use of immunosuppressants and frequent comorbidities. In the first part of this review we discuss (1) the epidemiology and risk factors for SARS-CoV-2 infection in LT recipients; (2) the clinical and laboratory features of COVID-19 in this specific population, highlighting differences in presenting signs and symptoms with respect to general populations and (3) the natural history and prognostic factors in LT recipients hospitalized with COVID-19, with particular focus on the possible role of immunosuppression. Thereafter, we review the potential therapeutic options for COVID-19 treatment and prevention. Specifically, we give an overview of current practice in immunosuppressant regimen changes, showing the potential benefits of this strategy, and explore safety and efficacy issues of currently approved drugs in LT recipients. The last topic is dedicated to the potential benefits and pitfalls of vaccination.

Respiratory viruses

Respiratory viruses are commonly detected in both healthy and immunocompromised children. In most healthy children, respiratory viruses are associated with self-limited upper respiratory tract infections and are not accompanied by significant morbidity. In immunocompromised hosts, including hematopoietic cell transplant recipients, solid organ transplant recipients, and oncology patients, respiratory viruses can be associated with significant clinical manifestations, including prolonged viral shedding, lower respiratory tract disease, the need for supplemental oxygen, late airflow obstruction, and even death. This chapter reviews the major respiratory viruses, including respiratory syncytial virus, human metapneumovirus, influenza, parainfluenza viruses, human rhinoviruses, and human coronaviruses. Other viruses can manifest as pulmonary infection; however, these viruses are discussed elsewhere (see Chapter 17 for discussion of cytomegalovirus and Chapter 22 for discussion of adenoviruses).

Risk Classification for Respiratory Viral Infections in Adult Solid Organ Transplantation Recipients

INTRODUCTION

Molecular testing such as nasopharyngeal viral polymerase chain reaction (PCR) (NVP) is available now in most hospitals and widely used to identify respiratory viral infections (RVIs) in solid organ transplantation (SOT) recipients.

MATERIALS AND METHODS

A retrospective multicenter study at 8 hospitals from March 1, 2016, to April 30, 2019. We included all adult SOT recipients who were admitted to the hospitals and had their first NVP post transplantation.

RESULTS

A total of 102 adult SOT recipients were enrolled. NVP test was positive in 33 (32.4%) SOT recipients and negative in 69 (67.6%). Median age was more than 60 years old with female predominance in both groups. The majority of patients who had positive NVP were hospitalized either in fall or winter seasons (91%). RVI symptoms were documented in about 73% of the positive NVP group. Rhinovirus was the most common identified virus (48.4%). On logistic regression analysis, clinical presentation in fall or winter seasons, presenting with upper respiratory infection (URI) symptoms and taking prednisone ≥10 mg/d were significantly associated with positive NVP. This model classified patients into 3 categories of risk for RVIs-low (none of the variables), 0%; intermediate (1 variable), 6.5%; and high (≥2 variables), 55.4% with P < .001 for all predictors.

CONCLUSION

SOT recipients who are taking prednisone (≥10 mg) and have URI symptoms in fall or winter seasons are more likely to have RVIs.

Community-acquired Respiratory Viruses Are a Risk Factor for Chronic Lung Allograft Dysfunction

Background

The relationship between community-acquired respiratory viruses (CARVs) and chronic lung allograft dysfunction (CLAD) in lung transplant recipients is still controversial.

Methods

We performed a prospective cohort study (2009–2014) in all consecutive adult patients (≥18 years) undergoing lung transplantation in the Hospital Universitari Vall d’Hebron (Barcelona, Spain). We systematically collected nasopharyngeal swabs from asymptomatic patients during seasonal changes, from patients with upper respiratory tract infectious disease, lower respiratory tract infectious disease (LRTID), or acute rejection. Nasopharyngeal swabs were analyzed by multiplex polymerase chain reaction. Primary outcome was to evaluate the potential association of CARVs and development of CLAD. Time-dependent Cox regression models were performed to identify the independent risk factors for CLAD.

Results

Overall, 98 patients (67 bilateral lung transplant recipients; 63.3% male; mean age, 49.9 years) were included. Mean postoperative follow-up was 3.4 years (interquartile range [IQR], 2.5–4.0 years). Thirty-eight lung transplant recipients (38.8%) developed CLAD, in a median time of 20.4 months (IQR, 12–30.4 months). In time-controlled multivariate analysis, CARV-LRTID (hazard ratio [HR], 3.00 [95% confidence interval {CI}, 1.52–5.91]; P = .002), acute rejection (HR, 2.97 [95% CI, 1.51–5.83]; P = .002), and cytomegalovirus pneumonitis (HR, 3.76 [95% CI, 1.23–11.49]; P = .02) were independent risk factors associated with developing CLAD.

Conclusions

Lung transplant recipients with CARVs in the lower respiratory tract are at increased risk to develop CLAD.

Molecular Diagnostic Advances in Transplant Infectious Diseases

PURPOSE OF REVIEW

The infectious complications of transplantation can have devastating consequences for patients. Early and accurate diagnosis is essential to good outcomes. This review describes recent advances in pathogen-directed diagnostic testing and discusses the role of new methods for transplant infectious diseases.

RECENT FINDINGS

Several molecular assays have been introduced into clinical practice in recent years. When the results of rapid testing are linked to patient-specific interventions, improved outcomes can be realized. Syndromic testing along with metagenomic next-generation sequencing (mNGS) represents novel approaches to infection diagnosis. However, the optimal use of these tests for transplant patients along with an overall assessment of cost-effectiveness demands further study. Molecular diagnostics are revolutionizing transplant care. Clinicians need to be aware of the current diagnostic landscape and have a working knowledge of the nuances related to test performance, result interpretation, and cost.

RNA respiratory viral infections in solid organ transplant recipients: Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the diagnosis, prevention, and management of RNA respiratory viral infections in the pre‐ and post‐transplant period. Viruses reviewed include influenza, respiratory syncytial virus (RSV), parainfluenza, rhinovirus, human metapneumovirus (hMPV), and coronavirus. Diagnosis is by nucleic acid testing due to improved sensitivity, specificity, broad range of detection of viral pathogens, automatization, and turnaround time. Respiratory viral infections may be associated with acute rejection and chronic lung allograft dysfunction in lung transplant recipients. The cornerstone of influenza prevention is annual vaccination and in some cases antiviral prophylaxis. Treatment with neuraminidase inhibitors and other antivirals is reviewed. Prevention of RSV is limited to prophylaxis with palivizumab in select children. Therapy of RSV upper or lower tract disease is controversial but may include oral or aerosolized ribavirin in some populations. There are no approved vaccines or licensed antivirals for parainfluenza, rhinovirus, hMPV, and coronavirus. Potential management strategies for these viruses are given. Future studies should include prospective trials using contemporary molecular diagnostics to understand the true epidemiology, clinical spectrum, and long‐term consequences of respiratory viruses as well as to define preventative and therapeutic measures.

Pediatric heart transplantation from an influenza B-positive donor

As heart transplantation demand is increasing without subsequent growth of the donor pool, need for expansion of acceptance criteria is paramount, particularly when considering critically ill, highly sensitized patients. We present a case report of a pediatric heart transplant recipient of an organ refused by 197 prior potential recipients due to the donor being infected with influenza virus. We perform a literature review of recent solid organ transplant cases from influenza-positive donors and conclude that the donor pool may be expandable by allowing donors with treatable infections to be included.

Prevention and Treatment of Respiratory Virus Infection

There is increasing recognition of infections caused by respiratory viruses (RVs) as a major cause of morbidity and mortality in solid organ transplant (SOT) recipients, especially within the thoracic and pediatric population. In addition to their direct, cytopathic, and tissue-invasive effects, RVs can create an inflammatory environment, autoimmune responses, resulting in acute and chronic rejection, although this relationship remains controversial. A laboratory diagnosis in SOT with respiratory syndrome should be performed with nucleic acid amplification tests on respiratory specimens, mainly nasopharyngeal swabs (NPS) and bronchoalveolar lavage (BAL). Treatment options remain limited and consist of supportive care, reduction of immunosuppression, and, if available, antiviral therapy. The use of immunomodulatory agents remains a clinical dilemma. Since treatment options for RVs are limited, maximizing prevention measures against viral infections in SOT is mandatory. The main preventive strategy against influenza remains the administration of yearly inactivated influenza vaccine in all SOT. The aim of this review is to summarize the evidence-based recommendations on the diagnostic, preventive, and therapeutic strategies to decrease the burden of RV infections in SOT recipients.

Management of Infection in Patients With Kidney Transplant

With the pervasive nature of chronic kidney disease, kidney transplantation is likely to continue to increase in the coming years. There are many infectious risks related to kidney transplant, including reactivation of latent infections, surgical complications, infectious risks related to immunosuppression, and nosocomial and community-acquired infections. These are described classically via timeline with early infections (first month), middle (1 to 6 months), and late (after 6 months). Kidney transplant patients may suffer from infections secondary to a vast array of organisms, including bacteria, fungi, and viruses. Certain infections, particularly viral infections such as cytomegalovirus, Epstein-Barr virus, and BK virus, may portend acute and chronic implications of the infection and its subsequent impact on graft function. Critical care physicians and nephrologists caring for patients with a renal transplant must understand the broad array of possible infections, atypical presentations, and nuanced implications for appropriate evaluation and subsequent therapy, combined with the need for possible prophylaxis and/or suppression. Multidisciplinary teams, including transplant physicians and infectious diseases physicians, are encouraged strongly.

Practical Guidance for Clinical Microbiology Laboratories: Viruses Causing Acute Respiratory Tract Infections

Respiratory viral infections are associated with a wide range of acute syndromes and infectious disease processes in children and adults worldwide. Many viruses are implicated in these infections, and these viruses are spread largely via respiratory means between humans but also occasionally from animals to humans. This article is an American Society for Microbiology (ASM)-sponsored Practical Guidance for Clinical Microbiology (PGCM) document identifying best practices for diagnosis and characterization of viruses that cause acute respiratory infections and replaces the most recent prior version of the ASM-sponsored Cumitech 21 document, Laboratory Diagnosis of Viral Respiratory Disease, published in 1986. The scope of the original document was quite broad, with an emphasis on clinical diagnosis of a wide variety of infectious agents and laboratory focus on antigen detection and viral culture. The new PGCM document is designed to be used by laboratorians in a wide variety of diagnostic and public health microbiology/virology laboratory settings worldwide. The article provides guidance to a rapidly changing field of diagnostics and outlines the epidemiology and clinical impact of acute respiratory viral infections, including preferred methods of specimen collection and current methods for diagnosis and characterization of viral pathogens causing acute respiratory tract infections. Compared to the case in 1986, molecular techniques are now the preferred diagnostic approaches for the detection of acute respiratory viruses, and they allow for automation, high-throughput workflows, and near-patient testing. These changes require quality assurance programs to prevent laboratory contamination as well as strong preanalytical screening approaches to utilize laboratory resources appropriately. Appropriate guidance from laboratorians to stakeholders will allow for appropriate specimen collection, as well as correct test ordering that will quickly identify highly transmissible emerging pathogens.

Viral infections in solid organ transplant recipients: novel updates and a review of the classics

PURPOSE OF REVIEW

To summarize new discoveries in viral pathogenesis and novel therapeutic and prophylactic strategies in organ transplant recipients.

RECENT FINDINGS

For decades, prophylaxis of cytomegalovirus (CMV) has been the standard preventive strategy, but new clinical trials are expected to determine the advantages of preemptive therapy over prophylaxis. Novel anti-CMV agents, such as maribavir and letermovir, are being studied for the treatment of resistant/refractory CMV as alternatives to foscarnet and cidofovir. CMV immune monitoring may offer individualized management plans. Epstein-Barr virus infections in transplant recipients are difficult to prevent and treat, though recent data suggest possible merit to pretransplant rituximab among high-risk transplant recipients. We review the groundbreaking HIV-to-HIV organ transplant trials, which are expected to revolutionize the care of HIV-infected individuals. Finally, we review topical developments in human herpesvirus 8, Zika virus, RNA respiratory viruses, adenovirus, norovirus, and polyoma viruses in organ transplantation.

SUMMARY

Ongoing trials to optimize CMV prophylaxis and treatment, and outcomes of HIV-to-HIV organ transplantation in the United States, have significant implications to optimize management of these viruses in transplant recipients. Assessment of new antivirals and antiviral strategies, such as adoptive immunotherapy, is warranted for refractory viral infections.

Severe infections in critically ill solid organ transplant recipients

BACKGROUND

Severe infections are among the most common causes of death in immunocompromised patients admitted to the intensive care unit. The epidemiology, diagnosis and treatment of these infections has evolved in the last decade.

AIMS

We aim to provide a comprehensive review of these severe infections in this population.

SOURCES

Review of the literature pertaining to severe infections in critically ill solid organ transplant recipients. PubMed and Embase databases were searched for documents published since database inception until November 2017.

CONTENT

The epidemiology of severe infections has changed in the immunocompromised patients. This population is presenting to the intensive care unit with specific transplantation procedure-related infections, device-associated infections, a multitude of opportunistic viral infections, an increasing number of nosocomial infections and bacterial diseases with a more limited therapeutic armamentarium. Both molecular diagnostics and imaging techniques have had substantial progress in the last decade, which will, we hope, translate into faster and more precise diagnoses, as well as more optimal empirical treatment de-escalation.

IMPLICATIONS

The key clinical elements to improve the outcome of critically ill solid organ transplant recipients depend on the knowledge of geographic epidemiology, specific surgical procedures, net state of immunosuppression, hospital microbial ecology, aggressive diagnostic strategy and search for source control, rapid initiation of antimicrobials and minimization of iatrogenic immunosuppression.

Respiratory Viruses and Other Relevant Viral Infections in the Lung Transplant Recipient

As advances occur in surgical technique, postoperative care, and immunosuppressive therapy, the rate of mortality in the early postoperative period following lung transplantation continues to decline. With the improvements in immediate and early posttransplant mortality, infections and their sequel as well as rejection and chronic allograft dysfunction are increasingly a major cause of posttransplant mortality. This chapter will focus on infections by respiratory viruses and other viral infections relevant to lung transplantation, including data regarding the link between viral infections and allograft dysfunction.

Post-transplant Viral Respiratory Infections in the Older Patient: Epidemiology, Diagnosis, and Management

Organ and stem cell transplantation has been one of the greatest advances in modern medicine, and is the primary treatment modality for many end-stage diseases. As our population ages, so do the transplant recipients, and with that comes many new challenges. Respiratory viruses have been a large contributor to the mortality and morbidity of solid organ transplant (SOT) and hematopoietic stem cell transplant (HSCT) recipients. Respiratory viruses are generally a long-term complication of transplantation and primarily acquired in the community. With the emergence of molecular methods, newer respiratory viruses are being detected. Respiratory viruses appear to cause severe disease in the older transplant population. Influenza vaccine remains the mainstay of prevention in transplant recipients, although immunogenicity of current vaccines is suboptimal. Limited therapies are available for other respiratory viruses. The next decade will likely bring newer antivirals and vaccines to the forefront. Our goal is to provide the most up to date knowledge of respiratory viral infections in our aging transplant population.

Opportunistic Pulmonary Infections in the Solid Organ Transplant Recipient: A Focus on Drug Therapy

Immunosuppression required to prevent allograft rejection in the solid organ transplant recipient increases vulnerability to infections. Given continuous environmental exposure, the lungs are increasingly susceptible to bacterial, viral, and fungal opportunistic infections. Drug therapy options for the treatment of opportunistic pulmonary infections are used infrequently. These medications are often classified as high risk with specific administration instructions, as well as a multitude of toxicities. Therefore, in this article, we will discuss select pulmonary opportunistic infections and their associated drug therapies.

Sepsis and Challenging Infections in the Immunosuppressed Patient in the Intensive Care Unit

In 2017, most intensive care units (ICUs) worldwide are admitting a growing population of immunosuppressed patients. The most common causes of pre-ICU immunosuppression are solid organ transplantation, hematopoietic stem cell transplantation, and infection due to human immunodeficiency virus. In this article, the authors review the most frequent infections that cause critical care illness in each of these 3 immunosuppressed patient populations.

Update in the treatment of non-influenza respiratory virus infection in solid organ transplant recipients

INTRODUCTION

Despite the improved outcomes in solid organ transplantation with regard to prevention of rejection and increased patient and graft survival, infection remains a common cause of morbidity and mortality. Respiratory viruses are a frequent and potentially serious cause of infection after solid organ transplantation. Furthermore, clinical manifestations of respiratory virus infection (RVI) may be more severe and unusual in solid organ transplant recipients (SOTRs) compared with the non-immunocompromised population. Areas covered: This article reviews the non-influenza RVIs that are commonly encountered in SOTRs. Epidemiologic and clinical characteristics are highlighted and available treatment options are discussed. Expert opinion: New diagnostic tools, particularly rapid molecular assays, have expanded the ability to identify specific RVI pathogens in SOTRs. This is not only useful from a treatment standpoint but also to guide infection control practices. More data are needed on RVIs in the solid organ transplant population, particularly regarding their effect on rejection and graft dysfunction. There is also a need for new antiviral agents active against these infections as well as markers that can identify which patients would most benefit from treatment.

Epidemiology and Immediate Indirect Effects of Respiratory Viruses in Lung Transplant Recipients: A 5-Year Prospective Study

The epidemiology of respiratory viruses (RVs) in lung transplant recipients (LTRs) and the relationship of RVs to lung function, acute rejection (AR) and opportunistic infections in these patients are not well known. We performed a prospective cohort study (2009-2014) by collecting nasopharyngeal swabs (NPSs) from asymptomatic LTRs during seasonal changes and from LTRs with upper respiratory tract infectious disease (URTID), lower respiratory tract infectious disease (LRTID) and AR. NPSs were analyzed by multiplex polymerase chain reaction. Overall, 1094 NPSs were collected from 98 patients with a 23.6% positivity rate and mean follow-up of 3.4 years (interquartile range 2.5-4.0 years). Approximately half of URTIDs (47 of 97, 48.5%) and tracheobronchitis cases (22 of 56, 39.3%) were caused by picornavirus, whereas pneumonia was caused mainly by paramyxovirus (four of nine, 44.4%) and influenza (two of nine, 22.2%). In LTRs with LRTID, lung function changed significantly at 1 mo (p = 0.03) and 3 mo (p = 0.04). In a nested case-control analysis, AR was associated with RVs (hazard ratio [HR] 6.54), Pseudomonas aeruginosa was associated with LRTID (HR 8.54), and cytomegalovirus (CMV) replication or disease was associated with URTID (HR 2.53) in the previous 3 mo. There was no association between RVs and Aspergillus spp. colonization or infection (HR 0.71). In conclusion, we documented a high incidence of RV infections in LTRs. LRTID produced significant lung function abnormalities. Associations were observed between AR and RVs, between P. aeruginosa colonization or infection and LRTID, and between CMV replication or disease and URTID.

Respiratory virus infection after allogeneic hematopoietic stem cell transplant in a tropical center: Predictive value of the immunodeficiency scoring index

Background

Respiratory virus infection (RVI) is a prevalent infection in patients after allogeneic hematopoietic stem cell transplant (allo‐HSCT) and can result in significant morbidity and mortality. Ability to assess the potential severity of RVI is important in the management of such patients.

Methods

We reviewed the cases of RVI in allo‐HSCT recipients and explored the predictive value of the immunodeficiency scoring index (ISI) established for respiratory syncytial virus (RSV) and its applicability for RVI caused by other respiratory viruses.

Results

RVI occurred year‐round in our tropical transplant center, with peaks in the middle and end of the year. Ninety‐five of the 195 recipients developed a total of 191 episodes of RVI, giving a cumulative incidence of 28% by 6 months and 52% by 24 months for the first episode of RVI. RSV, influenza, rhinovirus, and parainfluenza were the most common viruses. Pneumonia occurred in 63.64%, 42.31%, and 32.42% of adenovirus, influenza, and RSV RVI episodes, respectively, but was also non‐negligible in the more benign viruses, such as coronavirus (31.58%) and rhinovirus (23.68%). Nineteen of the 63 episodes of viral pneumonia required mechanical ventilation and 14 deaths occurred within 6 weeks of the RVI. Receiver operating characteristic analysis showed that an ISI of ≥8 predicted pneumonia with a positive predictive value of >80% for RVI caused by RSV, influenza, adenovirus, and parainfluenza, while it was not predictive for coronavirus and rhinovirus.

Conclusions

The ISI is a useful aid for decision‐making during clinic consultation for patients presenting with symptoms suggestive of an RVI.

HMGB1 blockade differentially impacts pulmonary inflammation and defense responses in poly(I:C)/LPS-exposed heart transplant mice

A large number of recipients are in a compromised immune defense condition because of the routine application of immunosuppressive regimens after heart transplantation. Our previous work demonstrated that blockade of high-mobility group box 1 (HMGB1) prolongs the graft survival. Whether and how HMGB1 blockade impacts respiratory responses against pathogen-like challenge in organ transplant recipients when it improves cardiac graft are not elucidated. At the present study, after abdominal heterotopic heart transplantation, the recipient mice were treated with HMGB1 mAb, and then challenged with poly(I:C) or LPS intratracheally on day 7 post transplantation. We found that the level of bronchoalveolar lavage (BAL) HMGB1 was elevated after heart transplantation, and aggravated responses to respiratory tract poly(I:C)/LPS challenge were observed. HMGB1 neutralizing mAb treatment in poly(I:C)-challenged recipient mice alleviated pulmonary histopathological changes, neutrophil infiltration and inflammatory cytokine release, but unaffected the level of IFN-β, the distribution of CD11b(+)CD27(+)/CD11b(+)CD27(-) NK cell subsets, and CD8(+) T cell responses. In LPS-exposed recipient mice, HMGB1 mAb treatment ameliorated pulmonary inflammatory damage and enhanced the phagocytosis of phagocytic cells. Thus, this study may establish a basis for the application of HMGB1 blockade to improve the outcomes of heart transplant recipients because HMGB1 inhibition ameliorates pulmonary inflammation, but maintains defense-associated responses.

Infections

Even if heart transplantation is an undisputed source of medical progress, several complications still hamper the outcome of transplanted patients. Among them, infections are associated with significant morbidity, mortality, and economic burden.

Depending on clinical and radiological signs and based on the time interval after transplantation, a broad spectrum of microbial pathogens can be responsible for these infections. This microbiological diversity, associated with altered clinical signs due to immunosuppressive drugs, is a cause of delayed diagnosis and treatment.

The objective of this overview is to provide a structured procedure to explore fever and specific symptoms that can be suggestive of infection in heart-transplanted patients. Furthermore, main preventive and curative strategies will be described.

The Impact of Infection on Chronic Allograft Dysfunction and Allograft Survival After Solid Organ Transplantation

Infectious diseases after solid organ transplantation (SOT) are a significant cause of morbidity and reduced allograft and patient survival; however, the influence of infection on the development of chronic allograft dysfunction has not been completely delineated. Some viral infections appear to affect allograft function by both inducing direct tissue damage and immunologically related injury, including acute rejection. In particular, this has been observed for cytomegalovirus (CMV) infection in all SOT recipients and for BK virus infection in kidney transplant recipients, for community-acquired respiratory viruses in lung transplant recipients, and for hepatitis C virus in liver transplant recipients. The impact of bacterial and fungal infections is less clear, but bacterial urinary tract infections and respiratory tract colonization by Pseudomonas aeruginosa and Aspergillus spp appear to be correlated with higher rates of chronic allograft dysfunction in kidney and lung transplant recipients, respectively. Evidence supports the beneficial effects of the use of antiviral prophylaxis for CMV in improving allograft function and survival in SOT recipients. Nevertheless, there is still a need for prospective interventional trials assessing the potential effects of preventive and therapeutic strategies against bacterial and fungal infection for reducing or delaying the development of chronic allograft dysfunction.

Renal transplantation in human immunodeficiency virus-positive patients: a report of four cases

INTRODUCTION

Renal transplantation (RT) in patients infected with human immunodeficiency virus (HIV) has significantly improved under the advent of combined antiretroviral therapy (cART). The authors describe their experience in RT in patients with HIV from September 2010 to June 2013.

CASES REPORT

Four patients underwent transplantation (3 with HIV-1 and 1 with HIV-2), three patients were male, and one was black. None were coinfected with hepatitis B virus (HBV) or hepatitis C virus (HCV). Etiology of kidney disease was HIV-associated nephropathy (2 patients), immunoglobulin (Ig)A nephropathy, and unknown. Average age at RT was 51 (range, 41-63) years. No patient was of high immunologic risk. Immunosuppression consisted of basiliximab for induction and prednisolone, tacrolimus (TAC), and mycophenolate mofetil for maintenance. TAC levels varied considerably in the early days (8.5-46 ng/mL), requiring major adjustments in TAC dose. Only the HIV-2 patient had delayed graft function. The follow-up of patients with HIV-1 was 37, 19, and 16 months, and 3 months for the HIV-2 patient. CD4+ T cells decreased in the early days after transplantation with subsequent improvement, along with persistent virological suppression. In the HIV-1 group there were no major infectious, cardiovascular, or neoplastic complications. Nevertheless, the HIV-2 patient died 3 months after RT due to H1N1 pneumonia complicated by pulmonary aspergillosis. Average estimated (CKD- EPI) glomerular filtration rate (eGFR) at 6 months was 85.6 mL/min/1.73 m(2).

CONCLUSION

Besides the difficulty in adjusting calcineurin inhibitors levels due to its interaction with antiretroviral therapy, namely with protease inhibitors, no patient had acute rejection. Furthermore, all patients presented an excellent control of viro-immunologic parameters. At the last follow-up neither cardiovascular events nor neoplastic complications were observed. Our results highlight the favorable outcome of RT in HIV-1-infected patients. The HIV-2 patient died due to severe infection, and the clinical management and potential benefit of RT in HIV-2-infected patients needs further study.

Poor positive predictive value of influenza-like illness criteria in adult transplant patients: a case for multiplex respiratory virus PCR testing

Background

Respiratory viral infections (RVIs) are a significant cause of morbidity and mortality among transplant patients. The CDC's influenza‐like illness (ILI) criteria (fever ≥100°F with cough and/or sore throat) are a screening tool for influenza with unknown applicability to the transplant population.

Methods

We reviewed all respiratory virus PCR tests performed on adult patients with a history of solid organ (SOT) or stem cell transplantation (HSCT) during the 2012–2013 influenza season. The positive (PPV) and negative predictive values (NPV) of ILI criteria were calculated.

Results

Of 126 transplant patients (66 HSCT, 60 SOT), 54 (42.8%) tested positive for an RVI by PCR: 24 influenza and 30 non‐influenza. Of 30 patients who met ILI criteria, 12 (40%) were positive for influenza. The PPV and NPV of ILI for influenza were 50% and 82.4%, respectively. Mortality was low (3.7%), but morbidity was high (14.8% required ICU stay) among transplant patients diagnosed with RVI.

Conclusions

Influenza and non‐influenza RVIs are associated with significant morbidity among transplant patients. CDC ILI criteria correlate poorly with PCR‐positive cases of influenza in transplant patients, but may be useful in excluding the diagnosis. Routine RVI PCR testing is recommended for better diagnosis and improved antiviral use in transplant patients with suspected RVI.

Selecting suitable solid organ transplant donors: Reducing the risk of donor-transmitted infections

Selection of the appropriate donor is essential to a successful allograft recipient outcome for solid organ transplantation. Multiple infectious diseases have been transmitted from the donor to the recipient via transplantation. Donor-transmitted infections cause increased morbidity and mortality to the recipient. In recent years, a series of high-profile transmissions of infections have occurred in organ recipients prompting increased attention on the process of improving the selection of an appropriate donor that balances the shortage of needed allografts with an approach that mitigates the risk of donor-transmitted infection to the recipient. Important advances focused on improving donor screening diagnostics, using previously excluded high-risk donors, and individualizing the selection of allografts to recipients based on their prior infection history are serving to increase the donor pool and improve outcomes after transplant. This article serves to review the relevant literature surrounding this topic and to provide a suggested approach to the selection of an appropriate solid organ transplant donor.

Influenza vaccination in immunocompromised patients: efficacy and safety

Yearly administration of the influenza vaccine is the main strategy to prevent influenza in immunocompromised patients. Here, we reviewed the recent literature regarding the clinical significance of the influenza virus infection, as well as the immunogenicity and safety of the influenza vaccine in HIV‑infected individuals, solid-organ and stem-cell transplant recipients and patients receiving biological agents. Epidemiological data produced during the 2009 influenza pandemic have confirmed that immunocompromised patients remain at high risk of influenza-associated complications, namely viral and bacterial pneumonia, hospitalization and even death. The immunogenicity of the influenza vaccine is overall reduced in immunocompromised patients, although a significant clinical protection from influenza is expected to be obtained with vaccination. Influenza vaccination is safe in immunocompromised patients. The efficacy of novel strategies to improve the immunogenicity to the vaccine, such as the use of adjuvanted vaccines, boosting doses and intradermal vaccination, needs to be validated in appropriately powered clinical trials.