Chronic Epstein-Barr virus disease: a workshop held by the National Institute of Allergy and Infectious Diseases

EBV Chronic Infections

The infection from Epstein-Barr virus (EBV) or virus of infectious mononucleosis, together with other herpes viruses' infections, represents a prototype of persistent viral infections characterized by the property of the latency. Although the reactivations of the latent infection are associated with the resumption of the viral replication and eventually with the "shedding", it is still not clear if this virus can determine chronic infectious diseases, more or less evolutive. These diseases could include some pathological conditions actually defined as "idiopathic"and characterized by the "viral persistence" as the more credible pathogenetic factor. Among the so-called idiopathic syndromes, the "chronic fatigue syndrome" (CFS) aroused a great interest around the eighties of the last century when, just for its relationship with EBV, it was called "chronic mononucleosis" or "chronic EBV infection".Today CFS, as defined in 1994 by the CDC of Atlanta (USA), really represents a multifactorial syndrome characterized by a chronic course, where reactivation and remission phases alternate, and by a good prognosis. The etiopathogenetic role of EBV is demonstrated only in a well-examined subgroup of patients, while in most of the remaining cases this role should be played by other infectious agents - able to remain in a latent or persistent way in the host - or even by not infectious agents (toxic, neuroendocrine, methabolic, etc.). However, the pathogenetic substrate of the different etiologic forms seems to be the same, much probably represented by the oxidative damage due to the release of pro-inflammatory cytokines as a response to the triggering event (infectious or not infectious).Anyway, recently the scientists turned their's attention to the genetic predisposition of the subjects affected by the syndrome, so that in the last years the genetic studies, together with those of molecular biology, received a great impulse. Thanks to both these studies it was possibile to confirm the etiologic links between the syndrome and EBV or other herpesviruses or other persistent infectious agents.The mechanisms of EBV latency have been carefully examined both because they represent the virus strategy to elude the response of the immune system of the host, and because they are correlated with those oncologic conditions associated to the viral persistence, particularly lymphomas and lymphoproliferative disorders. Just these malignancies, for which a pathogenetic role of EBV is clearly documented, should represent the main clinical expression of a first group of chronic EBV infections characterized by a natural history where the neoplastic event aroused from the viral persistence in the resting B cells for all the life, from the genetic predisposition of the host and from the oncogenic potentialities of the virus that chronically persists and incurs reactivations.Really, these oncological diseases should be considered more complications than chronic forms of the illness, as well as other malignancies for which a viral - or even infectious - etiology is well recognized. The chronic diseases, in fact, should be linked in a pathogenetic and temporal way to the acute infection, from whom start the natural history of the following disease. So, as for the chronic liver diseases from HBV and HCV, it was conied the acronym of CAEBV (Chronic Active EBV infection), distinguishing within these pathologies the more severe forms (SCAEBV) mostly reported in Far East and among children or adolescents. Probably only these forms have to be considered expressions of a chronic EBV infection "sensu scrictu", together with those forms of CFS where the etiopathogenetic and temporal link with the acute EBV infection is well documented. As for CFS, also for CAEBV the criteria for a case definition were defined, even on the basis of serological and virological findings. However, the lymphoproliferative disorders are excluded from these forms and mantain their nosographic (e.g. T or B cell or NK type lymphomas) and pathogenetic collocation, even when they occur within chronic forms of EBV infection. In the pathogenesis, near to the programs of latency of the virus, the genetic and environmental factors, independent from the real natural history of EBV infection, play a crucial role.Finally, it was realized a review of cases - not much numerous in literature - of chronic EBV infection associated to chronic liver and neurological diseases, where the modern techniques of molecular biology should be useful to obtain a more exact etiologic definition, not always possibile to reach in the past.The wide variety of clinical forms associated to the EBV chronic infection makes difficult the finding of a univocal pathogenetic link. There is no doubt, however, that a careful examination of the different clinical forms described in this review should be useful to open new horizons to the study of the persistent viral infections and the still not well cleared pathologies that they can induce in the human host.

Pathogenesis of chronic active Epstein-Barr virus infection: is this an infectious disease, lymphoproliferative disorder, or immunodeficiency?

Chronic active Epstein-Barr virus infection (CAEBV) is characterised by chronic or recurrent infectious mononucleosis-like symptoms, such as fever, hepatosplenomegaly, persistent hepatitis and extensive lymphadenopathy. Patients with CAEBV have high viral loads in their peripheral blood and/or an unusual pattern of EBV-related antibodies. This disease is rare but severe with high morbidity and mortality. Nearly three decades have passed since this disease was first identified, and recent advances in technology have increased our understanding of CAEBV pathophysiology. There is accumulating evidence that the clonal expansion of EBV-infected T or natural killer (NK) cells plays a central role in the pathogenesis of CAEBV. However, it remains unclear whether CAEBV is truly a monoclonal lymphoproliferative disorder. EBV-infected T or NK cells are able to evade the host cellular immune system due to the limited expression of viral proteins of reduced antigenicity. Recent studies suggest that infection of T or NK cells is a common event during primary EBV infection. A defect or single nucleotide polymorphism in host immune-modulating genes may allow for the expansion of virus infected cells giving rise to CAEBV. In this review, I summarise our current understanding of the pathogenesis of CAEBV and propose a model of CAEBV pathogenicity.

Recurrent acute disseminated encephalomyelitis associated with acute cytomegalovirus and Epstein-Barr virus infection

We describe a 5 6/12-year-old girl with recurrent episodes of acute disseminated encephalomyelitis following an acute cytomegalovirus infection and associated reactivated Epstein-Barr virus. Complete clinical recovery was obtained with intravenous immunoglobulin.

Severe chronic active Epstein-Barr virus infection accompanied by virus-associated hemophagocytic syndrome, cerebellar ataxia and encephalitis

We present a rare case of chronic active Epstein-Barr virus (EBV) infection showing various clinical outcomes. A 26-year-old man was admitted to our hospital due to persistent fever and dyspnea. Serologic response of the patient to EBV indicated chronic active infection. He showed pleuritis, parotitis, chronic hepatic dysfunction, disseminated intravascular coagulation, virus associated hemophaghocytic syndrome, acute rhabdomyolysis, acute renal failure, acute cerebellar ataxia, encephalitis and multiple brain abscesses. None of acyclovir, gancyclovir, prednisolone or interleukin-2 was effectual to abolish those abnormalities. This is the first report of transient cerebellar ataxia which aggravated to panencephalitis associated with chronic EBV infection.

Latent variable models of functional somatic distress

Latent variable models of functional somatic symptoms were estimated for a sample of 686 family medicine patients. Symptom items from the NIMH Diagnostic Interview Schedule were selected to approximate diagnoses of fibromyalgia syndrome (FMS), chronic fatigue syndrome (CFS), and irritable bowel syndrome (IBS). Confirmatory factor analysis demonstrated that hypothesized latent variables of somatic depression, somatic anxiety, FM-like, CF-like, and IB-like syndromes fit the observed covariations better than models hypothesizing fewer latent variables. Results offer tentative confirmation of functional somatic syndromes as discrete entities and suggest that relaxing the diagnostic criteria for somatization may identify individuals with distress limited to a single functional system.

Biological response modifiers and infectious diseases: actual and potential therapeutic agents

Biological response modifiers (BRMs) are agents which can modify the immune response to cancer or invasion of the organism by infectious agents. An explosive appearance of new BRMs has resulted from the development of recombinant gene technology and the availability of monoclonal antibodies. Colony-stimulating factors first became available for the prevention of neutropenia but may also have a role in the treatment of infections. Interleukin-1 is being tested as a modular of hematopoiesis and may be useful as a helper factor for T- and B-cell function. Immunoglobulins are being used against viral and bacterial infections while interferons can prevent viral upper respiratory infections and suppress or irradicate some viral hepatitides. Other BRMs which show promise include chemical agents and traditional herbal medicines.

Cytogenetic characterization of Epstein-Barr virus-associated T-cell malignancies

Recently, Epstein-Barr virus (EBV) infection has been found not only to be associated with Burkitt lymphoma and nasopharyngeal carcinoma but also with some T-cell malignancies. Cytogenetic studies were performed on four Chinese patients with EBV-associated T-cell neoplasms: three peripheral T-cell lymphomas and one large granular lymphocyte leukemia with coexpression of T-cell antigen. Clonal chromosomal abnormalities were detected in all four patients. Rearrangements of chromosome 7 were observed in three patients: one at 7p22, one at 7q35 or 36, and the remaining one at both sites. The last patient also had a chromosomal abnormality involving 14q11. Trisomy of part of the 1q segment was detected in two patients. The results revealed that the chromosomal abnormalities in these patients were similar to those observed in other T-cell lymphomas. Further studies on more patients are necessary to find out whether there are specific chromosomal aberrations in EBV-associated T-cell neoplasms.

Increased expression of Epstein-Barr virus in primary biliary cirrhosis patients

Peripheral blood mononuclear cells (PBMC, n = 26), formalin-fixed paraffin-embedded liver tissues (n = 11) and saliva (n = 15) of primary biliary cirrhosis (PBC) patients were used for the detection of Epstein-Barr virus (EBV) sequences by polymerase chain reaction (PCR) assay. The semiquantitative analysis of EBV-DNA was also carried out in a reconstructive experiment using an EBV-infected cell line. The PBMCs of PBC patients showed increased levels of EBV-DNA (61%) in contrast to chronic active hepatitis patients (19%), liver cirrhosis patients (14%) and healthy individuals (11%). Furthermore, formalin-fixed paraffin-embedded liver tissues, as well as saliva from PBC patients, also demonstrated increased levels of EBV-DNA when compared to healthy individuals and those with other liver diseases. The increased levels of EBV-DNA in the PBMC, liver tissue and saliva of the PBC patients suggest that those patients may have a depressed immune function against EBV infection.

Chronic fatigue syndrome: a conundrum

Chronic fatigue syndrome (CFS) is a multi-faceted disorder for which no etiology has been determined. This paper discusses the implications of the new clinical case definition of CFS on previous and future studies of this illness. The authors' own management approach is also discussed.

B-cell lymphoproliferative disorders after bone marrow transplant. An analysis of ten cases with emphasis on Epstein-Barr virus detection by in situ hybridization

Ten patients with B-cell lymphoproliferative disorders (BLPD) after bone marrow transplant were studied in a retrospective analysis of 81 specimens available from biopsy and autopsy material. Histologic review, immunophenotyping, and in situ hybridization (ISH) for Epstein-Barr virus (EBV) sequences were done. Sixty-four specimens showed morphologic evidence of BLPD, demonstrating a heterogeneous spectrum with various degrees of plasmacytoid differentiation. Immunophenotypic evidence of clonality was found in six patients. The ISH detected EBV sequences in all ten patients, including 60 of the 64 specimens with morphologic evidence of BLPD. In addition, ISH identified EBV-infected lymphoid cells in two of 17 sites without morphologic evidence of BLPD. These data demonstrate the utility of ISH for detecting EBV genome in this setting and provide further evidence for the etiologic role of EBV in the pathogenesis of BLPD.

Historic aspects of intravenous immunoglobulin therapy

The earliest preparations of immunoglobulins (Ig) decreased the susceptibility of agammaglobulinemic patients to infections caused by pneumococci, Haemophilus influenzae, meningococci, streptococci, and Pseudomonas aeruginosa. Intramuscular administration of such preparations was painful and traumatic, especially for children. Ethanol-fractionated Ig could not be administered intravenously (IV) because the IgG molecules tended to aggregate and thus were more likely to produce anaphylactoid reactions. New Ig preparations, isolated at low pH (e.g., pH 4) in the presence of traces of pepsin to inhibit reaggregation, were well tolerated when administered IV. Thus a new era of treatment and prophylaxis of disease using IV Ig (IVIG) was launched. The IVIG preparations revolutionized the management of virtually all immunodeficiency syndromes characterized by failure of antibody responses. Amelioration of antibody deficiency secondary to certain chronic diseases or surgical trauma can be achieved with these preparations. Newer uses of IVIG include treatment of some autoimmune diseases; in some conditions, the beneficial influences may be attributable to antiidiotype antibodies present in the IVIG. Another likely explanation is that IVIG inhibits damage to cells and tissues by antibody-mediated cellular cytotoxicity or blocks phagocytosis that is facilitated by Fc receptor mechanisms. The value of IVIG in preventing infection in patients undergoing bone marrow or organ transplantation and in the treatment and prophylaxis of life-threatening infections in neonates and premature infants also is reviewed.

Severe chronic active Epstein-Barr virus infection syndrome

Reports of unusually severe lymphoproliferative disorders associated with extremely high antibody titers against Epstein-Barr virus (EBV) have recently increased. The syndrome, which we designated severe chronic active EBV infection syndrome, is characterized by persistent or intermittent fever, lymphadenopathy, and hepatosplenomegaly and primarily affects children and young adults. Polyclonal gammopathy and bone marrow suppression are generally observed, and some patients develop B-cell or T-cell lymphoproliferation or lymphoma. Frequently, EBV genomes are detectable in tissues infiltrated with lymphoid cells. Additionally, it is difficult to establish spontaneous or B95-8 EBV-induced cell lines despite the expression of an activated EBV infection. We review and report here the published medical literature and our own experience regarding patients with severe chronic active EBV infection syndrome in an attempt to understand this enigmatic syndrome and the possible pathogenetic mechanism(s) responsible for this disorder.

Chronic fatigue syndrome and the psychiatrist

The number of patients who are identified as having chronic fatigue syndrome (CFS) has increased, and as a result, chronic fatigue syndrome has received widespread attention. Research has demonstrated that cognitive, affective and behavioural symptoms are prominent in CFS. Psychiatrists are therefore being asked to participate in the assessment and management of patients with this syndrome. This paper will provide an overview of the clinical characteristics of CFS and the current empirical findings related to its pathology, and will conclude with a discussion of the management of these patients.

[Chronic fatigue syndrome]

Reports on conditions of chronic fatigue associated with other somatopsychic symptoms after acute viral infections have led to the hypothesis of a "chronic fatigue syndrome" (CFS). Historical disease descriptions, like e.g. "myalgic encephalomyelitits", were updated by means of modern virological diagnostic techniques and data analysis. Several viral agents like enteroviruses, Epstein-Barr virus, Human-Herpesvirus 6 and other herpesviruses have been implicated for possible underlying infections. A preliminary disease definition by the Center for Disease Control (CDC) seeks to provide a rational basis for further etiological studies. In fact, there is growing consensus that the syndrome comprises various separate disease entities and causative agents. Today we can tentatively differentiate a "chronic mononucleosis" after infection with Epstein-Barr virus, an etiologically undetermined "postviral fatigue syndrome" and a fatigue syndrome of the myalgic type after Coxsackie-B virus infection. Furthermore, a valid diagnosis of CFS must be based on the exclusion of defined other diseases and the awareness of dealing with a hypothetical concept. As a result, current knowledge does not yet allow specific therapeutic recommendations.

Neurasthenia in the 1980s: chronic mononucleosis, chronic fatigue syndrome, and anxiety and depressive disorders

In the 1980s, patients suffering from unexplained fatigue and what seemed like a prolonged attack of acute mononucleosis were given the diagnosis of chronic mononucleosis or chronic infection with the Epstein-Barr virus. Although the diagnosis has great appeal, the Epstein-Barr virus does not cause the syndrome (CFS) of chronic fatigue, which has been renamed and redefined chronic fatigue syndrome to remove the inference that the virus is its cause. From a historical perspective, both syndromes represent the 1980s equivalent of neurasthenia, a disease of fatigue that influenced the development of psychiatric nosology. Because patients with depression and anxiety also have chronic fatigue and because most patients with CFS have an affective disorder, the assessment of organic causes of this syndrome requires careful psychiatric diagnosis and treatment. Defining chronic fatigue syndrome as a medical disorder may deprive patients of competent treatment of their affective disorder.

Chronic infectious mononucleosis; a case report

A 39-year-old woman had an adenitis colli followed by anaemia, splenomegaly, atypical lymphoid cells in blood with increased B-lymphocytes, reduced T-suppressor/cytotoxic cells, increased polyclonal IgM, high titres of EB VCA IgG, EB EA IgD&R +/- and EBNA IgG-. The disease progressed slowly for 2 years, splenectomy was followed by clinical improvement; spleen morphology was compatible with a benign disease of viral origin.

Chronic Epstein-Barr virus infections associated with coronary aneurysms

We recently reported virological studies in a patient with chronic active Epstein-Barr virus (EBV) infection in which T-lymphocytes were infected, and coronary aneurysms were detected by echocardiography. We report here the clinical features of this patient and suggest that EBV may cause coronary aneurysms and that an echocardiographic study should be performed in patients with chronic active EBV infection.

Epstein-Barr virus and human diseases: recent advances in diagnosis

Since the discovery of Epstein-Barr virus (EBV) from a cultured Burkitt's lymphoma cell line in 1964, the virus has been associated with Burkitt's lymphoma, nasopharyngeal carcinoma, and infectious mononucleosis. During the recent decade, EBV has been etiologically implicated in a broad spectrum of human diseases. The precise role of this virus in these diseases is not well understood, but clearly, defective immunosurveillance against the virus may permit an uncontrolled proliferation of EBV-infected cells. As a result, a growing number of cases of EBV-associated B-cell proliferative diseases or lymphoma have been noted in patients with primary and acquired immunodeficiencies. These lymphoproliferative diseases and others, such as chronic mononucleosis syndrome, are leading to new areas of investigation which are providing information regarding the pathogenetic mechanisms of EBV-induced diseases. The early accurate diagnosis of EBV infection can be achieved by performing EBV-specific serology, detecting for EBV-determined nuclear antigen in tissues, establishing spontaneous lymphoid cell lines, and using molecular hybridization techniques for demonstrating the presence of viral genome in affected lesions.

T-cell lymphomas containing Epstein-Barr viral DNA in patients with chronic Epstein-Barr virus infections

Fatal T-cell lymphomas developed in three patients with a chronic illness manifested by fever, pneumonia, dysgammaglobulinemia, hematologic abnormalities, and extraordinarily high titers of antibody to the Epstein-Barr virus (EBV) capsid antigen (greater than 10,000) and early antigen (greater than 640) but low titers to the EBV nuclear antigen (less than or equal to 40). To understand the pathogenesis of these tumors better, we determined the immunophenotype of the tumor cells and analyzed tumor-cell DNA for EBV genomes and for lymphoid-cell gene rearrangements. More than 80 percent of the cells in tumors had an activated helper T-cell phenotype (T4, T11, la positive). The EBV genome was found by in situ hybridization in tumor tissue from each patient. Southern blot assay of DNA digests from one patient showed the same pattern as that of the EBV-infected marmoset line, B95-8. DNA digests from two patients showed a monoclonal proliferation of T cells determined on the basis of uniform T-cell-receptor gene rearrangements and a single band for the joined termini of the EBV genome. We conclude that EBV may infect T cells and contribute to lymphomas in selected patients with severe EBV infections.

The many faces of Epstein-Barr virus

Epstein-Barr virus (EBV) persists for life in a person who has been infected. Investigators are uncertain what this means to the host, particularly an immunocompromised one. EBV is the most common cause of infectious mononucleosis, but the diagnosis must be based on clinical, hematologic, and serologic criteria because other agents are the cause in about 10% of cases. EBV is the first virus to be associated with a neoplasm--Burkitt's lymphoma. This childhood malignancy is relatively common in central Africa, and EBV is a cofactor in its development, although direct evidence for a causal relationship has not been found. In southern China, nasopharyngeal carcinoma is an important health problem in adults in areas where the infection rate of EBV in childhood is high. Rare cases of primary EBV infection that evolved into uncontrolled lymphoproliferative disease have also been reported. EBV's relationship to these diverse diseases, its varying effects on certain individuals and in certain geographic locations, and the testing of a vaccine against the virus are areas of ongoing study.

Polyclonal polymorphic B-cell lymphoproliferative disorder with prominent pulmonary involvement in children with acquired immune deficiency syndrome

Four cases of pediatric Acquired Immune Deficiency Syndrome (AIDS) with lymphoproliferative disorder are described and other lymphoid lesions in previously reported cases of pediatric AIDS are reviewed. The lymphoproliferative disorder was characterized by polyclonal, polymorphic B-cell content without evidence of cellular atypia, necrosis or prominent mitotic activity but with predominantly extranodal systemic and prominent pulmonary involvement. Since the lesion has overlapping features it is considered to be intermediate between benign and malignant lymphoproliferations and designated as polyclonal, polymorphic B-cell lymphoproliferative disorder (PBLD) of pediatric AIDS. The PBLD is part of a spectrum of lymphoid lesions in pediatric AIDS consisting of follicular lymphoid hyperplasia of nodal and extranodal sites, pulmonary lymphoid hyperplasia/lymphoid interstitial pneumonitis complex (PLH/LIP complex) in cases previously reported by the authors, and also malignant lymphoma reported by others. It is possible that Epstein-Barr virus (EBV) by itself or in synergism with human T-lymphotropic virus-type III (HTLV-III) is related to pathogenesis of PBLD in children with AIDS.

Non-sexually transmitted infectious diseases of the oral, nasal, and vaginal mucosae

The skin and mucous membranes are the principal barriers to invasion of the body by microorganisms. Besides functioning as a mechanical barrier, the mucosae are endowed with an array of still poorly characterized specific and nonspecific host defense capabilities. These include the production of mucus, secretory immunoglobulin (IgA), lysozyme, lactoferrin, and alpha-antitrypsin, in conjunction with a low-grade exudation of leukocytes.¹ In addition, the mucosal surfaces of the upper respiratory, gastrointestinal, and lower vaginal and urinary tracts support a large number of “nonpathogenic” microorganisms that comprise the so-called “normal flora.” This commensal flora plays an important and complex role in protecting the host from microbial invasion. Mechanisms for this protection likely include the following: (1) competition for the same nutrients (interference); (2) competition for the same receptors on host cells (tropism); (3) production of bacteriocins, that is, bacterial products that are toxic to other organisms, usually of the same species; and (4) stimulation of crossprotective immune factors such as the “natural antibodies.”¹

The “normal” flora is inconstant and may be altered by dietary factors, debilitation, hormonal events (such as menstruation, pregnancy, and possibly use of oral contraceptives), personal hygiene, medications, intercurrent infection, and probably many others. Antibiotic therapy and menstruation can have a profound effect on the composition of this group of microorganisms.² Disturbance of the delicate host-commensal relationship may cause a clinically significant infection due to these “nonpathogens.” This may occur in response to the aforementioned factors (eg, pregnancy predisposing to vaginal candidiasis) or because of disruption of the anatomic barrier (eg, local mucosal infection at a site of trauma, or injury from cytotoxic drugs) or in association with exogenous infection (eg, rhinoviral infection leading to secondary bacterial otitis media). Invasion by “normal flora” may result in serious systemic illness. A clear example of the latter is the development of infective endocarditis caused by viridans streptococci following a dental procedure.