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

Avidities of IgG directed against viral capsid antigen or early antigen: useful markers for significant Epstein-Barr virus serology

Classical Epstein-Barr virus (EBV) serology can be misleading in some cases due to the variability of the viral capsid antigen (VCA)-IgM response, persistent or reactivated VCA-IgM, or loss of anti-EBNA-1 during suppression of the cellular immune system. Therefore, we studied the usefulness and significance of avidity determinations of VCA-IgG and EA-IgG to achieve unequivocal interpretation of serological results. Avidities of EBV capsid antigen-specific IgG (VCA-IgG) and early antigen-specific IgG (EA-IgG) were determined by indirect immunofluorescence during and after acute EBV infection. Low-avidity antibodies were removed from antigen-antibody complexes by incubation with 6 M urea for 3 minutes. The analysis of 105 sera taken at defined time spans with regard to the onset of clinical symptoms allowed us to determine the kinetics of maturation of avidity of VCA-IgG. All sera had low-avidity antibodies at the onset of disease. More than 90% of the sera showed an avidity index below 0.25 during the first 10 days after the onset of disease. Fifty percent of the sera exhibited an avidity index of 0.25 or above 20-30 days after the onset of clinical symptoms. Sera from past infections uniformly exhibited avidity indices of 0.5 or 1. Avidity of EA-IgG may still be low when avidity of VCA-IgG is already borderline or high, thus allowing further differentiation of acute and recent infections. Avidity determination represents an important additional marker of serology in classical cases and allows diagnosis in aberrant cases, such as acute infections with low or undetectable VCA-IgM.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of FK-506 and cyclosporine regimens in pediatric renal transplantation

Clinical aspects of FK-506 or cyclosporine immunosuppression regimens were evaluated in 48 consecutive pediatric renal transplant recipients. Tapering and discontinuation of prednisone was employed only in children receiving FK-506 who experienced minor or no rejection episodes during the 1st posttransplant month. At 1 year follow-up, 17 of 22 (77%) of all children with functioning allografts were receiving no prednisone (n = 13) or a mean dosage of 0.07 mg/kg per day (n = 4). During the 1st month, acute cellular rejection was more common in the FK-506 group (0.58 vs. 0.21 rejections per patient, P < 0.05) but allograft survival (92%) and renal function at 1 year posttransplant were identical in both groups. Compared with the cyclosporine regimen, FK-506 immunosuppression may be associated with a higher incidence of cytomegalovirus or reversible Epstein-Barr virus-induced lymphoproliferative disease. However, the FK-506 group had less hirsutism and gingival hypertrophy and required fewer antihypertensive medications independent of steroid use. Height standard deviation scores and weight-for-height index improved only in pre-adolescents receiving FK-506 but no prednisone (P < 0.02 and P < 0.05, respectively), but did not differ between children on FK-506 plus prednisone and those in the cyclosporine group. We conclude that the major advantages of FK-506 over cyclosporine immunosuppression are a reduced severity of hypertension and an improved cosmetic appearance which may improve long-term medical compliance. When used as monotherapy, FK-506 also shows promise in relieving the growth retardation associated with cyclosporine regimens that include prednisone.

Suppression of human mononuclear cell response by Helicobacter pylori: effects on isolated monocytes and lymphocytes

Helicobacter pylori colonization of the human gastric mucosa causes a long-term, not self-limiting inflammation, suggesting that the microbe has properties to protect itself against the host immune defence system. Recently we were able to demonstrate that H. pylori suppresses the in vitro proliferative response of human peripheral blood mononuclear cells to antigens as well as to mitogens without affecting cell viability. The purpose of this study was to clarify which cell subsets of mononuclear cells are influenced by H. pylori. The use of monocytes which had been pretreated with a soluble cytoplasmic fraction of H. pylori (30 micrograms ml-1) led to a suppressed proliferation of T cells after PHA-activation. Activation of isolated T cells with PHA and PMA revealed that the proliferative response of lymphocytes could also be inhibited independently of monocytes. The anti-proliferative effect was associated with a reduction of IL-2 receptor (CD25) expression as well as an inhibition of blastogenesis. Furthermore, the spontaneous proliferation of EBV-transformed B cell lines was suppressed in a dose-dependent manner. FACS-analysis of HLA-DR, ICAM-1 and CD14 expression on the surface of monocytes revealed an influence of H. pylori on CD14 expression at a concentration of 30 micrograms ml-1, while the expression of HLA-DR and ICAM-1 was not affected at this concentration.

Manifestations of Epstein-Barr virus-associated disorders in liver

Epstein-Barr virus is a ubiquitous virus associated with a variety of different diseases and disorders. The manifestations of Epstein-Barr virus-associated diseases or disorders within the liver, which involve a broad spectrum of histologic and clinical features, ranging from hepatitis through lymphoproliferative disorders to lymphoma, are presented. An important aspect of Epstein-Barr virus expression and infection is the biology of the Epstein-Barr virus. Documentation of infection can be performed using serology to detect the interaction of Epstein-Barr virus with the immune system, and the detection of EBV proteins and use of molecular biologic techniques to identify the presence of EBV RNA, and DNA sequences. Of particular utility are in situ hybridization, Southern blot analysis, and polymerase chain reaction as diagnostic methods to identify specific RNA or DNA sequences. Epstein-Barr virus-associated diseases and disorders including infectious mononucleosis, sporadic fatal infectious mononucleosis, X-linked proliferative disorder (Duncan's disease), post-transplant lymphoproliferative disorders, lymphoma, and AIDS are discussed. The histopathologic findings present in liver associated with each disease are presented with illustrative examples. Handling the tissue and interaction with clinical services are also discussed as a method for appropriate diagnosis of Epstein-Barr virus-driven processes affecting the liver.

Prevalence of Taiwan variant of Epstein-Barr virus in throat washings from patients with head and neck tumors in Taiwan

The prevalence of the Epstein-Barr virus (EBV) Taiwan variant was investigated in the throat washing (TW) samples from patients with head and neck tumors, persons with nonmalignant diseases, and healthy adults in Taiwan. By using the EBV (BNLF-1 gene)-specific primers and PCR, the EBV latent membrane protein gene BNLF-1 was detected in 91 (61%) of the 150 TW samples from patients with tumors, including 25 (78%) of 32 patients with nasopharyngeal carcinoma and 66 (56%) of 118 other patients with head and neck tumors. The TW samples from the 26 patients with nonmalignant tumors and 53 healthy adults were also examined. Approximately 47% of these samples were positive for the EBV gene. The PCR products of the BNLF-1 gene were then subjected to XhoI digestion. Sixty-eight of 91 PCR products (75%) showed the loss of the XhoI site, which indicated the presence of a Taiwan strain of EBV in patients with tumors. The DNA sequence of the BNLF-1 gene of the Taiwan variant revealed that the loss of the XhoI site was due to a nucleotide change from a G to a T at position 169,426 in comparison with the sequence of prototype EBV B95-8 cells. Furthermore, the Taiwan strain appeared significantly more frequently in the TWs and tissue samples from patients with nasopharyngeal carcinoma (88%; P < 0.001) and laryngeal carcinoma (80%; P < 0.02) than in those samples from healthy adults (about 40%). These data indicate that a Taiwan variant of EBV may be closely associated with head and neck tumors and suggest that this variant may be important in the pathogenesis of head and neck tumors.

Evaluation of five enzyme immunoassays for detection of immunoglobulin M antibodies to Epstein-Barr virus viral capsid antigens

Five enzyme immunoassays for the detection of Epstein-Barr virus immunoglobulin M were evaluated versus indirect immunofluorescence assays with 128 serum specimens. The sensitivities and specificities, respectively, of these kits were as follows: Gull, 92 and 100%; Incstar, 53 and 100%; Ortho, 89 and 100%; Sigma, 78 and 86%; and BioWhittaker, 94 and 70%. Indeterminate results were produced by 2, 2, 0, 8, and 14 specimens with the Gull, Incstar, Ortho, Sigma, and BioWhittaker tests, respectively. The Gull and Sigma tests had the best day-to-day reproducibilities, and the Gull test was the easiest to use. No correlation between immunofluorescence titers and enzyme immunoassay values was observed.

HLA-B8,DR3 phenotype and the antibody response against Epstein-Barr virus

Antibodies against the viral capsid antigen (VCA) and nuclear antigens (EBNAs) of the Epstein-Barr virus (EBV) were determined in a sample of Sicilian population. A significant correlation was observed between HLA-B8,DR3 phenotype and reduced titres of antibodies to EBNAs, whereas HLA-B8,DR3 positive individuals displayed levels of antibodies to VCA comparable to those of HLA-B8,DR3 negative ones. These results further strengthen the suggestion that HLA-B8,DR3 positive subjects are low responders and that the depth of immune response depends on the fashion of antigenic challenge.

Detection of Epstein-Barr virus and human papillomavirus in head and neck tumors

The presence of Epstein-Barr virus (EBV) DNA and human papillomavirus (HPV) DNA in 74 head and neck tumor tissues was examined by the polymerase chain reaction and DNA sequencing analysis. EBV DNA sequence was detected in all 30 nasopharyngeal-carcinoma tissue samples and in 30 of 44 other head and neck tumor samples. HPV DNA sequence was detected in 14 of 30 nasopharyngeal-carcinoma tissue samples and in 11 of 44 other tumor samples. Coinfection of both viruses was observed in 14 nasopharyngeal-carcinoma tissue samples but only in 5 other head and neck tumor samples including 3 hypopharyngeal-carcinoma tissue samples. Our data indicate that EBV is closely associated with nasopharyngeal- carcinoma and may also be related to hypopharyngeal-carcinoma. In addition, a relatively high percentage of EBV-positive nasopharyngeal- and hypopharyngeal-carcinoma tissue specimens contained HPV sequence. The significance of the coexistence of EBV and HPV in these tumor tissues requires further study.

Epstein-Barr virus infection and associated diseases in children. II. Diagnostic and therapeutic strategies

Epstein-Barr virus (EBV), an ubiquitous human B lymphotropic virus, is the cause of infectious mononucleosis. Moreover, EBV infection can be followed by lymphoproliferative diseases in patients with inherited and acquired immunodeficiencies. Primary EBV infection may be a threat to all children after marrow or organ transplantation or those receiving chronic immunosuppressive treatment for various other reasons. The virus has been also implicated in the pathogenesis of different malignant tumours such as Burkitt lymphoma, nasopharyngeal carcinoma, Hodgkin disease and also some T-cell lymphomas. This review focuses on various aspects of virus-host interactions, immune mechanisms of the host, and the still experimental therapeutic approaches in EBV-associated diseases.

Epstein-Barr virus infection and associated diseases in children. I. Pathogenesis, epidemiology and clinical aspects

Epstein-Barr virus (EBV), an ubiquitous human B lymphotropic virus, is the cause of infectious mononucleosis. Moreover, EBV infection can be followed by lymphoproliferative diseases in patients with inherited and acquired immunodeficiencies. Primary EBV infection may be a threat to all children after marrow or organ transplantation or those receiving chronic immunosuppressive treatment for various other reasons. The virus has been also implicated in the pathogenesis of different malignant tumours such as Burkitt lymphoma, nasopharyngeal carcinoma, Hodgkin disease and some T-cell lymphomas. This review focuses on various aspects of virus-host interactions, immune mechanisms of the host, and the still experimental therapeutic approaches in EBV-associated diseases.

Primary immunodeficiency diseases and Epstein-Barr virus-induced lymphoproliferative disorders

Increased incidence of malignant disorders is noted in patients with both primary and acquired immunodeficiency diseases. The pathogenetic mechanism(s) for these disorders remain unclear. Defective immunosurveillance of these patients, however, is mainly postulated to be responsible for the increased risk of these malignant disorders. Of the malignant disorders, Epstein-Barr virus (EBV)-induced lymphoproliferative disorders (LPD) have been increasingly reported, possibly due to improved therapeutic management techniques such as bone marrow transplantation, which results in prolonged survival periods for the primary immunodeficiency; the dramatic development of immunosuppressive treatments for transplant recipients; and the growing numbers of acquired immunodeficiency syndrome (AIDS) patients. This review focuses on the primary immunodeficiency diseases and EBV-induced LPD, and discusses pathogenetic mechanism(s) for the increased incidence of these malignant disorders.

T lymphocyte anergy during acute infectious mononucleosis is restricted to the clonotypic receptor activation pathway

The transient T cell anergy associated with acute infectious mononucleosis (IM) caused by the Epstein-Barr virus has been analysed in a sample of 14 IM children. Peripheral blood mononuclear cells (PBMC) obtained from IM patients showed a significant specific impairment in their proliferative response to both phytohaemagglutinin (PHA; P less than 0.05) and to an anti-CD3 MoAb (P less than 0.001), although both responses reached normal control levels by addition of a submitogenic dose of either phorbol myristate acetate (PMA) or recombinant IL-2 (rIL-2). In contrast, activation signals delivered through other surface molecules (CD2, CD28) or other transmembrane pathways (PMA plus a calcium ionophore) elicited normal or high proliferative responses in most IM PBMC. In a group of five patients tested, the synthesis of IL-2 by IM PBMC in the presence of PMA was impaired when PHA or anti-CD3 was used as stimulus, but it reached normal levels with anti-CD2 or ionophore. Lastly, PHA failed to induce IL-2 alpha receptor (IL-2R alpha) expression in IM PBMC from four tested patients, but the presence of PMA completely corrected this defect. Taken together, these results strongly suggest that the T cell anergy associated with acute IM is due to a T cell receptor (TCR)-specific impairment in the induction of genes involved in T cell proliferation (including those coding for IL-2 and IL-2R alpha) upon membrane signalling to otherwise normal T lymphocytes, since CD2, CD28 and certain transmembrane activation pathways are uncoupled from CD3 in these particular pathological conditions (and perhaps in most in vivo situations). This and other similar experimental approaches to transient secondary immunodeficiencies may help to unravel the physiopathological role of different surface molecules in T cell activation.

Primary cerebral lymphoma: a study of 47 cases probed for Epstein-Barr virus genome

AIMS

To determine the prevalence of Epstein-Barr virus genome in primary cerebral lymphomas occurring in the absence of immune suppression.

METHODS

Forty eight consecutive patients with lymphomas restricted to the central nervous system were identified, all of whom had had neurosurgical biopsies performed at the National Hospitals for Neurology and Neurosurgery, London. Only five patients had some form of underlying immune deficiency; 43 were apparently normal. The tumours were studied with immunohistochemical markers and by in situ hybridisation, using a biotinylated probe to the internal repeat region of Epstein-Barr virus.

RESULTS

All the lymphomas were B cell in origin. Tumours from the five immunosuppressed patients all showed hybridisation, as did two of the "spontaneous" tumours.

CONCLUSIONS

This is the largest series of cerebral lymphomas so far probed for Epstein-Barr virus genome: as more are examined, it is suggested that a small proportion of the tumours from immunocompetent patients will also contain the virus.

Immunoglobulin production in severe combined immunodeficient (SCID) mice reconstituted with human peripheral blood mononuclear cells

Immunodeficient C.B-17 scid/scid (SCID) mice were reconstituted with human peripheral blood mononuclear cells and analyzed for humoral immunity. The majority of adoptively transferred animals had serum levels of 1-4 mg/ml of human IgG 8-12 weeks after i.p. reconstitution with 20 x 10(6) PBMC, whereas the IgM and especially IgA concentrations were considerably lower. The half-lives of human IgG, IgM, and IgA in SCID mice were 12 days, 36, and 23 hours, respectively. Furthermore, IgA was rapidly secreted into bile indicating that the low IgA concentration was mainly caused by a high turnover rate. IgG subclass distribution in mouse serum was similar to that found in the donor serum. Irradiation with 3 Gy prior to adoptive transfer resulted in increased levels of human IgG early after reconstitution, whereas both IgM and IgA concentrations were impaired. A polyclonal serum Ig pattern was found 4 weeks after transfer of human cells later frequently followed by a predominance of oligoclonal bands. Unexpectedly, oligoclonal bands were also found using donors with a negative Epstein-Barr virus serology. Human cells were found to reside in the peritoneal cavity for several months. Within 2 weeks of reconstitution, human cells were also identified in lymphoid structures in the vicinity of the liver hilus with a later spread to other lymphoid organs. Homing of human cells to skin and gut was not seen.

Effects of cyclosporine on human B-cell lymphoma development in vivo

Cyclosporine (CsA) is a potent immunosuppressive agent primarily affecting T-lymphocyte function. Patients receive CsA following organ transplantation to prevent rejection. These patients are at high risk for developing Epstein-Barr virus (EBV)-induced lymphoproliferative disease (LPD) or B-cell lymphoma (BCL). Severe Combined Immunodeficient (SCID) mice reconstituted with human peripheral blood leukocytes (PBL) develop fatal B-cell lymphomas of human origin following latent or active infection with EBV. This model was utilized to determine the role of CsA in the development of human BCL. SCID mice were reconstituted with PBL, latently or actively infected with EBV, and treated with CsA. Following active EBV infection, mice developed human BCL with or without CsA treatment. In contrast, treatment with CsA prevented the development of BCL in mice latently infected with EBV. This suggests a T-cell interaction with latently infected B-cells which is perturbed by CsA. Further understanding of this interaction and the occurrence of human BCL may allow the development of strategies to prevent, detect, or treat malignancies associated with immunosuppression.

The X-linked lymphoproliferative disease: from autopsy toward cloning the gene 1975-1990

Although X-linked lymphoproliferative disease (XLP) is rare (1-2 males per 1 x 10(6)), it serves as a model for discerning diverse diseases caused by Epstein-Barr virus (EBV) ranging from agammaglobulinemia to fatal infectious mononucleosis following infection with the virus. The study of patients with XLP has also paved the way to understanding how EBV induce diseases in children with primary immunodeficiency diseases, organ transplant recipients, and those with acquired immunodeficiency syndrome. This review is dedicated to the memory of Gordon Vawter, M.D., who generously provided insights into the causes of pathogenesis of immune deficiency and lymphoproliferative disorders.

Orthotopic liver transplantation, Epstein-Barr virus, cyclosporine, and lymphoproliferative disease: a growing concern

Lymphoproliferative disease (LPD) is a well-recognized complication of both solid organ and bone marrow transplantations. The occurrence of LPD in these settings is related in part to the use of the immunosuppressive agent cyclosporine. We report 12 cases of LPD after orthotopic liver transplantations in 132 pediatric patients. Lymphoproliferative disease occurred as one of three clinical syndromes: (1) lymphadenopathic, (2) systemic, and (3) lymphomatous. Effective management of LPD with excisional therapy or reduction of immunosuppressive medications or both resulted in the survival of 7 of 12 patients. In an alarming and increasing percentage of patients after orthotopic liver transplantation, progressive LPD develops with lethal outcome (5/12 patients). Early recognition of LPD and aggressive intervention may improve outcome in this group.

Detection of primary Epstein-Barr virus infection in a patient with X-linked lymphoproliferative disease receiving immunoglobulin prophylaxis

Serologic diagnosis for Epstein-Barr virus (EBV) infection is problematic when patients receive exogenous immunoglobulin. We recently diagnosed primary EBV infection by detecting EBV-determined nuclear antigen (EBNA) and EBV-DNA in peripheral blood mononuclear cells (PBMC) using immunofluorescence, in situ hybridization and polymerase chain reaction (PCR) techniques in a patient with X-linked lymphoproliferative disease (XLP) who received prophylactic immunoglobulins for EBV infection. These combined techniques may be helpful for early and accurate diagnosis of EBV infection in highly vulnerable patients.

SCID mouse model of Epstein-Barr virus-induced lymphomagenesis of immunodeficient humans

Immunodeficient humans are at very high risk of developing Epstein-Barr virus (EBV)-induced lymphomagenesis. Severe combined immunodeficient mice (SCID) have been shown to develop lymphoproliferative disease (LPD) following transfer of peripheral blood leukocytes (PBL) with latent EBV. To study mechanisms of lymphomagenesis, we compared results of engraftment of PBL from normal donors and immunodeficient donors with X-linked lymphoproliferative disease (XLP). Graft-versus-host disease (GVHD) developed in 6 of 10 SCID mice 4 to 8 weeks following transfer of PBL from normal donors. In contrast, none of 9 mice engrafted with PBL from XLP patients with T-cell defects showed GVHD. LPD developed in mice regardless of the immune competence of the donors. The expression of EBV-encoded proteins, results of immunophenotyping, and karyotyping of the LPD lesions revealed lethal oligoclonal LPD owing to transfer of latent EBV in B cells in mice engrafted with PBL from seropositive donors. Polyclonal LDP developed in mice engrafted with PBL from seronegative patients which were infected with B95-8 virus 6 weeks after transfer of the cells. This model is useful for investigating mechanisms of EBV-induced LDP in immunodeficient patients.

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.

Cytofluorimetric analysis of mitogen-activated peripheral blood lymphocytes of non-leukemic lymphoma patients reveals an abnormal disease-related expression pattern of activation antigens

The purpose of this study was to examine patterns of peripheral T-cell-activation antigen expression after polyclonal in vitro stimulation in early stages of lymphoproliferative diseases. With 18 patients afflicted with recently diagnosed, non-leukemic stages of B and T cell lymphoma cytofluorimetric analysis was performed with peripheral blood lymphocytes (PBL) after 72 h in culture with and without phytohemagglutinin, using antibodies against the differentiation antigens CD3, CD8, CD4, CD16, CD19, CDw14, and the activation antigens interleukin-2 receptor (IL-2R, CD25), HLA-DR (DR), CD56 and transferrin receptor (TR). Compared to healthy controls and patients with other diseases, a very significant reduction of large T cells bearing activation markers was found in all lymphoma cases. Furthermore, a pronounced inhibition in the expression of the activation markers IL-2R and TR, but not of DR, was detected on CD3+ cells in phytohemagglutinin-stimulated PBL of all lymphoma cells independently of DNA synthesis, as measured by [3H]thymidine uptake. Determination of the natural-killer-cell-(NK)-associated antigens CD16 and CD56, available for our studies in a CD16 + CD56 combination kit, revealed, after phytohemagglutinin stimulation, significantly increased expression values in 8 lymphoma patients so far investigated, as compared to 12 healthy controls. Thus, polyclonal activation combined with cytofluorimetric screening of activation antigens seems to give useful information on the functional defect(s) of PBL in an early state of lymphoma, and may therefore be of considerable diagnostic value. The observed pattern of T cell activation antigen expression after phytohemagglutinin stimulation may give further clues to the understanding of immune dysfunction(s) associated with lymphoma.

Detection of Epstein-Barr virus by polymerase chain reaction

The polymerase chain reaction (PCR) was used to study DNA extracted from the blood of 25 transplant patients, 5 patients with infectious mononucleosis, and 13 healthy subjects and autopsy or biopsy tissue from 29 patients with lymphoproliferative disorders. Primers were directed to conserved regions of the Epstein-Barr virus (EBV) genome encoding capsid protein gp220 and Epstein-Barr nuclear antigen 1. Specific EBV amplification was found in the blood of 11 of 25 transplant patients and all patients with infectious mononucleosis. All patients with lymphoproliferative disorders occurring in the presence of immunosuppression (eight organ transplant patients and two patients with acquired immunodeficiency syndrome) had biopsies positive for EBV by PCR. Only 1 of 19 samples from lymphomas or leukemias unrelated to immunosuppression contained EBV. PCR confirmed the very close association of EBV and lymphoproliferative disorders occurring in the presence of immunosuppression. The significance of detecting EBV sequences in the blood of transplant patients, particularly in relationship to lymphoproliferation, requires further study.

Characterization of Epstein-Barr virus-induced lymphoproliferation derived from human peripheral blood mononuclear cells transferred to severe combined immunodeficient mice

Mice with severe combined immunodeficiency (SCID) received 6 X 10(7) fresh human peripheral blood mononuclear cells (PBMC) intraperitoneally from Epstein-Barr virus (EBV)-seropositive and -seronegative donors. B95-8 EBV was inoculated intraperitoneally and intravenously to the mice 6 weeks after transfer of seronegative PBMC. Three of four mice transferred with PBMC from two EBV-seropositive donors and two of four mice from two EBV-seronegative donors inoculated with EBV developed fatal EBV-induced lymphoproliferative disease within 6 to 10 weeks. These tumors were oligoclonal or polyclonal by cytoplasmic immunoglobulin expression. Furthermore no consistent clonal chromosomal abnormalities were shown. Cell lines established from these tumors showed low cloning efficiency in soft agarose. In addition, latent membrane protein, B-lymphocyte activation antigen (CD23), and cell-adhesion molecules (ICAM-1, CD18) all were expressed in the EBV-positive infiltrating lymphoproliferative lesions in each mouse. These results suggest that lymphoid tumors are comparable to lymphoblastoid cell lines immortalized by EBV and are not malignant lymphomas such as Burkitt's lymphoma. This model may be useful for investigating mechanisms responsible for the growing numbers of lymphoproliferative diseases that are occurring in patients with inherited or acquired immunodeficiencies.

Adenovirus infection in patients with Kawasaki disease

Two outbreaks of Kawasaki disease at different times and areas (Kyoto in 1982 and Sapporo in 1985) of Japan were studied retrospectively for the presence of antibodies to adenoviruses and herpesviruses. Only 2 of 12 (16.7%) consecutive acute phase sera of patients from the outbreak in 1982 and 1 of 10 (10.0%) sera from 1985 showed positive antibodies for the common adenovirus antigen by a complement fixation (CF) test, whereas 10 of 16 (62.5%) age- and sex-matched controls during the outbreak of Kawasaki disease in 1985 were seropositive by the CF test. In contrast, using a recently developed enzyme-linked immunosorbent assay (ELISA), 9 patients (75.0%) in 1982 and 9 patients (90.0%) in 1985 had antibodies to adenovirus type 2. In addition, 5 of 10 (50.0%) of the 1982 and 6 of 9 (66.7%) of the 1985 patients who were seronegative for CF antibodies were positive for IgM antibodies to adenovirus type 2. Fifteen (93.8%) controls were positive for antibodies to adenovirus type 2 by ELISA and only two sera showed negative CF antibodies with positive IgM antibodies to adenovirus type 2. Sequential sera from 4 patients in 1985 had either IgM or IgG antibodies by ELISA and eventually three became seropositive by the CF test in time. Additionally, no significant difference was noted with antibody status to herpes simplex virus type 1 and 2 (HSV-1 and HSV-2), varicella zoster virus (VZV), and cytomegalovirus (CMV) between patients and controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Differential cellular susceptibility to Epstein-Barr virus infection in a patient with X-linked lymphoproliferative disease

Epstein-Barr virus (EBV) is often associated with lethal lymphoproliferative diseases in immunologically compromised individuals. Recently, we have studied a 20-month-old boy with X-linked lymphoproliferative disease (XLP) who had succumbed to infectious mononucleosis (IM) complicated by fulminant hepatitis and virus-associated hemophagocytic syndrome following EBV infection. EBV genomes were detected in peripheral blood lymphocytes (PBL), cervical and mesenteric lymph nodes, liver, spleen, thymus, and bone marrow. According to restriction endonuclease analyses, the EBV-DNA pattern was similar in all samples except for the EBV-DNA from the bone marrow. Additionally, circular EBV-DNA (suggesting a latent infection) predominated in spontaneously established lymphoblastoid cell lines (LCLs) derived from both the lymph node and cord lymphocytes co-cultured with PBL. In contrast, both circular and linear EBV-DNA (suggesting a lytic infection) were noted in spontaneously established LCLs derived from his PBL. Furthermore, LCLs derived from both the lymph node and cord lymphocytes co-cultured with PBL expressed fewer reactive cells for early antigen (EA) and viral capsid antigen (VCA) than spontaneous LCLs from his PBL, thus providing evidence for different B cellular susceptibility to EBV infection in this patient with XLP. Finally, defective EBV-specific cytotoxic T cell activity was observed in this patient. Latent EBV infected cells may easily escape immunosurveillance by the host. These findings may explain the fatal course of EBV infection in this patient.

Immunoserology of infectious diseases

The immune response to microorganisms not only participates in the elimination of unwanted organisms from the body, but also assists in diagnosis of infectious diseases. The nonspecific immune response is the first line of defense, assisting the body until the specific immune response can be mobilized to provide protective mechanisms. The specific immune response involves humoral or cell-mediated immunity or both, dependent on the nature of the organism and its site of sequestration. A variety of test systems have been developed to identify the causative organisms of infectious diseases. Test systems used in immunoserology have classically included methods of detecting antigen-antibody reactions which range from complement fixation to immunoassay methods. Relevant test systems for detecting antigens and antibodies are described. With numerous test systems available to detect antigens and antibodies, there can be confusion regarding selection of the appropriate system for each application. Methods for detecting antibody to verify immunity differ from immunologic methods to diagnose disease. Techniques to detect soluble antigens present in active infectious states may appear similar to those used to detect antibody, but their differences should be appreciated.

Immunovirological studies of fatal infectious mononucleosis in a patient with X-linked lymphoproliferative syndrome treated with intravenous immunoglobulin and interferon-alpha

We have studied a 19-year-old male with X-linked lymphoproliferative syndrome (XLP) and infectious mononucleosis (IM) who was treated with high-dose immunoglobulin (500 mg/kg/day) and recombinant interferon (IFN)-alpha (2 x 10(6) IU/m2/day). Fulminant hepatitis was delayed; however, virus-associated hemophagocytic syndrome, cholestatic jaundice, and renal failure occurred terminally. Initially, nonspecific natural killer (NK) cell activity against K562 cells was normal but it gradually decreased. Although reactive T cells were markedly increased in his blood during the acute phase, spontaneous EBV-positive cell lines were easily established. Additionally, his mononuclear cells produced IFN-gamma but not IFN-alpha prior to treatment. Based on results of in vitro studies, we conclude that both IFN-alpha and IFN-gamma production are likely necessary for inhibiting EBV immortalization in vitro. Both IFN-alpha and -gamma were produced in cultures of B95-8 EBV-infected mononuclear cells from EBV-seropositive healthy individuals. These results suggest that defective EBV-specific cytotoxic T cell activity accompanied with defective or discordant IFN-alpha and -gamma production permitted the development of fatal IM in this patient. Combined treatment with immunoglobulin and IFN-alpha appeared to be partially effective during the early stage of this disease.

Comparison of the classical immunofluorescent antibody tests for Epstein-Barr virus with commercially available test kits

Twenty reference sera with previously reported titers plus 10 normal seropositive and 10 seronegative sera were used to determine which assay for the detection of antibodies to Epstein-Barr virus should be utilized in our laboratory. By three commercially available test systems and by slides prepared in our laboratory, all techniques detected the same number of samples positive for IgG antibodies to viral capsid antigen (VCA) and Epstein-Barr virus-determined nuclear antigen (EBNA), but the geometric mean titers (GMTs) varied. Major discrepancies arose in the sensitivity of detection of early antigen-diffuse (EA-D) and -diffuse and restricted (EA-DR). Slides prepared in our laboratory gave the best results, detecting 12 of 12 (100%). Slides prepared according to Gull and Hillcrest detected 11 of 12 (92%), and those prepared according to Zeus detected 9 of 12 (75%). From these data, we conclude that all of these methods for detection of VCA and EBNA are adequate. However, in determining antibody levels to EA-D and EA-DR, great care should be taken as to the source of the slide and specificity and sensitivity.

Human herpesvirus 6 infection and Kawasaki disease

Eighteen of a total of 22 serum specimens (81.8%) from patients with Kawasaki disease were positive for immunoglobulin G or M antibodies to human herpesvirus 6, whereas 10 of 16 age- and sex-matched healthy controls (62.5%) were seropositive. Additionally, increased geometric mean antibody titers of immunoglobulin G were shown in these patients. These results suggest that the status of human herpesvirus 6 infection may be a reflection of the immunologic alterations that are associated with Kawasaki disease.

Interferon-gamma in a family with X-linked lymphoproliferative syndrome with acute Epstein-Barr virus infection

A 20-month-old male with fulminant infectious mononucleosis and the X-linked lymphoproliferative syndrome (XLP) was studied. Epstein-Barr virus (EBV)-determined nuclear antigen (EBNA) and EBV DNA were detected in various tissues. Despite a combined treatment with acyclovir, immunoglobulin, and methylprednisolone, the patient deteriorated rapidly. Following treatment with recombinant interferon-gamma (IFN-gamma), defervescence occurred and circulating EBNA-positive cells markedly decreased. IFN-gamma prior to treatment ranged from 10.8 to 24.5 U/ml in the patient's serum and increased linearly post exogenous IFN-gamma treatment. His natural killer (NK)-cell activity remained in the normal range throughout his illness but autologous EBV-infected cells were not killed in vitro by his peripheral blood lymphocytes (PBL). These results suggest that patients with the fatal infectious mononucleosis phenotype of XLP may produce endogenous IFN-gamma. Defective cytotoxic T cells against EBV-infected cells seem to be responsible for the fulminant infectious mononucleosis in this patient.