OBJECTIVE: To delineate the risk factors, symptom patterns, and longitudinal course of prolonged illnesses after a variety of acute infections. DESIGN: Prospective cohort study following patients from the time of acute infection with Epstein-Barr virus (glandular fever), Coxiella burnetii (Q fever), or Ross River virus (epidemic polyarthritis). SETTING: The region surrounding the township of Dubbo in rural Australia, encompassing a 200 km geographical radius and 104 400 residents. PARTICIPANTS: 253 patients enrolled and followed at regular intervals over 12 months by self report, structured interview, and clinical assessment. OUTCOME MEASURES: Detailed medical, psychiatric, and laboratory evaluations at six months to apply diagnostic criteria for chronic fatigue syndrome. Premorbid and intercurrent illness characteristics recorded to define risk factors for chronic fatigue syndrome. Self reported illness phenotypes compared between infective groups. RESULTS: Prolonged illness characterised by disabling fatigue, musculoskeletal pain, neurocognitive difficulties, and mood disturbance was evident in 29 (12%) of 253 participants at six months, of whom 28 (11%) met the diagnostic criteria for chronic fatigue syndrome. This post-infective fatigue syndrome phenotype was stereotyped and occurred at a similar incidence after each infection. The syndrome was predicted largely by the severity of the acute illness rather than by demographic, psychological, or microbiological factors. CONCLUSIONS: A relatively uniform post-infective fatigue syndrome persists in a significant minority of patients for six months or more after clinical infection with several different viral and non-viral micro-organisms. Post-infective fatigue syndrome is a valid illness model for investigating one pathophysiological pathway to chronic fatigue syndrome.

Background.@nbsp; Functional polymorphisms in immune response genes are increasingly recognized as important contributors to the marked individual differences in susceptibility to and outcomes of infectious disease. The acute sickness response is a stereotypical set of illness manifestations mediated by the proinflammatory cytokines induced by many different pathogens. The genetic determinants of severity of the acute sickness response have not previously been explored. Methods.@nbsp; We examined the impact of functional polymorphisms in cytokine genes with critical roles in the early immune response (tumor necrosis factor-alpha, interleukin-6, interleukin-10, and interferon-gamma) on the severity and duration of illness following acute infection with Epstein-Barr virus, Coxiella burnetii (the causative agent of Q fever), or Ross River virus. Results.@nbsp; We found that the interferon-gamma +874T/A and the interleukin-10 -592C/A polymorphisms significantly affected illness severity, cytokine protein levels, and the duration of illness. These cytokine genotypes acted in synergy to potentiate their influence on disease outcomes. Conclusions.@nbsp; These findings suggest that genetically determined variations in the intensity of the inflammatory response underpin the severity of the acute sickness response and predict the recovery time across varied infections.

Peripheral blood specimens and clinical data were obtained over a 12-month period from subjects in the Dubbo Infection Outcomes Study to examine cytokine production in postinfective fatigue syndrome. Ex vivo production of 8 cytokines was examined in 22 case patients and in 42 control subjects who recovered promptly. No significant differences were found. Ongoing production of the cytokines examined does not play a role in postinfective fatigue syndrome.

Background. Infectious mononucleosis (IM) commonly triggers a protracted postinfective fatigue syndrome (PIFS) of unknown pathogenesis.Methods. Seven subjects with PIFS with 6 or more months of disabling symptoms and 8 matched control subjects who had recovered promptly from documented IM were studied. The expression of 30,000 genes was examined in the peripheral blood by microarray analysis in 65 longitudinally collected samples. Gene expression patterns associated with PIFS were sought by correlation with symptom factor scores.Results. Differential expression of 733 genes was identified when samples collected early during the illness and at the late (recovered) time point were compared. Of these genes, 234 were found to be significantly correlated with the reported severity of the fatigue symptom factor, and 180 were found to be correlated with the musculoskeletal pain symptom factor. Validation by analysis of the longitudinal expression pattern revealed 35 genes for which changes in expression were consistent with the illness course. These genes included several that are involved in signal transduction pathways, metal ion binding, and ion channel activity.Conclusions. Gene expression correlates of the cardinal symptoms of PIFS after IM have been identified. Further studies of these gene products may help to elucidate the pathogenesis of PIFS.

ABSTRACT: BACKGROUND: Acute infectious diseases are typically accompanied by non-specific symptoms including fever, malaise, irritability and somnolence that usually resolve on recovery. However, in some individuals these symptoms persist in what is commonly termed post-infective fatigue. The objective of this pilot study was to determine the gene expression correlates of post-infective fatigue following acute Epstein Barr virus (EBV) infection. METHODS: We followed 5 people with acute mononucleosis who developed post-infective fatigue of more than 6 months duration and 5 HLA-matched control subjects who recovered within 3 months. Subjects had peripheral blood mononuclear cell (PBMC) samples collected at varying time points including at diagnosis, then every 2 weeks for 3 months, then every 3 months for a year. Total RNA was extracted from the PBMC samples and hybridized to microarrays spotted with 3,800 oligonucleotides. RESULTS: Those who developed post-infective fatigue had gene expression profiles indicative of an altered host response during acute mononucleosis compared to those who recovered uneventfully. Several genes including ISG20 (interferon stimulated gene), DNAJB2 (DnaJ [Hsp40] homolog and CD99), CDK8 (cyclin-dependent kinase 8), E2F2 (E2F transcription factor 2), CDK8 (cyclin-dependent kinase 8), and ACTN2 (actinin, alpha 2), known to be regulated during EBV infection, were differentially expressed in post-infective fatigue cases. Several of the differentially expressed genes affect mitochondrial functions including fatty acid metabolism and the cell cycle. CONCLUSIONS: These preliminary data provide insights into alterations in gene transcripts associated with the varied clinical outcomes from acute infectious mononucleosis.

Forty-five medical students were recruited to examine the effects of distress on the development of an immune response to the novel antigen, keyhole limpet hemocyanin (KLH). The subjects' level of distress was manipulated by immunizing them either at the time of an important viva voce examination (n=22) or during examination-free term time (n=23). This manipulation increased variance amongst the subjects, but the emphasis in this research was on individual distress as a predictor of immune function. In the group as a whole, the likelihood of developing DTH skin responses to KLH was reduced in the more distressed subjects (r=-.45; p=.002), independently of a number of behavioral (e.g., sleep disturbance) and demographic (e.g., sex) variables. Proliferation of T cells against KLH in vitro and the development of anti-KLH IgG antibodies were not related to levels of distress. Thus, cellular, rather than humoral, immune responses in vivo appear susceptible to the influence of distress. This immunization model provides the opportunity to further dissect the basis of these stress-immune pathways.

Postnatal infection may represent a preventable risk factor for onset of psychotic disorders in adolescence and early adulthood. The mechanism of action is likely to involve site-directed triggering of the brain's innate immune system, mediated principally through localised activation of microglial cells. This triggering may occur in response to systemic inflammatory stimuli, without direct involvement of the central nervous system. Microglial activation can represent a primary response or a secondary phenomenon at sites made vulnerable by prior injury; that is, areas containing previously activated microglia will respond more strongly to a new stimulus. The presence of activated microglia is indicative of a recent insult or active disease. It is not characteristic of long-established neurodevelopmental abnormalities. Activated microglia, acting through a variety of cytokine and other signal systems, have the capacity to significantly interfere with synaptic turnover and thus, over time, alter synaptic architecture and function. This pathophysiological path should be investigated more systematically as it may explain a novel "neuroprotective" mode of action for some existing antipsychotic compounds.

OBJECTIVE: The validity of the diagnosis of chronic fatigue syndrome and related chronic fatigue states remains controversial, particularly in psychiatry. This project utilized international epidemiological and clinical research data to test construct validity across diagnostic categories, health-care settings and countries. Relevant demographic, symptom and diagnostic data were obtained from 33 studies in 21 countries. The subjects had fatigue lasting 1-6 months (prolonged fatigue), or >6 months (chronic fatigue), or met diagnostic criteria for chronic fatigue syndrome. METHOD: Common symptom domains were derived by factor analytic techniques. Mean scores on each symptom factor were compared across diagnostic categories, health-care settings and countries. RESULTS: Data were obtained on 37,724 subjects (n = 20,845 female, 57%), including from population-based studies (n = 15,749, 42%), studies in primary care (n = 19 472, 52%), and secondary or specialist tertiary referral clinics (n = 2503, 7%). The sample included 2013 subjects with chronic fatigue, and 1958 with chronic fatigue syndrome. A five-factor model of the key symptom domains was preferred ('musculoskeletal pain/fatigue','neurocognitive difficulties','inflammation','sleep disturbance/fatigue' and 'mood disturbance') and was comparable across subject groups and settings. Although the core symptom profiles were similar, some differences in symptoms were observed across diagnostic categories, health-care settings and between countries. CONCLUSIONS: The construct validity of chronic fatigue and chronic fatigue syndrome is supported by an empirically derived factor structure from existing international datasets.

Using ex vivo antigen-specific T-cell analysis, we found that symptomatic cytomegalovirus recrudescence in transplant recipients was co-incident with reduced expression of IFN-gamma by virus-specific CD8(+) T-cells and an up-regulation of CD38 expression on these T-cells, although there was no significant change in the absolute number of virus-specific cells (as assessed by MHC-peptide multimers). In contrast, HLA class I-matched transplant patients with asymptomatic viral recrudescence showed increased expansion of antigen-specific T-cells and highly stable IFN-gamma expression by epitope-specific T-cells. These studies suggest that a strong functional T-cell response plays a crucial role in defining the clinical outcome of acute viral recrudescence.

While the role of CC chemokines in mononuclear cell trafficking and activation has been well studied, the functional role of CC chemokines in the regulation of polymorphonuclear neutrophil (PMN) recruitment in vivo has not been widely examined. Bacterial infection of the cornea (keratitis) is a relatively common, sometimes sight-threatening disease, which features acute inflammation with ulceration and PMN infiltration. Here, we demonstrate a critical role for the chemokines, CCL2 and CCL3, in the Pseudomonas aeruginosa-induced model of corneal infection in BALB/c mice. Treatment of mice with anti-CCL2 or anti-CCL3 antibodies resulted in a significant reduction in severity of corneal damage and PMN infiltration at 1 and 7 days after infection compared to control antibody-treated eyes, but did not significantly alter the rate of bacterial clearance from the cornea. Our findings provide strong evidence that CCL2 and CCL3 are critical regulators of PMN recruitment, and may lead to therapeutic strategies via targeting of the CC chemokines, CCL2 and CCL3, in the management of P. aeruginosa keratitis.Immunology and Cell Biology advance online publication, 19 June 2007; doi:10.1038/sj.icb.7100082.

Primary Epstein-Barr virus (EBV) infection often results in infectious mononucleosis and is associated with serious sequelae. No treatment is approved for EBV infection, and an antiviral intervention would be significant. The objectives of this study are to characterize the pharmacokinetics and explore the pharmacodynamics of acyclovir in plasma and oral washings of 8 subjects receiving 7 days of valacyclovir 1500 mg twice daily for EBV infectious mononucleosis. Virologic and clinical responses are assessed over 12 days. Acyclovir is measured by liquid chromatography/ultraviolet detection. EBV DNA is quantitated by TaqMan polymerase chain reaction. NONMEM VI and linear regression are used for data analysis. Acyclovir profiles in plasma and oral washings are consistent with a 1-compartment model. Final model estimates of clearance, volume of distribution, and fraction of acyclovir in oral wash supernatant are 49.9 L/h, 74.1 L, and 1.14%, respectively. The quantity of EBV DNA in oral washings and blood, and the severity of illness, measured by a graded scale, decrease during treatment. After treatment, viral rebound occurs in oral washings but not in blood, and the severity of illness continues to decline. Acyclovir pharmacokinetic parameters do not correlate with response metrics. These results support further studies of valacyclovir for EBV infectious mononucleosis.

Epstein-Barr Virus (EBV) is one of the most successful human viruses, infecting more than 90% of the adult population worldwide and persisting for the lifetime of the host. Individuals with a history of symptomatic primary EBV infection, called infectious mononucleosis, carry a moderately higher risk of developing multiple sclerosis (MS). In addition, EBV-specific immune responses, which crucially regulate the host-virus balance in healthy virus carriers, are altered in patients with MS. Although no data so far unequivocally support a direct etiologic role of the virus, recent studies allow for the development of testable hypotheses as to how EBV infection potentially promotes autoimmunity and central nervous system (CNS) tissue damage in MS.

Regulatory T cells (T(reg)) provide a balance to immune T cell activation thereby protecting the body from pathogen-induced immunopathology. Several persistent viruses induce T(reg) that subvert protective immune mechanisms and promote viral persistence. Epstein-Barr virus (EBV) generally infects children subclinically and persists thereafter, but primary infection in early adulthood may cause immunopathological damage manifest as infectious mononucleosis. In this study the role of T(reg) was investigated in acute infectious mononucleosis and healthy EBV seropositive donors. The proportion of CD4(+)CD25(high) T cells in blood from infectious mononucleosis patients was significantly lower than in seropositive donors (P = 0.05). Using the FOXP3 marker for T(reg) the same frequency and extra-follicular distribution of T(reg) was noted in infectious mononucleosis and control tonsils. Regulatory cytokines, interleukin (IL)-10 and transforming growth factor (TGF)-beta, were significantly raised in infectious mononucleosis compared to seropositive donor plasma (P = 0.0001, P = 0.0004 respectively) although levels of IL-10 peaked earlier in infectious mononucleosis than TGF-beta. Previous studies identified EBV latent membrane protein (LMP)-1-induced T(reg) activity [Marshall et al.(2003): J Immunol 170:6183-6189; Marshall et al.(2007): Brit J Haematol 139:81-89], and in this study a significant reduction in interferon-gamma production was found from infectious mononucleosis but not seropositive donor lymphocytes after stimulation with a recall antigen when LMP-1 peptide PRG was added (P = 0.03). It is possible that T(reg) are important in controlling primary EBV infection to a subclinical level in most cases and that infectious mononucleosis represents a failure of this protective mechanism.

BACKGROUND: Chronic active Epstein Barr virus (EBV)-infection is characterized by mononucleosis like symptoms including fatigue, lymphadenopathy and/or hepatosplenomegaly and serologic evidence for ongoing EBV replication. Interferon-gamma (IFN-gamma) triggers several antiviral mechanisms in target cells including the induction of indoleamine-2,3-dioxygenase (IDO), which degrades the essential amino acid tryptophan to kynurenine. Because tryptophan is a precursor of the neurotransmitter 5-hydroxytryptamine (serotonin), tryptophan depletion by IDO can cause mood disturbances in patients with chronic immune activation. METHODS: This study investigated the tryptophan metabolism in 20 patients with chronic active EBV-infection, who were followed up for 4 to 8 months and in 10 healthy age-matched controls. The clinical suspicion of chronic active EBV infection was verified by the presence of circulating antibodies against EBV early antigen (EA) and virus capsid antigen (VCA). RESULTS: Patients with detectable EBV-DNA had higher serum neopterin (p<0.01) and lower tryptophan concentrations (p=0.01) than EBV-DNA negative patients. Serum concentrations of neopterin, indicating Th-1 mediated immune activation via IFN-gamma, were positively correlated to enhanced tryptophan degradation (rs=0.650, p<0.001) in patients, but not in healthy individuals. Patients suffering from more severe symptoms (as assessed by questionnaires) tended to have aggravated tryptophan degradation. CONCLUSION: Our data show that EBV viremia is associated with cell-mediated immune activation and increased tryptophan degradation, which may partly account for the symptoms found in this disorder.

In this report, the authors present a detailed immunological and virological assessment of an immunocompetent 17-year-old Caucasian male with a fatal Epstein-Barr virus (EBV) infectious mononucleosis presenting with meningoencephalitis and hemophagocytic syndrome. The patient with serologically confirmed EBV infectious mononucleosis was admitted to the hospital because of 3 weeks' fever. Fine-needle aspiration of lymph nodes showed reactive hyperplasia with prominent hemophagocytosis. Percentages of intracellular interferon-gamma (IFN-gamma) in CD4(+) and CD8(+) T cells in the peripheral blood progressively increased during the course of disease (10.2% and 8.5% on day 35; 30.1% and 53.2% on day 44; 42.2% and 75.2% on day 50; 36.1% and 50.6% on day 59, respectively). On day 50, the patient developed meningoencephalitis. Brain computed tomography (CT) was normal. Brain magnetic resonance imaging (MRI) showed multifocal inflammatory lesions in frontal and temporal cortex of the right hemisphere as well as severe perivascular inflammatory reaction. The patient was treated with steroids, cyclosporin A, and methotrexate intratecally. Following treatment, EBV viremia in the blood and cerebrospinal fluid (CSF) decreased from pretreatment values (54,490 copies of EBV DNA/ml and 39,500 copies/ml, respectively) to 8715 copies/ml in the blood and 14,690 in the CSF. Despite treatment, the patient remained unconscious and died of sepsis and pneumonia 3 months after initial symptoms. Immunohistochemical staining showed the presence of EBV in both perivascular infiltrates and grey matter. Enhanced Th1 response as shown by high levels of IFN-gamma in peripheral blood lymphocytes may be a predictor of severe complications during acute EBV infection. Early implementation of immunosuppressive therapy in these patients should be considered.

BACKGROUND AND PURPOSE: To delineate the clinical manifestations in different age groups and to define the viral load in patients with Epstein-Barr virus-associated infectious mononucleosis (EBV-associated IM). METHODS: We reviewed data on 69 children with EBV-associated IM from November 2001 to October 2005. Clinical features were evaluated among four age groups:<3 years, 3 to 5 years, 6 to 9 years and 10 to 18 years. EBV viral load was measured by quantitative real-time polymerase chain reaction (PCR) in 13 patients with 15 specimens. RESULTS: Majority of the children were younger than 7 years of age (76.8%) and the male-to-female ratio was 1.6:1. The symptoms and signs included fever (91.3%), tonsillopharyngitis (88.4%), lymphadenopathy (78.3%) and hepatitis (75.4%). The younger age group had higher monocyte count, lower occurrence of hepatitis, and lower glutamic-oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) levels than the older age group. The median (range) EBV viral load of peripheral blood mononuclear cells (PBMCs) and plasma in IM patients was 738 (0-7455) copies/mug DNA and 51 (0-957) copies/mL plasma, respectively. The PBMC detection rate was high in the early (within 10 days after onset) and late phase (>10 days after onset)[90-100%]. The plasma detection rate in the early phase (66.7%) was higher than that in the late phase (40%). CONCLUSIONS: The younger age group of EBV-associated IM patients had higher monocyte count, lower occurrence of hepatitis, and lower GOT and GPT levels than the older age group. The PBMC detection rate was almost equally high in both the early and late phases, while the plasma detection rate was higher in the early phase. Quantitative real-time PCR of EBV DNA is useful for diagnosing and monitoring EBV-associated IM, especially in younger children.

Background. Infectious mononucleosis (IM) commonly triggers a protracted postinfective fatigue syndrome (PIFS) of unknown pathogenesis.Methods. Seven subjects with PIFS with 6 or more months of disabling symptoms and 8 matched control subjects who had recovered promptly from documented IM were studied. The expression of 30,000 genes was examined in the peripheral blood by microarray analysis in 65 longitudinally collected samples. Gene expression patterns associated with PIFS were sought by correlation with symptom factor scores.Results. Differential expression of 733 genes was identified when samples collected early during the illness and at the late (recovered) time point were compared. Of these genes, 234 were found to be significantly correlated with the reported severity of the fatigue symptom factor, and 180 were found to be correlated with the musculoskeletal pain symptom factor. Validation by analysis of the longitudinal expression pattern revealed 35 genes for which changes in expression were consistent with the illness course. These genes included several that are involved in signal transduction pathways, metal ion binding, and ion channel activity.Conclusions. Gene expression correlates of the cardinal symptoms of PIFS after IM have been identified. Further studies of these gene products may help to elucidate the pathogenesis of PIFS.

Epstein-Barr virus (EBV) provides a useful model to study cellular immunity to a genetically stable, persistent human virus. Different sets of proteins expressed during EBV's lytic and cell transforming infections induce qualitatively different cellular immune responses. The factors governing immunodominance hierarchies and the biological effectiveness of these different responses are now being revealed. Analysis of infectious mononucleosis (IM), a clinical syndrome that can arise during primary EBV infection, has allowed the evolution of the responses to be tracked over time, giving an understanding of the immune response kinetics and of those determinants affecting selection into memory. Furthermore, following IM, expression of the receptor for the homeostatic cytokine IL-15 on NK and T cells is lost within these individuals. This experiment of nature provides a system to advance understanding of immunological homeostasis in humans, illustrating how data obtained from the study of EBV have wider significance to the immunological community.

BACKGROUND: Infectious mononucleosis decreases the productivity of many college students and Epstein-Barr virus (EBV) infection may result in long-term immune damage. OBJECTIVES: Evaluate the antiviral effect of valacyclovir during EBV-related acute infectious mononucleosis and explore potential clinical benefits. STUDY DESIGN: University students who presented during the first 7 days of illness were randomized to receive valacyclovir 3g/day for 14 days or not. The quantity of Epstein-Barr virus (EBV) DNA in oral and whole blood samples was determined by real-time (TaqMan) PCR. The primary outcome was the proportion of subjects with laboratory-confirmed primary EBV infection who had >/=2log(10) decrease in EBV copies/mL in oral washes during the treatment period. Secondary outcomes included clinical effects. RESULTS: Twenty subjects were studied. The proportion of valacyclovir recipients versus control subjects who had >/=2log(10) decrease in EBV copies was significantly greater for both oral wash fluid-derived cell pellet (P=0.03) and supernatant (P=0.001) samples. At the end of the treatment period, the number of reported symptoms (P=0.03) and the severity of illness (P=0.049) were reduced among valacyclovir recipients as compared with controls. CONCLUSIONS: Valacyclovir therapy caused a reduction of EBV excretion and possibly produced a clinical benefit in infectious mononucleosis. Because our study was small and not placebo-controlled, these results must be confirmed by a larger, placebo-controlled trial.