Persistent epstein-barr virus infection mimicking juvenile chronic myelogenous leukemia: immunologic and hematologic studies

Epstein-Barr virus (EBV) infections may induce a diverse clinical picture, ranging from the well characterized infectious mononucleosis (IM) syndrome to the rare X-linked lymphoproliferative syndrome. We describe two unrelated children, a 21-mo-old white boy and a 15-mo-old black girl, who presented with the clinical and laboratory findings characteristically seen in juvenile chronic myelogenous leukemia (JCML). Results of periodic serodiagnostic tests indicated that they likely have persistent infection with EBV. Both had elevated IgG antibody to viral capsid antigen (greater than or equal to 1:320) and antibody to early antigen (1:20-1:40) that have persisted for 3 yr of more. Both patients had EBV-specific suppressor cell activity, decreased natural killer cell activity, and diminished antibody- dependent cell-mediated cytotoxicity (ADCC) activity. These changes suggest an underlying defect in the immunoregulatory network controlling EBV infection. The patients have shown clinical improvement without treatment. It appears that EBV infections are capable of inducing symptoms similar to those seen in JCML. Careful evaluation for evidence of EBV infection in patients presenting with symptoms compatible with JCML seems warranted.     

Acute respiratory failure and cerebral hemorrhage due to primary Epstein-Barr virus infection

Epstein-Barr virus (EBV) is a ubiquitous human herpesvirus with worldwide distribution. Primary infection with EBV occurs early in life and typically presents as infectious mononucleosis. The usual course of the disease is benign and most patients recover uneventfully. Severe infections are reported particularly in immunocompromised patients. Mild, asymptomatic pneumonitis is reported in about 5-10% of cases of infectious mononucleosis, but severe pneumonitis with hypoxemia is very rare in immunocompetent individuals. We report a young female adolescent in whom an acute EBV infection led to severe bilateral pneumonitis, a systemic inflammatory response and intracerebral bleeding. The clinical course and results of quantitative viral DNA determinations in plasma are presented.     

Quantitative analysis of Epstein-Barr virus (EBV)-specific CD8+ T cells in patients with chronic active EBV infection

To clarify the pathogenesis of chronic active Epstein-Barr virus (EBV) infection, EBV-specific CD8+ T cells were enumerated, by use of human leukocyte antigen (HLA)-A*2402-restricted tetramers, in 8 patients with chronic active EBV infection, 10 patients with infectious mononucleosis, and 16 EBV-seropositive healthy control subjects. In most of the patients with chronic active EBV infection, EBV-specific CD8+ T cells were not detected. Of note, latent membrane protein 2-specific CD8+ T cells were not detectable in any patients with chronic active EBV infection. In contrast, EBV-specific CD8+ T cells were detected in patients with infectious mononucleosis and in healthy control subjects. Low frequencies of EBV-specific CD8+ T cells may be one of the immunological features of chronic active EBV infection.     

Epstein-Barr-Virus-Infektion nach pädiatrischer Nierentransplantation

Due to its mild cytopathic effects, Epstein-Barr virus (EBV) rarely causes severe clinical symptoms in immunocompetent hosts. While infants often remain asymptomatic during EBV infections, young immunocompetent adolescents and adults typically develop signs of infectious mononucleosis. Also, immunocompromised pediatric renal transplant recipients exhibit mostly mild acute EBV-related clinical symptoms. However, immunosuppressive therapy after pediatric renal transplantation may lead to an uncontrolled malignant proliferation of EBV infected B cells, due to the lack of T cell-specific regulation, and thus to post-transplant lymphoproliferative disease (PTLD). Pediatric patients bear an increased risk of PTLD, as they are often EBV seronegative at the time of transplantation and develop EBV primary infection after receiving an EBV positive kidney. The EBV-specific serology and EBV viral load constitute insufficient surrogate markers for the risk assessment of PTLD. An uncritical reduction of immunosuppressive therapy, based solely on the presence of a high, persistent EBV load, may put patients at risk of transplant rejection and subsequent graft failure and should therefore be avoided. Treatment of PTLD comprises reduction of immunosuppression, administration of rituximab in cases of CD20 antigen expression and possibly chemotherapy. The 5-year survival rate after PTLD amounts to approximately 61–87%, with involvement of the bone marrow and/or central nervous system being a risk factor for poor survival. An EBV vaccine is currently not available. An antiviral chemoprophylaxis with (val-)ganciclovir, however, reduces the incidence of EBV primary infection in patients with a high-risk seroconstellation (donor EBV positive, recipient EBV negative) and, hence, potentially the rate of PTLD.     

Ganciclovir and the treatment of Epstein-Barr virus hepatitis

Epstein-Barr virus (EBV) is part of the herpesvirus family that infects up to 90% of the population. Initial infection is often subclincal in children but will generally result in symptomatic infectious mononucleosis in adolescents and adults. Ganciclovir has been utilized in immunocompromised patients with EBV encephalitis and post-liver transplant for EBV fulminant hepatitis. Herein, the successful use of ganciclovir in two immunocompetent patients with severe EBV hepatitis is reported.     

Enhanced serological and virological findings of Epstein-Barr virus in patients with AIDS and AIDS-related complex

The potential involvement of Epstein-Barr virus (EBV) in AIDS was examined by determining the type of EBV-specific antibody responses and the EBV content or lymphoproliferative ability present in selected body fluids of patients with AIDS or AIDS-related complex. The results were compared with two control groups. An enhanced antibody response to a broad spectrum of EBV antigens was found in patients with AIDS or AIDS-related complex. The pattern of virus-specific antibody responses resembled that associated with a persistent or reactivated infection. The content of EBV in oropharyngeal secretions and the lymphoproliferative ability in peripheral blood from patients with AIDS or AIDS-related complex was significantly greater than that from healthy controls and approached levels detected in the control group with infectious mononucleosis. These findings, together with recent reports of cellular-level interaction between EBV and human T lymphotropic virus type III, suggest that EBV may have a contributory role in these disorders.     

Chronic, active Epstein-Barr virus infection

Chronic active Epstein-Barr virus (EBV) infection is an uncommon outcome of EBV infection and may present as a waxing and waning or fulminant syndrome. Unlike acute infectious mononucleosis, wherein EBV establishes lifelong infection and survives by maintaining a delicate balance with the host as a latent infection, in chronic active EBV infection the host-virus balance is disturbed. The mechanisms by which this balance becomes perturbed are likely to be heterogenous and may involve host immune factors, viral factors, or both. A number of subtle immunologic defects have been reported in patients with chronic active EBV infection. Enhanced expression of viral genes has also been noted in some cases. Treatment of chronic active EBV infection has proven difficult, but new modalities including etoposide-based regimens and adoptive transfer of EBV-specific cytotoxic T lymphocytes have shown promise.     

Benign and malignant Epstein-Barr virus-associated B-cell lymphoproliferative diseases

Most Epstein-Barr virus (EBV) infections in infants and children are asymptomatic, while infection of adolescents or adults often results in infectious mononucleosis. The symptoms of infectious mononucleosis are primarily due to the T-cell proliferative response to EBV-infected B cells; thus, antiviral therapy does not affect the clinical course of disease. Failure of the cellular immune response to control EBV-induced B-cell proliferation can result in severe disease. Patients with the X-linked lymphoproliferative disease (XLPD) have a mutation in the SAP gene and EBV infection often leads to fatal infectious mononucleosis. Transplant recipients may develop lymphoproliferative disease, which often responds to treatment that enhances the immune response against EBV-infected B cells. About 50% of Hodgkin's and 20% of Burkitt's lymphomas in the United States contain EBV DNA. While chemotherapy and/or radiation therapy are mainstays of treatment, clinical trials are being developed using cytotoxic T cells directed against EBV proteins in these tumors.     

Epstein-Barr virus-induced diseases in boys with the X-linked lymphoproliferative syndrome (XLP): update on studies of the registry

Analyses of 100 subjects with the X-linked lymphoproliferative syndrome (XLP) in 25 kindreds revealed four major interrelated phenotypes: infectious mononucleosis, malignant B-cell lymphoma, aplastic anemia, and hypogammaglobulinemia. Eighty-one of the patients died. Two male subjects were asymptomatic but showed immunodeficiency to Epstein-Barr virus (EBV). Seventy-five subjects had the infectious mononucleosis phenotype and concurrently, 17 subjects of this group had aplastic anemia. All subjects with aplastic anemia died within a week. Aplastic anemia did not accompany hypogammaglobulinemia or malignant lymphoma phenotypes. Hypogammaglobulinemia had been detected before infectious mononucleosis in three subjects, after infectious mononucleosis in five subjects, and was not associated with infectious mononucleosis in 11 boys with hypogammaglobulinemia. In nine subjects infectious mononucleosis appeared to have evolved into malignant lymphoma; however, the majority of patients with malignant lymphoma showed no obvious antecedent infectious mononucleosis. One subject had infectious mononucleosis following recurrent malignant lymphoma. Twenty-six of 35 lymphomas were in the terminal ileum. Results of immunologic and virologic studies of 15 survivors revealed combined variable immunodeficiency and deficient antibody responses to EBV-specific antigens. Mothers of boys with XLP exhibited abnormally elevated titers of antibodies of EBV. Subjects of both sexes with phenotypes of XLP should be investigated for immunodeficiency to EBV. Persons with inherited or acquired immunodeficiency may be vulnerable to life-threatening EBV-induced diseases.     

Evaluation of enzyme-linked immunosorbent assays with two synthetic peptides of Epstein-Barr virus for diagnosis of infectious mononucleosis

To diagnose infectious mononucleosis caused by Epstein-Barr virus (EBV), a peptide from the EBV nuclear antigen (EBNA) 1 (p107) and an EBNA 2 peptide (polyproline) were used as antigens in enzyme-linked immunosorbent assays for IgG and IgM. Well-characterized serum samples (360) from healthy individuals and patients with EBV or cytomegalovirus infections were examined. The p107 IgG and IgM assays were also tested with serum from 1000 patients with suspected EBV-related disorders. The p107 and polyproline IgG assays were 100% specific for EBV seropositivity. Low p107 IgG titers (less than 1000) were found in 98% of patients with EBV infectious mononucleosis but also in 18% of patients with other diseases. A p107-to-polyproline IgG ratio of less than 1 was 98% specific for EBV infectious mononucleosis; sensitivity was 86%. In EBV capsid antigen-IgG seropositive patients, a p107 IgG titer of less than 1000 together with a p107 IgG-to-IgM ratio of less than 1 was 98% sensitive and specific for EBV infectious mononucleosis. Thus, this ratio appears adequate to measure EBNA antibodies for diagnosis of EBV mononucleosis.     

Clinical and laboratory evaluation of cytomegalovirus-induced mononucleosis in previously healthy individuals. Report of 82 cases

The present report describes the clinical and laboratory profile of 82 previously healthy individuals who developed cytomegalovirus (CMV)-induced mononucleosis. Many of these patients posed initial diagnostic problems and were hospitalized with diagnoses such as fever of undetermined origin, active viral hepatitis, acute leukemia, probable systemic lupus erythematosus, autoimmune hemolytic anemia, and severe pancytopenia. These patients underwent a variety of diagnostic biopsies, including liver biopsies (6) and bone marrow aspirations (9). Four patients had exploratory laparotomies, 1 for a ruptured spleen, and another had a splenectomy following an erroneous initial diagnosis of agnogenic myeloid metaplasia. There was no apparent clinical response to a short course of steroid therapy in 3 of 5 cases and acyclovir in another. The vast majority of these patients demonstrated infectious mononucleosis-type reactive blood smears, negative heterophil antibody studies, mildly or moderately elevated aspartate aminotransferase activity, and evidence for subclinical hemolysis on serial specimens. The peak serum bilirubin levels were above 2.0 mg/dl in only 2 of 71 cases tested, both of the latter patients having significant hemolysis (hemoglobin values 8.6-9.3 g/dl). The CMV-IgM test had a high sensitivity for detection of CMV macroglobulins (positive in 81 of 82 cases). In contrast, complement-fixing antibodies to CMV showed diagnostic four-fold titer changes in only 39/82 cases (47.6%). Despite its great sensitivity, the CMV-IgM test is limited by a one-way crossreaction of acute Epstein-Barr virus (EBV)-IM sera and spurious positive reactions in some sera due to the presence of rheumatoid factors. Based on EBV-specific serologic studies, the 82 patients with CMV-IM could be divided into 4 groups: 3 patients without antibodies to EBV; 2) 69 patients with uncomplicated serologic data indicative of long-past EBV infections; (3) 6 patients with unusual antibody profiles, e.g., anti-D responses; and (4) 5 patients, including 1 originally susceptible to EBV, with apparent dual CMV/EBV infections. At the conclusion of our study, final diagnoses and initial hematologic data were correlated in 750 cases in which CMV macroglobulins were searched for. The vast majority of patients with active CMV infections initially demonstrated either markedly or moderately reactive peripheral blood smears. These data support our impression that diagnostic tests for CMV, as well as for EBV, are seldom indicated in symptomatic previously healthy patients whose blood smears during the acute phase (first several weeks) of their illnesses are either nonreactive or minimally reactive.     

A boy with fatal infectious mononucleosis suspected as the first Japanese case of X-linked lymphoproliferative syndrome

We report a case of a 10-month-old boy who died of severe hepatic failure after a prolonged course of infectious mononucleosis. He also presented interstitial pneumonitis, meningoencephalitis and aplastic anaemia. Epstein-Barr virus (EBV)-specific cytotoxic T lymphocyte (CTL) activity had not been detected in his peripheral blood during the course of the illness. Studies of his mother revealed a severe reactivation pattern of anti-EBV antibodies and decreased EBV-specific CTL activity. An X-linked familial susceptibility to EBV infection such as X-linked lymphoproliferative syndrome (XLP) might be associated with his fatal EBV infection.     

Prolonged illness after infectious mononucleosis is associated with altered immunity but not with increased viral load

BACKGROUND: Primary Epstein-Barr virus (EBV) infection causes a spectrum of characteristics that range from asymptomatic seroconversion to severe infectious mononucleosis (IM), sometimes with prolonged symptoms and disability. We examined the relationships between clinical course, number of viral copies, and immunological parameters in a prospective cohort of subjects with recent IM. METHODS: Eight case patients with at least 6 months of disabling symptoms and 31 matched control subjects who had recovered promptly were included. Symptom scores were recorded at regular intervals over the course of 12 months. Cellular EBV load, EBV-specific antibody responses, lymphocyte subsets, and EBV-specific interferon (IFN)- gamma induction were measured. RESULTS: In case patients with prolonged illness, the severity of acute-phase symptoms was greater, the development of anti-EBV nuclear antigen-1 immunoglobulin G was more rapid, and the time to development of the peak IFN- gamma response to the majority of latent-cycle EBV peptides was generally slower than those in control subjects. However, in both groups, neither viral nor immune parameters correlated with the severity or duration of symptoms. CONCLUSIONS: The resolution of symptomatic IM is not determined by control of viremia, nor is it easily explained by altered host responses to EBV infection. The detailed determinants of delayed recovery remain to be elucidated.     

Epstein-Barr virus-specific CD8(+) T cells that re-express CD45RA are apoptosis-resistant memory cells that retain replicative potential

During acute infection, latent and lytic Epstein-Barr virus (EBV) epitope-specific CD8(+) T cells have a CD45RO(+) CD45RA(-) phenotype. However, after resolution of the infection, a large proportion of these cells, particularly those specific for lytic viral epitopes, re-express the CD45RA molecule. The role of CD8(+) CD45RA(+) T cells in ongoing immunity to EBV and other viruses is unknown. We now demonstrate that, relative to their CD45RO(+) counterparts, the EBV-specific CD8(+) T cells that revert to CD45RA expression after acute infectious mononucleosis are not in cell cycle, have longer telomeres, and are more resistant to apoptosis partly because of increased Bcl-2 expression. However, the EBV-specific CD8(+) CD45RA(+) T cells have shorter telomeres than the total CD8(+) CD45RA(+) T-cell pool and predominantly express low levels of the CCR7 chemokine receptor, indicating that they are not naive cells. In addition, EBV-specific CD8(+) CD45RA(+) T cells can be induced to proliferate and exhibit potent cytotoxic activity against target cells loaded with specific peptide. Our results strongly suggest, therefore, that EBV-specific CD8(+) CD45RA(+) T cells represent a stabilized virus-specific memory pool and not terminally differentiated effector cells. The identification of mechanisms that enable stable virus-specific CD8(+) T cells to persist after acute infection may lead to the enhancement of antiviral immunity in immunocompromised and elderly persons.     

EBV-associated mononucleosis leads to long-term global deficit in T-cell responsiveness to IL-15

In mice, interleukin-7 (IL-7) and IL-15 are involved in T-cell homeostasis and the maintenance of immunologic memory. Here, we follow virus-induced responses in infectious mononucleosis (IM) patients from primary Epstein-Barr virus (EBV) infection into long-term virus carriage, monitoring IL-7 and IL-15 receptor (IL-R) expression by antibody staining and cytokine responsiveness by STAT5 phosphorylation and in vitro proliferation. Expression of IL-7Ralpha was lost from all CD8+ T cells, including EBV epitope-specific populations, during acute IM. Thereafter, expression recovered quickly on total CD8+ cells but slowly and incompletely on EBV-specific memory cells. Expression of IL-15Ralpha was also lost in acute IM and remained undetectable thereafter not just on EBV-specific CD8+ populations but on the whole peripheral T- and natural killer (NK)-cell pool. This deficit, correlating with defective IL-15 responsiveness in vitro, was consistently observed in patients up to 14 years after IM but not in patients after cytomegalovirus (CMV)-associated mononucleosis, or in healthy EBV carriers with no history of IM, or in EBV-naive individuals. By permanently scarring the immune system, symptomatic primary EBV infection provides a unique cohort of patients through which to study the effects of impaired IL-15 signaling on human lymphocyte functions in vitro and in vivo.     

Epstein-Barr virus-associated T-/natural killer cell lymphoproliferative diseases

Epstein-Barr virus (EBV) is a ubiquitous virus that infects the majority of the world population by adulthood. The major target for infection is the B lymphocyte, and acute infection causes vigorous EBV-specific killer T-cell responses exemplified clinically by acute infectious mononucleosis (IM). EBV infection usually persists latently life-long without eliciting any clinical symptoms. Rarely, active EBV infection is prolonged, with abnormal expansions of EBV-infected T or NK cells, conditions collectively defined here as EBV-associated T/NK lymphoproliferative diseases. Hemophagocytic lymphohistiocytosis (HLH), chronic active EBV infection (CAEBV), NK lymphoma/leukemia, and T-cell lymphoma are entities included in this category. Hypersensitivity to mosquito bite (HMB) represents a unique syndrome characterized by expansion of EBV-infected NK cells in the peripheral circulation and within the inflammatory skin lesions induced by mosquito bites. Target cell specificity, defects in host immune responses, and strain differences of EBV may account for ectopic EBV infections and for the unique clinical presentations characteristic of each illness.     

Epstein-Barr virus and the elderly host

The ability of the Epstein-Barr virus (EBV) to cause latent lifelong infection in the host and its capabilities of transformation may have important implications for the elderly host. Reports in the literature and hospital records were reviewed to determine the activity of EBV in the elderly. Seroepidemiologic surveys demonstrated that 90%-97% of adults more than 60 years old were seropositive for EBV. Geometric mean antibody titers and the percentage of individuals with high antibody titers to EBV increased with age--changes that were not associated with clinical illness. Only 29 cases of infectious mononucleosis have been reported in adults more than 60 years old. The elderly with infectious mononucleosis had significantly fewer occurrences of pharyngitis, lymphadenopathy, and splenomegaly when compared with young adults. The cases of two patients with illnesses that did not meet full criteria for infectious mononucleosis but may still have represented clinical manifestations of EBV infection are presented. Other EBV-associated diseases reported in the elderly include nasopharyngeal carcinoma and possibly B cell lymphoproliferative disease but not a chronic mononucleosis-like syndrome.     

Heterophil-negative infectious mononucleosis and mononucleosis-like illnesses. Laboratory confirmation of 43 cases.

During a 50-month period the diagnosis of heterophil antibody negative infectious mononucleosis or of a mononucleosis-like illness was made in 43 patients with a variable clinical picture and significant numbers of atypical lymphocytes. Epstein-Barr virus (EBV)-related serologic tests revealed that seven patients had primary EBV infections based on the detection of immunoglobulin M (IgM) antibodies to EB-viral capsid antigens (IgM-VCA) and the absence of anti-Epstein-Barr virus associated nuclear antigen (EBNA) on most initial specimens (six of seven cases). Thirty cases were due to active cytomegalovirus (CMV) infections and both detectable CMV-macroglobulins (≧1:32) and significant anti-CMV titers were present by a complement fixation technic. Abnormalities in liver function were less marked in CMV than in EBV infections in age-matched subjects. Of the remaining six cases, one was due to rubella and one to toxoplasmosis. Four cases were of undetermined etiology. Serums from 38.1 per cent of the patients with heterophil-antibody positive infectious mononucleosis were found to “cross react” in the IgM-CMV test, but serums from patients with acute CMV infection did not cross react in the VCA-specific IgM test. In nine of 36 cases without heterophil antibody (six due to CMV, one due to toxoplasmosis and one apparent infectious hepatitis), anti-D or -R of the early-antigen (EA) complex was detected (1:10 to 1:40), raising the question of reactivation of the EBV-carrier state by intervening infections mainly of viral origin.     

Epstein-Barr virus: the hematologic and oncologic consequences of virus-host interaction

Varicella-zoster virus (VZV) and Epstein-Barr virus (EBV) are two of the human herpesviruses. The others include herpes simplex virus (HSV) type 1, HSV type 2, and cytomegalovirus (CMV). In a series of two articles, we review the clinical diseases caused by VZV and EBV infections; we pay particular attention to the manifestations of these two viral infections in immunosuppressed and immunocompromised patients. In addition to the clinical reviews, each of the two articles begins with a brief discussion of the molecular aspects of VZV and EBV, respectively; this introduction describes features of the genome and immunogenic viral proteins which have clinical relevance. A model for pathogenesis is included. The first review concerns VZV infections. Recent data about the DNA sequence of the entire VZV genome are included, as well as a review of the VZV glycoproteins. Primary VZV infection (chickenpox) and VZV reactivation (zoster) are described in detail in both healthy individuals and people with cancer. The decade-long VZV vaccine trials in children with leukemia receive special emphasis because they have engendered considerable interest and debate. The second review (published here) covers EBV infections. This virus has been implicated in the causation of a wide variety of human hematological and oncological disorders, besides classical infectious mononucleosis. In particular, Burkitt's lymphoma, nasopharyngeal carcinoma, and lymphoproliferative disorders are strongly associated with EBV infection of the transformed cells. In addition, immunologically mediated cytopenias occasionally follow EBV infection. Finally, treatment regimens with antiviral chemotherapy and other agents are discussed for both VZV and EBV infections.     

A prospective clinical study of Epstein-Barr virus and host interactions during acute infectious mononucleosis

BACKGROUND: Characterizing virus-host interactions during self-limited infectious mononucleosis could explain how Epstein-Barr virus (EBV) replication is normally controlled and provide insight into why certain immunocompromised patients fail to contain it. METHODS: University students had an average of 7 clinical and virologic evaluations during acute infectious mononucleosis. EBV was quantified in 697 samples of oral wash fluid, whole blood, peripheral blood mononuclear cells (PBMCs), and plasma by a real-time (TaqMan) polymerase chain reaction (qEBV) assay developed in our laboratory. RESULTS: Twenty of 25 subjects had serologically confirmed primary EBV infection. EBV was cleared from whole blood by a first-order process with a median half-life of 3 days, and its quantity was associated with severity of illness (r2=0.82). Oral shedding persisted at a median of >or=1x104 copies/mL for 32 weeks and was unrelated to severity of illness. Subjects with nonprimary EBV infection shed virus intermittently, and median quantities for all samples became undetectable within 4 weeks. CONCLUSIONS: Using a novel qEBV assay, we demonstrated that young adults with primary EBV infection rapidly cleared virus from blood but not from the oropharynx. High oral concentrations of EBV in asymptomatic persons who have resumed normal activities support the concept that infectious mononucleosis is most likely acquired by kissing.