Adenovirus related lymphohistiocytic hemophagocytosis: Case report and literature review

Macrophage Activation Syndrome in Viral Sepsis

Macrophage activation syndrome (MAS) is a life-threatening systemic hyperinflammatory syndrome triggered by various infections, particularly viral infections, autoimmune disorders, and malignancy. The condition is characterized by an increased production of proinflammatory cytokines resulting in a cytokine storm and has been associated with poor clinical outcomes. During the COVID-19 pandemic, patients with severe manifestations developed features similar to those of MAS, although these characteristics remained well defined within the lung. Additionally, other viral infections including EBV, the herpes family of viruses, hepatitis viruses, influenza, HIV, and hemorrhagic fevers can be complicated by MAS. The diagnosis and management of the condition remain challenging due to the lack of consensus on specific guidelines, especially among the adult population. Currently, therapeutic options primarily rely on medications that are typically used to treat primary hemophagocytic lymphohistiocytosis, such as corticosteroids and etoposide. In addition, cytokine-targeted therapies present promising treatment options. The objective of this review is to discuss the emergence of MAS in the context of viral infections including, but not limited to, its occurrence in COVID-19.

Adenovirus: Epidemiology, Global Spread of Novel Types, and Approach to Treatment

Adenoviruses (AdVs) are DNA viruses that typically cause mild infections involving the upper or lower respiratory tract, gastrointestinal tract, or conjunctiva. Rare manifestations of AdV infections include hemorrhagic cystitis, hepatitis, hemorrhagic colitis, pancreatitis, nephritis, or meningoencephalitis. AdV infections are more common in young children, due to lack of humoral immunity. Epidemics of AdV infection may occur in healthy children or adults in closed or crowded settings (particularly military recruits). The vast majority of cases are self-limited. However, the clinical spectrum is broad and fatalities may occur. Dissemination is more likely in patients with impaired immunity (e.g., organ transplant recipients, human immunodeficiency virus infection). Fatality rates for untreated severe AdV pneumonia or disseminated disease may exceed 50%. More than 100 genotypes and 52 serotypes of AdV have been identified and classified into seven species designated HAdV-A through -G. Different types display different tissue tropisms that correlate with clinical manifestations of infection. The predominant types circulating at a given time differ among countries or regions, and change over time. Transmission of novel strains between countries or across continents and replacement of dominant viruses by new strains may occur. Treatment of AdV infections is controversial, as prospective, randomized therapeutic trials have not been done. Cidofovir has been the drug of choice for severe AdV infections, but not all patients require treatment. Live oral vaccines are highly efficacious in reducing the risk of respiratory AdV infection and are in routine use in the military in the United States but currently are not available to civilians.

Human Adenovirus Type 7 Infections in Hubei, China During 2018-2019: Epidemic Features and Genetic Characterization of the Detected Viruses

Human adenoviruses (HAdVs) type 7 can cause severe respiratory disease. During the period between December 2018 and August 2019, HAdV-7 infection was identified in 129 patients in Wuhan Children's Hospital, Hubei Province, China. Samples were collected from hospitalized children and metagenomic sequencing was applied to detect the HAdV infections. Hemophagocytic lymphohistiocystosis (HLH) related to HAdV infections was observed in some patients clinically and patients were divided into two groups based on this to test the differences among clinical indicators. Genome variation, in silico restriction endonuclease analysis (REA), and phylogenetic analyses were carried out to show the genome characterization of HAdV-7 in this study. It was found that many indicators, such as all blood routine indicators, in patients of the HLH group showed significant levels. In this study, REA revealed that HAdV-7 might belong to genome 7d and genome variation analysis displayed the stable genome of HAdV. HAdV-7 is an ongoing threat to the public, and global surveillance should be established.

Tree Shrew as an Emerging Small Animal Model for Human Viral Infection: A Recent Overview

Viral infection is a global public health threat causing millions of deaths. A suitable small animal model is essential for viral pathogenesis and host response studies that could be used in antiviral and vaccine development. The tree shrew (Tupaia belangeri or Tupaia belangeri chinenesis), a squirrel-like non-primate small mammal in the Tupaiidae family, has been reported to be susceptible to important human viral pathogens, including hepatitis viruses (e.g., HBV, HCV), respiratory viruses (influenza viruses, SARS-CoV-2, human adenovirus B), arboviruses (Zika virus and dengue virus), and other viruses (e.g., herpes simplex virus, etc.). The pathogenesis of these viruses is not fully understood due to the lack of an economically feasible suitable small animal model mimicking natural infection of human diseases. The tree shrew model significantly contributes towards a better understanding of the infection and pathogenesis of these important human pathogens, highlighting its potential to be used as a viable viral infection model of human viruses. Therefore, in this review, we summarize updates regarding human viral infection in the tree shrew model, which highlights the potential of the tree shrew to be utilized for human viral infection and pathogenesis studies.

From Upper Respiratory Symptoms to Hemophagocytic Lymphohistiocytosis: Case Report of a Human Adenovirus Infection in Haploidentical Hematopoietic Stem Cell Transplant Recipient

Human adenovirus infection is rare in adult population, except for in immunocompromised individuals. Recipients of allogenic haploidentical hematopoietic stem cell transplantation are reported at high risk for human adenovirus, which is often lethal when it evolves into the disseminated form. Despite existent guidelines, prevention, early diagnosis, and therapeutics remain challenging. Here, we report the case of a fatal evolution of human adenovirus respiratory infection and discuss the actual recommendations to prevent recurrence of this major issue.

Risk Factors for the Development of Hemophagocytic Lymphohistiocytosis in Children With Severe Adenovirus Pneumonia: A Single-Center Retrospective Study

Objective: To investigate and analyze the relevant risk factors for hemophagocytic lymphohistiocytosis (HLH) in children with severe adenovirus pneumonia (SAP). Methods: A retrospective study of children with SAP was performed in 30 cases developing HLH and 94 cases not developing HLH from December 2018 to August 2019. The binary logistic regression analysis was used to identify risk factors that were significantly associated with the development of HLH after the univariate analysis, and the receiver operating characteristic (ROC) curve was performed to find out the cut-off value for the significant relevant factors. Results: Two factors were associated with the development of HLH, which were the length of fever (OR = 1.331, 95%CI: 1.002-1.769) and triglycerides (TG) (OR = 17.345, 95%CI: 1.358-221.538). The cut-off value of the length of fever was 12.5 days, and the cut-off value of TG was 3.02 mmol/L. Conclusion: Children with SAP who had a duration of fever over 12.5 days and the TG level over 3.02 mmol/L are more likely to develop HLH.

Human Adenovirus 7-Associated Hemophagocytic Lymphohistiocytosis-Like Illness: Clinical and Virological Characteristics in a Cluster of Five Pediatric Cases

BACKGROUND

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening condition of immune dysregulation. Children often suffer from primary genetic forms of HLH, which can be triggered by infection. Others suffer from secondary HLH as a complication of infection, malignancy, or rheumatologic disease. Identifying the exact cause of HLH is crucial, as definitive treatment for primary disease is hematopoietic stem cell transplant. Adenoviruses have been associated with HLH but molecular epidemiology data are lacking.

METHODS

We describe the clinical and virologic characteristics of 5 children admitted with adenovirus infection during 2018-2019 who developed HLH or HLH-like illness. Detailed virologic studies, including virus isolation and comprehensive molecular typing were performed.

RESULTS

All patients recovered; clinical management varied but included immunomodulating and antiviral therapies. A genetic predisposition for HLH was not identified in any patient. Adenovirus isolates were recovered from 4/5 cases; all were identified as genomic variant 7d. Adenovirus type 7 DNA was detected in the fifth case. Phylogenetic analysis of genome sequences identified two clusters - one related to strains implicated in 2016-2017 outbreaks in Pennsylvania and New Jersey, the other related to a 2009 Chinese strain.

CONCLUSIONS

It can be challenging to determine whether HLH is the result of an infectious pathogen alone or genetic predisposition triggered by an infection. We describe 5 children from the same center presenting with an HLH-like illness after onset of adenovirus type 7 infection. None of the patients were found to have a genetic predisposition to HLH. These findings suggest that adenovirus 7 infection alone can result in HLH.

Adenovirus infection in children hospitalized with pneumonia in Guangzhou, China

Background

HAdV infection can cause a variety of diseases. Although infections with HAdVs often are mild, life‐threatening respiratory disease can occur. Pneumonia is one of the more serious types of HAdV‐induced respiratory disease in children. In this study, we determined the prevalence and genotype of HAdVs among children hospitalized with pneumonia in Guangzhou, China.

Methods

Nasopharyngeal swabs (NPSs) were collected from children hospitalized with pneumonia in Guangzhou, China, from January 2013 to June 2019. HAdVs were detected by real‐time polymerase chain reaction assay, and hexon, fiber, and penton gene were amplified and used for phylogenetic analysis. Epidemiological data were analyzed using SPSS16.0 software.

Results and Conclusions

A total of 1778 children hospitalized with pneumonia were enrolled. The overall HAdV detection rate was 3.26%. And the yearly detection rate varied from around 2.5% in 2013‐2017 to around 6% in 2018‐2019. Children >5 years had the highest HAdV infection rate. 92.86% of HAdV sequences obtained in this study were belonged to species B, and no recombination was observed. HAdV‐B7 and HAdV‐B3 were the common types detected in the study period, with the predominant HAdV genotype shifted from HAdV‐B3 in 2015‐2016 to HAdV‐B7 in 2017‐2018. The discrepancies in HAdV detection rates in different study period and changes of HAdV predominant types over time highlighted the importance of continued surveillance.