Follow-up of human adenovirus viral load in pediatric hematopoietic stem cell transplant recipients

Adenovirus infection in adult patients undergoing allogeneic hematopoietic stem cell transplant: Incidence, clinical management, and outcome

BACKGROUND

Adenovirus infection (ADVi) is an emergent complication in adult patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT) and is associated with poor outcome. Available data on risk factors and optimal management of ADVi in adult allo-HSCT recipients are limited, and recommendations on monitoring and pre-emptive therapy are mainly based on pediatric data.

METHODS

In this single-center, retrospective study, we reported all cases of positive ADV-DNA from adult patients undergoing allo-HSCT in the period 2014-2019. The study aimed to describe the incidence of ADVi at day +180 post-transplant. Secondly to describe timing, clinical presentation, risk factors, and outcome of ADVi and to analyze the application of a screening strategy in our cohort.

RESULTS

In 445 allo-HSCT recipients, the day +180 incidence was: 9% (39/445) for ADVi, 5% (24/445) for ADV viremia (ADVv), and 3% (15/445) for localized ADVi. The median time to ADVi was 65 (IQR 19; 94) days after HSCT. ADVv-related mortality was 13% (3/24), all cases occurring with blood max-ADV-DNA > 10^3 cp/mL. Independent risk factors for ADVi were diagnosis of lymphoproliferative disease (p = .011) and acute graft-versus-host-disease (p = .021).

CONCLUSIONS

In our cohort, ADVi and ADVv were more frequent than previously reported. ADVv with max-ADV-DNA > 10^3 cp/mL was associated with ADV-related mortality, thus careful monitoring and early initiation of treatment are advisable.

Molecular epidemiology and phylogenetic analyses of human adenovirus in pediatric patients with acute respiratory infections from Hangzhou during COVID-19 pandemic

Background

Acute Respiratory Infections (ARIs) are a major cause of morbidity and mortality worldwide. Human Adenovirus (HAdV), responsible for 5%-10% of children's ARIs, is one of the most prevalent pathogens. Our study aimed to analyze the epidemiology and phylogenesis of HAdV in pediatric patients with ARIs in Hangzhou during the COVID-19 pandemic.

Method

Between November 2020 and March 2021, we collected 1,442 nasopharyngeal swabs from children with ARIs at Children's Hospital, Zhejiang University School of Medicine. Epidemiological statistics, phylogenetic and amino acid (AA) mutation analysis were conducted.

Results

Our findings revealed that 386 (26.77%) samples tested positive for HAdV, with the highest rate in children aged 6-18 years and the lowest in children aged 0-1 year, indicating a different age preference of HAdV compared with pre-pandemic period. Outpatients had a significantly higher positive rate than inpatients. Moreover, patients with HAdV-coinfection exhibited more severe clinical symptoms than those with HAdV-single infection. Our phylogenetic analysis demonstrated that species HAdV-C (type 1, 2, 6) were the predominant circulating strains in Hangzhou during the COVID-19 pandemic. Further AA mutation analysis identified seventeen mutations of particular concern for biological characterization.

Conclusion

In conclusion, our study provides valuable epidemiological and molecular data that will aid in epidemiological surveillance, antiviral therapies and the development of specific vaccine types, leading to improve public health.

Droplet digital PCR development for adenovirus load monitoring in children after hematopoietic stem cell transplantation

Human adenovirus (AdV) reactivation after hematopoietic stem cell transplantation (HSCT) is associated with life-threatening clinical manifestations. Real-time quantitative PCR (qPCR) has been widely used to measure AdV loads. However, qPCR has not been standardized for AdV. Droplet digital polymerase chain reaction (ddPCR) enables the absolute quantification of viral loads that is a novel pathogen detection technology. DdPCR would enable a more accurate AdV DNA detection compared to qPCR. In this study, ddPCR was developed for AdV DNA and compared its performance characteristics with qPCR. Then, AdV DNAemia incidence during the first 12 weeks after allogenic HSCT was retrospectively examined by qPCR and ddPCR in 97 HSCT episodes using the preserved 545 DNA samples. DdPCR showed better reproducibility and sensitivity, as well as equivalent quantifiability compared to qPCR. AdV DNA among HSCT patients was detected in 11 (2.0%) and 49 (9.0%) of 545 samples by qPCR and ddPCR, respectively. AdV DNA levels of >1000 copies/mL were observed in five cases by qPCR and/or ddPCR. However, two developed fulminant hepatitis and died, while other patients remained asymptomatic with subsequently undetectable AdV DNA. In conclusion, ddPCR was more sensitive and reproducible in detecting AdV DNA among pediatric HSCT recipients than qPCR. DdPCR represents the potential to provide a more accurate DNAemia detection, determine cutoff values for treatment initiation, and antiviral efficacy assessment.