Human Herpesvirus Research Articles

A systematic review and meta-analysis of HHV-6 and mortality after hematopoietic cell transplant.

Human herpesvirus-6B (HHV-6B) reactivation has been associated with non-relapse mortality (NRM) and overall mortality (OM) following allogeneic hematopoietic stem cell transplant (HCT). We performed a systematic review and meta-analysis to better quantify the association. Studies were included if they systematically tested a cohort of HCT recipients for HHV-6 infection or reactivation and described mortality for patients with and without HHV-6B. Random effects models were used to assess the pooled effect of HHV-6B positivity on each outcome of interest. Bayesian aggregation was additionally performed if models included 10 or fewer studies. Eight studies were included in the NRM analysis, which demonstrated a significant association between HHV-6 detection and NRM (pooled effect: 1.84; 95% CI: 1.29-2.62) without significant heterogeneity (I2 = 0.0%, p = 0.55). A Bayesian aggregation of the raw data used to construct the NRM random effects model supported these findings (95% credible interval: 0.15-1.13). Twenty-five studies were included in OM analysis, which showed a significant positive association (pooled effect: 1.37; 95% CI: 1.07-1.76), though considerable heterogeneity was observed (I2 = 36.7%, p < 0.05). HHV-6 detection is associated with NRM and OM following HCT. Randomized trials are warranted to evaluate if preventing or treating HHV-6B reactivation improves outcomes.

Long COVID syndrome: An unfolding enigma.

Post-acute sequelae of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) disease (COVID-19), called as long COVID syndrome, is a major global public health issue after recovery from COVID-19. The disease occurs in symptomatic patients irrespective of illness severity. The symptoms continue after four wk of recovery from acute illness and persist beyond three months. Risk factors for long COVID include older age, female gender, multiple co-morbidities including diabetes mellitus, prior chronic respiratory illnesses, hospitalized patients with severe disease, especially receiving assisted ventilation, high viral load, reactivation of Epstein Barr (EB) virus and human herpes virus 6 (HH6), circulating auto antibodies against various organs and type I interferon. The prevalence varies from 10 to 20 per cent, and most data have been reported from high-income countries. Any system can get involved in long COVID. The symptoms include fatigue, cognition impairment, cough and dyspnoea, anosmia, hair loss and diarrhoea, among others. While there are no laboratory tests for confirmation of diagnosis, reduced complement C7 complexes at six months, and a two-gene biomarker including FYN and SARS-CoV-2 antisense ribonucleic acid (RNA) are emerging as potentially useful biomarkers for long COVID. There should be no alternative disease to explain various symptoms. Vaccination against SARS-CoV-2 and early use of oral antiviral nirmatrelvir within the first five days in patients with acute mild disease having various risk factors for progression to severe disease help in preventing long COVID. Several clinical trials are underway for the treatment of long COVID and the results of these are eagerly awaited. Physical and mental rehabilitation at home, at community level or in the hospital setting as appropriate is essential in patients with long COVID.

The cellular paraspeckle component SFPQ associates with the viral processivity factor ORF59 during lytic replication of Kaposi's Sarcoma-associated herpesvirus (KSHV)

Kaposi's sarcoma-associated herpesvirus (KSHV) relies on many cellular proteins to complete replication and generate new virions. Paraspeckle nuclear bodies consisting of core ribonucleoproteins splicing factor proline/glutamine-rich (SFPQ), Non-POU domain-containing octamer-binding protein (NONO), and paraspeckle protein component 1 (PSPC1) along with the long non-coding RNA NEAT1, form a complex that has been speculated to play an important role in viral replication. Paraspeckle bodies are multifunctional and involved in various processes including gene expression, mRNA splicing, and anti-viral defenses. To better understand the role of SFPQ during KSHV replication, we performed SFPQ immunoprecipitation followed by mass spectrometry from KSHV-infected cells. Proteomic analysis showed that during lytic reactivation, SFPQ associates with viral proteins, including ORF10, ORF59, and ORF61. These results are consistent with a previously reported ORF59 proteomics assay identifying SFPQ. To test if the association between ORF59 and SFPQ is important for replication, we first identified the region of ORF59 that associates with SFPQ using a series of 50 amino acid deletion mutants of ORF59 in the KSHV BACmid system. By performing co-immunoprecipitations, we identified the region spanning amino acids 101–150 of ORF59 as the association domain with SFPQ. Using this information, we generated a dominant negative polypeptide of ORF59 encompassing amino acids 101–150, that disrupted the association between SFPQ and full-length ORF59, and decreased virus production. Interestingly, when we tested other human herpesvirus processivity factors (EBV BMRF1, HSV-1 UL42, and HCMV UL44) by transfection of each expression plasmid followed by co-immunoprecipitation, we found a conserved association with SFPQ. These are limited studies that remain to be done in the context of infection but suggest a potential association of SFPQ with processivity factors across multiple herpesviruses.

Clinical and Histopathologic Characteristics of Acute Severe Hepatitis Associated With Human Herpesvirus 6 Infection.

Acute severe hepatitis associated with active human herpesvirus 6 (HHV-6) infection is a rare life-threatening condition with unclear clinical course and histopathology. In this study, we retrospectively analyzed 5 patients with indeterminate acute severe hepatitis found to have active hepatic HHV-6 infection during care. All patients were previously healthy children presenting with a nonspecific prodrome. Four developed acute liver failure (ALF) and 3 received liver transplantation. The explanted livers and biopsies demonstrated a centrilobular pattern of necroinflammation characterized by moderate to marked central perivenulitis and confluent centrilobular to panlobular necrosis in 4 cases, accompanied by marked hepatocellular swelling and milder portal inflammation in 3. Central perivenulitis was more prominent in comparison to a control of group of ALF without HHV-6 ( P =0.01). When compared with the children with acute severe hepatitis associated with adenovirus encountered in the recent outbreak, both central perivenulitis and centrilobular necrosis were significant predictors for association with HHV-6 ( P <0.01). Liver immunohistochemistry detected HHV-6 structural protein in biliary epithelium in all cases and a predominance of CD8 + T cells in the perivenular inflammatory infiltrate. Among the 4 patients with ALF, one received early anti-HHV-6 therapy and had transplant-free survival, while the other 3 received either general prophylactic antiviral treatment only (n=2) or late anti-HHV-6 therapy (n=1) and needed liver transplantation. Our findings were similar to those in previously reported cases. In summary, acute severe hepatitis associated with HHV-6 tends to affect children, progress to ALF, and exhibit characteristic centrilobular necroinflammation which likely represents an immune-mediated process.

Single cell and TCR analysis of immune cells from AAV gene therapy-dosed Duchenne muscular dystrophy patients

Clinical trials for Duchenne muscular dystrophy (DMD) are assessing the therapeutic efficacy of systemically delivered adeno-associated virus (AAV) carrying a modified DMD transgene. High vector doses (>1E14 vg/kg) are needed to globally transduce skeletal muscles; however, such doses trigger immune-related adverse events. Mitigating these immune responses is crucial for widespread application of AAV-based therapies. We used single-cell RNA-sequencing and T-cell receptor (TCR)-sequencing on peripheral blood mononuclear cells from five participants prior to, and after, dosing. One subject in the high-dose cohort experienced thrombotic microangiopathy (TMA). Few changes in cell frequencies occurred after treatment; however, differential gene expression demonstrated induction of interferon response genes in most T-cell types. T-cell clonotype and clumping analysis showed the expansion or appearance of groups of related TCR sequences in the post-treatment samples. Three of these expanded clumps could be assigned to prior Human Herpesvirus infections, two of which were present in the participant that exhibited TMA. These data provide insight on the mechanistic basis of human immune-AAV interactions and lay a foundation for improved understanding of why TMA arises in some patients and not others.

Diagnostic Dilemmas: A Review of Reported Cases of Human Herpesvirus 6 Encephalitis in Immunocompetent Adults

Abstract Human herpesvirus 6 (HHV-6) is associated with its presentation in the pediatric population as roseola infantum. Rarely, it is the causative agent of encephalitis, with most cases reported among the immunocompromised population due to reactivation. This review article analyzes the published records of cases labeled HHV-6 encephalitis in immunocompetent adults, aiming to understand the diagnostic methods behind each case and explore the complexities of such a diagnosis. We note significant variability in the methods used to come to a diagnosis of HHV-6 encephalitis, as well as inconsistent approaches to treatment of this condition. Given the rarity of HHV-6 encephalitis in immunocompetent adults, there are no clearly structured diagnostic guidelines for this condition in this patient population. We highlight several diagnostic methods that provide more convincing evidence of true HHV-6 encephalitis and may provide a basis for further development of guidelines for the diagnosis and treatment of this condition.

Elucidating the causal nexus between antibody-mediated immunity and autoimmune diseases: Insights from bidirectional mendelian randomization, gene expression profiling, and drug sensitivity analysis

ObjectiveThis study aimed to elucidate the causal relationships between antibodies and autoimmune diseases using Mendelian randomization (MR). MethodsData on 46 antibodies were obtained from genome-wide association studies (GWAS). Autoimmune disease data were sourced from the FinnGen consortium and the IEU OpenGWAS project. Inverse-variance weighted (IVW) analysis was the primary method, supplemented by heterogeneity and sensitivity analyses. We also examined gene expression near significant SNPs and conducted drug sensitivity analyses. ResultsAntibodies and autoimmune diseases exhibit diverse interactions. Antibodies produced after Polyomavirus infection tend to increase the risk of several autoimmune diseases, while those following Human herpesvirus 6 infection generally reduce it. The impact of Helicobacter pylori infection varies, with different antibodies affecting autoimmune diseases in distinct ways. Overall, antibodies significantly influence the risk of developing autoimmune diseases, whereas autoimmune diseases have a lesser impact on antibody levels. Gene expression and drug sensitivity analyses identified multiple genes and drugs as potential treatment options for ankylosing spondylitis (AS), with the AIF1 gene being particularly promising. ConclusionsBidirectional MR analysis confirms complex causal relationships between various antibodies and autoimmune diseases, revealing intricate patterns of post-infection antibody interactions. Several drugs and genes, notably AIF1, show potential as candidates for AS treatment, offering new avenues for research. Further exploration of the underlying mechanisms is necessary.

Kaposi Sarcoma in Two Lung Transplant Recipients: A Single-Center Experience

Kaposi's Sarcoma (KS) is a malignant vascular tumor commonly seen in immunocompromised individuals, particularly patients with acquired immunodeficiency syndrome. Lung transplant patients are at a high risk of developing KS due to a strong immunosuppressive regimen that can lead to donor-derived infection or reactivation of recipient human herpes virus - 8, the causative organism for KS. In this overview, we describe two recipients of lung transplants that developed pulmonary KS with poor outcomes. We review the diagnosis, bronchoscopy findings, treatment and surveillance strategies for pulmonary KS.

Human herpesvirus reactivation and its potential role in the pathogenesis of post-acute sequelae of SARS-CoV-2 infection.

The emergence of SARS-CoV-2 has precipitated a global pandemic with substantial long-term health implications, including the condition known as post-acute sequelae of SARS-CoV-2 infection (PASC), commonly referred to as Long COVID. PASC is marked by persistent symptoms such as fatigue, neurological issues, and autonomic dysfunction that persist for months beyond the acute phase of COVID-19. This review examines the potential role of herpesvirus reactivation, specifically Epstein-Barr virus (EBV) and cytomegalovirus (CMV), in the pathogenesis of PASC. Elevated antibody titers and specific T cell responses suggest recent herpesvirus reactivation in some PASC patients, although viremia is not consistently detected. SARS-CoV-2 exhibits endothelial trophism, directly affecting the vascular endothelium and contributing to microvascular pathologies. These pathologies are significant in PASC, where microvascular dysfunction may underlie various chronic symptoms. Similarly, herpesviruses like CMV also exhibit endothelial trophism, which may exacerbate endothelial damage when reactivated. Evidence suggests that EBV and CMV reactivation could indirectly contribute to the immune dysregulation, immunosenescence, and autoimmune responses observed in PASC. Additionally, EBV may play a role in the genesis of neurological symptoms through creating mitochondrial dysfunction, though direct confirmation remains elusive. The reviewed evidence suggests that while herpesviruses may not play a direct role in the pathogenesis of PASC, their potential indirect effects, especially in the context of endothelial involvement, warrant further investigation.

HerpesDRG: a comprehensive resource for human herpesvirus antiviral drug resistance genotyping

The prevention and treatment of many herpesvirus associated diseases is based on the utilization of antiviral therapies, however therapeutic success is limited by the development of drug resistance. Currently no single database cataloguing resistance mutations exists, which hampers the use of sequence data for patient management. We therefore developed HerpesDRG, a drug resistance mutation database that incorporates all the known resistance genes and current treatment options, built from a systematic review of available genotype to phenotype literature. The database is released along with an R package that provides a simple approach to resistance variant annotation and clinical implication analysis from common sanger and next generation sequencing data. This represents the first openly available and community maintainable database of drug resistance mutations for the human herpesviruses (HHV), developed for the community of researchers and clinicians tackling HHV drug resistance.

Comparative analysis of metagenomic and targeted next-generation sequencing for pathogens diagnosis in bronchoalveolar lavage fluid specimens.

Although the emerging NGS-based assays, metagenomic next-generation sequencing (mNGS) and targeted next-generation sequencing (tNGS), have been extensively utilized for the identification of pathogens in pulmonary infections, there have been limited studies systematically evaluating differences in the efficacy of mNGS and multiplex PCR-based tNGS in bronchoalveolar lavage fluid (BALF) specimens. In this study, 85 suspected infectious BALF specimens were collected. Parallel mNGS and tNGS workflows to each sample were performed; then, we comparatively compared their consistency in detecting pathogens. The differential results for clinically key pathogens were confirmed using PCR. The microbial detection rates of BALF specimens by the mNGS and tNGS workflows were 95.18% (79/83) and 92.77% (77/83), respectively, with no significant difference. mNGS identified 55 different microorganisms, whereas tNGS detected 49 pathogens. The comparative analysis of mNGS and tNGS revealed that 86.75% (72/83) of the specimens were complete or partial concordance. Particularly, mNGS and tNGS differed significantly in detection rates for some of the human herpesviruses only, including Human gammaherpesvirus 4 (P<0.001), Human betaherpesvirus 7 (P<0.001), Human betaherpesvirus 5 (P<0.05) and Human betaherpesvirus 6 (P<0.01), in which tNGS always had higher detection rates. Orthogonal testing of clinically critical pathogens showed a total coincidence rate of 50% for mNGS and PCR, as well as for tNGS and PCR. Overall, the performance of mNGS and multiplex PCR-based tNGS assays was similar for bacteria and fungi, and tNGS may be superior to mNGS for the detection of DNA viruses. No significant differences were seen between the two NGS assays compared to PCR.

Diagnostic challenges in patients with Castleman disease, a single center experience from Hungary.

Castleman disease is a rare and atypical lymphoproliferative disorder characterized by diverse clinical manifestations. It has both unicentric and multicentric forms, the latter with further subdivisions, i.e., human herpesvirus 8-associated and idiopathic forms. The diagnosis of Castleman disease is often delayed, as it is rare, and because it shares clinical features with different autoimmune, inflammatory, and malignant lymphoproliferative disorders. The first-line treatment in unicentric form is mainly surgical, while in idiopathic Castleman disease, anti-interleukin-6 treatment is the therapy of choice. In virus-associated diseases, antiretroviral therapy and rituximab are recommended. In Hungary, only a few cases of Castleman disease have been published. This report presents our twodecades of experience in the challenging diagnosis and management of this rare disorder, most properly underdiagnosed in Hungary. We provide insights into seven unicentric and five idiopathic multicentric Castleman disease cases, the latter ones especially highlighting the diagnostic and therapeutic challenges due to the variable and unique clinical features both of patients and diseases, e.g., bronchiolitis obliterans, stage IV diabetic renal failure, anti-HBc positivity, siltuximab treatment period, respectively.

Status Epilepticus with Fever in a Toddler with Pyogenic Meningitis Due to Complicated Acute Sphenoid Sinusitis

We present a toddler with acute sphenoid sinusitis presenting as status epilepticus with fever, intracranial abscess and meningitis. Cerebrospinal fluid (CSF) analysis suggested bacterial meningitis, but polymerase chain reaction (PCR) test was positive for human herpes virus-6 (HHV-6). We highlight diagnosis and treatment of this uncommon condition.

Exploring waterborne viruses in groundwater: Quantification and Virome characterization via passive sampling and targeted enrichment sequencing

Aquifers, which provide drinking water for nearly half the world's population, face significant challenges from microbial contamination, particularly from waterborne viruses such as human adenovirus (HAdV), norovirus (NoV) and enterovirus (EV). This study, conducted as part of the UPWATER project, investigates the sources of urban groundwater contamination using viral passive sampling (VPS) and target enrichment sequencing (TES). We assessed the abundance of eight viral pathogens (HAdV, EV, NoV genogroup I and II, rotavirus, influenza A virus, hepatitis E virus and SARS-CoV-2) and investigated the virome diversity of groundwater in the aquifer of the Besòs River Delta in Catalonia. Over a period of 7 months, we collected 114 samples from the aquifer using nylon and nitrocellulose membranes to adsorb viruses over a 10-day period. Human faecal contamination was detected in nearly 50 % of the groundwater samples, with mean HAdV total counts ranging from 1.23E+02 to 3.66E+03 GC, and occasional detections of EV and NoV GI and GII. In addition, deep sequencing revealed a diverse virome in the aquifer, with detection of human pathogens, including adenovirus, astrovirus, calicivirus, enterovirus, herpesvirus, papillomavirus and rotavirus. Time-integrated sampling using VPS increases the likelihood of virus detection and, when combined with TES, can provide a deeper understanding of virus prevalence in this important water compartment. This approach is expected to streamline long-term monitoring efforts and enable small communities or water managers with limited resources to effectively manage their groundwater reservoirs.

Sequence analysis of isolated strains of herpes zoster virus among patients with shingles.

Herpes zoster, or shingles, is caused by the varicella-zoster virus (VZV), which initially presents as chickenpox in children. VZV is a global health concern, especially in winter and spring, affecting 10-20% of adults over 50 and posing a 30% risk for the general population. This study used PCR to detect VZV, confirming results with duplicated DNA samples and identifying 234 bp fragments by targeting the gpB gene. This study examined 50 herpes zoster cases from October 2020 to April 2021, involving 30 males and 20 females aged 10 to 90, diagnosed by dermatologists. Data were collected via a questionnaire. PCR detected VZV by amplifying the gpB and MCP genes from skin lesion samples. Six positive 234-bp PCR products were sequenced at Macrogen Inc. in Seoul, South Korea. Six DNA samples with 234 bp amplicons were sequenced, showing 99-100% similarity to human alpha herpesvirus sequences in the gpB gene. NCBI BLAST matched these sequences to a reference (GenBank acc. MT370830.1), assigning accession numbers LC642111, LC642112, and LC642113. Eight nucleic acid substitutions caused amino acid changes in the gpB protein: isoleucine to threonine, serine to isoleucine, and threonine to Proline. These variants were deposited in NCBI GenBank as gpB3 samples. The study found high sequence similarity to known VZV sequences, identifying six nucleic acid variations and eight SNPs. Notable amino acid changes in the gpB protein were deposited in NCBI GenBank as the gpB3 sample.

Evidence of “Silent” Hepatitis B Virus Infection in Psoriasis, Vitiligo, and Pityriasis Rosea Cases: A Pilot Study

Abstract Background: Psoriasis (PS), vitiligo (VT), and Pityriasis rosea (PR) are chronic skin diseases often occurring as a consequence of exaggerated immune responses. These skin manifestations can be triggered as a result of the molecular mimicry between viral protein (s) and host protein (s), which could generate auto-antibodies. In addition, it can be hypothesised that skin diseases are manifestations of the reduced immunity that is observed in chronic hepatitis B virus (HBV)-infected individuals. Aims and Objective: To investigate the presence of HBV in PS, VT, and PR cases and Human Herpes Virus (HHV) 6 and 7 in PR cases. Materials and Methods: DNA extracted from healthy controls (n = 20), PS (n = 10), VT (n = 11), and PR (n = 12) were subjected to HBV-S gene-specific polymerase chain reactions (PCRs) and HHV 6-UL57 and HHV7-UL10 gene-specific PCRs. PCR products of positive samples (HBV and HHV 6 and 7 DNA) of expected length were bi-directionally sequenced using overlapping primers. Sequence identification was performed by NCBI BLAST and analysed by multiple sequence alignment. HBV DNA copy number was determined through quantitative real-time PCR. The blood samples were also tested for HBV serological markers and Interferon gamma (IFN-γ) by enzyme immunoassays. Results: The PCR data and Immunoassay study revealed that seven out of 12 PR, six out of 10 PS, and six out of 11 VT cases had signs of HBV infection. HHV 6 DNA was detected in four, whereas HHV 7 DNA was found in two of the 12 PR blood samples. PR6 presented the evidence of both HHV 6 and 7 co-infections. Conclusion: Observing the correlation of HBV with skin diseases, albeit at the pilot level, a larger study is warranted to identify HBV infection in skin disease patients. The evidence of HHV 6 and HHV 7 DNA in PR cases supports the HHV infection linkage with PR.

Distribution characteristics of human herpes viruses in the lower respiratory tract and their impact on 30-day mortality in community-acquired pneumonia patients.

Human herpes viruses (HHVs) are commonly detected in community-acquired pneumonia (CAP) patients, particularly those with complex complications, attracting increased attention from clinical practitioners. However, the significance of detecting HHVs in bronchoalveolar lavage fluid (BALF) with CAP patients is still unclear. This study retrospectively analyzed BALF samples from 64 CAP patients at the Kunming Third People's Hospital between August 2021 and December 2023. Metagenomic next generation sequencing (mNGS) was conducted on BALF samples during CAP onset. Multivariate Cox regression models were used to identify independent risk factors for 30-day all-cause mortality in CAP. HHVs were found in 84.4% of CAP patients, which were the most common pathogens (45.1%), followed by bacteria (30.2%) and fungi (11.5%). Bacterial-viral co-infections were most common, occurring in 39 patients. Notably, there was no significant difference in HHV presence between severe and non-severe CAP patients (EBV: P = 0.431, CMV: P = 0.825), except for HHV-7 (P = 0.025). In addition, there was no significant difference in the 30-day mortality between HHV positive and HHV negative groups (P = 0.470), as well as between the HHV-7 positive and HHV-7 negative groups (P = 0.910). However, neither HHVs nor HHV-7 was independent risk factors for 30-day mortality in CAP patients (HHVs: HR 1.171, P = 0.888; HHV-7: HR 1.947, P = 0.382). In summary, among the prevalent presence of multiple HHVs, EBV and CMV were the most prevalent in CAP patients. Patients with sCAP were more susceptible to HHV-7 than those with non-sCAP. These results provide valuable insights for clinicians in guiding appropriate interventions for CAP treatment.

Comparison of IL-6, IL-10, and TNFα levels between PLWHIV with and without Kaposi Sarcoma and healthy controls.

Kaposi sarcoma (KS) is an angioproliferative disease caused by human herpesvirus 8 (HHV-8) and is mediated by cytokines in an immunodeficient environment. This study aimed to compare IL-6, IL-10, and TNFα levels among AIDS patients with disseminated KS (DKS), treatment naïve patients living with HIV (PLWHIV) without DKS, and healthy controls. Secondary outcomes were to compare cytokines levels in patients with DKS and unfavorable outcomes, as well as an analysis of the behavior of cytokines over time. This cohort study was performed at two centers in Mexico City. Three groups were included. Group 1: HIV+ treatment naïve with DKS, Group 2: HIV+ treatment naïve without KS, and Group 3: HIV negative, healthy controls. Plasmatic IL-6, IL-10, and TNFα levels were measured at baseline and over time in Groups 1 and 2. Seventy-six patients were included: 39 (52%) in Group 1, 17 (22%) in Group 2, and 20 (26%) in Group 3. The median baseline IL-6, IL-10, and TNFα levels were significantly higher in group 1. In group 1, baseline IL-6 was higher in patients who died than in survivors (14.4 vs 5.8 pg/mL p=0.048). Patients with severe immune reconstitution inflammatory syndrome due to KS (S-IRIS-KS) had higher IL-6 values than those without it (14.4 vs 5.8 pg/mL p=0.004). In the repeated-measures model in group 1, IL-10 levels were higher in patients who died (p<0.001) and developed IRIS-KS (p=0.01). IL-6, IL-10, and TNF α levels were markedly higher in patients with DKS. IL-6 and IL-10 levels were higher in patients with unfavorable outcomes.

Analysis of pulmonary microecology and clinical characteristics of patients carrying human herpesvirus.

Aim: To investigate the impact of human herpes virus (HHV) carriage on lung microbiota, and its correlation with clinical features and laboratory indicators in patients.Methods: Retrospective analysis was conducted on 30 outpatient lung infection cases, which were divided into HHV (n=15) and non-HHV (n=15) groups. mNGS detected microbial composition. Microbial diversity and abundance were tested using Shannon and Chao1 indices. Their relationship with laboratory indicators were explored.Results: Significant differences in microbial abundance and distribution were found between two groups (p<0.05). Moreover, HHV group showed negative correlations (p<0.05) between Prevotella, Porphyromonas, Streptococcus and basophil/eosinophil percentages.Conclusion: HHV carriage impacts lung microbiota, emphasizing the need for clinicians to pay attention to HHV reactivation in outpatient lung infection patients.

Human Herpesvirus 6-A Rare Aetiologic Agent for CNS Infections in Immunocompetent Individuals or an Underestimation?

Background: Human herpesvirus 6 (HHV-6) is considered a ubiquitous virus, with many countries reporting a seroprevalence of more than 80-90% among the general population. However, this virus is unique among herpesviruses in its ability to integrate into the genetic material of the host's cells. Thus, there are three ways by which HHV-6 can cause an active infection-primary infection, reactivation of a latent acquired infection, or activation of iciHHV-6 (inherited chromosomally integrated HHV-6). Whole blood quantitative polymerase chain reaction (qPCR) is very useful in distinguishing between iciHHV-6 and primary infection/reactivation. Our aim is to assess the role of HHV-6 in the aetiology of central nervous system (CNS) infections in adults and children, to describe all HHV-6-positive cases in an attempt to determine the susceptible population and to identify potential risk factors that can be linked to HHV-6 meningoencephalitis. Methods: We performed a retrospective study involving patients that were admitted to Prof. Dr. Matei Bals National Institute of Infectious Diseases, Bucharest, Romania, with a diagnosis of meningitis or encephalitis. We only selected the clinical records of patients that had a multiplex PCR Biofire® FilmArray® meningitis/encephalitis panel. Results: We report a 5% HHV-6 positivity in the cerebrospinal fluid (CSF) of patients with CNS infections tested with a commercial multiplex PCR M/E (meningitis/encephalitis) panel. Additionally, 2% to 4% of the total study population (n = 100) had active HHV-6 infections, which denotes 40 to 80% of the HHV-6-positive samples. We did not observe any statistically significant correlation between HHV-6 positivity in the CSF and variables such as age, sex, or comorbidities, including obesity, diabetes, hypertension, immunosuppression, or oncologic disease. Therefore, no risk factors could be linked with HHV-6 positivity in the CSF. Conclusions: although multiplex qualitative PCR is highly useful for providing rapid results and identifying nearly every pathogen that can cause meningitis/encephalitis, we have to be aware of this type of test's limitations. All patients with HHV-6 detectable in their CSF via a multiplex PCR test should also undergo qPCR testing from both CSF and blood to prevent over-diagnosing HHV-6 CNS infections, to avoid unnecessary antiviral treatments, and ensure the accurate identification of the true diagnosis.