Human rhinovirus detection in the lower respiratory tract of hematopoietic cell transplant recipients: association with mortality

Hidden in plain sight: the impact of human rhinovirus infection in adults

BACKGROUND

Human rhinovirus (HRV), a non-enveloped RNA virus, was first identified more than 70 years ago. It is highly infectious and easily transmitted through aerosols and direct contact. The advent of multiplex PCR has enhanced the detection of a diverse range of respiratory viruses, and HRV consistently ranks among the most prevalent respiratory pathogens globally. Circulation occurs throughout the year, with peak incidence in autumn and spring in temperate climates. Remarkably, during the SARS-CoV-2 pandemic, HRV transmission persisted, demonstrating its resistance to stringent public health measures aimed at curbing viral transmission.

MAIN BODY

HRV is characterised by its extensive genetic diversity, comprising three species and more than 170 genotypes. This diversity and substantial number of concurrently circulating strains allows HRVs to frequently escape the adaptive immune system and poses formidable challenges for the development of effective vaccines and antiviral therapies. There is currently a lack of specific treatments. Historically, HRV has been associated with self-limiting upper respiratory infection. However, there is now extensive evidence highlighting its significant role in severe lower respiratory disease in adults, including exacerbations of chronic airway diseases, such as asthma and chronic obstructive pulmonary disease (COPD), as well as pneumonia. These severe manifestations can occur even in immunocompetent individuals, broadening the clinical impact of this ubiquitous virus. Consequently, the burden of rhinovirus infections extends across various healthcare settings, from primary care to general hospital wards and intensive care units. The impact of HRV in adults, in terms of morbidity and healthcare utilisation, rivals that of the other major respiratory viruses, including influenza and respiratory syncytial virus. Recognition of this substantial burden underscores the critical need for novel treatment strategies and effective management protocols to mitigate the impact of HRV infections on public health.

CONCLUSION

This review examines the epidemiology, clinical manifestations, and risk factors associated with severe HRV infection in adults. By drawing on contemporary literature, we aim to provide a comprehensive overview of the virus's significant health implications. Understanding the scope of this impact is essential for developing new, targeted interventions and improving patient outcomes in the face of this persistent and adaptable pathogen.

Pulmonary Immunocompromise in Stem Cell Transplantation and Cellular Therapy

Hematopoietic cell transplantation (HCT) and cellular therapies, such as chimeric-antigen receptor T-cell (CAR-T) treatments, are potentially curative treatments for certain hematologic malignancies and some nonmalignant disorders. However, pulmonary complications, both infectious and noninfectious, remain a significant cause of morbidity and mortality in patients who receive cellular therapies. This review article provides an overview of pulmonary complications encountered in the context of HCT and CAR-T. The authors discuss mechanisms of underlying immunocompromise that lead to a rise in infections. Additionally, they highlight key noninfectious complications of HCT that can mimic acute infections and suggest diagnostic approaches and preventive strategies to distinguish these entities promptly.

Effects of long-term corticosteroid use on susceptibility to respiratory viruses: a narrative review

BACKGROUND

Synthetic glucocorticoids are among the most commonly administered drugs due to their potent immunomodulatory properties. However, they may put patients at risk for infections. Their effect on the incidence of respiratory viral infections (RVIs) remains unclear.

OBJECTIVES

The aim of this review is to provide an insightful overview of the most up-to-date evidence regarding the extent to which the use of corticosteroids (CSs) influences the risk of RVIs.

SOURCES

The PubMed database was searched for studies on the association between CSs and RVIs from inception until 15 December 2023.

CONTENT

CSs have differing impacts on the risk of RVIs in asthma and chronic obstructive pulmonary disease, influenced by both the specific virus and the type and dose of CSs. Furthermore, current data demonstrate that CSs may increase the risk of RVIs in patients with systemic lupus erythematosus, rheumatoid arthritis, vasculitis, solid tumours, haematological malignancies, and among transplant recipients.

IMPLICATIONS

Large-scale studies are imperative to inform a more accurate and personalized risk stratification for RVIs. This, in turn, will point towards new strategies for RVI prevention and associated morbidity and mortality in high-risk populations.

Diffuse Alveolar Hemorrhage in Hematopoietic Cell Transplantation

Diffuse alveolar hemorrhage (DAH) is a morbid syndrome that occurs after autologous and allogeneic hematopoietic cell transplantation in children and adults. DAH manifests most often in the first few weeks following transplantation. It presents with pneumonia-like symptoms and acute respiratory failure, often requiring high levels of oxygen supplementation or mechanical ventilatory support. Hemoptysis is variably present. Chest radiographs typically feature widespread alveolar filling, sometimes with peripheral sparing and pleural effusions. The diagnosis is suspected when serial bronchoalveolar lavages return increasingly bloody fluid. DAH is differentiated from infectious causes of alveolar hemorrhage when extensive microbiological testing reveals no pulmonary pathogens. The cause is poorly understood, though preclinical and clinical studies implicate pretransplant conditioning regimens, particularly those using high doses of total-body-irradiation, acute graft-versus-host disease (GVHD), medications used to prevent GVHD, and other factors. Treatment consists of supportive care, systemic corticosteroids, platelet transfusions, and sometimes includes antifibrinolytic drugs and topical procoagulant factors. Therapeutic blockade of tumor necrosis factor-α showed promise in observational studies, but its benefit for DAH remains uncertain after small clinical trials. Even with these treatments, mortality from progression and relapse is high. Future investigational therapies could target the vascular endothelial cell biology theorized to contribute to alveolar bleeding and pathways that contribute to susceptibility, inflammation, cellular resilience, and tissue repair. This review will help clinicians navigate through the limited evidence to diagnose and treat DAH, counsel patients and families, and plan for future research.

Epidemiological Characteristics and Outcome of Viral Respiratory Tract Infections in the First Year After Allogeneic Hematopoietic Cell Transplantation

Adverse outcomes of viral respiratory tract infections (RTIs) have been reported in recipients of allogeneic hematopoietic cell transplantation. Using a laboratory-developed multiparameter polymerase chain reaction in a consecutive series of 242 patients, we found the highest incidence of viral RTI in the preengraftment phase. The occurrence of multiple episodes of viral RTI or viral pneumonia was significantly associated with a higher hazard of nonrelapse mortality in the first year after transplantation. We observed a 90-day mortality of 19.7% after viral RTI, which was significantly different between patient groups stratified according to the immunodeficiency scoring index.

Are any specific respiratory viruses more severe than others in recipients of allogeneic stem cell transplantation? A focus on lower respiratory tract disease

In the general population, influenza virus, respiratory syncytial virus, and SARS-CoV-2 are considered the most severe community-acquired respiratory viruses (CARVs). However, allogeneic stem cell transplant (allo-SCT) recipients may also face severe courses from other CARVs. This retrospective study compared outcomes of various CARV lower respiratory tract diseases (LRTD) in 235 adult allo-SCT recipients, excluding co-infection episodes. We included 235 adults allo-SCT recipients experiencing 353 CARV LRTD consecutive episodes (130 rhinovirus, 63 respiratory syncytial virus, 43 influenza, 43 human parainfluenza virus, 23 human metapneumovirus, 19 Omicron SARS-CoV-2, 17 common coronavirus, 10 adenovirus and 5 human bocavirus) between December 2013 and June 2023. Day 100 overall survival ranged from 78% to 90% without significant differences among CARV types. Multivariable analysis of day 100 all-cause mortality identified corticosteroid use of >1 to <30 mg/d [Hazard ratio (HR) 2.45, p = 0.02) and ≥30 mg/d (HR 2.20, p = 0.015) along with absolute lymphocyte count <0.2 × 109/L (HR 5.82, p < 0.001) and number of CARV episodes as a continuous variable per one episode increase (HR 0.48, p = 0.001) as independent risk factors for all-cause mortality. Degree of immunosuppression, rather than intrinsic CARV virulence, has the most significant impact on mortality in allo-SCT recipients with CARV-LRTD.

Pretransplant ribavirin and interferon-α therapy for rhinovirus interstitial pneumonia in a RAG1-deficient infant

Severe combined immunodeficiency (SCID) is one of the most serious inborn errors of immunity leading to a fatal infection in early infancy. Allogeneic hematopoietic cell transplantation (HCT) or elective gene therapy prior to infection or live-attenuated vaccination is the current standard of curative treatment. Even in the era of newborn screening for SCID, pretransplant control of severe infection is challenging for SCID. Multiple pathogens are often isolated from immunocompromised patients, and limited information is available regarding antiviral strategies to facilitate curative HCT. We herein present a case of successfully controlled pretransplant pneumonia after ribavirin and interferon-α therapy in an infant with RAG1-deficiency. A four-month-old infant presented with severe interstitial pneumonia due to a co-infection of rhinovirus and Pneumocystis jirovecii. The tentative diagnosis of SCID prompted to start antibiotics and trimethoprim-sulfamethoxazole on ventilatory support. Because of the progressive respiratory failure four days after treatment, ribavirin and then pegylated interferon-α were started. He showed a drastic response to the treatment that led to a curative HCT 32 days after admission. This patient received the genetic diagnosis of RAG1-deficiency. Currently, he is an active 3-year-old boy with normal growth and development. The review of literature indicated that rhinovirus had a comparable or rather greater impact on the mortality of pediatric patients than respiratory syncytial virus. Considered the turn-around time to the genetic diagnosis of SCID, prompt ribavirin plus interferon-α therapy may help to control severe rhinovirus pneumonia and led to the early curative HCT for the affected infants.

Patterns and predictors of positive multiplex polymerase chain reaction respiratory panel among patients with acute respiratory infections in a single center in Lebanon

BACKGROUND

Infectious agents associated with community-acquired acute respiratory infections (ARIs) remain understudied in Lebanon. We aim to assess the microbiological profiles of ARIs by employing polymerase chain reaction (PCR) and identifying predictors of positive PCR results among patients admitted for ARI.

METHODS AND RESULTS

We conducted a retrospective single-center study at the American University of Beirut Medical Center, including all respiratory PCR panels performed on pediatric (< 18) and adult (≥ 18) patients presenting with an ARI from January 2015 to March 2018, prior to the onset of the COVID-19 pandemic. We aimed to identify the epidemiological patterns of ARIs and the factors associated with positive PCRs in both adult and pediatric patients. Among 281 respiratory PCRs, 168 (59.7%) were positive for at least one pathogen, with 54.1% positive PCR for viruses, 7.8% for bacteria species, and 3.9% with virus-bacteria codetection. Almost 60% of the patients received antibiotics prior to PCR testing. PCR panels yielded more positive results in pediatric patients than in adults (P = 0.005). Bacterial detection was more common in adults compared to pediatrics (P < 0.001). The most common organism recovered in the entire population was Human Rhinovirus (RhV) (18.5%). Patients with pleural effusion on chest CT were less likely to have a positive PCR (95% Cl: 0.22-0.99). On multivariate analysis, pediatric age group (P < 0.001), stem cell transplant (P = 0.006), fever (P = 0.03) and UTRI symptoms (P = 0.004) were all predictive of a positive viral PCR.

CONCLUSION

Understanding the local epidemiology of ARI is crucial for proper antimicrobial stewardship. The identification of factors associated with positive respiratory PCR enhances our understanding of clinical characteristics and potential predictors of viral detection in our population.

Within-Host Rhinovirus Evolution in Upper and Lower Respiratory Tract Highlights Capsid Variability and Mutation-Independent Compartmentalization

BACKGROUND

Rhinovirus (RV) infections can progress from the upper (URT) to lower (LRT) respiratory tract in immunocompromised individuals, causing high rates of fatal pneumonia. Little is known about how RV evolves within hosts during infection.

METHODS

We sequenced RV complete genomes from 12 hematopoietic cell transplant patients with infection for up to 190 days from both URT (nasal wash, NW) and LRT (bronchoalveolar lavage, BAL). Metagenomic and amplicon next-generation sequencing were used to track the emergence and evolution of intrahost single nucleotide variants (iSNVs).

RESULTS

Identical RV intrahost populations in matched NW and BAL specimens indicated no genetic adaptation is required for RV to progress from URT to LRT. Coding iSNVs were 2.3-fold more prevalent in capsid over nonstructural genes. iSNVs modeled were significantly more likely to be found in capsid surface residues, but were not preferentially located in known RV-neutralizing antibody epitopes. Newly emergent, genotype-matched iSNV haplotypes from immunocompromised individuals in 2008-2010 could be detected in Seattle-area community RV sequences in 2020-2021.

CONCLUSIONS

RV infections in immunocompromised hosts can progress from URT to LRT with no specific evolutionary requirement. Capsid proteins carry the highest variability and emergent mutations can be detected in other, including future, RV sequences.

Clinical Outcomes of Human Rhinovirus/Enterovirus Infection in Pediatric Hemopoietic Cell Transplant Patients

BACKGROUND

Respiratory viral infections are common among pediatric transplant patients, with human rhinovirus (HRV) being the most frequent. In pediatric patients undergoing hemopoietic cell transplant (HCT), infection with HRV has been associated with progression to lower respiratory tract infection (LRTI) and adverse outcomes. We describe the clinical presentation and outcomes of HRV infection in children undergoing HCT.

METHODS

Single-center retrospective study. HCT recipients who were positive for HRV/EV (HRV+) or negative for any respiratory virus (VN) by BioFire® FilmArray® panel between October 2014 and December 2017, were included. Primary outcomes were progression to LRTI, ICU admission, all-cause mortality at 3 and 6 months, and respiratory event-related mortality at 6 months.

RESULTS

227 patients (160 allogeneic HCT) were included. Of all patients, 108/227 (47.6%) were HRV+. From all HRV+, 95/108 (88%) were symptomatic and 68/107 (63.6%) of the diagnosis were made pretransplant. The median age of HRV+ was significantly lower than VN patients (5 vs 10 years). Cough and rhinorrhea were more frequently observed in HRV+ (53.7 and 60% vs 19.8 and 22.8%, respectively). No differences were found between both groups pretransplant and overall in rates progression to LRTI, ICU admission, mechanical ventilation, all-cause within 3 and 6 months, and mortality related with respiratory failure. No significant association was found between the severity of respiratory disease and the type of conditioning, type of transplant, or absolute lymphocyte count.

CONCLUSIONS

HRV infection is frequently detected in HCT recipients but is not associated with severity of respiratory disease, need for intensive care unit or mortality, including those diagnosed before transplant, suggesting that delaying HCT in this scenario may not be needed. Multicenter larger studies are required to confirm these findings.

Risk factors for severity in seasonal respiratory viral infections and how they guide management in hematopoietic cell transplant recipients

PURPOSE OF REVIEW

Seasonal respiratory virus infections (RVIs) often progress to severe diseases in hematopoietic cell transplant (HCT) recipients. This review summarizes the current evidence on risk factors for the severity of RVIs in this high-risk population and provides clinical management.

RECENT FINDINGS

The likelihood of the respiratory viral disease progression depends on the immune status of the host and the type of virus. Conventional host factors, such as the immunodeficiency scoring index and the severe immunodeficiency criteria, have been utilized to estimate the risk of progression to severe disease, including mortality. Recent reports have suggested nonconventional risk factors, such as hyperglycemia, hypoalbuminemia, prior use of antibiotics with broad anaerobic activity, posttransplant cyclophosphamide, and pulmonary impairment after RVIs. Identifying novel and modifiable risk factors is important with the advances of novel therapeutic and preventive interventions for RVIs.

SUMMARY

Validation of recently identified risk factors for severe RVIs in HCT recipients is required. The development of innovative interventions along with appropriate risk stratification is critical to improve outcomes in this vulnerable population.

Respiratory virus infections after allogeneic stem cell transplantation: Current understanding, knowledge gaps, and recent advances

Before the COVID-19 pandemic, common community-acquired seasonal respiratory viruses (CARVs) were a significant threat to the health and well-being of allogeneic hematopoietic cell transplant (allo-HCT) recipients, often resulting in severe illness and even death. The pandemic has further highlighted the significant risk that immunosuppressed patients, including allo-HCT recipients, face when infected with SARS-CoV-2. As preventive transmission measures are relaxed and CARVs circulate again among the community, including in allo-HSCT recipients, it is crucial to understand the current state of knowledge, gaps, and recent advances regarding CARV infection in allo-HCT recipients. Urgent research is needed to identify seasonal respiratory viruses as potential drivers for future pandemics.

Remdesivir or Nirmatrelvir/Ritonavir Therapy for Omicron SARS-CoV-2 Infection in Hematological Patients and Cell Therapy Recipients

BACKGROUND

Scarce data exist that analyze the outcomes of hematological patients with SARS-CoV-2 infection during the Omicron variant period who received treatment with remdesivir or nirmatrelvir/ritonavir.

METHODS

This study aims to address this issue by using a retrospective observational registry, created by the Spanish Hematopoietic Stem Cell Transplantation and Cell Therapy Group, spanning from 27 December 2021 to 30 April 2023.

RESULTS

This study included 466 patients, 243 (52%) who were treated with remdesivir and 223 (48%) with nirmatrelvir/ritonavir. Nirmatrelvir/ritonavir was primarily used for mild cases, resulting in a lower COVID-19-related mortality rate (1.3%), while remdesivir was preferred for moderate to severe cases (40%), exhibiting a higher mortality rate (9%). A multivariate analysis in the remdesivir cohort showed that male gender (odds ratio (OR) 0.35, p = 0.042) correlated with a lower mortality risk, while corticosteroid use (OR 9.4, p < 0.001) and co-infection (OR 2.8, p = 0.047) were linked to a higher mortality risk. Prolonged virus shedding was common, with 52% of patients shedding the virus for more than 25 days. In patients treated with remdesivir, factors associated with prolonged shedding included B-cell malignancy as well as underlying disease, severe disease, a later onset of and shorter duration of remdesivir treatment and a higher baseline viral load. Nirmatrelvir/ritonavir demonstrated a comparable safety profile to remdesivir, despite a higher risk of drug interactions.

CONCLUSIONS

Nirmatrelvir/ritonavir proved to be a safe and effective option for treating mild cases in the outpatient setting, while remdesivir was preferred for severe cases, where corticosteroids and co-infection significantly predicted worse outcomes. Despite antiviral therapy, prolonged shedding remains a matter of concern.

Not all respiratory infections were SARS-CoV-2 during the pandemic, analysis in a clinic on the Colombian Caribbean coast

INTRODUCTION

Acute Respiratory Infections (ARIs) are considered one of the leading causes of morbidity and mortality worldwide. Children under five and older adults are most likely to die from this cause.

OBJECTIVE

To describe the behavior of infection by respiratory viruses other than SARS-CoV-2 during the pandemic in a clinic in the Colombian Caribbean.

METHODS

This descriptive and retrospective study evaluates the characteristics, associated comorbidities, and requirements of hospitalization or Intensive Care Unit in patients diagnosed with respiratory viral infections treated at IMAT Oncomedica clinic from July 2020 to August 2022.

RESULTS

This study evaluated 351 patients with respiratory symptoms, observing an exponential increase in cases of respiratory infection as of April 2022, with a high proportion of syncytial virus infections mainly in children under 18 years of age (22.1%) and Human Rhinovirus/Enterovirus in patients with solid tumors and hematological disorders (48.8%), the latter was associated with a higher rate of hospitalization and ICU requirement in the individuals evaluated.

CONCLUSIONS

Respiratory viruses other than SARS-CoV-2, such as Rhino/Enterovirus, RSV, and adenovirus, are circulating in the population at a clinic on the Colombian Caribbean coast. The findings should motivate public health authorities to conduct more thorough surveillance in the rest of the state.

Within-host rhinovirus evolution in upper and lower respiratory tract highlights capsid variability and mutation-independent compartmentalization

Background

Human rhinovirus (HRV) infections can progress from the upper (URT) to lower (LRT) respiratory tract in immunocompromised individuals, causing high rates of fatal pneumonia. Little is known about how HRV evolves within hosts during infection.

Methods

We sequenced HRV complete genomes from 12 hematopoietic cell transplant patients with prolonged infection for up to 190 days from both URT (nasal wash, NW) and LRT (bronchoalveolar lavage, BAL) specimens. Metagenomic (mNGS) and amplicon-based NGS were used to study the emergence and evolution of intra-host single nucleotide variants (iSNVs).

Results

Identical HRV intra-host populations in matched NW and BAL specimens indicated no genetic adaptation is required for HRV to progress from URT to LRT. Microbial composition between matched NW and BAL confirmed no cross-contamination during sampling procedure. Coding iSNVs were 2.3-fold more prevalent in capsid over non-structural genes, adjusted for length. iSNVs modeled onto HRV capsid structures were significantly more likely to be found in surface residues, but were not preferentially located in known HRV neutralizing antibody epitopes. Newly emergent, serotype-matched iSNV haplotypes from immunocompromised individuals from 2008-2010 could be detected in Seattle-area community HRV sequences from 2020-2021.

Conclusion

HRV infections in immunocompromised hosts can progress from URT to LRT with no specific evolutionary requirement. Capsid proteins carry the highest variability and emergent mutations can be detected in other, including future, HRV sequences.

Rhinovirus/enterovirus identification by electron microscopy in lower respiratory tract infection in a patient with relapsed myelodysplastic syndrome after allogeneic hematopoietic cell transplantation and donor lymphocyte infusion

Donor lymphocyte infusion (DLI) is a curable treatment option, inducing a graft-versus-tumor effect in patients with relapsed hematological malignancies after allogeneic hematopoietic cell transplantation (allo-HCT). However, not only graft-versus-host disease but also pulmonary complications are problematic adverse events after DLI. Although viral infections can be associated with pulmonary complications after DLI, the mechanism underlying these complications remains unclear. Detecting the causative virus infections after pulmonary complications following DLI is challenging, as invasive examinations, such as bronchoalveolar lavage and lung biopsies, are necessary. Family Picornaviridae, including Human-Rhinovirus (HRV) and Enterovirus (EnV), can induce fatal lower respiratory tract infection (LRTI) in recipients who undergo allo-HCT, which can be underdiagnosed. We encountered a 62-year-old man with relapsed myelodysplastic syndrome 20 days after a second HLA-haplo-identical allo-HCT and 4 DLI procedures who was later found to have HRV and EnV LRTI by postmortem electron microscopy. Despite high-dose immunosuppression, severe hypoxemia did not improve, and he succumbed to respiratory failure. Immunosuppressive therapy for idiopathic pneumonia syndrome after allo-HCT may be effective, but its efficacy for acute respiratory failure after DLI is controversial. Our case indicated that the control of viral replication should be prioritized over that of inflammation in HRV and EnV LRTI after DLI.

Polymicrobial Infections in the Immunocompromised Host: The COVID-19 Realm and Beyond

Immunosuppression changes both susceptibility to and presentation of infection. Infection with one pathogen can also alter host response to a different, unrelated pathogen. These interactions have been seen across multiple infection domains where bacteria, viruses or fungi act synergistically with a deleterious impact on the host. This phenomenon has been well described with bacterial and fungal infections complicating influenza and is of particular interest in the context of the COVID-19 pandemic. Modulation of the immune system is a crucial part of successful solid organ and hematopoietic stem cell transplantation. Herein, we present three cases of polymicrobial infection in transplant recipients. These case examples highlight complex host–pathogen interactions and the resultant clinical syndromes.

Exposure to antibiotics with anaerobic activity before respiratory viral infection is associated with respiratory disease progression after hematopoietic cell transplant

We examined associations between specific antibiotic exposures and progression to lower respiratory tract disease (LRTD) following individual respiratory viral infections (RVIs) after hematopoietic cell transplantation (HCT). We analyzed allogeneic HCT recipients of all ages with their first RVI during the first 100 days post-HCT. For the 21 days before RVI onset, we recorded any receipt of specific groups of antibiotics, and the cumulative sum of the number of antibiotics received for each day (antibiotic-days). We used Cox proportional hazards models to assess the relationship between antibiotic exposure and progression to LRTD. Among 469 patients with RVI, 124 progressed to LRTD. Compared to no antibiotics, use of antibiotics with broad anaerobic activity in the prior 21 days was associated with progression to LRTD after adjusting for age, virus type, hypoalbuminemia, neutropenia, steroid use, and monocytopenia (HR 2.2, 95% CI 1.1-4.1). Greater use of those antibiotics (≥7 antibiotic days) was also associated with LRTD in adjusted models (HR 2.2, 95% CI 1.1-4.3). Results were similar after adjusting for lymphopenia instead of monocytopenia. Antibiotic use is associated with LRTD after RVI across different viruses in HCT recipients. Prospective studies using anaerobe-sparing antibiotics should be explored to assess impact on LRTD in patients undergoing HCT.

Respiratory viruses in hematopoietic cell transplant candidates: impact of preexisting lower tract disease on outcomes

In myeloablative allogeneic HCT recipients, pretransplant LRD by any virus was associated with increased mortality.

Pretransplant respiratory virus infections (RVIs) have been shown to negatively affect hematopoietic cell transplantation (HCT) outcomes. The impact of and need for delay of HCT for pretransplant infection with human rhinovirus (HRV) or endemic human coronavirus (HCoV; 229E, OC43, NL63, and HKU1) remain controversial. We analyzed the impact of symptomatic RVI within ≤90 days before HCT on overall mortality, posttransplant lower respiratory tract disease (LRD), and days alive and out of hospital (DAOH) by day 100 post-HCT in multivariable models. Among 1,643 adult HCT recipients (58% allogeneic recipients), 704 (43%) were tested for RVI before HCT, and 307 (44%) tested positive. HRV was most commonly detected (56%). Forty-five (15%) of 307 HCT recipients had LRD with the same virus early after HCT. Pretransplant upper respiratory tract infection (URI) with influenza, respiratory syncytial virus, adenovirus, human metapneumovirus, parainfluenza virus, HRV, or endemic HCoV was not associated with increased overall mortality or fewer DAOH. However, in allogeneic recipients who received myeloablative conditioning, LRD due to any respiratory virus, including HRV alone, was associated with increased overall mortality (adjusted hazard ratio, 10.8 [95% confidence interval, 3.29-35.1] for HRV and 3.21 [95% confidence interval, 1.15-9.01] for all other viruses). HRV LRD was also associated with fewer DAOH. Thus, the presence of LRD due to common respiratory viruses, including HRV, before myeloablative allogeneic HCT was associated with increased mortality and hospitalization. Pretransplant URI due to HRV and endemic HCoV was not associated with these outcomes. Improved management strategies for pretransplant LRD are warranted.

Novel factors to predict respiratory viral disease progression in allogeneic hematopoietic cell transplant recipients

We assessed novel factors and the immunodeficiency scoring index (ISI) to predict progression to lower respiratory tract infection (LRTI) among hematopoietic cell transplant (HCT) recipients presenting with upper respiratory tract infection (URTI) with 12 viruses in the PCR era. We retrospectively analyzed the first respiratory virus detected by multiplex PCR in allogeneic HCT recipients (4/2008-9/2018). We used Cox proportional hazards models to examine factors for progression to LRTI within 90 days among patients presenting with URTI. A total of 1027 patients (216 children and 811 adults) presented with URTI only. Among these, 189 (18%) progressed to LRTI (median: 12 days). Multivariable models demonstrated a history of  >1 transplant, age  ≥40 years, time post-HCT (≤30 days), systemic steroids, hypoalbuminemia, hyperglycemia, cytopenia, and high ISI (scores 7-12) were associated with an increased risk of progression to LRTI. Respiratory syncytial virus and human metapneumovirus showed the highest progression risk. Patients with ≥3 independent risk factors or high ISI scores were highly likely to progress to LRTI. We identified novel risk factors for progression to LRTI, including history of multiple transplants and hyperglycemia, suggesting an intervention opportunity with glycemic control. ISI and number of risk factors appear to predict disease progression across several viruses.

Airway disease in hematologic malignancies

INTRODUCTION

Hematologic malignancies are cancers of the blood, bone marrow and lymph nodes and represent a heterogenous group of diseases that affect people of all ages. Treatment generally involves chemotherapeutic or targeted agents that aim to kill malignant cells. In some cases, hematopoietic stem cell transplantation (HCT) is required to replenish the killed blood and stem cells. Both disease and therapies are associated with pulmonary complications. As survivors live longer with the disease and are treated with novel agents that may result in secondary immunodeficiency, airway diseases and respiratory infections will increasingly be encountered. To prevent airways diseases from adding to the morbidity of survivors or leading to long-term mortality, improved understanding of the pathogenesis and treatment of viral bronchiolitis, BOS, and bronchiectasis is necessary.

AREAS COVERED

This review focuses on viral bronchitis, BOS and bronchiectasis in people with hematological malignancy. Literature was reviewed from Pubmed for the areas covered.

EXPERT OPINION

Airway disease impacts significantly on hematologic malignancies. Viral bronchiolitis, BOS and bronchiectasis are common respiratory manifestations in hematological malignancy. Strategies to identify patients early in their disease course may improve the efficacy of treatment and halt progression of lung function decline and improve quality of life.

Rhinovirus Infections among Hematopoietic Stem Cell Transplant Recipients: A Pre-Transplant Dilemma?

Respiratory viral infections (RVIs) in allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients can be of concern due to the patients’ depressed immune status, but few data are available about the significance of a pre-transplant positive testing. In this retrospective observational study, we analyzed a cohort of patients that were transplanted between 1 January 2010 and 31 October 2019 in the Geneva University Hospitals with at least one RVI before or after transplantation. At least one RVI was detected in 319/533 (63.5%) transplanted patients. Rhinoviruses were most frequently identified (37%), followed by human coronaviruses (17.1%), parainfluenza viruses (13.9%), and influenza viruses (9.9%). First infection in the post-transplant period occurred at a mean time of 334 days (SD 338). Specific analysis of a subgroup of 65 patients with pre-transplant RVIs was performed. Among them, 39 (59%) patients had symptoms and 14 (21.2%) had a lower respiratory tract infection. Four patients (6.1%) (three rhinovirus and one influenza) needed an intensive care unit admission, of which, three (4.5%) (two rhinovirus and one influenza) were intubated. The patient with influenza infection diagnosed the day of the transplantation died within the first 30 days of the infection. Two patients with rhinovirus infection died within 3 months of unrelated causes. Our data show that rhinovirus infections are predominant in allo-HSCT patients, including among pre-transplant infections; however, mortality due to pre-transplant RVI is low and was only clearly identified in one patient with influenza infection. RVI within the month preceding allo-HSCT is not associated with direct morbidity or mortality in this cohort.

Pulmonary Complications After Pediatric Stem Cell Transplant

The number of disorders that benefit from hematopoietic stem cell transplantation (HSCT) has increased, causing the overall number of HSCT to increase accordingly. Disorders treated by HSCT include malignancy, benign hematologic disorders, bone marrow failure syndromes, and certain genetic diagnoses. Thus, understanding the complications, diagnostic workup of complications, and subsequent treatments has become increasingly important. One such category of complications includes the pulmonary system. While the overall incidence of pulmonary complications has decreased, the morbidity and mortality of these complications remain high. Therefore, having a clear differential diagnosis and diagnostic workup is imperative. Pulmonary complications can be subdivided by time of onset and whether the complication is infectious or non-infectious. While most infectious complications have clear diagnostic criteria and treatment courses, the non-infectious complications are more varied and not always well understood. This review article discusses pulmonary complications of HSCT recipients and outlines current knowledge, gaps in knowledge, and current treatment of each complication. This article includes some adult studies, as there is a significant paucity of pediatric data.

Characteristics of viral pneumonia in non-HIV immunocompromised and immunocompetent patients: a retrospective cohort study

BACKGROUND

Concerning viral pneumonia, few large-scale comparative studies have been published describing non-HIV immunocompromised and immunocompetent patients, but the epidemiological characteristics of different viruses or underlying diseases in immunocompromised hosts are lacking.

METHODS

We retrospectively recruited patients hospitalised with viral pneumonia from six academic hospitals in China between August 2016 and December 2019. We measured the prevalence of comorbidities, coinfections, nosocomial infections, and in-hospital mortalities.

RESULTS

Of the 806 patients, 370 were immunocompromised and 436 were immunocompetent. The disease severity and in-hospital mortality of immunocompromised patients were higher than those of immunocompetent patients. During the influenza season, an increased number of cases of influenza virus (IFV) infection were found in the immunocompromised group, followed by cases of cytomegalovirus (CMV) and respiratory syncytial virus (RSV) infection. During the non-influenza season, CMV was the main virus detected in the immunocompromised group, while RSV, adenovirus (AdV), parainfluenza virus (PIV), and rhinovirus (HRV) were the main viruses detected in the immunocompetent group. Pneumonia caused by Pneumocystis jirovecii (22.4%), Aspergillus spp. (14.1%), and bacteria (13.8%) were the most frequently observed coinfections in immunocompromised patients but not in immunocompetent patients (Aspergillus spp. [10.8%], bacteria [7.1%], and Mycoplasma spp. [5.3%]). CMV infection and infection with two-or-more viruses were associated with a higher in-hospital mortality rate than non-IFV infection. However, patients with IFV and non-IFV infection in immunocompromised patients had similar disease severity and prognosis.

CONCLUSIONS

Immunocompromised patients have a high frequency of coinfections, and a higher mortality rate was observed among those infected with CMV and two-or-more viruses. In addition, patients with IFV and non-IFV infection in immunocompromised patients had similar same disease severity and prognosis. The type of viral infection varied with seasons.

Defining substrate selection by rhinoviral 2A proteinase through its crystal structure with the inhibitor zVAM.fmk

Picornavirus family members cause disease in humans. Human rhinoviruses (RV), the main causative agents of the common cold, increase the severity of asthma and COPD; hence, effective agents against RVs are required. The 2A proteinase (2A^pro), found in all enteroviruses, represents an attractive target; inactivating mutations in poliovirus 2A^pro result in an extension of the VP1 protein preventing infectious virion assembly. Variations in sequence and substrate specificity on eIF4G isoforms between RV 2A^pro of genetic groups A and B hinder 2A^pro as drug targets. Here, we demonstrate that although RV-A2 and RV-B4 2A^pro cleave the substrate GAB1 at different sites, the 2A^pro from both groups cleave equally efficiently an artificial site containing P1 methionine. We determined the RV-A2 2A^pro structure complexed with zVAM.fmk, containing P1 methionine. Analysis of this first 2A^pro-inhibitor complex reveals a conserved hydrophobic P4 pocket among enteroviral 2A^pro as a potential target for broad-spectrum anti-enteroviral inhibitors.

Sub-structure-based screening and molecular docking studies of potential enteroviruses inhibitors

Rhinoviruses (RV), especially Human rhinovirus (HRVs) have been accepted as the most common cause for upper respiratory tract infections (URTIs). Pleconaril, a broad spectrum anti-rhinoviral compound, has been used as a drug of choice for URTIs for over a decade. Unfortunately, for various complications associated with this drug, it was rejected, and a replacement is highly desirable. In silico screening and prediction methods such as sub-structure search and molecular docking have been widely used to identify alternative compounds. In our study, we have utilised sub-structure search to narrow down our quest in finding relevant chemical compounds. Molecular docking studies were then used to study their binding interaction at the molecular level. Interestingly, we have identified 3 residues that is worth further investigation in upcoming molecular dynamics simulation systems of their contribution in stable interaction.

Risk factors for seasonal human coronavirus lower respiratory tract infection after hematopoietic cell transplantation

We demonstrate risk factors for HCoV LRTI in allogeneic HCT recipients and significance of virologic documentation by BAL on mortality.

Hyperglycemia associated with steroid use appears to be a strong predictor of HCoV disease progression.

Data are limited regarding risk factors for lower respiratory tract infection (LRTI) caused by seasonal human coronaviruses (HCoVs) and the significance of virologic documentation by bronchoalveolar lavage (BAL) on outcomes in hematopoietic cell transplant (HCT) recipients. We retrospectively analyzed patients undergoing allogeneic HCT (4/2008-9/2018) with HCoV (OC43/NL63/HKU1/229E) detected by polymerase chain reaction during conditioning or post-HCT. Risk factors for all manifestations of LRTI and progression to LRTI among those presenting with HCoV upper respiratory tract infection (URTI) were analyzed by logistic regression and Cox proportional hazard models, respectively. Mortality rates following HCoV LRTI were compared according to virologic documentation by BAL. A total of 297 patients (61 children and 236 adults) developed HCoV infection as follows: 254 had URTI alone, 18 presented with LRTI, and 25 progressed from URTI to LRTI (median, 16 days; range, 2-62 days). Multivariable logistic regression analyses showed that male sex, higher immunodeficiency scoring index, albumin <3 g/dL, glucose >150 mg/dL, and presence of respiratory copathogens were associated with occurrence of LRTI. Hyperglycemia with steroid use was associated with progression to LRTI (P < .01) in Cox models. LRTI with HCoV detected in BAL was associated with higher mortality than LRTI without documented detection in BAL (P < .01). In conclusion, we identified factors associated with HCoV LRTI, some of which are less commonly appreciated to be risk factors for LRTI with other respiratory viruses in HCT recipients. The association of hyperglycemia with LRTI might provide an intervention opportunity to reduce the risk of LRTI.

Viral Loads and Disease Severity in Children with Rhinovirus-Associated Illnesses

The role of rhinoviruses (RVs) in children with clinical syndromes not classically associated with RV infections is not well understood. We analyzed a cohort of children ≤21 years old who were PCR+ for RV at a large Pediatric Hospital from 2011 to 2013. Using univariate and multivariable logistic regression, we analyzed the associations between demographic, clinical characteristics, microbiology data, and clinical outcomes in children with compatible symptoms and incidental RV detection. Of the 2473 children (inpatients and outpatients) with an RV+ PCR, 2382 (96%) had compatible symptoms, and 91 (4%) did not. The overall median age was 14 months and 78% had underlying comorbidities. No differences in RV viral loads were found according to the presence of compatible symptoms, while in children with classic RV symptoms, RV viral loads were higher in single RV infections versus RV viral co-infections. Bacterial co-infections were more common in RV incidental detection (7.6%) than in children with compatible symptoms (1.9%, p < 0.001). The presence of compatible symptoms independently increased the odds ratio (OR, 95% CI) of hospitalization 4.8 (3.1-7.4), prolonged hospital stays 1.9 (1.1-3.1), need for oxygen 12 (5.8-25.0) and pediatric intensive care unit (PICU) admission 4.13 (2.0-8.2). Thus, despite comparable RV loads, disease severity was significantly worse in children with compatible symptoms.

Characteristics of respiratory virus infections in autologous hematopoietic stem cell transplantation patients, a prospective study, Bern, Switzerland, 2015-2017

BACKGROUND

The epidemiology of respiratory virus infections (RVI) in patients undergoing autologous haematopoietic stem cell transplantation (auto-SCT) is not well described.

METHODS

Our goal was to describe the epidemiology of respiratory virus infections (RVI) in patients undergoing autologous haematopoietic stem cell transplantation (auto-SCT) in a single tertiary centre observation study during two respiratory virus seasons (2015-2017). All symptomatic auto-SCT patients were tested for RVI by nasopharyngeal swab.

RESULTS

156 transplantation episodes were included, 69% were male and, the median age was 57 years. We detected 19 RVIs in 156 transplantation episodes (12%). The median time to RVI after hospitalization was 13 days [IQR 7-13] and 15/19 (79%) had a possible nosocomial origin (occurrence ≥ 5 days after admission). The nosocomial infections included 5/15 (33%) 'severe' RVIs (3 influenza viruses, 1 parainfluenza virus, and 1 adenovirus) as well as 10/15 (66%) non-severe virus infections (including human rhinovirus and human coronavirus).

CONCLUSION

In approximately 10% of auto-SCT transplantation episodes, an RVI with likely nosocomial origin was detected and included 'severe viruses' such as influenza. Our study suggests that infection prevention measures in auto-SCT patients can be improved.

ABBREVIATIONS

AdV: adenovirus; ALL: acute lymphatic leukaemia; AML: acute myeloid leukaemia; auto-SCT: autologous haematopoietic stem cell transplantation; hCoV: human coronavirus; HD: Hodgkin's disease; hMPV: human metapneumovirus; HRV: human rhinovirus; HSCT: allogeneic haematopoietic stem cell transplantation; IQR: interquartile range; GCT: germ cell tumour; MM: multiple myeloma; NHL: non-Hodgkin lymphoma; PIV: parainfluenza virus; RSV: respiratory syncytial virus.

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).

Frequency of asymptomatic and symptomatic respiratory virus detection in pediatric hematopoietic cell transplant patients

Respiratory viral infections are common and can cause significant morbidity and mortality in pediatric patients undergoing hematopoietic cell transplantation (HCT). The prevalence of disease has been primarily identified from retrospective studies using standard-of-care specimens. The incidence of both asymptomatic respiratory viral detection and symptomatic respiratory viral detection in this high-risk population is not well described. We performed longitudinal, active, prospective surveillance in pediatric HCT patients. Subjects underwent weekly midturbinate swabs (MTSs) for the detection of 18 respiratory viruses and subtypes peri-HCT and 100 days post-HCT. Clinical data were obtained from the medical record. From September 2015 to February 2017, 24 children underwent 29 HCT, and 284 MTSs were collected. Forty-two (15%) specimens were virus-positive from 10 (42%) subjects. Specimens from children undergoing allogeneic HCT were more likely to have a virus detected (17% vs 8%, P = .04) compared with specimens from children undergoing autologous HCT. Sixteen (38%) detections were not associated with symptoms. Almost half (8/17) of the unique viral infections occurred during the HCT hospitalization after a negative specimen, suggesting nosocomial acquisition, and preceded detection from a clinical specimen. Rhinovirus, the most common virus detected, was the only virus detected in 33 (81%) virus-positive specimens; only 11 (33%) rhinovirus detections were asymptomatic. Asymptomatic detection of coronavirus and bocavirus occurred. Asymptomatic respiratory virus detection occurred in more than one-third of the children undergoing HCT. The acquisition of respiratory viruses during HCT hospitalization suggests nosocomial acquisition. Early detection of respiratory viruses during asymptomatic periods could have infection prevention and treatment implications.

The clinical benefit of instituting a prospective clinical community-acquired respiratory virus surveillance program in allogeneic hematopoietic stem cell transplantation

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Rapid detection methods used as first diagnostic test for CARVs may delayed the start of antiviral therapy in a significant number of influenza and RSV cases.

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Syndromic multiplex RT-PCR-based prospective clinical CARV survey in allo-HCT recipients translates into a lower mortality rate as compared to standard clinical practice based on RSV and influenza virus rapid detection test.

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We found that donor/recipient HLA mismatch, CARV LRTD and high-risk ISI were also associated with higher mortality.

Background

There is a lack of studies comparing clinical outcomes among retrospective versus prospective cohorts of allogeneic stem cell transplant (allo-HCT) recipients with community acquired respiratory virus (CARV) infections.

Methods

We compare outcomes in two consecutive cohorts of allo-HCT recipients with CARV infections. The retrospective cohort included 63 allo-HCT recipients with 108 CARV infections from January 2013 to April 2016 who were screened and managed following standard clinical practice based on influenza and respiratory syncytial virus rapid antigen detection methods. The prospective cohort was comprised of 144 consecutive recipients with 297 CARV episodes included in a prospective interventional clinical surveillance program (ProClinCarvSur-P) based on syndromic multiplex PCR as first-line test from May 2016 to December 2018 at a single transplant center.

Results

CARV infections in the retrospective cohort showed more severe clinical features at the time of diagnosis compared to the prospective cohort (fever 83% vs. 57%, hospital admission 69% vs. 28% and lower respiratory tract 58% vs. 31%, respectively, p ≤ 0.002 for all comparisons). Antiviral therapy was more commonly prescribed in the prospective cohort (69 vs. 43 treated CARV episodes), particularly at the upper respiratory tract disease stage (34 vs. 12 treated CARV episodes). Three-month all-cause mortality was significantly higher in the retrospective cohort (n = 23, 37% vs. n = 10, 7%, p < 0.0001). Multivariate logistic regression analysis showed that recipients included in ProClinCarvSur-P had lower mortality rate [odds ratio 0.31, 95% confidence interval 0.12–0.7, p = 0.01].

Conclusion

This study report on outcome differences when reporting retrospective vs. prospective CARV infections after allo-HCT. Recipients included in a ProClinCarvSur-P had lower mortality.

Clinical Significance of Upper Airway Virus Detection in Critically Ill Hematology Patients

RATIONALE

Noninvasive diagnostic multiplex molecular tests may enable the early identification and treatment of viral infections in critically ill immunocompromised patients.

OBJECTIVES

To assess the association between viral detection in nasopharyngeal swabs and ICU mortality in critically ill hematology patients.

METHODS

This was a post hoc analysis of a prospective cohort of critically ill hematology patients admitted to 17 ICUs. Nasal swabs sampled and frozen at ICU admission were tested using a multiplex PCR assay. Predictors of ICU mortality and assay positivity were identified.

MEASUREMENTS AND MAIN RESULTS

Of the 747 patients (447 with acute respiratory failure [ARF]), 21.3% had a virus detected (56.4% rhinovirus/enterovirus and 30.7% influenza/parainfluenza/respiratory syncytial viruses). Overall ICU and hospital mortality rates were 26% and 37%, respectively. Assay positivity was associated with lymphoproliferative disorders, hematopoietic stem cell transplantation, treatment with steroids or other immunosuppressants, ARF (25.5% vs. 16.3%; P = 0.004), and death in the ICU (28.9% vs. 19.3%; P = 0.008). The association with ICU mortality was significant for all viruses and was strongest for influenza/parainfluenza/respiratory syncytial viruses. In patients with ARF, detection of any respiratory virus was independently associated with ICU mortality (odds ratio, 2.07; 95% confidence interval, 1.22-3.50).

CONCLUSIONS

Respiratory virus detection in the upper airway by multiplex PCR assay is common in critically ill hematology patients. In patients with ARF, respiratory virus detection was independently associated with ICU mortality. Multiplex PCR assay may prove helpful for the risk stratification of hematology patients with ARF. Studies to understand whether respiratory tract viruses play a causal role in outcomes are warranted.

Are Community Acquired Respiratory Viral Infections an Underestimated Burden in Hematology Patients?

Despite a plethora of studies demonstrating significant morbidity and mortality due to community-acquired respiratory viral (CRV) infections in intensively treated hematology patients, and despite the availability of evidence-based guidelines for the diagnosis and management of respiratory viral infections in this setting, there is no uniform inclusion of respiratory viral infection management in the clinical hematology routine. Nevertheless, timely diagnosis and systematic management of CRV infections in intensively treated hematology patients has a demonstrated potential to significantly improve outcome. We have briefly summarized the recently published data on CRV infection epidemiology, as well as guidelines on the diagnosis and management of CRV infections in patients intensively treated for hematological malignancies. We have also assessed available treatment options, as well as mentioned novel agents currently in development.

Delaying haematopoietic stem cell transplantation in children with viral respiratory infections reduces transplant-related mortality

Viral respiratory infections (VRIs) contribute to the morbidity and transplant‐related mortality (TRM) after allogeneic haematopoietic stem cell transplantation (HSCT) and strategies to prevent and treat VRIs are warranted. We monitored VRIs before and after transplant in children undergoing allogeneic HSCT with nasopharyngeal aspirates (NPA) and assessed the impact on clinical outcome. Between 2007 and 2017, 585 children underwent 620 allogeneic HSCT procedures. Out of 75 patients with a positive NPA screen (12%), transplant was delayed in 25 cases (33%), while 53 children started conditioning with a VRI. Patients undergoing HSCT with a positive NPA screen had a significantly lower overall survival (54% vs. 79%) and increased TRM (26% vs. 7%) compared to patients with a negative NPA. Patients with a positive NPA who delayed transplant and cleared the virus before conditioning had improved overall survival (90%) and lower TRM (5%). Pre‐HSCT positive NPA was the only significant risk factor for progression to a lower respiratory tract infection and was a major risk factor for TRM. Transplant delay, whenever feasible, in case of a positive NPA screen for VRIs can positively impact on survival of children undergoing HSCT.

The effect of timing on community acquired respiratory virus infection mortality during the first year after allogeneic hematopoietic stem cell transplantation: a prospective epidemiological survey

The effect of timing of community acquired respiratory virus (CARV) infection after allogeneic hematopoietic stem cell transplant (allo-HCT) is an as yet unsettled issue. We evaluate this issue by including all consecutive allo-HCT recipients with molecularly-documented CARV infection during the first year after transplant. The study cohort was drawn from a prospective longitudinal survey of CARV in allo-HCT recipient having respiratory symptoms conducted from December 2013 to December 2018 at two Spanish transplant centers. Respiratory viruses in upper and/or lower respiratory specimens were tested using multiplex PCR panel assays. The study cohort comprised 233 allo-HCT recipients with 376 CARV infection episodes diagnosed during the first year after allo-HCT. Overall, 60% of CARV episodes occurred within the first 6 months (227 out of 376). Thirty patients (13%) had died at 3 months after CARV detection, of which 25 (83%) were recipients developing CARV within the first 6 months after transplant. Multivariate analysis identified four risk factors for mortality: ATG used as part of conditioning regimen [odds ratio (OR) 2.8, 95% confidence interval (C.I.) 1.21-6.4, p = 0.01], CARV lower respiratory tract disease (OR 3.4, 95% C.I. 1.4-8.4, p = 0.007), CARV infection within the first 6 months of transplant (OR 3.04, 95% C.I. 1.1-8.7, p = 0.03), and absolute lymphocyte count <0.2 × 109/L (OR 2.4, 95% C.I. 1-5.3, p = 0.04). Developing CARV infection within the first 6 months was associated with higher mortality. Our data supports that the timing of CARV development after allo-HCT could be of major interest.

Community-Acquired Respiratory Viruses in Transplant Patients: Diversity, Impact, Unmet Clinical Needs

Patients undergoing solid-organ transplantation (SOT) or allogeneic hematopoietic cell transplantation (HCT) are at increased risk for infectious complications. Community-acquired respiratory viruses (CARVs) pose a particular challenge due to the frequent exposure pre-, peri-, and posttransplantation. Although influenza A and B viruses have a top priority regarding prevention and treatment, recent molecular diagnostic tests detecting an array of other CARVs in real time have dramatically expanded our knowledge about the epidemiology, diversity, and impact of CARV infections in the general population and in allogeneic HCT and SOT patients. These data have demonstrated that non-influenza CARVs independently contribute to morbidity and mortality of transplant patients. However, effective vaccination and antiviral treatment is only emerging for non-influenza CARVs, placing emphasis on infection control and supportive measures. Here, we review the current knowledge about CARVs in SOT and allogeneic HCT patients to better define the magnitude of this unmet clinical need and to discuss some of the lessons learned from human influenza virus, respiratory syncytial virus, parainfluenzavirus, rhinovirus, coronavirus, adenovirus, and bocavirus regarding diagnosis, prevention, and treatment.

Age-dependent determinants of infectious complications profile in children and adults after hematopoietic cell transplantation: lesson from the nationwide study

Incidence and outcome of microbiologically documented bacterial/viral infections and invasive fungal disease (IFD) in children and adults after hematopoietic cell transplantation (HCT) were compared in 650 children and 3200 adults in multicenter cross-sectional nationwide study. Infections were diagnosed in 60.8% children and 35.0% adults, including respectively 69.1% and 63.5% allo-HCT, and 33.1% and 20.8% auto-HCT patients. The incidence of bacterial infections was higher in children (36.0% vs 27.6%; p < 0.0001). Infections with Gram-negative bacteria were more frequent than Gram-positives in adults (64.6% vs 44.8%; p < 0.0001). Outcome of bacterial infections was better in children (95.5% vs 91.4%; p = 0.0011). The IFD incidence (25.3% vs 6.3%; p < 0.0001) and outcome (88.0% vs 74.9%; p < 0.0001) were higher in children. The incidence of viral infections was higher in children after allo-HCT (56.3% vs 29.3%; p < 0.0001), and auto-HCT (6.6% vs 0.8%; p < 0.0001). Outcome of viral infections was better in children (98.6% vs 92.3%; p = 0.0096). Infection-related mortality was 7.8% in children and 18.4% in adults (p < 0.0001). No child after auto-HCT died of infection. Adult age, mismatched transplants, acute leukemia, chronic GVHD, CMV reactivation, infection with Gram-negatives, and duration of infection > 21 days were risk factors for death from infection. In conclusion, pediatric patients have 2.9-fold higher incidence and 2.5-fold better outcome of infections than adults after HCT.

Respiratory virus associated with surgery in children patients

Background

Viral respiratory infection (VRI) is a common contraindication to elective surgery. Asymptomatic shedding among pediatric surgery patients (PSPs) could potentially lead to progression of symptomatic diseases and cause outbreaks of respiratory diseases. The aim of this study is to investigate the incidence of infection among mild symptomatic PSP group and asymptomatic PSP group after surgical procedure.

Methods

We collected the induced sputum from enrolled 1629 children (under 18 years of age) with no respiratory symptom prior to pediatric surgery between March 2017 and February 2019. We tested 16 different respiratory virus infections in post-surgery mild symptomatic PSP group and asymptomatic PSP group using a quantitative real-time reverse transcriptase polymerase chain reaction (qRT-PCR) assay panel. We analyzed symptom data and quantitative viral load to investigate the association between viruses, symptoms and viral quantity in qRT-PCR-positive PSPs.

Results

Out of 1629 children enrolled, a total of 204 respiratory viruses were present in 171 (10.50%) PSPs including 47 patients with mild symptoms and 124 with no symptoms after surgery. Commonly detected viruses were human rhino/enterovirus (HRV/EV, 42.19%), parainfluenza virus 3 (PIV3, 24.48%), coronavirus (CoV NL63, OC43, HKU1, 11.46%), and respiratory syncytial virus (RSV, 9.9%). PIV3 infection with a higher viral load was frequently found in PSPs presenting with mild symptoms, progressing to pneumonia with radiographic evidence after surgery. HRV/EV were the most commonly detected pathogens in both asymptomatic and mild symptomatic PSPs. CoV (OC43, HKU1) infections with a higher viral load were mostly observed in asymptomatic PSPs progressing to alveolar or interstitial infiltration.

Conclusions

Our study suggested that PIV3 is a new risk factor for VRI in PSPs. Employing a more comprehensive, sensitive and quantitative method should be considered for preoperative testing of respiratory viruses in order to guide optimal surgical timing.

Respiratory Virus Infections of the Stem Cell Transplant Recipient and the Hematologic Malignancy Patient

Respiratory virus infections in hematologic stem cell transplant recipients and patients with hematologic malignancies are increasingly recognized as a cause of significant morbidity and mortality. The often overlapping clinical presentation makes molecular diagnostic strategies imperative for rapid diagnosis and to inform understanding of the changing epidemiology of each of the respiratory viruses. Most respiratory virus infections are managed with supportive therapy, although there is effective antiviral therapy for influenza. The primary focus should remain on primary prevention infection control procedures and isolation precautions, avoidance of ill contacts, and vaccination for influenza.

Societal Implications of the Internet of Pathogens

The growth of pathogen genomics shows no signs of abating. Whole-genome sequencing of clinical viral and bacterial isolates continues to grow in nearly exponential bounds. Reductions in cost driven by new technology have created a seamless environment for generating, sharing, and analyzing pathogen genomes. The high-resolution view of infectious disease transmission dynamics offered by analyzing whole genomes from pathogens, coupled with the genomicist ethic of widespread data sharing, has created a veritable Internet of pathogens, which inadvertently produces new threats to patient privacy and protected heath information. The health care system, and society more generally, have yet to explore the far-reaching privacy concerns raised by readily accessible pathogen genomic data. The recent use of human genomic databases, the existence of freely available alternative data and metadata sources, and lax regulation of collecting publicly available genomes to identify individuals in a criminal context raise concerning parallels about what is possible with pathogen genomics. The growing ability to ascertain culpability for infectious disease transmission at a nearly individual level could change our perspective on disease outbreaks from one based on public health to one based on individual liability. These technological breakthroughs in the absence of an understanding of potential privacy and liability issues lead to questions about the dominant paradigm of better living through pathogen genomics.

Pulmonary infectious complications after hematopoietic stem cell transplantation: a practical guide to clinicians

PURPOSE OF REVIEW

The current review highlights the most relevant articles on lung infections following hematopoietic stem cell transplantation (HCT) published over the last year. Between 30 and 50% of HCT recipients will develop pulmonary infiltrates. These pulmonary complications may be infectious (caused by virus, bacteria, fungi, or protozoa) or noninfectious (e.g., fluid overload, heart failure, transfusion reactions like transfusion associated lung injury and transfusion-associated circulatory overload, drug reactions, engraftment syndrome, idiopathic pneumonia syndrome, diffuse alveolar hemorrhage, cryptogenic organizing pneumonia, and bronchiolitis obliterans syndrome).

RECENT FINDINGS

New data on the yield of bronchoscopy and bronchoalveolar lavage (BAL), the prevalence and clinical manifestations of respiratory viruses and the usefulness of molecular techniques for diagnosis have been published. In addition, guidelines or meta-analyses on the management of neutropenic fever, serological diagnosis of fungal infections and diagnosis and management of Pneumocystis and aspergillosis have been published.

SUMMARY

Respiratory viruses are important pathogens after HCT. PCR in the BAL is becoming the diagnostic modality of choice for a variety of infections. The best approach for the empirical management of pulmonary infiltrates following HCT remains to be defined.

Association Between Children's Hospital Visitor Restrictions and Healthcare-Associated Viral Respiratory Infections: A Quasi-Experimental Study

We investigated the effect of annual winter visitor restrictions on hospital respiratory virus transmission. The healthcare-associated (HA) viral respiratory infection (VRI) transmission index (number of HA VRIs per 100 inpatient community-associated VRIs) was 59% lower during the months in which visitor restrictions were implemented. These data prompt consideration for instituting year-round visitor restrictions.

Respiratory Virus Infections in Hematopoietic Cell Transplant Recipients

Highly immunocompromised pediatric and adult hematopoietic cell transplant (HCT) recipients frequently experience respiratory infections caused by viruses that are less virulent in immunocompetent individuals. Most of these infections, with the exception of rhinovirus as well as adenovirus and parainfluenza virus in tropical areas, are seasonal variable and occur before and after HCT. Infectious disease management includes sampling of respiratory specimens from nasopharyngeal washes or swabs as well as sputum and tracheal or tracheobronchial lavages. These are subjected to improved diagnostic tools including multiplex PCR assays that are routinely used allowing for expedient detection of all respiratory viruses. Disease progression along with high mortality is frequently associated with respiratory syncytial virus, parainfluenza virus, influenza virus, and metapneumovirus infections. In this review, we discuss clinical findings and the appropriate use of diagnostic measures. Additionally, we also discuss treatment options and suggest new drug formulations that might prove useful in treating respiratory viral infections. Finally, we shed light on the role of the state of immune reconstitution and on the use of immunosuppressive drugs on the outcome of infection.

Respiratory Viral Infections in Transplant Recipients

Respiratory viral infections (RVIs) are common among the general population; however, these often mild viral illnesses can lead to serious morbidity and mortality among recipients of hematopoietic stem cell and solid organ transplantation. The disease spectrum ranges from asymptomatic or mild infections to life-threatening lower respiratory tract infection or long-term airflow obstruction syndromes. Progression to lower respiratory tract infection or to respiratory failure is determined by the intrinsic virulence of the specific viral pathogen as well as various host factors, including the type of transplantation, status of the host’s immune dysfunction, the underlying disease, and other comorbidities. This chapter focuses on the epidemiology, clinical manifestations, diagnosis, and management of RVIs in this susceptible population and includes respiratory syncytial virus, parainfluenza virus, human metapneumovirus, influenza virus, human coronavirus, and human rhinovirus. The optimal management of these infections is limited by the overall paucity of available treatment, highlighting the need for new antiviral drug or immunotherapies.

Respiratory Viral Infections in Children and Adolescents with Hematological Malignancies

Background

Despite the introduction of a polymerase chain reaction (PCR) test for the diagnosis of respiratory viral infection (RVI), guidance on the application of this test and the management of RVI in immunocompromised children is lacking. This study evaluated the clinical characteristics of RVI and established strategies for the PCR test in children and adolescents with hematological malignancies.

Methods

This study included children and adolescents with underlying hematological malignancies and respiratory symptoms, in whom a multiplex PCR test was performed. Patients in whom RVI was identified and not identified were categorized into Groups I and II, respectively. Group I was sub-divided into patients with upper and lower respiratory infections. The medical records of the enrolled patients were retrospectively reviewed.

Results

A total of 93 respiratory illnesses were included. Group I included 46 (49.5%) cases of RVI, including 31 (67.4%) upper and 15 (32.6%) lower respiratory infections. Rhinovirus (37.0%) was the most common viral pathogen. Significantly more patients in Group I had community-acquired respiratory illnesses (p=0.003) and complained of rhinorrhea (p<0.001) and sputum (p=0.008) than those in Group II. In Group I, significantly more patients with lower respiratory infections had uncontrolled underlying malignancies (p=0.038) and received re-induction or palliative chemotherapy (p=0.006) than those with upper respiratory infections.

Conclusions

A multiplex PCR test should be considered for RVI diagnosis in immunocompromised children and adolescents with respiratory symptoms, especially in those with rhinorrhea or sputum prominent over a cough. The early application of the PCR test in patients with uncontrolled underlying malignancies may improve outcomes.

Respiratory Viral Infections in Patients With Cancer or Undergoing Hematopoietic Cell Transplant

Survival rates for pediatric cancer have steadily improved over time but it remains a significant cause of morbidity and mortality among children. Infections are a major complication of cancer and its treatment. Community acquired respiratory viral infections (CRV) in these patients increase morbidity, mortality and can lead to delay in chemotherapy. These are the result of infections with a heterogeneous group of viruses including RNA viruses, such as respiratory syncytial virus (RSV), influenza virus (IV), parainfluenza virus (PIV), metapneumovirus (HMPV), rhinovirus (RhV), and coronavirus (CoV). These infections maintain a similar seasonal pattern to those of immunocompetent patients. Clinical manifestations vary significantly depending on the type of virus and the type and degree of immunosuppression, ranging from asymptomatic or mild disease to rapidly progressive fatal pneumonia Infections in this population are characterized by a high rate of progression from upper to lower respiratory tract infection and prolonged viral shedding. Use of corticosteroids and immunosuppressive therapy are risk factors for severe disease. The clinical course is often difficult to predict, and clinical signs are unreliable. Accurate prognostic viral and immune markers, which have become part of the standard of care for systemic viral infections, are currently lacking; and management of CRV infections remains controversial. Defining effective prophylactic and therapeutic strategies is challenging, especially considering, the spectrum of immunocompromised patients, the variety of respiratory viruses, and the presence of other opportunistic infections and medical problems. Prevention remains one of the most important strategies against these viruses. Early diagnosis, supportive care and antivirals at an early stage, when available and indicated, have proven beneficial. However, with the exception of neuraminidase inhibitors for influenza infection, there are no accepted treatments. In high-risk patients, pre-emptive treatment with antivirals for upper respiratory tract infection (URTI) to decrease progression to LRTI is a common strategy. In the future, viral load and immune markers may prove beneficial in predicting severe disease, supporting decision making and monitor treatment in this population.