Single-Cell Transcriptomic Analysis of Epstein-Barr Virus-Associated Hemophagocytic Lymphohistiocytosis

Epstein-Barr virus (EBV) infection can lead to infectious mononucleosis (EBV-IM) and, more rarely, EBV-associated hemophagocytic lymphohistiocytosis (EBV-HLH), which is characterized by a life-threatening hyperinflammatory cytokine storm with immune dysregulation. Interferon-gamma (IFNγ) has been identified as a critical mediator for primary HLH; however, the detailed role of IFNγ and other cytokines in EBV-HLH is not fully understood. In this study, we used single-cell RNA sequencing to characterize the immune landscape of EBV-HLH and compared it with EBV-IM. Three pediatric patients with EBV-HLH with different backgrounds, one with X-linked lymphoproliferative syndrome type 1 (XLP1), two with chronic active EBV disease (CAEBV), and two patients with EBV-IM were enrolled. The TUBA1B + STMN1 + CD8 + T cell cluster, a responsive proliferating cluster with rich mRNA detection, was explicitly observed in EBV-IM, and the upregulation of SH2D1A-the gene responsible for XLP1-was localized in this cluster. This proliferative cluster was scarcely observed in EBV-HLH cases. In EBV-HLH cases with CAEBV, upregulation of LAG3 was observed in EBV-infected cells, which may be associated with an impaired response by CD8 + T cells. Additionally, genes involved in type I interferon (IFN) signaling were commonly upregulated in each cell fraction of EBV-HLH, and activation of type II IFN signaling was observed in CD4 + T cells, natural killer cells, and monocytes but not in CD8 + T cells in EBV-HLH. In conclusion, impaired responsive proliferation of CD8 + T cells and upregulation of type I IFN signaling were commonly observed in EBV-HLH cases, regardless of the patients' background, indicating the key features of EBV-HLH.

Nanopore sequencing in distinguishing between wild-type and vaccine strains of Varicella-Zoster virus

BACKGROUND

The introduction of varicella vaccines into routine pediatric immunization programs has led to a considerable reduction in varicella incidence. However, there have been reports of varicella, herpes zoster, and meningitis caused by the vaccine strain of varicella-zoster virus (VZV), raising concerns. Establishing the relationship between the wild-type and vaccine strains in VZV infections among previously vaccinated individuals is crucial. Differences in the single nucleotide polymorphisms (SNPs) among vaccine strains can be utilized to identify the strain. In this study, we employed nanopore sequencing to identify VZV strains and analyzed clinical samples.

METHODS

We retrospectively examined vesicle and cerebrospinal fluid samples from patients with VZV infections. One sample each of the wild-type and vaccine strains, previously identified using allelic discrimination real-time PCR and direct sequencing, served as controls. Ten samples with undetermined VZV strains were included. After DNA extraction, a long PCR targeting the VZV ORF62 region was executed. Nanopore sequencing identified SNPs, allowing discrimination between the vaccine and wild-type strains.

RESULTS

Nanopore sequencing confirmed SNPs at previously reported sites (105,705, 106,262, 107,136, and 107,252), aiding in distinguishing between wild-type and vaccine strains. Among the ten unknown samples, nine were characterized as wild strains and one as a vaccine strain. Even in samples with low VZV DNA levels, nanopore sequencing was effective in strain identification.

CONCLUSION

This study validates that nanopore sequencing is a reliable method for differentiating between the wild-type and vaccine strains of VZV. Its ability to produce long-read sequences is remarkable, allowing simultaneous confirmation of known SNPs and the detection of new mutations. Nanopore sequencing can serve as a valuable tool for the swift and precise identification of wild-type and vaccine strains and has potential applications in future VZV surveillance.

MicroRNA expression profiling of urine exosomes in children with congenital cytomegalovirus infection

Congenital cytomegalovirus (cCMV) infection can damage the central nervous system in infants; however, its prognosis cannot be predicted from clinical evaluations at the time of birth. Urinary exosomes can be used to analyze neuronal damage in neuronal diseases. To investigate the extent of neuronal damage in patients with cCMV, exosomal miRNA expression in the urine was investigated in cCMV-infected infants and controls. Microarray analysis of miRNA was performed in a cohort of 30 infants, including 11 symptomatic cCMV (ScCMV), 7 asymptomatic cCMV (AScCMV), and one late-onset ScCMV cases, and 11 healthy controls (HC). Hierarchical clustering analysis revealed the distinct expression profile of ScCMV. The patient with late-onset ScCMV was grouped into the ScCMV cluster. Pathway enrichment analysis of the target mRNAs differed significantly between the ScCMV and HC groups; this analysis also revealed that pathways related to brain development were linked to upregulated pathways. Six miRNAs that significantly different between groups (ScCMV vs. HC and ScCMV vs. AScCMV) were selected for digital PCR in another cohort for further validation. Although these six miRNAs seemed insufficient for predicting ScCMV, expression profiles of urine exosomal miRNAs can reveal neurological damage in patients with ScCMV compared to those with AcCMV or healthy infants.

Comparison of plasma proteomic profiles of patients with Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis and infectious mononucleosis

Primary Epstein-Barr virus (EBV) infection occasionally causes EBV-infectious mononucleosis (EBV-IM) and EBV-hemophagocytic lymphohistiocytosis (EBV-HLH). Although EBV-IM is mostly mild and self-limiting, EBV-HLH is a life-threatening disease characterized by excessive immune activation. However, the pathogenesis of EBV-HLH is yet to be fully elucidated. A diagnostic biomarker for EBV-HLH is desirable because early diagnosis and treatment are critical for the effective management of patients. In this study, the proteomic profiling of plasma was performed using liquid chromatography-mass spectrometry to identify proteins specific to EBV-IM and EBV-HLH. Furthermore, pathway analysis was performed for the proteins upregulated in patients with EBV-IM and EBV-HLH. Compared to healthy controls, 63 and 18 proteins were upregulated in patients with EBV-IM and EBV-HLH, respectively. Pathway and process enrichment analyses revealed that the complement system was the most enriched category of upregulated proteins in EBV-IM, whereas proteins related to immune effector processes were the most enriched in EBV-HLH. Among the 18 proteins upregulated in EBV-HLH, seven were exclusive to EBV-HLH. These specific proteins were associated with three pathways, and apolipoprotein E was commonly found in all the pathways. Proteomic analysis may provide new insights into the host response to EBV infection and the pathogenesis of EBV-related diseases.

Next-generation sequencing-based detection of Ureaplasma in the gastric fluid of neonates with respiratory distress and chorioamnionitis

BACKGROUND

Respiratory distress is common in neonates admitted to neonatal intensive care units. Additionally, infectious diseases such as intrauterine infections or vertical transmission are important underlying causes of respiratory failure. However, pathogens often cannot be identified in neonates, and there are many cases in which antibacterial drugs are empirically administered. Next-generation sequencing (NGS) is advantageous in that it can detect trace amounts of bacteria that cannot be detected by culturing or bacteria that are difficult to cultivate. However, there are few reports on the diagnosis of infectious diseases using NGS in the neonatal field, especially those targeting respiratory distress.

OBJECTIVE

The purpose of our study was to investigate the microorganisms associated with neonatal respiratory distress and to determine whether less invasive collection specimens such as plasma and gastric fluid are useful.

METHODS

Neonates were prospectively recruited between January and August 2020 from Nagoya University Hospital. The inclusion criteria were as follows: 1) admission to the neonatal intensive care unit; 2) respiratory distress presentation within 48 h of birth; and 3) suspected infection, collection of blood culture, and administration of antibiotics. Plasma samples and blood cultures were simultaneously collected. Gastric fluid samples were also collected if the patient was not started on enteral nutrition. Information on the patients and their mothers were collected from the medical records. DNA was extracted from 140 µL of plasma and gastric fluid samples. DNA sequencing libraries were prepared, and their quality was analyzed. DNA libraries were sequenced using high-throughput NGS. The NGS data of plasma and gastric fluid samples were analyzed using the metagenomic pipeline PATHDET, which calculated the number of reads assigned to microorganisms and their relative abundance. Putative pathogens were listed.

RESULTS

Overall, 30 plasma samples and 25 gastric fluid samples from 30 neonates were analyzed. Microorganism-derived reads of gastric fluid samples were significantly higher than those of plasma samples. Transient tachypnea of the newborn was the most common cause of respiratory distress with 13 cases (43%), followed by respiratory distress syndrome with 7 cases (23%). There were 8 cases (29%) of chorioamnionitis and 7 cases (25%) of funisitis pathologically diagnosed. All blood cultures were negative, and only two gastric fluid cultures were positive for group B Streptococcus (Patient 15) and Candida albicans (Patient 24). Putative pathogens that met the positive criteria for PATHET were detected in four gastric fluid samples, one of which was group B Streptococcus from Patient 15. In the gastric fluid sample of Patient 24, Candida albicans were detected by NGS but did not meet the positive criteria for PATHDET. Cluster analysis of the plasma samples divided them into two study groups, and the indicator genera of each cluster (Phormidium or Toxoplasma) are shown in Figure 1. Clinical findings did not show any significant differences between the two groups. Cluster analysis of the gastric fluid samples divided them into three study groups, and the indicator genera of each cluster (Ureaplasma, Nostoc, and Streptococcus) are shown in Figure 2. The incidence rate of chorioamnionitis was significantly higher in Ureaplasma group than in the other two groups.

CONCLUSION

Gastric fluid may be useful for assessing neonatal patients with respiratory distress. To the best of our knowledge, this was the first study to reveal that the presence of Ureaplasma in the gastric fluid of neonates with respiratory distress was associated with chorioamnionitis. The early diagnosis of intra-amniotic infections using gastric fluid and its treatment may change the treatment strategy for neonatal respiratory distress. Screening for Ureaplasma in neonates with respiratory distress may reduce the need for empirical antibiotic administration. Further research is required to confirm these findings.

Proteomic Analysis Reveals Novel Plasma Biomarkers for Neurological Complications in Patients With Congenital Cytomegalovirus Infection

BACKGROUND

Congenital cytomegalovirus (cCMV) infection is a leading cause of nonhereditary neurological complications. When considering antiviral treatment, it is important to differentiate between symptomatic and asymptomatic patients. This study aimed to identify candidate plasma biomarkers for neurological complications of cCMV infection using proteomic analysis.

METHODS

This study retrospectively enrolled five patients with symptomatic cCMV infection, four with asymptomatic cCMV infection with isolated sensorineural hearing loss (SNHL), and five with asymptomatic cCMV infection. The plasma samples were collected during neonatal period. The peptides were analyzed using liquid chromatography-mass spectrometry. The concentrations of differentially expressed proteins were validated using an enzyme-linked immunosorbent assay.

RESULTS

A total of 456 proteins were identified and quantified. The levels of 80 proteins were significantly different between patients with and without cCMV-related symptoms including isolated SNHL. The levels of 31 proteins were significantly different between patients with and without neuroimaging abnormalities. The plasma concentrations of Fms-related receptor tyrosine kinase 4 in patients with cCMV-related symptoms were significantly higher than those in patients with asymptomatic cCMV infection. Moreover, plasma peptidylprolyl isomerase A levels were significantly higher in patients with neuroimaging abnormalities than in those without.

CONCLUSIONS

Proteomic analysis of patients with cCMV infection showed that Fms-related receptor tyrosine kinase 4 and peptidylprolyl isomerase A could be novel diagnostic biomarkers for neurological complications of cCMV infection.

Time course of skin rash, computed tomography findings, and viral load in a rheumatoid arthritis patient with severe varicella pneumonia

Varicella-zoster virus (VZV) infection in adults or immunocompromised patients has a more severe presentation compared to the mild disease in children. To the best of our knowledge, no reports have described the clinical course of VZV pneumonia focusing on time course of skin rash, chest computed tomography (CT) findings, and viral load. Furthermore, no reports have described the reactivation of human herpes virus 6 (HHV-6) in VZV pneumonia. Here, we report a case of severe VZV pneumonia that resulted in reactivation of HHV-6 in a patient with rheumatoid arthritis (RA). A 66-year-old female treated for RA was admitted to our hospital with papules. Her chest CT showed granular infiltrates, micronodules, and ground-glass opacities. The day after admission, because the typical skin rashes and chest CT findings were observed, she was diagnosed with VZV pneumonia and treated with acyclovir. Her skin rash then crusted over five days and entered the healing process, whereas it took approximately two weeks for her respiratory condition and chest CT findings to improve. In addition, VZV deoxyribonucleic acid (DNA) gradually decreased with treatment. On the 34th day of admission, VZV DNA was not found in the serum sample but remained in the sputum sample. Furthermore, although reactivation of HHV-6 was observed, viremia resolved without treatment. Clinicians should be able to recognize the differences in the improvement of skin rashes, respiratory status, and chest CT findings. In addition, treatment for HHV-6 reactivation should be carefully determined for each case.

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.

Human leukocyte antigen 7/8-matched unrelated bone marrow transplantation using anti-thymocyte globulin in children

Human leukocyte antigen (HLA) mismatched unrelated donor transplantation is associated with an increased risk of graft-versus-host disease, graft failure, and infection, which increases post-transplant morbidity and mortality. In this single-center retrospective study, outcomes were evaluated in 30 consecutive children who underwent bone marrow transplantation (BMT) from HLA 1 allele-mismatched (HLA 7/8-matched) unrelated donors with rabbit anti-thymocyte globulin (rATG) as graft-versus-host disease (GVHD) prophylaxis. The 3-year overall survival (OS), event-free survival (EFS), and GVHD-relapse-free survival rates were 91.7% (95% CI 70.5%-91.9%), 88.3% (95% CI 67.5%-96.1%), and 73.9% (95% CI 52.4%-86.8%), respectively. Grade II-IV and III-IV acute GVHD occurred in 10 (33%) and 2 (7.0%) patients, respectively. The 3-year cumulative incidence of chronic GVHD was 7.8%. No fatal viral infections occurred. The study results show the feasibility of HLA 7/8-matched unrelated BMT with ATG to achieve favorable outcomes and acceptable GVHD, especially for patients who lack a fully matched donor.

Correlation of cytomegalovirus viral load between whole blood and plasma of congenital cytomegalovirus infection under valganciclovir treatment

BACKGROUND

Congenital cytomegalovirus (CMV) infection (cCMV) can cause sensorineural hearing loss and neurodevelopmental disabilities in children. Oral valganciclovir (VGCV) therapy has been reported to improve long-term audiological and neurodevelopmental outcomes in patients with cCMV. The levels of CMV DNA in whole blood have been monitored in previous studies. However, quantitative methods using whole blood have not been standardized. Recently, the plasma viral load has been standardized and widely used in CMV-associated diseases.

METHODS

CMV viral loads in whole blood and plasma were serially measured in 24 patients with a confirmatory diagnosis of cCMV during oral VGCV therapy using an in-house real-time PCR assay. Plasma samples were assayed using the Cobas 6800 system (Roche Diagnostics) in addition to an in-house assay.

RESULTS

Plasma CMV viral loads were remarkably decreased at the end of therapy compared to before therapy. A significant correlation of CMV levels between whole blood and plasma was observed (Spearman's ρ = 0.566). The levels of CMV DNA before therapy were significantly correlated with the period of decreasing the viral loads to below the detection limit, not only in whole blood (Spearman's ρ = 0.901) but also in plasma (Spearman, ρ = 0.804). Finally, CMV viral loads between the in-house assay and commercially available standardized assay in 75 plasma samples with positive PCR results for CMV were compared; a significant correlation was observed between the results of both assays.

CONCLUSIONS

There was a significant correlation between the two assays (Spearman, ρ = 0.882), suggesting that CMV plasma viral loads measured by the standardized assay are widely used to monitor the levels of CMV DNA in patients with cCMV during oral VGCV therapy.

542. Nanopore and Illumina sequencing for pathogen metagenomics and host transcriptomics of cerebrospinal fluid in infantile central nervous system infections

Background

Infantile central nervous system infections (CNSIs) can be life-threatening and severe sequelae can be observed in encephalitis and bacterial meningitis. The causative microorganism is unknown in > 40% of patients with aseptic infections. This study aimed to analyze metagenome for detection of pathogen, and transcriptome for host reaction of infection in a single cerebrospinal fluid (CSF) sample using two different next-generation sequencing (NGS) platforms, Illumina and Nanopore.

Methods

Twenty-eight CNSIs patients (< 12 months), treated between June 2012 and April 2020, were enrolled. A total of 49 clinical samples (28 CSF and 21 blood) from 28 patients were collected. Extracted RNA, which was obtained from 23 CSF in sufficient quantities, was sequenced using both Nanopore and Illumina platforms to compare their performances in the detection of pathogens. Human-derived reads subtracted during pathogen detection were used for host transcriptomic analysis from both Nanopore and Illumina sequencing. All the extracted DNA from 28 CSF and 21 blood, was sequenced using Illumina sequencer for the detection of pathogens. Data analysis was performed on the in-house PATHDET pipeline.

A flowchart for pathogen detection and transcriptome analysis

Pathogen detection was performed on the in-house PATHDET pipeline and transcriptome analysis was performed by using the secondary outputs.

Results

RNA sequencing of CSF samples in 23 cases revealed potential viral pathogens in 10 cases: coxsackievirus B5 (4 cases), coxsackievirus B4 (3 cases), coxsackievirus B2 (1 case), echovirus E7 (1 case), and human parechovirus 3 (1 case). DNA sequencing was performed in 28 cases using Illumina sequencing, and Proteus mirabilis (1 case, consistent with the culture test) and human parvovirus B19 (1 case) were detected. The results of Nanopore sequencing and Illumina sequencing were consistent. However, the mapping coverage and depth to the detected pathogen genome of Nanopore sequencing was superior to that of Illumina sequencing. MX1, ISG15, and OAS1 were differentially expressed genes in patients with identified pathogens via metagenomic NGS, both the Nanopore and Illumina sequencing, and were associated with antiviral roles in innate immunity.

A pie chart for patients with central nervous system infections (CNSIs)

Results of next-generation sequencing (NGS) and the detected pathogen candidates using DNA/RNA workflows.

Performance of Nanopore and Illumina sequencing for pathogen genome mapping

The sequencing output, which is 100,000 reads randomly extracted from original sequencing reads, was mapped to the pathogen reference genome to determine (A) mapping coverage and (B) mapping depth.

Volcano plot of all genes analyzed in Nanopore and Illumina sequencing

Volcano plots showing differentially expressed genes in the cerebrospinal fluid between identified-pathogen and unidentified-pathogen samples from (A) Nanopore sequencing and (B) Illumina RNA sequencing.

Conclusion

The use of Nanopore sequencing for metagenomic diagnostics of CSF samples should help to understand both pathogens and host immune responses of CNSI and could shed light on the pathogenesis of these infections.

Disclosures

All Authors: No reported disclosures.

Performance of Nanopore and Illumina metagenomic sequencing for pathogen detection and transcriptome analysis in infantile central nervous system infections

Background

Infantile central nervous system infections (CNSIs) can be life-threatening and cause severe sequelae. However, the causative microorganism remains unknown in >40% of patients with aseptic infections. This study aimed to analyze the metagenome for detection of pathogens and the transcriptome for host immune responses during infection in a single cerebrospinal fluid (CSF) sample using 2 different next-generation sequencing (NGS) platforms, Nanopore and Illumina.

Methods

Twenty-eight CNSIs patients (<12 months) were enrolled, and 49 clinical samples (28 CSF and 21 blood) were collected. The DNA extracted from all 49 samples was sequenced using the Illumina sequencer for the detection of pathogens. Extracted RNA was obtained in sufficient quantities from 23 CSF samples and subjected to sequencing on both Nanopore and Illumina platforms. Human-derived reads subtracted during pathogen detection were used for host transcriptomic analysis from both Nanopore and Illumina sequencing.

Results

RNA metagenomic sequencing using both sequencing platforms revealed putative viral pathogens in 10 cases. DNA sequencing using the Illumina sequencer detected 2 pathogens. The results of Nanopore and Illumina RNA sequencing were consistent; however, the mapping coverage and depth to the detected pathogen genome of Nanopore RNA sequencing were greater than those of Illumina. Host transcriptomic analysis of Nanopore sequencing revealed highly expressed genes related to the antiviral roles of innate immunity from pathogen-identified cases.

Conclusions

The use of Nanopore RNA sequencing for metagenomic diagnostics of CSF samples should help to elucidate both pathogens and host immune responses of CNSI and could shed light on the pathogenesis of these infections.

Post-exposure prophylaxis to prevent varicella in immunocompromised children

Background

Varicella-zoster virus (VZV) infection can cause life-threatening events in immunocompromised patients. Post-exposure prophylaxis (PEP) is required to prevent secondary VZV infection. Limited evidence is available for the use of acyclovir (ACV)/valacyclovir (VCV) as PEP.

Methods

Herein, we retrospectively analyzed immunocompromised paediatric patients with significant exposure to VZV. Patients administered PEP were categorized into four groups: 1) ACV/VCV group; 2) intravenous immunoglobulin (IVIG) group; 3) ACV/VCV/IVIG group; 4) vaccine group.

Results

Among 69 exposure events, 107 patients were administered PEP (91, ACV/VCV; 16, ACV/VCV/IVIG) and 10 patients did not receive PEP (non-PEP group). The index case was diagnosed based on clinical symptoms in 55 cases (79.7%). Fourteen cases (20.3%) were confirmed using direct virological diagnostic procedures. In the PEP group, only 2 patients (2.2%) developed secondary VZV infections. Additionally, 2 patients in the non-PEP group (20.0%) developed secondary VZV infection. The incidence of secondary VZV infection was significantly lower in the PEP group than in the non-PEP group (P=0.036). Among patients administered PEP, no antiviral drug-induced side effects were detected.

Conclusions

Antiviral agents administered as PEP are effective and safe for preventing VZV infections in immunocompromised patients. Rapid virological diagnosis of index cases might allow efficient administration of PEP after significant exposure to VZV infection.

Detection of antiviral drug resistance in patients with congenital cytomegalovirus infection using long-read sequencing: a retrospective observational study

BACKGROUND

Congenital human cytomegalovirus (cCMV) infection can cause sensorineural hearing loss and neurodevelopmental disabilities in children. Ganciclovir and valganciclovir (GCV/VGCV) improve long-term audiologic and neurodevelopmental outcomes for patients with cCMV infection; however, antiviral drug resistance has been documented in some cases. Long-read sequencing can be used for the detection of drug resistance mutations. The objective of this study was to develop full-length analysis of UL97 and UL54, target genes with mutations that confer GCV/VGCV resistance using long-read sequencing, and investigate drug resistance mutation in patients with cCMV infection.

METHODS

Drug resistance mutation analysis was retrospectively performed in 11 patients with cCMV infection treated with GCV/VGCV. UL97 and UL54 genes were amplified using blood DNA. The amplicons were sequenced using a long-read sequencer and aligned with the reference gene. Single nucleotide variants were detected and replaced with the reference sequence. The replaced sequence was submitted to a mutation resistance analyzer, which is an open platform for drug resistance mutations.

RESULTS

Two drug resistance mutations (UL54 V823A and UL97 A594V) were found in one patient. Both mutations emerged after 6 months of therapy, where viral load increased. Mutation rates subsided after cessation of GCV/VGCV treatment.

CONCLUSIONS

Antiviral drug resistance can emerge in patients with cCMV receiving long-term therapy. Full-length analysis of UL97 and UL54 via long-read sequencing enabled the rapid and comprehensive detection of drug resistance mutations.

MicroRNA expression profiling of cerebrospinal fluid/serum exosomes in children with human herpesvirus 6-associated encephalitis/encephalopathy by high-throughput sequencing

Primary human herpesvirus 6 (HHV-6) infection is sometimes accompanied by acute encephalopathy with reduced subcortical diffusion (AED) in immunocompetent children. We investigated exosomal microRNA (miRNA) expression profiles in cerebrospinal fluid (CSF) and sera of patients with HHV-6-associated AED (n = 5) and febrile seizure (FS) (n = 5) using high-throughput sequencing. A total of 176 and 663 miRNAs were identified in CSF and serum exosomes, respectively. Comparative analysis determined that some miRNAs (miR-381-3p, miR-155) were exclusively expressed in the CSF exosomes of AED but not of FS patients, suggesting their potential application as novel diagnostic biomarkers for AED.

Next-Generation Sequencing to Detect Pathogens in Pediatric Febrile Neutropenia: A Single-Center Retrospective Study of 112 Cases

Background

Febrile neutropenia (FN) is a frequent complication in immunocompromised patients. However, causative microorganisms are detected in only 10% of patients. This study aimed to detect the microorganisms that cause FN using next-generation sequencing (NGS) to identify the genome derived from pathogenic microorganisms in the bloodstream. Here, we implemented a metagenomic approach to comprehensively analyze microorganisms present in clinical samples from patients with FN.

Methods

FN is defined as a neutrophil count <500 cells/µL and fever ≥37.5°C. Plasma/serum samples of 112 pediatric patients with FN and 10 patients with neutropenia without fever (NE) were sequenced by NGS and analyzed by a metagenomic pipeline, PATHDET.

Results

The putative pathogens were detected by NGS in 5 of 10 FN patients with positive blood culture results, 15 of 87 FN patients (17%) with negative blood culture results, and 3 of 8 NE patients. Several bacteria that were common in the oral, skin, and gut flora were commonly detected in blood samples, suggesting translocation of the human microbiota to the bloodstream in the setting of neutropenia. The cluster analysis of the microbiota in blood samples using NGS demonstrated that the representative bacteria of each cluster were mostly consistent with the pathogens in each patient.

Conclusions

NGS technique has great potential for detecting causative pathogens in patients with FN. Cluster analysis, which extracts characteristic microorganisms from a complex microbial population, may be effective to detect pathogens in minute quantities of microbiota, such as those from the bloodstream.

A unique three-way Philadelphia chromosome variant t(4;9;22)(q21;q34;q11.2) in a newly diagnosed patient with chronic phase chronic myeloid leukemia: a case report and review of the literature

Background

Chronic myeloid leukemia is a hematologic malignancy associated with the fusion of two genes: BCR and ABL1. This fusion results from a translocation between chromosomes 9 and 22, which is called the Philadelphia chromosome. Although the Philadelphia chromosome is present in more than 90% of patients with chronic myeloid leukemia, 5–8% of patients with chronic myeloid leukemia show complex variant translocations. Herein, we report a unique case of a three-way translocation variant in chronic phase chronic myeloid leukemia.

Case presentation

A 40-year-old Asian male who presented with leukocytosis was diagnosed with chronic phase chronic myeloid leukemia. Cytogenetic karyotyping analysis showed 46,XY,t(4;9;22)(q21;q34;q11.2). He was treated with bosutinib and then changed to dasatinib because of intolerance, and MR4.5 (BCR-ABL/ABL ≦ 0.0032%, international scale) was achieved after 17 months of continuous treatment.

Conclusion

This was the 14th case of t(4;9;22), in particular, a new variant Ph translocation involved in chromosome 4q21 and the first successful case treated with tyrosine kinase inhibitors in the world. We summarize previous case reports regarding three-way variant chromosome translocation, t(4;9;22) and discuss how this rare translocation is linked to prognosis.

Temporal dynamics of the plasma microbiome in recipients at early post-liver transplantation: a retrospective study

Background

Immunosuppression during liver transplantation (LT) enables the prevention and treatment of organ rejection but poses a risk for severe infectious diseases. Immune modulation and antimicrobials affect the plasma microbiome. Thus, determining the impact of immunosuppression on the microbiome may be important to understand immunocompetence, elucidate the source of infection, and predict the risk of infection in LT recipients. We characterized the plasma microbiome of LT recipients at early post-LT and assessed the association between the microbiome and clinical events.

Results

In this study, 51 patients who received LT at Nagoya University Hospital from 2016 to 2018 were enrolled. Plasma samples were retrospectively collected at the following time points: 1) within a week after LT; 2) 4 ± 1 weeks after LT; 3) 8 ± 1 weeks after LT; and 4) within 2 days after a positive blood culture. A total of 111 plasma samples were analyzed using shotgun next-generation sequencing (NGS) with the PATHDET pipeline. Relative abundance of Anelloviridae, Nocardiaceae, Microbacteriaceae, and Enterobacteriaceae significantly changed during the postoperative period. Microbiome diversity was higher within a week after LT than that at 8 weeks after LT. Antimicrobials were significantly associated with the microbiome of LT recipients. In addition, the proportion of Enterobacteriaceae was significantly increased and the plasma microbiome diversity was significantly lower in patients with acute cellular rejection (ACR) than non-ACR patients. Sequencing reads of bacteria isolated from blood cultures were predominantly identified by NGS in 8 of 16 samples, and human herpesvirus 6 was detected as a causative pathogen in one recipient with severe clinical condition.

Conclusions

The metagenomic NGS technique has great potential in revealing the plasma microbiome and is useful as a comprehensive diagnostic procedure in clinical settings. Temporal dynamics of specific microorganisms may be used as indirect markers for the determination of immunocompetence and ACR in LT recipients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-021-02154-w.

[Recent advances in pathophysiology, diagnosis and treatment of steroid-refractory graft-versus-host disease]

Acute graft-versus-host disease (GVHD) is a major life-threating complication that occurs after allogeneic cell transplantation. Although steroids remain the first-line treatment, approximately one-third of patients will eventually develop steroid-resistant or steroid-refractory GVHD (SR-GVHD), which has an extremely poor prognosis. Many novel strategies that showed promising response rates in early phase I/II trials for the prevention and treatment of acute GVHD exhibited disappointing effects on patient survival in the SR-GVHD setting. The discovery of novel treatments has been further complicated by the absence of a clinically-relevant animal model. Nevertheless, the combined knowledge from translational studies using bone marrow transplantation models and clinical trials including SR-GVHD patients has begun to reveal novel mechanisms for inhibiting T cell signaling and promoting tissue regeneration, which has contributed to a better understanding of the SR-GVHD pathophysiology. Herein, we discuss recently elucidated cellular and molecular mechanisms that may provide the rational for novel biologically-driven treatments for SR-GVHD.

1224. Investigation of Infectious Etiologies in the Lower Respiratory Tract from Pediatric Patients with Unexpected Cardiopulmonary Deterioration using Next-Generation Sequencing

Background

In pediatric patients, unexpected cardiopulmonary deterioration with or without following cardiopulmonary arrest (CPA) are rare events, but can be caused by any of several etiologies, including infectious diseases. The most common cause of out-of-hospital CPA in children ≤12 years old was sudden infant death syndrome (SIDS), whereas infectious diseases were responsible for approximately 10% of the CPA cases. However, the role of infection may have been underestimated as triggers of SIDS or CPA. This study aimed to investigate the infectious etiologies in pediatric patients with unexpected cardiopulmonary deterioration using next-generation sequencing (NGS).

Methods

A total of 16 pediatric patients who were admitted to the pediatric intensive care unit with unexpected cardiopulmonary deterioration with or without following CPA were enrolled. Ten bronchoalveolar fluid (BALF) and six transtracheal aspirates (TTA) samples obtained in the acute phase were used to prepare NGS libraries. The libraries were sequenced on HiSeq and analyzed using metagenome analysis tools.

Results

In ten of 16 patients, one or more bacterial/viral pathogens were detected in the BALF or TTA specimens using NGS. Compared to the conventional culture and viral antigen test results, an additional 6 bacterial (e.g., Chlamydia trachomatis) and 4 viral pathogens (e.g., coxsackievirus A6 and human coronavirus NL63) were identified by NGS in four of ten patients in whom no causative pathogen had been identified by conventional culture and viral antigen tests. A summary of the detected pathogens is listed in Table 1. Notably, sequencing results allowed us to define genotypes for all of the detected viruses in a single NGS assay per patient. Furthermore, based on phylogenetic analysis of the VP1 region, the coxsackievirus A6 strain detected in this study belongs to lineage E2 and harbors an amino acid change (T283A), a substitution that has potential to cause severe illness.

Table 1

Conclusion

Our results suggest that viral and bacterial infection are common triggers in unexpected cardiopulmonary deterioration in pediatric patients. NGS has the potential to contribute to the clarification of the etiology of pediatric critical illness.

Disclosures

All Authors: No reported disclosures

1212. Temporal Dynamics of the Plasma Microbiome in Recipients at Early Post-liver Transplantation

Background

Immunosuppression during liver transplantation (LT) enables the prevention and treatment of organ rejection, but poses a risk for severe infectious diseases. Antimicrobials are often required for patients after LT. Recently, the genomes of multiple microorganisms have been detected in blood, which is essentially sterile. Immune modulation and antimicrobials affect the blood microbiome. Thus, determining the impact of immunosuppression and antimicrobials on the microbiome may be important to understand immunocompetence, predict clinical adverse events after LT such as acute cellular rejection (ACR), and treat infectious diseases.

Methods

Fifty-one patients who received LT at Nagoya University Hospital from 2016 to 2018 were enrolled. Plasma samples were retrospectively collected within a week after LT, 4±1 weeks after LT, 8±1 weeks after LT, and within 2 days after a positive blood culture. A total of 111 plasma samples were analyzed using shotgun next-generation sequencing (NGS). Sequence data were imported into the custom-made analysis pipeline PATHDET.

Results

The relative abundance of Anelloviridae, Nocardiaceae, Microbacteriaceae, and Enterobacteriaceae significantly changed during the postoperative period (figure 1). Microbiome diversity was higher within a week after LT than at 8 weeks after LT. Antimicrobials were significantly associated with the microbiome of LT recipients. In addition, the proportion of Enterobacteriaceae was significantly decreased (figure 2) and the plasma microbiome diversity was significantly higher in patients with ACR than in non-ACR patients. Finally, sequencing reads of bacteria isolated from blood cultures were predominantly identified by NGS in 8 of 16 samples (figure 3), and human herpesvirus 6 was detected as a causative pathogen in one recipient with severe infectious diseases.

Change in the relative abundance of each microorganism at the family level of taxonomic hierarchy in plasma samples after liver transplantation

Conclusion

The metagenomic NGS technique has great potential in revealing the plasma microbiome and is useful as a comprehensive diagnostic procedure in clinical settings. Temporal dynamics of specific microorganisms may be used as indirect markers for the determination of immunocompetence and ACR in LT recipients.

Disclosures

All Authors: No reported disclosures

MRI findings in children with congenital cytomegalovirus infection retrospectively diagnosed with dried umbilical cord

PURPOSE

Brain MRI provides important information about suspected congenital CMV infection in neonatally underdiagnosed children. This study aimed to describe MRI findings in children in whom congenital CMV infection was not suspected during the neonatal period and was proven retrospectively.

METHODS

We enrolled 31 children referred to the pediatric neurology clinic with neurological symptoms who were proven to have congenital CMV infection based on dried umbilical cord samples. Upon diagnosis, MR and CT images were assessed using the van der Knaap scoring system integrated with additional variables. Two investigators independently assessed all images.

RESULTS

The age at diagnosis was < 12 months in 14, 12-24 months in 11, and > 24 months in 6 patients. The initial symptom triggering clinic referral was delayed development in 22, seizure in 5, deafness in 3, and hemiplegia in 1 patient. Of the 31 children, 30 had a white matter (WM) abnormality predominant in the deep WM of the parietal lobe (n = 25). Anterior temporal lesions were observed in 21 children. Cortical lesions were observed in 7 children, suggestive of polymicrogyria. No child had cerebellar or brainstem abnormalities. Brain CT was performed in 22 of 31 children, and 11 showed punctate cerebral calcification in the periventricular and/or deep WM.

CONCLUSION

Patients with congenital CMV infection with delayed neurological symptoms show a relatively uniform pattern of parietal-dominant multifocal WM lesions and anterior temporal lesions, with or without polymicrogyria.

Comprehensive pathogen detection in sera of Kawasaki disease patients by high-throughput sequencing: a retrospective exploratory study

Background

Kawasaki disease (KD) is an idiopathic systemic vasculitis that predominantly damages coronary arteries in children. Various pathogens have been investigated as triggers for KD, but no definitive causative pathogen has been determined. As KD is diagnosed by symptoms, several days are needed for diagnosis. Therefore, at the time of diagnosis of KD, the pathogen of the trigger may already be diminished. The aim of this study was to explore comprehensive pathogens in the sera at the acute stage of KD using high-throughput sequencing (HTS).

Methods

Sera of 12 patients at an extremely early stage of KD and 12 controls were investigated. DNA and RNA sequences were read separately using HTS. Sequence data were imported into the home-brew meta-genomic analysis pipeline, PATHDET, to identify the pathogen sequences.

Results

No RNA virus reads were detected in any KD case except for that of equine infectious anemia, which is known as a contaminant of commercial reverse transcriptase. Concerning DNA viruses, human herpesvirus 6B (HHV-6B, two cases) and Anelloviridae (eight cases) were detected among KD cases as well as controls. Multiple bacterial reads were obtained from KD and controls. Bacteria of the genera Acinetobacter, Pseudomonas, Delfita, Roseomonas, and Rhodocyclaceae appeared to be more common in KD sera than in the controls.

Conclusion

No single pathogen was identified in serum samples of patients at the acute phase of KD. With multiple bacteria detected in the serum samples, it is difficult to exclude the possibility of contamination; however, it is possible that these bacteria might stimulate the immune system and induce KD.

Immune cell infiltration landscapes in pediatric acute myocarditis analyzed by CIBERSORT

BACKGROUND

Myocarditis is an inflammatory disease of the myocardium, which leads to cardiac dysfunction and heart failure. Previous studies have suggested that complex cross-talk between innate and adaptive immune responses is involved in the pathogenesis of acute myocarditis. Immunohistochemistry is the current standard method for the evaluation of infiltrating immune cells, however, it is difficult to investigate and quantify many immune cell populations using this technique.

METHODS

Endomyocardial biopsy samples of five pediatric patients with myocarditis were analyzed by cell-type identification by estimating relative subsets of RNA transcript (CIBERSORT), a computational method for quantifying cell fractions from tissue gene expression profiles. CIBERSORT results were then compared with immunohistochemistry analyses.

RESULTS

Significant results of immune infiltrate deconvolution were obtained in four patients with fulminant myocarditis by CIBERSORT analysis. Among 22 immune cell types, 19 cell types were detected in one or more patients. Activated NK cells were the most prevalent population in two patients, whereas activated memory CD4⁺ T cells and M2 macrophages were the most prevalent population in one patient each. Overall CIBERSORT results were consistent with those of immunohistochemistry, although some discrepancies were observed.

CONCLUSIONS

Infiltrating immune cell subsets detected by CIBERSORT analysis can reflect the time course of innate and adaptive immune responses in acute myocarditis. CIBERSORT may have the potential to characterize the detail of infiltrating immune cells in myocardial tissues and provide novel insights into the pathogenesis of acute myocarditis.

Viral DNA Loads in Various Blood Components of Patients With Epstein-Barr Virus-Positive T-Cell/Natural Killer Cell Lymphoproliferative Diseases

To evaluate diagnostic values for Epstein-Barr virus (EBV) DNA loads in different blood components of patients with EBV-positive T-cell/natural killer cell lymphoproliferative diseases, EBV DNA loads were compared among disease categories in each blood component from 59 patients. Plasma viral loads were significantly higher in "active" disease in chronic active EBV infection. EBV DNA was not detected in the plasma from 7 patients in whom EBV DNA was detected in peripheral blood mononuclear cells and whole blood. Diagnostic cutoff values for whole blood EBV DNA loads of patients with chronic active EBV infection compared with those of infectious mononucleosis was 104.2 (15 800) IU/mL.

540 Assessment of left ventricular ejection fraction from echocardiographic images using machine learning algorithm

Background

Precise and reliable echocardiographic assessment of LVEF is needed for clinical decision-making. LVEF is currently determined through an observer dependent process that requires manual tracing. To remove this manual tracing step, which is both time-consuming and user dependent, automatic computer aided diagnosis systems may be useful in the clinical setting.

Purpose

The aim of this study was to evaluate whether a 3-dimensional convolutional neural networks (3DCNN) could estimate left ventricular ejection fraction (LVEF) and differentiate types of heart failure (preserved EF/reduced EF) using conventional 2-dimensional echocardiographic images.

Methods

We developed a deep learning model to automatically estimate LVEF from echocardiographic data. The 3DCNN model was trained on a dataset of 340 patients. The dataset creation consisted of three main steps: firstly, for each exam, cine-loops showing the parasternal and apical views were manually selected; then, 10 sequential frames were extracted from each 1 beat and; finally, each frame was pre-processed to fit the learning model. Each patient has 2 views, resulting in a total of 6,800 images. Reference LVEF measurement was calculated by two highly experienced readers in each case.

Results

A good correlation was found between estimated LVEF based on apical 2 and 4 chamber views and reference LVEF (r =0.88, p &lt;0.001) (Figure). For classification of heart failure types based on LVEF (LVEF ≥50% or &lt;50%), the area under the receiver-operating characteristic curve by the 3DCNN algorithm was over 0.95.

Conclusions

The 3DCNN can be applied to estimate and classify the LVEF in the clinical setting. Furthermore, this work will serve as a driver for future research using million image databases.

Abstract 540 Figure.

P1526 Updated prevalence of lambls excrescences using the latest three-dimensional transesophageal echocardiography

Background

Lambl’s excrescences (LEs), filiform strands that occur at sites of cardiac valves, have been suggested the cause cryptogenic stroke. The diagnosis is primarily based upon the echocardiographic study, but conventional two-dimensional transthoracic echocardiography has limitation to detect such as small strands. Latest three dimensional-transesophageal echocardiography (3D-TEE) have high-resolution images with many slices, so small structures are able to be clearly visible and detected.

Purpose

The aim of this study was to assess the prevalence of LEs using the latest 3D-TEE images.

Methods

We retrospectively reviewed consecutive 140 patients who underwent 3D-TEE from November 2018 to May 2019. Forty-seven patients were excluded due to unmeasurable, such as mitral valve prolapse, severe aortic stenosis, prosthetic valves and poor-quality images. We carefully evaluated the mitral and aortic valve leaflets in order to find mobile string structure (diameter &lt;1 mm and length 1–20 mm) in each cardiac cycle. Total analyzed images were over 50 slices per one patient.

Results

Among 93 patients, 83 patients (89%) was detected the presence of LEs. No difference in age and gender were found between patients with LEs and patients without LEs. Of the total 83 patients, there were 35 patients with strands on mitral valve, 32 patients with strands on aortic valve, and 16 patients with strands on both valves. Distribution of LEs at each valve leaflet were shown in Figure. Right coronary cusp of aortic valve (42%) and P2 of mitral valve (35%) were high prevalence among leaflets.

Conclusions

3D-TEE provides an update prevalence of LEs. The prevalence of LEs might be potentially high in the real world.

Abstract P1526 Figure.

1792. Viral DNA Loads in Various Blood Components of Patients with EBV-Positive T/NK Cell Lymphoproliferative Diseases

Background

Epstein–Barr virus (EBV) is associated with T- and NK-cell lymphoproliferative disorders (EBV T/NK-LPD). For diagnosis of EBV T/NK-LPD, quantification of EBV DNA loads in peripheral blood by real-time PCR has been widely used. However, optimal blood components and cut-off values for diagnosis were not fully evaluated.

Methods

Fifty-nine patients with EBV T/NK-LPD including chronic active EBV infection (CAEBV), severe mosquito bite allergy, hydroa vacciniforme-like lymphoproliferative disorder (HV), and EBV- hemophagocytic lymphohistiocytosis (EBV-HLH) were enrolled. EBV DNA loads were compared among disease categories in each blood component from the same whole blood sample. The association between EBV DNA loads and disease activity were evaluated in CAEBV patients. Furthermore, the diagnostic cut-off value for EBV DNA loads in whole blood from CAEBV patients as compared with infectious mononucleosis patients was determined.

Results

EBV DNA loads in whole blood and peripheral blood mononuclear cells (PBMCs) were not significantly different among disease categories, whereas EBV DNA loads in plasma were significantly higher in EBV- HLH patients than in HV patients. EBV DNA loads in whole blood and PBMCs showed strong correlation (Figure 1). EBV DNA loads in plasma were significantly higher in CAEBV patients with active disease than in those with inactive disease (median: 10^4.5 IU/mL vs. 10^0.8 IU/mL, P < 0.001) (Figure 2). Diagnostic cut-off values for whole blood EBV DNA loads of CAEBV patients as compared with those of infectious mononucleosis was 10^4.2 ( = 15,800) IU/mL (Figure 3).

Conclusion

Measuring EBV DNA loads in whole blood can be considered as initial evaluation for diagnosis of EBV T/NK-LPD. EBV DNA loads in plasma are more closely related to disease activity of CAEBV than EBV DNA loads in whole blood and PBMCs.

Disclosures

All authors: No reported disclosures.

242. Comprehensive Pathogen Detection for Pediatric Febrile Neutropenia by Metagenomic Next-Generation Sequencing

Background

Febrile neutropenia (FN) is a common complication in patients with solid tumors and hematologic malignancies. Identification of the causative microorganisms would contribute to optimization of antimicrobial treatment and thus improve the outcome of FN. However, causative microorganisms are detected in only 10% to 20% of FN patients. Next-generation sequencing (NGS) allows us to comprehensively analyze all microorganisms present in a clinical sample. In this study, we aimed to utilize NGS for the detection of microbial pathogens in infectious diseases and elucidate the infection source in FN.

Methods

FN is defined by two characteristics: (1) neutrophils count < 500/µL, and (2) fever ≥38.0°C. From 2016 to 2018, 112 plasma/serum samples of pediatric FN patients (11 positive blood cultures) were analyzed. Serum samples from 10 neutropenic patients without fever were also analyzed as controls. Shotgun sequencing method was applied for these samples. The metagenomic analyses were performed through the pipeline PATHDET, which has been newly established in our laboratory. Diagnosis based on NGS results was made based on the following criteria: (1) number of reads from all pathogens per million reads (PR) >650, (2) a specific pathogen’s reads per million reads (RPM) >200, and (3) diversity index >3.0. The NGS results were compared with those from blood culture.

Results

Sequencing reads of bacteria isolated through blood culture were identified by NGS in all 11 plasma/serum samples leading to the diagnosis of FN. The causative pathogens were diagnosed by NGS using the above criteria in 11 patients. However, the results were consistent with those of blood culture in only 4 samples. Of 101 cases with negative blood culture results, the causative pathogens were detected in 17 cases: Acinetobacter soli (2 cases), Burkholderia cepacian (1 case), Klebsiella variicola (1 case), and Roseomonas sp. (1 case) were identified at the species level. In addition, 7 cases (e.g., Acinetobacter) were identified at the genus level, and 5 cases (e.g., Enterobacteriaceae) were identified at the family level.

Conclusion

Metagenomic NGS technique has great potential for detecting causative pathogens with greater efficiency than the conventional methods.

Disclosures

All authors: No reported disclosures.

P3437Impact of epicardial adipose tissue on global longitudinal strain: a study in patients with normal left ventricular ejection fraction

Background

Epicardial adipose tissue (EAT) locates anatomically and functionally contiguous to the myocardium and coronary arteries. It has been suggested that EAT accumulation is associated with cardiac remodeling and impaired cardiac performance. However, its role in left ventricular (LV) wall strain remains unclear.

Purpose

In this study, we aimed to clarify: whether EAT accumulation is related to global longitudinal (GLS), circumferential (CS) and radial strain (RS); and if so, in which extent or by which amount of EAT are required to deteriorate these strain.

Methods

Total 180 patients who had no obstructive coronary artery disease (CAD) on multi-detector computed tomography (MDCT) coronary angiography and normal left ventricular ejection fraction (LVEF) on conventional echocardiography were recruited. Cardiac CT was used to quantify EAT volume (EATV) and echocardiographic speckle tracking was used to measure the GLS, CS and RS. EATV index (EATV/Body surface area) was determined as: EAT volume, the sum of the EAT area from the base to the apex of the heart (cm3)/body surface area (m2). Adipose tissue was determined as the density range between −190 and −30 Hounsfield unit. According to the median value (68 cm3/m2), patients were divided into lower and higher EATV index two groups.

Results

In higher EATV index group (95±19 cm3/m2), mean age, body mass index (BMI), prevalence of hyperlipidemia and prevalence of CAD were larger than in lower EATV index group (48±14 cm3/m2). Male gender, hypertension, diabetes, smoking and LV mass index were comparable between two groups. Patients in higher EATV index had lower GLS than those in lower EATV index (−19.4±1.2% vs. −18.8±1.3%, p=0.002). However, there were no significant difference between two groups regarding to the CS and RS. Linear regression analysis showed that there was strong correlation between EATV index and GLS (R=0.216, p=0.004); whereas, both RS and CS were strongly associated with the interventricular septum thickness (RS: R=0.248, p=0.003; CS: R= −0.192, p=0.023) and relative wall thickness (RS: R=0.178, p=0.036; CS: R= −0.184, p=0.030) but not with EATV; on multiple regression analysis, EATV was a predictor of GLS independent of age, male gender, BMI, diabetes, hyperlipidemia, hypertension and CAD (Adjusted R2=0.238, p<0.001).

Conclusion

EATV is independently associated with GLS despite the preserved LVEF and lacking of obstructive CAD, and may play a significant role in estimating impaired longitudinal LV performance.

Metagenomic analysis using next-generation sequencing of pathogens in bronchoalveolar lavage fluid from pediatric patients with respiratory failure

Next-generation sequencing (NGS) has been applied in the field of infectious diseases. Bronchoalveolar lavage fluid (BALF) is considered a sterile type of specimen that is suitable for detecting pathogens of respiratory infections. The aim of this study was to comprehensively identify causative pathogens using NGS in BALF samples from immunocompetent pediatric patients with respiratory failure. Ten patients hospitalized with respiratory failure were included. BALF samples obtained in the acute phase were used to prepare DNA- and RNA-sequencing libraries. The libraries were sequenced on MiSeq, and the sequence data were analyzed using metagenome analysis tools. A mean of 2,041,216 total reads were sequenced for each library. Significant bacterial or viral sequencing reads were detected in eight of the 10 patients. Furthermore, candidate pathogens were detected in three patients in whom etiologic agents were not identified by conventional methods. The complete genome of enterovirus D68 was identified in two patients, and phylogenetic analysis suggested that both strains belong to subclade B3, which is an epidemic strain that has spread worldwide in recent years. Our results suggest that NGS can be applied for comprehensive molecular diagnostics as well as surveillance of pathogens in BALF from patients with respiratory infection.

Serological screening of immunoglobulin M and immunoglobulin G during pregnancy for predicting congenital cytomegalovirus infection

Background

Cytomegalovirus (CMV) is one of the most frequent pathogens for congenital infections. Most cases of congenital CMV infection (cCMV) are asymptomatic at birth, but sensorineural hearing loss (SNHL) or neurodevelopmental delay can appear later in childhood. This prospective study examined the practicability of serological screening for anti-CMV immunoglobulin (Ig) G and anti-CMV IgM in pregnant women.

Methods

A total of 11,753 pregnant women were examined for CMV IgG and CMV IgM during the first or second trimester. When IgM was positive, IgG was reevaluated more than two weeks later. When IgG was negative, IgG was reevaluated in the second or third trimester. All neonates from mothers with positive/borderline IgM or IgG seroconversion underwent polymerase chain reaction assay for CMV using urine samples to diagnose cCMV. Levels of IgG and IgM were compared between mothers with and without cCMV. Receiver operating characteristic (ROC) curves for IgM titers were analyzed.

Results

Eight of 500 neonates (1.6%) born from mothers with positive IgG and positive IgM, and 3 of 13 neonates (23.1%) born from mothers with IgG seroconversion were diagnosed with cCMV. Neither IgM titers nor IgG titers differed significantly between cCMV and non-cCMV groups. The area under the ROC curve was 0.716 and the optimal cut-off for IgM was 7.28 index (sensitivity = 0.625, specificity = 0.965, positive predictive value = 0.238, negative predictive value = 0.993). Titers of IgG were not frequently elevated in pregnant women with positive IgM during the observation period, including in those with cCMV. All 11 cCMV cases were asymptomatic at birth and none had shown SNHL or developmental delay as of the last regular visit (mean age, 40 months).

Conclusions

Seroconversion of CMV IgG and high-titer IgM during early pregnancy are predictors of cCMV. High IgM titer (> 7.28 index) is a predictor despite relatively low sensitivity. Levels of IgG had already plateaued at first evaluation in mothers with cCMV. Maternal screening offered insufficient positive predictive value for diagnosing cCMV, but allowed identifying asymptomatic cCMV cases in an early stage.

2513. The Utility of Next-Generation Sequencing for Detection of Causative Viruses in Sera of Patients With Acute Myocarditis

Background

Myocarditis is an inflammatory disease of the myocardium with a wide range of clinical presentations, occasionally leading to cardiac dysfunction and heart failure. Although viral infections are considered to be the most common etiology of myocarditis, identification of the causative virus is still challenging. Recently, next-generation sequencing (NGS) has been applied in the diagnosis of infectious diseases. The aim of this study was to evaluate the utility of NGS for detection of causative viruses in sera of patients with acute myocarditis.

Methods

Twelve pediatric and five adult patients hospitalized for acute myocarditis were included in this study. Serum samples before initiation of treatment were collected in the acute phase and analyzed with NGS-based approach. To detect pathogen-derived sequencing reads, we performed DNA and RNA sequencing for each sample.

Results

An average of 20,062,443 and 19,506,189 total reads were obtained in DNA and RNA sequencing libraries, respectively. Viral sequence reads were detected in 7 (41%) of the 17 myocarditis patients. Substantial sequence reads of GB virus C (GBV-C) reads were detected from one patient by RNA sequencing; however, its pathogenicity to human is unknown. Detection of Epstein–Barr virus, human parvovirus B19, and respiratory syncytial virus reads by NGS was consistent with PCR or antigen test results. Conversely, the number of detected virus-derived reads was small in most cases. No significant bacterial or fungal reads other than normal bacterial flora was detected.

Conclusion

NGS-based approach may have potential to detect the causative viruses and contribute to clarification of the etiology of acute myocarditis.

Disclosures

All authors: No reported disclosures.

Identification of potential pathogenic viruses in patients with acute myocarditis using next-generation sequencing

Myocarditis is an inflammatory disease of the myocardium and leads to cardiac dysfunction and heart failure. Although viral infections are considered to be the most common etiology of myocarditis, the identification of the causative virus is still challenging. Recently, next-generation sequencing (NGS) has been applied in the diagnosis of infectious diseases. The aim of the current study was to comprehensively analyze potential pathogenic microorganisms using NGS in the sera of patients with myocarditis. Twelve pediatric and five adult patients hospitalized for acute myocarditis were included. Serum samples in the acute phase were obtained and analyzed using NGS to detect pathogen-derived DNA and RNA. Viral sequence reads were detected in 7 (41%) of the 17 myocarditis patients by NGS. Among these patients, detection of Epstein-Barr virus, human parvovirus B19, torque teno virus, and respiratory syncytial virus reads by NGS was consistent with polymerase chain reaction or antigen test results in one patient each. A large number of human pegivirus reads were detected from one patient by RNA sequencing; however, its pathogenicity to human is unknown. Conversely, the number of detected virus-derived reads was small in most cases, and the pathophysiological role of these viruses remains to be clarified. No significant bacterial or fungal reads other than normal bacterial flora was detected. These data indicate that comprehensive detection of virus-derived DNA and RNA using NGS can be useful for the identification of potential pathogenic viruses in myocarditis.

Antitumor effects of duvelisib on Epstein-Barr virus-associated lymphoma cells

Epstein–Barr virus (EBV) is a ubiquitous oncogenic virus that is associated with B cell lymphomas, including Burkitt lymphoma and Hodgkin lymphoma. Previous studies have shown that the phosphatidylinositol 3‐kinase (PI3K)/Akt pathway is activated in EBV‐associated lymphomas and can be a novel therapeutic target. An oral dual inhibitor of PI3Kγ and PI3Kδ, duvelisib, is in clinical trials for the treatment of lymphoid malignancies. In this study, we evaluated how duvelisib affects the activity of the PI3K/Akt signaling pathway and if it has antitumor effects in EBV‐associated lymphoma cell lines. We found that the PI3K/Akt signaling pathway was activated in most of the B and T cell lymphoma cell lines tested. Additionally, duvelisib treatment inhibited cellular growth in the tested cell lines. Overall, B cell lines were more susceptible to duvelisib than T and NK cell lines in vitro regardless of EBV infection. However, the additional influence of duvelisib on the tumor microenvironment was not assessed. Duvelisib treatment induced both apoptosis and cell cycle arrest in EBV‐positive and ‐negative B cell lines, but not in T cell lines. Furthermore, duvelisib treatment reduced the expression of EBV lytic genes (BZLF1 and gp350/220) in EBV‐positive B cell lines, suggesting that duvelisib suppresses the lytic cycle of EBV induced by B cell receptor signaling. However, duvelisib did not induce a remarkable change in the expression of EBV latent genes. These results may indicate that there is therapeutic potential for duvelisib administration in the treatment of EBV‐associated B cell lymphomas and other B cell malignancies.

Tofacitinib induces G1 cell-cycle arrest and inhibits tumor growth in Epstein-Barr virus-associated T and natural killer cell lymphoma cells

Epstein-Barr virus (EBV) infects not only B cells, but also T cells and natural killer (NK) cells, and is associated with T or NK cell lymphoma. These lymphoid malignancies are refractory to conventional chemotherapy. We examined the activation of the JAK3/STAT5 pathway in EBV-positive and -negative B, T and NK cell lines and in cell samples from patients with EBV-associated T cell lymphoma. We then evaluated the antitumor effects of the selective JAK3 inhibitor, tofacitinib, against these cell lines in vitro and in a murine xenograft model. We found that all EBV-positive T and NK cell lines and patient samples tested displayed activation of the JAK3/STAT5 pathway. Treatment of these cell lines with tofacitinib reduced the levels of phospho-STAT5, suppressed proliferation, induced G1 cell-cycle arrest and decreased EBV LMP1 and EBNA1 expression. An EBV-negative NK cell line was also sensitive to tofacitinib, whereas an EBV-infected NK cell line was more sensitive to tofacitinib than its parental line. Tofacitinib significantly inhibited the growth of established tumors in NOG mice. These findings suggest that tofacitinib may represent a useful therapeutic agent for patients with EBV-associated T and NK cell lymphoma.

Comprehensive Detection of Pathogens in Immunocompromised Children with Bloodstream Infections by Next-generation Sequencing

Background

Bloodstream infection (BSI) is a severe complication in immunocompromised patients. Prompt identification of causative microorganisms would improve the outcome of BSI due to optimization of antimicrobial treatment. Next-generation sequencing (NGS) allows us to analyze comprehensively and quantitatively all microorganisms present in a clinical sample in comparison with blood culture. However, there are currently no established methods to identify causative pathogens by NGS.

Methods

BSI was defined by the following criteria: (i) pathogen isolated from blood culture and (ii) fever ≥38.0°C or C-reactive protein >1.0mg/dl. Thirty-five pediatric patients (12 with BSI and 23 with suspected BSI/negative blood culture) were enrolled. Plasma/serum samples were used for sequencing and the results were compared with those from blood culture. The bacterial reads per million reads of the sequence depth (BR) and relative importance values of the dominant bacteria (P1) were applied to identify causative pathogens.

Results

Sequencing reads of bacteria isolated in blood culture were identified by NGS in all plasma/serum samples at the onset of BSI. Additionally, bacteria isolated in blood culture were identical to the dominant bacteria by NGS in 8 of 12 patients with BSI. Causative microorganisms were detected when the NGS results fulfilled the criteria of BR >200 and P1 >0.5. In two patients with catheter-related BSI, causative bacteria were detected in the plasma/serum at 7 days before disease onset. Causative pathogens (Tatlockia micdadei, Escherichia coli, and human adenovirus 2) were identified in three of 23 patients in the suspected BSI group. A total of 62 resistance genes were detected in nine patients with sequences covering 5–100% of references.

Conclusion

An NGS-based approach has great potential for analysis of causative microorganisms in BSI and may help to diagnose a disease before disease onset. Antimicrobial resistance genes can also be found through sequence data processing.

Disclosures

All authors: No reported disclosures.

Epstein-Barr virus infection-induced inflammasome activation in human monocytes

Inflammasomes are cytoplasmic sensors that regulate the activity of caspase-1 and the secretion of interleukin-1β (IL-1β) or interleukin-18 (IL-18) in response to foreign molecules, including viral pathogens. They are considered to be an important link between the innate and adaptive immune responses. However, the mechanism by which inflammasome activation occurs during primary Epstein-Barr virus (EBV) infection remains unknown. Human B lymphocytes and epithelial cells are major targets of EBV, although it can also infect a variety of other cell types. In this study, we found that EBV could infect primary human monocytes and the monocyte cell line, THP-1, inducing inflammasome activation. We incubated cell-free EBV with THP-1 cells or primary human monocytes, then confirmed EBV infection using confocal microscopy and flow cytometry. Lytic and latent EBV genes were detected by real-time RT-PCR in EBV-infected monocytes. EBV infection of THP-1 cells and primary human monocytes induced caspase-dependent IL-1β production, while EBV infection of B-cell or T-cell lines did not induce IL-1β production. To identify the sensor molecule responsible for inflammasome activation during EBV infection, we examined the mRNA and the protein levels of NLR family pyrin domain-containing 3 (NLRP3), absent in melanoma 2 (AIM2), and interferon-inducible protein 16 (IFI16). Increased AIM2 levels were observed in EBV-infected THP-1 cells and primary human monocytes, whereas levels of IFI16 and NLRP3 did not show remarkable change. Furthermore, knockdown of AIM2 by small interfering RNA attenuated caspase-1 activation. Taken together, our results suggest that EBV infection of human monocytes induces caspase-1-dependent IL-1β production, and that AIM2, acting as an inflammasome, is involved in this response.

Primary psoas abscess caused by group A streptococcus in a child: Case report with microbiologic findings

Primary abscess of the iliopsoas muscle in children is uncommon, especially due to Streptococcus pyogenes (group A streptococcus: GAS), which causes a variety of diseases ranging from pharyngitis to invasive life-threatening infection. We present primary iliopsoas abscess in a nine-year-old boy presenting with fever, mild disturbance of consciousness, limp, and pain in the right loin. Magnetic resonance imaging and isolation of GAS from both blood and abscess samples led us to the confirmative diagnosis. The patient recovered after treatment comprising drainage and intravenous antibiotics. The CovRS system is one of the best-characterized systems with two-component signal transduction in the GAS, and mutations in covRS induce overproduction of various virulence factors that play a crucial role in invasive GAS infection. RopB, also known as a GAS regulator, influences the expression of multiple regulatory networks to coregulate virulence factor expression in GAS. In the present case, sequence analysis revealed the isolated GAS as emm type 6 with alterations in covS, whereas the covR and ropB genes were intact. The covS alterations might have influenced the virulence of the strain causing this severe GAS infection.