Lasting Immunological Imprint of Primary Epstein-Barr Virus Infection With Associations to Chronic Low-Grade Inflammation and Fatigue

Reactivation of Latent Herpesviruses and a Faulty Antiviral Response may Contribute to Chronic Multi-Symptom and Multi-System Illnesses in U.S. Military Veterans

Chronic multi-symptom illness (CMI) is a broad term utilized by the Department of Veterans Affairs to refer to complex conditions of unknown etiology where individuals experience symptoms that lack a clear medical diagnosis. In this study, we sought to determine if herpesvirus reactivation and the antiviral response could be involved in CMI. Longitudinal serology studies conducted in two military veteran cohorts diagnosed with CMI or Gulf War Illness (GWI) revealed an increased prevalence of IgG (55% and 83%, respectively) and IgM antibodies (80%-90% and 100%, respectively) to the deoxyuridine triphosphate nucleotidohydrolase (dUTPase) protein of multiple herpesviruses compared to age/gender-matched healthy controls (5% and 7% for IgG and IgM respectively, p < 0.001) by ELISA. Despite the ongoing viral reactivation in CMI veterans, IFN-γ levels surprisingly stayed mostly unchanged from healthy control levels, while in GWI were significantly upregulated. Interestingly, MCP-1/CCL-2 levels were significantly increased in some CMI veterans compared to GWI and healthy controls (p = 0.0009). Our data provide evidence suggesting aberrant antiviral response and immune dysfunction in CMI veterans and supports the premise that decreased serum levels of IFN-γ together with heightened MCP-1 and dUTPase antibodies to multiple herpesviruses may be useful to identify CMI veterans with deficient antiviral response.

Long-term Effects of COVID-19 on Sleep Patterns

OBJECTIVE

To examine the long-term impact of Coronavirus disease-2019 (COVID-19) on sleep patterns and the prevalence of sleep disorders and to increase public health awareness of long-term COVID-19.

MATERIAL AND METHODS

Using the Massachusetts General Brigham Research Patient Data Registry, Severe acute respiratory syndrome-Coronavirus-2 (SARS-CoV-2) positive patients were surveyed about their sleep patterns before and after the viral infection. Information related to comorbid conditions and medications was obtained through chart review.

RESULTS

Two hundred and forty-six completed surveys were analyzed. Average age was 53.3±16.3 years, and they were predominantly non-hispanic white (84.1%) and female (74.3%). The mean body mass index (kg/m2) was 29.9±6.9, and a greater proportion were non-smokers (63.2%). After COVID-19, there was an increase in the percentage of participants reporting difficulty initiating (39±49% vs. 31±46% prior to COVID-19 infection P = 0.01). Similarly, the participants reported difficulty in maintaining sleep after COVID infection (57% vs. 43% prior to infection P < 0.001). Additionally, there was an increase in the use of sleep aids (30% vs. 24% before the infection P = 0.003). The participants also reported a decrease in feeling rested and an increase in the need for napping (58% vs. 36%, P < 0.0001) and (27% vs. 40%, P < 0.0001) respectively. The sleep symptoms persisted beyond 12 months in 28% of the participants.

CONCLUSION

SARS-CoV-2 infection had negative effects on sleep, and a significant proportion of adults experienced insomnia and daytime sleepiness beyond 12 months after recovering from the initial infection.

Evidence of aberrant anti-epstein-barr virus antibody response, though no viral reactivation, in people with post-stroke fatigue

BACKGROUND

Fatigue is a common complication of stroke that has a significant impact on quality of life. The biological mechanisms that underly post-stroke fatigue are currently unclear, however, reactivation of latent viruses and their impact on systemic immune function have been increasingly reported in other conditions where fatigue is a predominant symptom. Epstein-Barr virus (EBV) in particular has been associated with fatigue, including in long-COVID and myalgic encephalomyelitis/chronic fatigue syndrome, but has not yet been explored within the context of stroke.

AIMS

We performed an exploratory analysis to determine if there is evidence of a relationship between EBV reactivation and post-stroke fatigue.

METHODS

In a chronic ischemic stroke cohort (> 5 months post-stroke), we assayed circulating EBV by qPCR and measured the titres of anti-EBV antibodies by ELISA in patients with high fatigue (FACIT-F < 40) and low fatigue (FACIT-F > 41). Statistical analysis between two-groups were performed by t-test when normally distributed according to the Shapiro-Wilk test, by Mann-Whitney test when the data was not normally distributed, and by Fisher's exact test for categorical data.

RESULTS

We observed a similar incidence of viral reactivation between people with low versus high levels of post-stroke fatigue (5 of 22 participants (24%) versus 6 of 22 participants (27%)). Although the amount of circulating EBV was similar, we observed an altered circulating anti-EBV antibody profile in participants with high fatigue, with reduced IgM against the Viral Capsid Antigen (2.244 ± 0.926 vs. 3.334 ± 2.68; P = 0.031). Total IgM levels were not different between groups indicating this effect was specific to anti-EBV antibodies (3.23 × 105 ± 4.44 × 104 high fatigue versus 4.60 × 105 ± 9.28 × 104 low fatigue; P = 0.288).

CONCLUSIONS

These data indicate that EBV is not more prone to reactivation during chronic stroke recovery in those with post-stroke fatigue. However, the dysregulated antibody response to EBV may be suggestive of viral reactivation at an earlier stage after stroke.

Inflammatory Markers in Children and Adolescents with Functional Somatic Disorders: A Systematic Review

Functional somatic disorders (FSDs) are common in children and adolescents. Recent findings suggest that low-grade inflammation has a role in the development and maintenance of pediatric FSDs. This systematic review included studies with original data on systemic inflammatory markers in children and adolescents with an FSD compared to individuals without an FSD. The literature search identified 1374 articles. After assessment, a total of 15 studies met the inclusion criteria. In total, 41 serum or plasma cytokines were assayed in a population of 696 children and adolescents. Altered cytokine levels in patients with FSDs were reported in 12 studies, whereas three studies found no significant differences when comparing patients with FSDs and controls. The cytokine levels were significantly elevated in nine studies (i.e., IL-2, IL-6, IL-8, IL-12 (p70), CRP, hsCRP, IP-10, MCP-1, sTIM-3, sCD25 and TNF-α). The findings indicate that inflammatory response may have a role in the pathophysiology of pediatric FSDs. However, the included studies showed limited quality with potential risk of bias, small study populations and a narrow spectrum of included FSDs, which limits the generalizability of the results. To further explore the potential link between inflammatory markers and pediatric FSDs, future research using a longitudinal study design is recommended.

Infectious Diseases

Microglia, brain-resident innate immune cells, have been extensively studied in neurodegenerative contexts like Alzheimer's disease. The Coronavirus disease 2019 (COVID-19) pandemic highlighted how peripheral infection and inflammation can be detrimental to the neuroimmune milieu and initiate microgliosis driven by peripheral inflammation. Microglia can remain deleterious to brain health by sustaining inflammation in the central nervous system even after the clearance of the original immunogenic agents. In this chapter, we discuss how pulmonary infection with Severe Acute Respiratory Syndrome CoronaVirus 2 (SARS-CoV-2) can lead to neurovascular and neuroimmune inflammation causing the neurological syndrome of post-acute sequelae of COVID-19 (PASC). Further, we incorporate lessons from the Human Immunodeficiency Virus' (HIV's) effects on microglial functioning in the era of combined antiretroviral therapies (cART) that contribute to HIV-1 associated neurocognitive disorders (HAND). Finally, we describe roles for mixed lineage kinase 3 (MLK3) and leucine-rich repeat kinase (LRRK2) as key regulators of multiple inflammatory and apoptotic pathways important to the pathogenesis of PASC and HAND. Inhibition of these pathways provides a therapeutically synergistic method of treating both PASC and HAND.

Aberrant neutrophil degranulation in hospitalized patients with COVID-19 partially remains for 6 months

Neutrophils are important players in COVID-19, contributing to tissue damage by release of inflammatory mediators, including ROS and neutrophil elastase. Longitudinal studies on the effects of COVID-19 on neutrophil phenotype and function are scarce. Here, we longitudinally investigated the phenotype and degranulation of neutrophils in COVID-19 patients (28 nonhospitalized and 35 hospitalized patients) compared with 17 healthy donors (HDs). We assessed phenotype, degranulation, CXCL8 (IL-8) release, and ROS generation within 8 days, at one or 6 month(s) after COVID-19 diagnosis. For degranulation and ROS production, we stimulated neutrophils, either with ssRNA and TNF or granulocyte-macrophage colony-stimulating factor and N-Formylmethionyl-leucyl-phenylalanine. During active COVID-19, neutrophils from hospitalized patients were more immature than from HDs and were impaired in degranulation and ROS generation, while neutrophils from nonhospitalized patients only demonstrated reduced CD66b+ granule release and ROS production. Baseline CD63 expression, indicative of primary granule release, and CXCL8 production by neutrophils from hospitalized patients were elevated for up to 6 months. These findings show that patients hospitalized due to COVID-19, but not nonhospitalized patients, demonstrated an aberrant neutrophil phenotype, degranulation, CXCL8 release, and ROS generation that partially persists up to 6 months after infection.

The immunology of long COVID

Long COVID is the patient-coined term for the disease entity whereby persistent symptoms ensue in a significant proportion of those who have had COVID-19, whether asymptomatic, mild or severe. Estimated numbers vary but the assumption is that, of all those who had COVID-19 globally, at least 10% have long COVID. The disease burden spans from mild symptoms to profound disability, the scale making this a huge, new health-care challenge. Long COVID will likely be stratified into several more or less discrete entities with potentially distinct pathogenic pathways. The evolving symptom list is extensive, multi-organ, multisystem and relapsing-remitting, including fatigue, breathlessness, neurocognitive effects and dysautonomia. A range of radiological abnormalities in the olfactory bulb, brain, heart, lung and other sites have been observed in individuals with long COVID. Some body sites indicate the presence of microclots; these and other blood markers of hypercoagulation implicate a likely role of endothelial activation and clotting abnormalities. Diverse auto-antibody (AAB) specificities have been found, as yet without a clear consensus or correlation with symptom clusters. There is support for a role of persistent SARS-CoV-2 reservoirs and/or an effect of Epstein-Barr virus reactivation, and evidence from immune subset changes for broad immune perturbation. Thus, the current picture is one of convergence towards a map of an immunopathogenic aetiology of long COVID, though as yet with insufficient data for a mechanistic synthesis or to fully inform therapeutic pathways.

Infection, Dysbiosis and Inflammation Interplay in the COVID Era in Children

For over three years, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in children and adolescents has generated repercussions, especially a few weeks after infection, for symptomatic patients who tested positive, for asymptomatic ones, or even just the contacts of an infected person, and evolved from severe forms such as multisystem inflammatory syndrome in children (MIS-C) to multifarious clinical manifestations in long COVID (LC). Referred to under the umbrella term LC, the onset of persistent and highly heterogeneous symptoms such as fatigue, post-exertion malaise, cognitive dysfunction, and others have a major impact on the child's daily quality of life for months. The first aim of this review was to highlight the circumstances of the pathophysiological changes produced by COVID-19 in children and to better understand the hyperinflammation in COVID-19 and how MIS-C, as a life-threatening condition, could have been avoided in some patients. Another goal was to better identify the interplay between infection, dysbiosis, and inflammation at a molecular and cellular level, to better guide scientists, physicians, and pediatricians to advance new lines of medical action to avoid the post-acute sequelae of SARS-CoV-2 infection. The third objective was to identify symptoms and their connection to molecular pathways to recognize LC more easily. The fourth purpose was to connect the triggering factors of LC with related sequelae following acute SARS-CoV-2 injuries to systems and organs, the persistence of the virus, and some of its components in hidden reservoirs, including the gut and the central nervous system. The reactivation of other latent infectious agents in the host's immune environments, the interaction of this virus with the microbiome, immune hyperactivation, and autoimmunity generated by molecular mimicry between viral agents and host proteins, could initiate a targeted and individualized management. New high-tech solutions, molecules, probiotics, and others should be discovered to innovatively solve the interplay between RNA persistent viruses, microbiota, and our immune system.

Exposure to SARS-CoV-2 and Infantile Diseases

Background and Aim  Immune response against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in newborns and children after prophylactic immunization is currently a relevant research topic. The present study analyzes the issue by examining the possibility that the anti-SARS-CoV-2 immune responses are not uniquely directed against the virus but can-via molecular mimicry and the consequent cross-reactivity-also hit human proteins involved in infantile diseases. Methods  Human proteins that-if altered-associate with infantile disorders were searched for minimal immune pentapeptide determinants shared with SARS-CoV-2 spike glycoprotein (gp). Then, the shared pentapeptides were analyzed for immunologic potential and immunologic imprinting phenomena. Results  Comparative sequence analysis shows that: (1) numerous pentapeptides (namely, 54) are common to SARS-CoV-2 spike gp and human proteins that, when altered, are linked to infantile diseases; (2) all the shared peptides have an immunologic potential since they are present in experimentally validated SARS-CoV-2 spike gp-derived epitopes; and (3) many of the shared peptides are also hosted in infectious pathogens to which children can have already been exposed, thus making immunologic imprint phenomena feasible. Conclusion  Molecular mimicry and the consequent cross-reactivity can represent the mechanism that connects exposure to SARS-CoV-2 and various pediatric diseases, with a fundamental role of the immunologic memory and the history of the child's infections in determining and specifying the immune response and the pathologic autoimmune sequela.

Different risk factors distinguish myalgic encephalomyelitis/chronic fatigue syndrome from severe fatigue

Fatigue is a common reason that patients seek medical care. Only a fraction of these patients meet criteria for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). To determine if ME/CFS is just a more extreme form of fatigue, or a qualitatively different condition, we assessed whether risk factors for ME/CFS and for Severe Fatigue were similar. An email questionnaire that inquired about symptoms of Severe Fatigue and ME/CFS was completed by 41,802 US female nurses from whom detailed medical and lifestyle information had been collected since 1989: 102 met criteria for ME/CFS, 522 had Severe Fatigue, and 41,178 individuals were without significant chronic fatigue. We used Cox proportional hazards regression to estimate the Hazard Ratio (HR) of Severe Fatigue and of ME/CFS with each of several potential risk factors, according to the level of exposure to each risk factor. The risk of Severe Fatigue was significantly increased among participants who were older, had a higher BMI in adulthood, used hormone therapy, had increased alcohol intake and decreased caffeine intake. In contrast, these risk factor associations were not seen in people with ME/CFS. A self-reported past history of acute infectious mononucleosis was associated with a non-significantly increased Hazard Ratio of later ME/CFS (HR 1.77, 0.87-3.61) and, to a lesser extent, of Severe Fatigue (HR 1.28, 0.98-1.66). The different contribution of various risk factors to Severe Fatigue and ME/CFS suggests that ME/CFS has a qualitatively different underlying biology from the more common state of Severe Fatigue.

Inflammatory markers and pulmonary function in adolescents and young adults 6 months after mild COVID-19

Introduction

Both public and scientific attention have shifted from the acute COVID-19 illness to the chronic disability experienced by a proportion of COVID-19 convalescents. Post COVID-19 condition, a term used for long-lasting symptoms after COVID-19, can affect individuals across all disease severity and age groups. Data on post-COVID-19 symptomatology, epidemiology and pathophysiology in adolescents and young adults are scarce. To date, little is known on the immunological and pulmonary trends in these patients after COVID-19. This study investigated immunological markers and pulmonary function in non-hospitalized patients in this group at 6 months after initial mild COVID-19 infection.

Methods

Non-hospitalized SARS-CoV-2 positive (n = 405) and SARS-CoV-2 negative (n = 111) adolescents and young adults (aged 12-25 years) were followed prospectively for six months after SARS-CoV-2 PCR testing. At baseline and at six months follow-up, all participants underwent an assessment including clinical examination, questionnaires, spirometry, and blood sampling. Cross-sectional comparisons of blood biomarkers; including white blood cell counts, CRP, GDF-15, a 27-multiplex cytokine assay, complement activation products and SARS-CoV-2 antibodies; and spirometry measures were performed after classification of all participants according to their COVID-19 status and adherence to post-COVID-19 case criteria. Associations between biomarkers and COVID-19 symptoms were explored.

Results

No difference in pulmonary function was detected between the groups. COVID-19 convalescents had higher levels of chemokines eotaxin, MCP-1 and IP-10 than non-infected controls. The increase was modest and not associated with long-lasting COVID-19 symptoms.

Discussion

Elevated inflammatory mediators were found in adolescents and young adults six months after mild COVID-19, but there was no association with post-COVID-19 condition.

Assessing Biomarkers in Viral Infection

Current biomarkers to assess the risk of complications of both acute and chronic viral infection are suboptimal. Prevalent viral infections like human immunodeficiency virus (HIV), hepatitis B and C virus, herpes viruses, and, more recently, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) may be associated with significant sequelae including the risk of cardiovascular disease, other end-organ diseases, and malignancies. This review considers some biomarkers which have been investigated in diagnosis and prognosis of key viral infections including inflammatory cytokines, markers of endothelial dysfunction and activation and coagulation, and the role that more conventional diagnostic markers, such as C-reactive protein and procalcitonin, can play in predicting these secondary complications, as markers of severity and to distinguish viral and bacterial infection. Although many of these are still only available in the research setting, these markers show promise for incorporation in diagnostic algorithms which may assist to predict adverse outcomes and to guide therapy.

Characteristics of immunological events in Epstein-Barr virus infection in children with infectious mononucleosis

BACKGROUNDS & AIMS

Epstein-Barr virus (EBV) infection occurs commonly in children and may cause acute infectious mononucleosis (AIM) and various malignant diseases. Host immune responses are key players in the resistance to EBV infection. We here assessed the immunological events and laboratory indicators of EBV infection, as well as determined the clinical usefulness of evaluating the severity and efficacy of antiviral therapy in AIM patients.

METHODS

We enrolled 88 children with EBV infection. The immune environment was defined by immunological events such as frequencies of lymphocyte subsets, phenotypes of T cells, and their ability to secrete cytokines, and so on. This environment was analyzed in EBV-infected children with different viral loads and in children in different phases of infectious mononucleosis (IM) from disease onset to convalescence.

RESULTS

Children with AIM had higher frequencies of CD3⁺ T and CD8⁺ T cells, but lower frequencies of CD4⁺ T cells and CD19⁺ B cells. In these children, the expression of CD62L was lower and that of CTLA-4 and PD-1 was higher on T cells. EBV exposure induced granzyme B expression, but reduced IFN-γ secretion, by CD8⁺ T cells, whereas NK cells exhibited reduced granzyme B expression and increased IFN-γ secretion. The frequency of CD8⁺ T cells was positively correlated with the EBV DNA load, whereas the frequencies of CD4⁺ T cells and B cells were negatively correlated. During the convalescent phase of IM, CD8⁺ T cell frequency and CD62L expression on T cells were restored. Moreover, patient serum levels of IL-4, IL-6, IL-10, and IFN-γ were considerably lower throughout the convalescent phase than throughout the acute phase.

CONCLUSION

Robust expansion of CD8⁺ T cells, accompanied by CD62L downregulation, PD-1 and CTLA-4 upregulation on T cells, enhanced granzyme B production, and impaired IFN-γ secretion, is a typical characteristic of immunological events in children with AIM. Noncytolytic and cytolytic effector functions of CD8⁺ T cells are regulated in an oscillatory manner. Furthermore, the AST level, number of CD8⁺ T cells, and CD62L expression on T cells may act as markers related to IM severity and the effectiveness of antiviral treatment.

Tissue specific signature of HHV-6 infection in ME/CFS

First exposure to various human herpesviruses (HHVs) including HHV-6, HCMV and EBV does not cause a life-threatening disease. In fact, most individuals are frequently unaware of their first exposure to such pathogens. These herpesviruses acquire lifelong latency in the human body where they show minimal genomic activity required for their survival. We hypothesized that it is not the latency itself but a timely, regionally restricted viral reactivation in a sub-set of host cells that plays a key role in disease development. HHV-6 (HHV-6A and HHV-6B) and HHV-7 are unique HHVs that acquire latency by integration of the viral genome into sub-telomeric region of human chromosomes. HHV-6 reactivation has been linked to Alzheimer's Disease, Chronic Fatigue Syndrome, and many other diseases. However, lack of viral activity in commonly tested biological materials including blood or serum strongly suggests tissue specific localization of active HHV-6 genome. Here in this paper, we attempted to analyze active HHV-6 transcripts in postmortem tissue biopsies from a small cohort of ME/CFS patients and matched controls by fluorescence in situ hybridization using a probe against HHV-6 microRNA (miRNA), miR-aU14. Our results show abundant viral miRNA in various regions of the human brain and associated neuronal tissues including the spinal cord that is only detected in ME/CFS patients and not in controls. Our findings provide evidence of tissue-specific active HHV-6 and EBV infection in ME/CFS, which along with recent work demonstrating a possible relationship between herpesvirus infection and ME/CFS, provide grounds for renewed discussion on the role of herpesviruses in ME/CFS.

Systemic antibody responses against human microbiota flagellins are overrepresented in chronic fatigue syndrome patients

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating disease with an unclear etiology and pathogenesis. Both an involvement of the immune system and gut microbiota dysbiosis have been implicated in its pathophysiology. However, potential interactions between adaptive immune responses and the microbiota in ME/CFS have been incompletely characterized. Here, we profiled antibody responses of patients with severe ME/CFS and healthy controls against microbiota and viral antigens represented as a phage-displayed 244,000 variant library. Patients with severe ME/CFS exhibited distinct serum antibody epitope repertoires against flagellins of Lachnospiraceae bacteria. Training machine learning algorithms on this antibody-binding data demonstrated that immune responses against gut microbiota represent a unique layer of information beyond standard blood tests, providing improved molecular diagnostics for ME/CFS. Together, our results point toward an involvement of the microbiota-immune axis in ME/CFS and lay the foundation for comparative studies with inflammatory bowel diseases and illnesses characterized by long-term fatigue symptoms, including post-COVID-19 syndrome.