Activation of suppressor T cells during Epstein-Barr-virus-induced infectious mononucleosis

Continuous Label-Free Electronic Discrimination of T Cells by Activation State

The sensitivity and speed with which the immune system reacts to host disruption is unrivaled by any detection method for pathogenic biomarkers or infectious signatures. Engagement of cellular immunity in response to infections or cancer is contingent upon activation and subsequent cytotoxic activity by T cells. Thus, monitoring T cell activation can reliably serve as a metric for disease diagnosis as well as therapeutic prognosis. Rapid and direct quantification of T cell activation states, however, has been hindered by challenges associated with antigen target identification, labeling requirements, and assay duration. Here we present an electronic, label-free method for simultaneous separation and evaluation of T cell activation states. Our device utilizes a microfluidic design integrated with nanolayered electrode structures for dielectrophoresis (DEP)-driven discrimination of activated vs naïve T cells at single-cell resolution and demonstrates rapid (<2 min) separation of T cells at high single-pass efficiency as quantified by an on-chip Coulter counter module. Our device represents a microfluidic tool for electronic assessment of immune activation states and, hence, a portable diagnostic for quantitative evaluation of immunity and disease state. Further, its ability to achieve label-free enrichment of activated immune cells promises clinical utility in cell-based immunotherapies.

Limited Utility of Serology and Heterophile Test in the Early Diagnosis of Epstein–Barr Virus Mononucleosis in a Child after Renal Transplantation

Background: Epstein–Barr virus (EBV) infection is associated with significant morbidity and mortality in renal transplant (RT) recipients. The spectrum of illness ranges from infectious mononucleosis (IM) to post-transplant lymphoproliferative disorder (PTLD). In association with clinical signs and symptoms, virus-specific serology and heterophile antibody tests are widely used in confirming the diagnosis of IM in the general population. However, these tests may have a limited role in immunosuppressed RT recipients from seropositive donor, especially in children who were EBV-seronegative prior to the transplant. The aim of this study is to evaluate the utility of these tests in the early diagnosis of IM in this subset of patients. Methods: This is a case study with a review of literature. Results: Here, we present a 14-year-old male with hemophilia B who presented with fever, fatigue, sore throat, palatal petechial rash, exudative tonsillitis and cervical lymphadenopathy 3 months post-RT. He was EBV seronegative prior to RT and received a deceased donor kidney transplant from a seropositive donor. Induction was done with Thymoglobulin and maintenance immunosuppression consisted of tacrolimus and mycophenolate. Initial heterophile antibody test (monospot) was negative, but became positive at 5 months and remained positive at 9 months follow-up post-RT. EBV viral capsid antigens (VCA) IgM and IgG, early antigen (EA) and nuclear antigen (EBNA) were all negative at the time of presentation. VCA IgM and IgG both became positive at 5 months and peaked at 9 months follow-up, however the EA and EBNA remained negative. EBV viral load as measured by polymerase chain reaction (PCR) was negative for the first 3 months post-RT but became positive at presentation, peaked at 6 months and started declining thereafter. Peripheral blood smear examination showed no absolute and atypical lymphocytosis. Cytomegalovirus PCR in the blood and throat culture for streptococcus were negative. There was no splenomegaly. He was managed conservatively with intravenous fluids, bed rest, antipyretics and reduction of immunosuppression. Conclusions: EBV serological markers have a limited role in the early diagnosis of EBV-IM following RT in prior seronegative children. Initial heterophile antibody test may also be negative, and hence a repeat test may be necessary. Once becoming positive, the VCA IgM may remain persistently elevated for prolonged duration. In addition to the suppressed cellular immunity secondary to immunosuppression, humoral response to viral infections is also delayed in transplant recipients, especially in the early transplant period. Hence, routine monitoring with PCR is superior to serology in diagnosing IM early and monitoring the EBV infection post-RT for timely evaluation and management.

S-S-PEG-COOH Self-Assembled Monolayer on Gold Surface Enabled a Combined Assay for Serological EBV Antibody Isotypes

PURPOSE

Epstein-Barr virus (EBV) is a ubiquitous human gamma herpes virus that infects human epithelial cells and B lymphocytes. It would be potentially valuable to develop novel combined assays to benefit screening for large panels of samples of EBV infectious diseases.

EXPERIMENTAL DESIGN

A simple antigen-probed biochip that is modified with S-S-PEG-COOH and is used as a label-free high-throughput screening method for a combined detection of EBV capsid antigen IgM antibody, capsid antigen IgG antibody, and nuclear antigen IgG antibody.

RESULTS

This protein biochip has similar feasibility, sensitivity, and specificity in comparison with Liaison chemiluminescent immunoassay (CLIA). Detection limit of the EBV antibodies by the biochip is almost identical to that by CLIA-L (2.91 U mL^-1 vs 3.00 U mL^-1 for EBNA-1 IgG, 8 U mL^-1 vs10 U mL^-1 for EBV-VCA IgG, and 3.5 U mL^-1 vs 10 U mL^-1 for EBV-VCA IgM). Tests of the three serological antibodies against EBV by the biochip are consistent with the CLIA-L method in 274 clinical sera, respectively. Finally, the combined biochip is successfully utilized for diagnostic identification of EBV infection in 14 patients with infectious mononucleosis (IM) and 25 patients with systemic lupus erythematosus SLE, as well as additional 10 known real-time PCR positive patients.

CONCLUSIONS AND CLINICAL RELEVANCE

This biochip format will enable concurrent detection of antibodies against EBV infection and confirm infection status of EBV. It will be a versatile tool for large-scale epidemiological screening in view of its miniaturization and high throughput.

EBV-Specific Immune Response: Early Research and Personal Reminiscences

Early research on Epstein-Barr virus (EBV) developed from serological observations that were made soon after the discovery of the virus. Indeed, the definition of the humoral response to a variety of EBV proteins dominated the early literature and was instrumental in providing the key evidence for the association of the virus with infectious mononucleosis (IM), Burkitt's lymphoma (BL), and nasopharyngeal carcinoma (NPC). Each of these disease associations involved a distinct pattern of serological reactivity to the EBV membrane antigens (MA), early antigens (EA), and the EBV nuclear antigen (EBNA). When it became generally accepted that the marked lymphocytosis , which is a hallmark of acute IM, was dominated by T cells, considerable effort was directed toward untangling the specificities that might be associated with restricting the proliferation of newly infected B cells. Early evidence was divided between support for both EBV non-specific and/or HLA non-restricted components. However, all results needed to be reassessed in light of the observation that T cells died by apoptosis within hours of separation from fresh blood from acute IM patients. The observation that EBV-infected cultures from immune (but not non-immune) individuals began to die (termed regression) about 10 days post-seeding, provided the first evidence of a specific memory response which was apparently capable of controlling the small pool of latently infected B cells which all immune individuals possess. In this early era, CD8(+) T cells were thought to be the effector population responsible for this phenomenon, but later studies suggested a role for CD4(+) cells. This historical review includes reference to key early observations in regard to both the specific humoral and cellular responses to EBV infection from the time of the discovery of the virus until 1990. As well, we have included personal recollections in regard to the events surrounding the discovery of the memory T cell response since we believe they add a human dimension to a chapter focussed on early history.

A rare case of infectious mononucleosis complicated by guillain-barre syndrome

Infectious mononucleosis is a clinical syndrome characterized by fever, lymphadenopathy and pharyngitis. Neurologic complications of infectious mononucleosis, such as the development of Guillain-Barre syndrome, have been rarely reported and usually present late in the course of the disease. We describe a case of a 29 year old male with no significant past medical history who was diagnosed with Guillain-Barre syndrome following an infection with Epstein-Barr virus associated infectious mononucleosis. Supportive treatment resulted in full recovery.

Rituximab and cyclosporine therapy for accelerated phase Chediak-Higashi syndrome

A 19-month-old male with Chediak-Higashi syndrome developed Epstein-Barr virus (EBV)-associated accelerated phase. Real-time polymerase chain reaction showed high EBV-DNA levels in plasma and peripheral blood mononuclear cells. His condition was refractory to conventional treatments for hemophagocytic lymphohistiocytosis, including corticosteroids, cyclosporine, and etoposide. In situ hybridization revealed higher proportion of EBER-1-positive cells in CD19+ cell fraction than in CD8+ cell fraction. Complete remission was achieved by combination therapy with rituximab and cyclosporine; subsequent bone marrow transplantation was successful. Combination therapy with rituximab and cyclosporine could be effective in patients with EBV-infected T and B cells.

Epigenetic dysregulation of epstein-barr virus latency and development of autoimmune disease

Epstein-Barr virus (EBV) is ahumanherpesvirus thatpersists in the memory B-cells of the majority of the world population in a latent form. Primary EBV infection is asymptomatic or causes a self-limiting disease, infectious mononucleosis. Virus latency is associated with a wide variety of neoplasms whereof some occur in immune suppressed individuals. Virus production does not occur in strict latency. The expression of latent viral oncoproteins and nontranslated RNAs is under epigenetic control via DNA methylation and histone modifications that results either in a complete silencing of the EBV genome in memory B cells, or in a cell-type dependent usage of a couple of latency promoters in tumor cells, germinal center B cells and lymphoblastoid cells (LCL, transformed by EBV in vitro). Both, latent and lytic EBV proteins elicit a strong immune response. In immune suppressed and infectious mononucleosis patients, an increased viral load can be detected in the blood. Enhanced lytic replication may result in new infection- and transformation-events and thus is a risk factor both for malignant transformation and the development of autoimmune diseases. An increased viral load or a changed presentation of a subset of lytic or latent EBV proteins that cross-react with cellular antigens may trigger pathogenic processes through molecular mimicry that result in multiple sclerosis (MS), systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA).

Pure red cell aplasia in a patient with trisomy X chromosome abnormality and reactivated Epstein-Barr virus infection

We describe a woman with a congenital chromosome anomaly, 47,XXX, who developed chronic pure red cell aplasia (PRCA). The patient had serologic reactivity consistent with that of reactivated Epstein-Barr virus (EBV) infection, as judged by high titers for anti-EBV viral capsid antigen (VCA) immunoglobulin G (IgG) and anti-early antigen (EA) IgG. Detection of EBV genome in peripheral blood cells and cell-free serum also supported the diagnosis. Although EBV infection has been implicated in the pathogenesis of acute PRCA, the viral infection rarely results in a chronic disease state. So far, only 1 case of EBV-associated chronic PRCA has been reported, to the best of our knowledge. Chronic PRCA also is known to occur on an autoimmune basis. Individuals carrying an extra X chromosome, such as XXY and XXX, are prone to development of immune abnormalities. Our patient had an anti-DNA autoantibody and a positive result of the direct Coombs test. The pathogenesis of PRCA in this case seemed to involve multiple factors. In addition to the infectious agent, host factors may have played a role. Although the etiologic link between chronic PRCA and trisomy X remains to be elucidated, our findings suggest the importance of karyotype analysis as well as search for infectious agents in patients with chronic PRCA.

Systemic lupus erythematosus and B-cell hematologic neoplasm

The association of systemic lupus erythematosus (SLE) and B-cell malignancy is widely reported in the literature. Here we report nine cases of concurrent of SLE or discoid lupus erythematosus (DLE) and lymphoma or plasma cell disorder. A MEDLINE search was done using the keywords, 'SLE' and 'lymphoma' and the characteristics of all identified cases were summarized and analyzed, along with data from our own cases. Numerous variants of B-cell malignancies were encountered in these patients. B-cell malignancy occurs after the diagnosis and treatment of SLE in most reported cases, although it may precede SLE, or occur synchronously with it. The age at onset of the B-cell neoplasm in SLE patients is similar to that in the general population. Mortality in patients with both diseases is associated with progressive B-cell neoplasm, sepsis secondary to either disease, or both. B-cell malignancy and SLE seem to run independent clinical courses rather than being affected by each other. The use of immunosuppressive drugs is common in patients with SLE diagnosed prior to B-cell lymphoma, arguing that the effect of immunosuppression on the pathogenesis of lymphoma can not be excluded. Three areas worthy of study regarding the probable mechanisms for the occurrence of SLE and B-cell malignancies are discussed. A tumor suppressor gene PTEN may link the two disorders via a defective apoptosis pathway to eliminate hyperactive B and T cells in SLE. The accumulation of clonally expanded hyperactive B-cells that recognize self-antigens in the lymph nodes of SLE may predispose these B-cells to DNA breaks, facilitating tumorigenesis. Lastly, EBV infection, found to have a high prevalence in SLE patients, may serve as a common etiological factor in both disorders.

Herpesviruses in HIV-periodontitis

BACKGROUND/AIMS

Human herpesvirus-associated diseases exhibit elevated morbidity and mortality in patients infected with human immunodeficiency virus (HIV). This study aimed to investigate the occurrence of herpesviruses in HIV-periodontitis.

METHOD

Gingival biopsies from periodontitis lesions of 21 HIV-patients and 14 non HIV-patients were studied. Nested-polymerase chain reaction methods were employed to detect human cytomegalovirus, Epstein-Barr virus type 1 and 2 (EBV-1, EBV-2), herpes simplex virus, human herpes virus (HHV)-6, HHV-7 and HHV-8.

RESULTS

Gingival biopsies from HIV-periodontitis lesions showed on average 4.0 herpesvirus species and gingival biopsies from HIV periodontitis lesions of non-HIV patients revealed an average of 1.9 herpesvirus species (p<0.001). Occurrence of 4 to 6 different herpesviruses was more common in HIV- than in non HIV-gingival biopsies (71% vs. 7%) (p<0.001). EVB-2 was detected in 12 (57%) biopsies from HIV-periodontitis but was absent in non HIV-periodontitis biopsies (p= 0.002). HHV-6 also occurred in significantly higher frequency in HIV-periodontitis (71%) than in non HIV-periodontitis (21%) (p=0.01). HHV-8 was detected only in biopsies from HIV-periodontitis lesions..

CONCLUSION

HIV-periodontitis seems to be associated with elevated occurrence of EBV-2, HHV-6 and herpesvirus co-infections compared to periodontitis in non-HIV-patients. The periodontopathic significance of herpesviruses in HIV-periodontitis constitutes a research topic of considerable interest.

Epstein-Barr virus infection in the pathogenesis of nasopharyngeal carcinoma

The association of nasopharyngeal carcinoma (NPC) with the Epstein-Barr virus (EBV) was firmly established as early as 1973. Nevertheless, the role for the virus in the pathogenesis of NPC is still controversial. In this article, the evidence implicating EBV in the development of NPC is reviewed, focusing on the cellular site of EBV persistence, the association of the virus with different NPC histotypes, the tumour cell phenotype in the context of viral latent gene expression, and the possible role of the lymphoid stroma.

Virus-induced immune dysregulation as a triggering factor for the development of drug rashes and autoimmune diseases: with emphasis on EB virus, human herpesvirus 6 and hepatitis C virus

There are a considerable amount of empirical and theoretic medical literature regarding the possible role of viruses in the development of drug rashes and autoimmune diseases: under these conditions, interactions of viruses with the immune system would serve as an accelerating factor of disease pathogenesis. Recent reports have provided evidence to indicate that immune responses against infections with Epstein Barr (EB) virus and human herpesvirus 6 (HHV-6), which are lymphotropic members of the herpes virus group, not only aid the direct elimination of the virus but also contribute to a favorable milieu for the initiation or acceleration of drug rashes. Viruses that can persist for the lifetime of the host despite strong immune responses against them, such as EB virus and hepatitis C virus (HCV), would be also relevant to the pathogenesis of autoimmune diseases. HCV has been reportedly associated with a wide variety of dermatoses that, in common, show histologically the lichenoid tissue reaction. Although porokeratosis that manifests lichenoid histopathological features had long been regarded as being associated with immunosuppression, we found that HCV could act as trigger for the development of porokeratosis during states of immunosuppression. Thus, the main purpose of this review is to describe recent work on the etiology of drug rashes and autoimmune disease with special reference to viral infections.

Strong response of T cells in infants with dual infection by Epstein-Barr virus and cytomegalovirus

BACKGROUND

Although a reversed CD4/CD8 ratio and increased proportion of CD8+ HLA-DR+ T cells are well known as the characteristic immune response in infectious mononucleosis (IM), it has not been elucidated whether these immune responses are affected by patient age and pathogenetic viruses.

METHODS

T cell subsets were analyzed by two-color flow cytometry using fluorescein isothiocyanate- and phycoerythrin-conjugated monoclonal antibodies in 115 infants and children aged from 4 months to 10 years with IM due to Epstein-Barr virus (EBV), cytomegalovirus (CMV) and dual infection with both viruses.

RESULTS

A reversed CD4/CD8 ratio and increased proportions of CD4+/HLA-DR+ T cells, CD8+ T cells and CD8+/HLA-DR+ T cells became more prominent as the age of the patients became older. No differences were observed in proportions of T cell subsets between EBV- and CMV-infection among patients aged from 6 to 17 months. Although the responses of these T cells were weak in infants with single virus infection by EBV and CMV, markedly strong T cell responses comparable with those in older children were observed in infants with EBV/CMV dual infection. Clinical symptoms were more severe in patients with EBV/CMV dual infection than those with EBV or CMV alone.

CONCLUSION

The manner of these T cell responses in the acute phase of IM was considered to be age dependent, although strong T cell responses and severe disease were observed in EBV/CMV dual infection irrespective of patient age.

Herpesvirus infection of inflammatory cells in human periodontitis

Human cytomegalovirus (HCMV) and Epstein-Barr virus type 1 (EBV-1) are frequently detected in human periodontitis lesions. However, no information is available on the types of gingival cells infected by herpesviruses. The present study determined the presence of herpesviruses in polymorphonuclear neutrophils, monocytes, macrophages and T and B lymphocytes in biopsies of periodontitis lesions from 20 adults. A nested polymerase chain reaction method was employed to detect HCMV, EBV-1, EBV-2, human herpes virus-6 and herpes simplex virus (HSV) in periodontal tissue biopsy and in gingival cell fractions separated by immunomagnetic cell sorting. Tissue specimens from 18 (90%) and cell fractions from 14 (70%) patients demonstrated herpesviruses. Periodontitis-derived monocytes and macrophages revealed HCMV in cell fractions from 11 (55%) patients and HSV in cells from 1 (5%) patient. T lymphocytes harbored HCMV in cell fractions from 4 (20%) patients and HSV in cell fractions from 4 (20%) patients. B lymphocytes showed EBV-1 in cell fractions from 9 (45%) patients. Periodontal polymorphonuclear neutrophils demonstrated no herpesviruses. This study suggests that HCMV mainly infects periodontal monocytes, macrophages and less frequently T lymphocytes and that EBV-1 infects periodontal B lymphocytes. The possible etio-pathologic significance of periodontal herpesvirus infection is discussed.

Relationship between herpesviruses and adult periodontitis and periodontopathic bacteria

BACKGROUND

Various mammalian viruses and specific bacteria seem to play important roles in the pathogenesis of human periodontitis. This study examined the relationship between subgingival herpesviruses and periodontal disease and potential periodontopathic bacteria in 140 adults exhibiting either periodontitis or gingivitis.

METHODS

A nested-polymerase chain reaction (PCR) method determined the presence of Epstein-Barr virus type 1 and type 2 (EBV-1, EBV-2), human cytomegalovirus (HCMV), and herpes simplex virus (HSV) and a 16S rRNA PCR detection method identified Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Bacteroides forsythus, Prevotella intermedia, Prevotella nigrescens, and Treponema denticola.

RESULTS

Using a logistic analysis, EBV-1 showed significant positive association with P. gingivalis (odds ratio [OR] 3.37), and with coinfections of P. gingivalis and P. intermedia (OR 4.03); P. gingivalis and B. forsythus (OR 3.84); P. gingivalis and T. denticola (OR 4.17); P. gingivalis, B. forsythus, and T. denticola (OR 4.06); and P. gingivalis, P. nigrescens, and T. denticola (OR 3.29). EBV-1 also showed positive association with severe periodontitis (OR 5.09), with increasing age (OR 1.03), and with periodontal probing depth at the sample sites (OR 1.77). HCMV was positively associated with coinfections of P. gingivalis and P. nigrescens (OR 3.23); P. gingivalis, B. forsythus, and P. nigrescens (OR 3.23); and P. gingivalis, P. nigrescens, and T. denticola (OR 2.59); with severe periodontitis (OR 4.65); and with age (OR 1.03). Patients with mixed viral infections revealed significant associations with P. gingivalis (OR 2.27), and with coinfections of P. gingivalis and B. forsythus (OR 2.06); P. gingivalis and P. nigrescens (OR 2.91); P. gingivalis, B. forsythus, and P. nigrescens (OR 2.91); and P. gingivalis, P. nigrescens, and T. denticola (OR 2.70) with the clinical diagnosis of slight (OR 3.73), moderate (OR 3.82), or severe periodontitis (OR 4.36), and with probing depth at the sample sites (OR 1.39). HSV and EBV-2 showed no significant associations with any of the variables tested.

CONCLUSIONS

The results indicate that subgingival EBV-1, HCMV, and viral coinfections are associated with the subgingival presence of some periodontal pathogens and periodontitis. Herpesviruses may exert periodontopathic potential by decreasing the host resistance against subgingival colonization and multiplication of periodontal pathogens.

Inactivating mutations in an SH2 domain-encoding gene in X-linked lymphoproliferative syndrome

X-linked lymphoproliferative syndrome (XLP) is an inherited immunodeficiency characterized by increased susceptibility to Epstein-Barr virus (EBV). In affected males, primary EBV infection leads to the uncontrolled proliferation of virus-containing B cells and reactive cytotoxic T cells, often culminating in the development of high-grade lymphoma. The XLP gene has been mapped to chromosome band Xq25 through linkage analysis and the discovery of patients harboring large constitutional genomic deletions. We describe here the presence of small deletions and intragenic mutations that specifically disrupt a gene named DSHP in 6 of 10 unrelated patients with XLP. This gene encodes a predicted protein of 128 amino acids composing a single SH2 domain with extensive homology to the SH2 domain of SHIP, an inositol polyphosphate 5-phosphatase that functions as a negative regulator of lymphocyte activation. DSHP is expressed in transformed T cell lines and is induced following in vitro activation of peripheral blood T lymphocytes. Expression of DSHP is restricted in vivo to lymphoid tissues, and RNA in situ hybridization demonstrates DSHP expression in activated T and B cell regions of reactive lymph nodes and in both T and B cell neoplasms. These observations confirm the identity of DSHP as the gene responsible for XLP, and suggest a role in the regulation of lymphocyte activation and proliferation. Induction of DSHP may sustain the immune response by interfering with SHIP-mediated inhibition of lymphocyte activation, while its inactivation in XLP patients results in a selective immunodeficiency to EBV.

Recurrent hepatosplenomegaly and peripheral blood cytopenia, persistent Epstein-Barr virus infection and central nervous system manifestation in a patient with lymphadenopathy and low serum uric acid

We describe a 27-month-old boy who was first admitted to our hospital on 7 January 1995 with nasal bleeding. From 6 months of age he has had lymphadenopathy, low levels of serum uric acid, increased levels of serum lactate dehydrogenase and hyper gamma-globulinemia. From the age of 18 months he has had persistent Epstein-Barr virus (EBV) infection (target cells; B cells), recurrent episodes of thrombocytopenia, anemia and hepatosplenomegaly. Dysmobility of the left leg and arm from a central nervous system complication during a relapse with pancytopenia on March 1995, was also observed. Relapses of thrombocytopenia with increases of platelet-associated immunoglobulin G and hepatosplenomegaly have been observed approximately every 2 months, and two relapses of pancytopenia were accompanied with weak positivity of Coombs test and low level of haptoglobin. These recurrent episodes were improved with prednisolone. However, now in June 1997 we have not been able to diagnose what underlies the above clinical symptoms, except that the patient has a persistent EBV infection.

Characteristics and responses of EBV immortalized B cells from periodontal disease patients

OBJECTIVE

This study was designed to examine human B cell responses to Actinobacillus actinomycetemcomitans (Aa). The general hypothesis to be tested was that Epstein-Barr virus (EBV) immortalized B cells could be used to investigate variations in B cell responsiveness of periodontitis patients to periodontal pathogens, and that B cells derived from the peripheral blood of periodontal disease patients infected with Aa demonstrate differences in in vitro activities compared to periodontally healthy subjects.

DESIGN

EBV-transformed B cell lines were used to analyze immunoglobulin and Aa-specific antibody responses, as well as to determine the frequencies of cells producing immunoglobulin (Ig) of a specific isotype and detect clones secreting antibodies specific for Aa. Lymphoblastoid cells lines (LCL) were derived by clonal transformation of peripheral blood lymphocytes from 10 Aa-infected patients with adult periodontitis (Aa-AP) and seven normal subjects.

METHODS

The B cells were incubated in Aa-coated polystyrene plates to separate adherent and non-adherent cells, and stimulate the cells with the whole bacteria. In addition, the B cells were stimulated with Aa LPS, E. coli LPS, or the polyclonal B cell activators (PBAs), pokeweed mitogen (PWM) and Staphylococcus aureus protein A (SpA). Both adherent and non-adherent cell populations were cultured for up to 15 days.

MAIN OUTCOME MEASURE

Total immunoglobulins (Igs) and antibody (IgG, IgA, IgM) levels to Aa in the culture supernatants were assessed using an ELISA. The distribution of IgG, IgA, IgM and Aa-specific antibody producing cells was analyzed by a double immunoenzymatic staining technique.

RESULTS

IgM levels produced by the LCLs were significantly increased vs IgG and IgA (P < 0.001). Three days after Aa stimulation, a marked increase in the level of total Igs and Aa-specific antibody was observed in adherent cells from Aa-AP (P < 0.05-0.03). Aa-specific antibody levels were significantly higher in the supernatants from Aa-AP vs normals throughout the culture interval (P < 0.03). There was also a significant increase in Aa-specific antibody levels after stimulation with Aa LPS or E. coli LPS (P < 0.05), whereas PWM and SpA had no significant effect on antibody to Aa. There was a predominance of IgM cells compared to IgG and IgA isotypes (P < 0.04) in LCLs from Aa-infected patients. After stimulation with Aa, a significant increase in the number of IgA (111%) and IgG (48%) secreting cells was observed, concomitant with a 74% decrease in the Ig-negative cell population. Total Aa+ cells increased significantly after stimulation (P < 0.001), predominated by Aa-specific IgG and IgM antibody producing cells.

CONCLUSIONS

These results showed that LCLs from Aa-infected patients were polyclonal with respect to isotype distribution. Further stimulation with Aa revealed a shift to cytoplasmic IgG and IgA expression, as well as increases in the Aa-specific B cell population. In contrast, the PBAs stimulated the LCLs to synthesize primarily IgM. Additionally, the findings indicated that: (1) without T cells, polyclonal activation of B cells may lead to elevated Aa-specific B cell populations; and (2) the presence of previously sensitized B cells is required to exert an antigen specific antibody response in the LCL. We conclude that secondary activation of primed B cells by oral bacteria or their products in advanced periodontal lesions may contribute to the local accumulation of significant numbers of Ig-producing cells. This report also suggested that EBV-mediated transformation can be used to probe B cell-bacterial interactions in studies of periodontitis.

Human Herpesviridae in acute necrotizing ulcerative gingivitis in children in Nigeria

Herpesviruses have been implicated in the pathogenesis of human periodontitis. The present study investigated whether herpesviruses are present in the lesions of acute necrotizing ulcerative gingivitis. Sixty-two Nigerian children, aged 3-14 years, were studied. Twenty-two children had acute necrotizing ulcerative gingivitis and were also malnourished, 20 exhibited no acute necrotizing ulcerative gingivitis but were malnourished and 20 were free of acute necrotizing ulcerative gingivitis and in a good nutritional state. Polymerase chain reaction methods were used to determine the presence of human cytomegalovirus (HCMV), Epstein-Barr virus type 1 and type 2 (EBV-1, EBV-2), herpes simplex virus (HSV), human herpes virus 6 (HHV-6), human papilloma virus and human immunodeficiency virus type 1 in crevicular fluid specimens collected by paper points. Of the 22 acute necrotizing ulcerative gingivitis patients, 15 (68%) revealed viral infection and 8 (36%) viral coinfection. Thirteen (59%) acute necrotizing ulcerative gingivitis patients demonstrated HCMV, 6 (27%) EBV-1, 5 (23%) HSV and 1 (5%) HHV-6. Only 2 (10%) subjects from each group not affected by acute necrotizing ulcerative gingivitis showed viral presence, and no control subject revealed viral coinfection. These findings suggest that HCMV and possibly other herpesviruses contribute to the onset and/or progression of acute necrotizing ulcerative gingivitis in malnourished Nigerian children.

Epstein-Barr virus (EBV) infection in infectious mononucleosis: virus latency, replication and phenotype of EBV-infected cells

Primary Epstein-Barr virus (EBV) infection may manifest itself as a benign lymphoproliferative disorder, infections mononucleosis (IM). EBV infection has been characterized in lymphoreticular tissues from nine patients with IM using the abundantly expressed EBV-encoded nuclear RNAs (EBERs) as a marker of latent infection. Expression of the virus-encoded nuclear antigen (EBNA) 2 and of the latent membrane protein (LMP) 1 was seen in variable proportions of cells in all cases. Double labelling revealed heterogeneous expression patterns of these proteins. Thus, in addition to cells revealing phenotypes consistent with latencies I (EBNA2-/LMP1-) and III (EBNA2+/LMP1+), cells displaying a latency II pattern (EBNA2-/LMP1+) were observed. Cells expressing EBNA2 but not LMP1 were also detected; whilst this may represent a transitory phenomenon, the exact significance of this observation is at present uncertain. EBER-specific in situ hybridization in conjunction with immunohistochemistry revealed expression of the EBERs mainly in B-lymphocytes, many of which showed features of plasma cell differentiation. By contrast, convincing evidence of latent EBV infection was not found in T-cells, epithelial or endothelial cells. Double-labelling immunohistochemistry revealed expression of the replication-associated BZLF1 protein in small lymphoid cells, often showing plasmacytoid differentiation. There was no unambiguous expression of this protein in other cell types. These results suggest that B-cells are the primary target of EBV infection and that plasma cells may be a source of infectious virus found in the saliva of IM patients.

Biology and adoptive cell therapy of Epstein-Barr virus-associated lymphoproliferative disorders in recipients of marrow allografts

Epstein-Barr virus (EBV) is an ubiquitous herpesvirus which is carried as a latent infection of B lymphocytes and salivary gland epithelial cells in over 90% of normal adults. Latently infected EBV-transformed B cells circulate at low frequency in the blood for the life of the host. These transformed B cells stimulate a heterogeneous and complex host cell response, ultimately leading to the development and maintenance of high frequencies of HLA-restricted T cells specific for the EBV-encoded nuclear antigens EBNA2-EBNA6 and the latency membrane proteins LMP-1 and LMP-2. Responses to latent EBV-encoded proteins are hierarchical with responses to certain epitopes predominating, dependent upon the HLA genotype of the host. Profound suppression of T-cell immunity may permit the emergence of polyclonal, oligoclonal or monoclonal EBV antigen-expressing lymphoproliferative disorders or malignant B-cell lymphomas expressing these latent EBV antigens. Adoptive transfer of small numbers of peripheral blood mononuclear cells or HLA-partially matched T cells from in vitro expanded EBV-specific T-cell lines derived from a seropositive marrow donor has induced durable regressions of bulky, widely metastatic monoclonal EBV lymphomas in a high proportion of cases. This review describes the current state of knowledge and hypothesis regarding the biology and immunology of EBV infection in the normal host, the features of donor, host and virus which contribute to the development of EBV-associated lymphoproliferative diseases and the mechanisms whereby they are controlled by adoptive transfer of immune T cells.

Mammalian viruses in human periodontitis

A prior investigation has demonstrated a higher prevalence of human cytomegalovirus (HCMV) and Epstein-Barr virus (EBV) in subgingival specimens from periodontitis patients than from gingivitis patients. This study aimed to determine the frequency of HCMV, EBV-1, EBV-2, herpes simplex virus (HSV) and human immunodeficiency virus (HIV) in subgingival samples from 27 adults who each contributed both a periodontitis and a gingivitis site. Viral detection was performed using a nested-polymerase chain reaction method. Twenty-four subjects (89%) yielded at least one of the five test viruses from deep periodontal pockets, whereas only 15 (56%) showed viruses from shallow periodontal sites (P = 0.015; chi-square test). Viral co-infection occurred more frequently in deep than in shallow periodontal sites (P = 0.015). HCMV was detected with higher frequency in deep than in shallow periodontal sites (P = 0.023). The possible periodontopathogenic mechanisms of mammalian viruses in human periodontitis are discussed. The role and importance of HCMV and other mammalian viruses in the initiation and progression of destructive periodontal disease merits further investigation.

HCV infection in a patient with hyper IgM syndrome

The association between an acquired form of hyper-IgM syndrome and a chronic hepatitis C virus (HCV) infection in a 71-year-old female patient is described. Both diseases were diagnosed at the age of 58 years. She was started on intramuscular and then intravenous immunoglobulin replacement therapy. HCV RNA was detected in 1992. The patient remained in well-balanced clinical condition until 1994, when total and specific anti-HCV IgM levels increased and the patient developed an IgM kappa monoclonal gammopathy. Adherent cells and B cells were HCV RNA positive, while T cells were HCV RNA negative. Anti-IgM reactivity was specifically directed to the core antigen of the HCV. The patient we describe showed a picture of a late-onset form of hypogammaglobulinemia with a progressive increase in IgM antibodies, possibly due to the concomitant HCV infection. It is possible that the immunodeficiency might also result from the HCV infection, with formation of specific antibodies belonging to the IgM class, and that the worsening of the clinical condition may be directly related to the persistent viral infection.

Analysis of a family containing three members with common variable immunodeficiency

BACKGROUND

Common variable immunodeficiency (CVID), a diverse immunodeficiency syndrome characterized by low immune globulin levels and recurrent infections, has been observed in families with the HLA A1 B8 DR3 haplotype.

METHODS

We report a two-generation family with three members affected by CVID. Immunoglobulin levels, antibody titers, lymphocyte marker analyses, T cell proliferation assays, and HLA typing were performed on the affected family members.

RESULTS

Studies of the affected patients revealed low levels of immunoglobulin G and A; normal tetanus, rubella and rubeola antibody titers; low B cell numbers; normal T cell numbers; normal CD4/CD8 ratios and normal lymphocyte proliferation studies. HLA typing did not reveal the HLA A1 B8 DR3 haplotype previously associated with familial CVID.

CONCLUSION

We report a family with a unique presentation of CVID involving possible genetic inheritance other than the HLA A1 B8 DR3 haplotype and possessing lymphocyte characteristics distinct from those usually seen in sporadic CVID.

Epstein-Barr virus infection associated with interstitial nephritis and chronic fatigue

Severe renal disease in the setting of Epstein-Barr virus (EBV) infection is exceedingly rare. We report here the case of a 22-year-old man with acute EBV infection associated with severe interstitial nephritis. The patient developed chronic fatigue and chronic renal failure with a serological profile typical of primary EBV infection. Clinical improvement with anti-EBNA seroconversion occurred after acyclovir therapy. Our patient illustrates that chronic fatigue with major organ dysfunction and a serological profile of primary infection can be seen in chronic EBV infection. In such a case, acyclovir may prove beneficial.

Hepatitis C virus infection in Italian patients with hypogammaglobulinemia

We investigated the presence of hepatitis C virus (HCV) infection in 58 patients with humoral immunodeficiencies. Forty-three of these patients had common variable immunodeficiency (CVI), 2 had sporadic hyperimmunoglobulin M (HIM) syndrome, 2 had immunoglobulin G subclass deficiency, 4 had ataxia-telangiectasia (AT), and 7 had X-linked agammaglobulinemia (XLA). Patients with late-onset hypogammaglobulinemia (those with CVI, HIM, or immunoglobulin G subclass deficiency) had a 38.2% prevalence of HCV infection. In patients with XLA or AT, HCV infection was not detectable. Most of the HCV-infected patients had persistent viremia, with histologic findings of chronic hepatitis. Although patients positive for HCV ribonucleic acid (RNA) had received several lots of immunoglobulin, we were unable to detect any correlation between the time that alanine aminotransferase levels increased and the time that intravenous immunoglobulin therapy was given, except in one patient with CVI. Moreover, we found no differences in the number of blood transfusions, surgical procedures, or administrations of intravenous or intramuscular immunoglobulin between HCV RNA-positive and HCV RNA-negative groups. We concluded that: (1) the incidence of HCV infection in patients with hypogammaglobulinemia is much higher than that reported in the Italian general population; (2) although patients with hypogammaglobulinemia have persistent viremia, they do not show an aggressive course of HCV disease, nor does hepatocarcinoma develop; and (3) intravenous immunoglobulins are only one of several possible causes of HCV transmission in patients with humoral immunodeficiencies.

HCV infection in patients with primary defects of immunoglobulin production

We tested for infection with hepatitis C virus (HCV) in 58 patients affected by humoral immunodeficiencies: 43 common variable immunodeficiency (CVI), two hyper IgM syndrome (HIM), two IgG subclass deficiency, four ataxia-telangiectasia (AT), and seven X-linked agammaglobulinaemia (XLA). While the assessment of serum specific HCV antibodies in some of these patients was not informative because of the impairment in specific antibody production, the reverse transcriptase polymerase chain reaction (RT-PCR) assay used to detect serum HCV RNA was a useful method for diagnosing infection. We found that 38% of late onset hypogammaglobulinaemic patients (CVI, HIM or IgG subclass deficiency) had evidence of HCV infection. HCV infection was not detectable in patients with XLA or AT. The majority of our patients had persistent viraemia, and those who underwent liver biopsy showed histological findings of chronic hepatitis. Moreover, we could demonstrate in vitro that eight of 18 HCV-infected patients were actively producing anti-HCV antibodies, despite their impaired antibody production. The high rate of HCV infection in hypogammaglobulinaemic patients could be related to several nosocomial routes of transmission, including intravenous immune globulin administration. Despite the persistent viremia only two patients had cirrhosis and none had hepatocarcinoma.

Chronic intestinal candidiasis as a possible etiological factor in the chronic fatigue syndrome

The chronic candidiasis syndrome, also known as the Candida-related complex, putatively caused by the overgrowth of Candida albicans in the gastrointestinal tract and secondarily in the genital organs, is briefly described. Patients with this disorder have many of the same symptoms as those with the chronic fatigue syndrome, except for the recurrent flu-like symptoms of the latter disorder. The positive response of a large number of patients with the chronic fatigue syndrome (CFS) to an oral antifungal agent and a diet for intestinal candidiasis has been described by another clinician. There is evidence that Candida albicans infection of the mucous membranes depresses T cell and natural killer (NK) cell function. Similar abnormalities of immune function are found in the CFS. The function of cytotoxic T cells, T helper cells, and NK cells is important in preventing reactivation of infections from Epstein-Barr virus, cytomegalovirus, and other herpesviruses. Reactivation of one or more of these viruses could lead to the expression of the flu-like symptoms in the CFS. Yet the immune dysfunction found in this disorder has been considered the primary underlying causal factor. It is proposed that chronic intestinal candidiasis may be an agent which leads to immune depression in many CFS patients and therefore that it could be a causal factor in CFS.

Interleukin-10 inhibits apoptotic cell death in infectious mononucleosis T cells

T lymphocytes from patients with acute EBV-induced infectious mononucleosis rapidly die by apoptosis in vitro. Because human and viral IL-10 are likely to be induced during acute EBV infection and display a variety of functions on human T cells, we examined IL-10 effects on infectious mononucleosis T cell death. After 12 h of incubation in medium alone, only 35.6 (+/- 8.2%) of the originally seeded infectious mononucleosis T cells were viable. Addition of human IL-10 (100 U/ml) to T cell cultures significantly improved recovery of viable cells (71.3 +/- 6.2%, P = 0.0156). Viral IL-10 had comparable effects to human IL-10 in this system. Protection from death by human and viral IL-10 (100 U/ml) was dose dependent and continued over a 6-d culture period. The human IL-10 effect was neutralized by the anti-human IL-10 mAb 19F1. Morphology and analysis of DNA after separation on agarose gels showed that IL-10 inhibits loss of cell volume, chromatin condensation, and DNA fragmentation, characteristics of death by apoptosis. As assessed by [3H]thymidine incorporation, the T cells were not induced to proliferate by IL-10 above the level exhibited when first removed from blood. T cells protected from death by IL-10 proliferated to IL-2 and spontaneously killed sensitive targets as effectively as medium-precultured T cells. Thus, IL-10 promotes the survival of infectious mononucleosis T cells otherwise destined to die by apoptosis and may be critical for the establishment of immunologic memory after resolution of the illness.

Transforming growth factor beta-1 (TGF-beta 1) released by an Epstein-Barr virus (EBV) positive spontaneous lymphoblastoid cell line from a patient with Kostmann's congenital neutropenia inhibits the growth of normal committed haemopoietic progenitors in vitro

This study reports the characterization of a spontaneous lymphoblastoid cell line (LCL) raised from the peripheral blood of a patient with Kostmann's congenital neutropenia. The LCL was composed of EBV-infected polyclonal B cells and displayed surface markers and pattern of growth in vitro typical of normal LCLs. The supernatant of the LCL contained a colony inhibiting activity (CIA) that decreased the cloning efficiency of normal committed haemopoietic progenitors and was identified as immunoreactive transforming growth factor beta 1 (TGF-beta 1) by neutralization experiments with a specific antiserum. Control studies with a panel of LCLs spontaneously derived from the peripheral blood of patients seropositive for Epstein-Barr virus (EBV) infections showed that 5/30 LCLs produced a CIA. This CIA was not identifiable as TGF-beta 1 but rather was due to the combined effects of tumour necrosis factor alpha (TNF alpha), tumour necrosis factor beta (TNF beta) and interferon alpha (IFN alpha), that were present in the LCL supernatants. The hypothesis that the B cells latently infected by EBV in vivo and possibly expanded as a consequence of the infection may have contributed to the inhibition of the patient granulopoiesis by releasing TGF-beta 1 will be discussed.

Update on immunology of head and neck cancer

The history of immunotherapy in head and neck cancer is filled with disappointing results and clinical trials of nonspecific immunotherapeutic protocols. Most of these protocols did not concern themselves with some of the possible underlying etiologies of immunosuppression, such as alcoholism, malnutrition, aging, and the oncologic therapies that the patients were undergoing. These factors must be appreciated, and attempts must be made to deal with their devastating effects. It is also becoming increasingly apparent that the humoral immune system does have a major impact on the effectiveness of the cellular immune system, and that the various components of this system need to be more fully understood. The complexity of these interactions will probably not allow for an effective immunotherapeutic protocol to be attained in the near future. It is, however, more likely that the establishment of immunoprognosis and immunodiagnosis may be achieved as these complex interactions are more fully identified and understood.

Phenotypic characterization of CD8+ T cell populations in HIV disease and in anti-HIV immunity

The CD8+ T cell population is believed to play an important role in the control of viral infection, both for suppression of viral replication and for cytotoxic activity against viral infected cells. Elevated numbers of CD8+ T cells have been demonstrated in HIV infection, and CD8+ cytotoxic T cell (CTL) activity is associated with the early, asymptomatic stage of disease. We investigated the phenotypic characteristics of the CD8 population, in whole blood, in HIV disease and determined the predominant CD8+ subpopulation involved in anti-HIV CTL activity. We found that CD8+ T cells co-expressing markers of activation (HLA-DR), memory (CD45RO, CD29), and cytotoxic activity (S6F1) were significantly elevated in the early stages of disease, while the numbers of naive (CD45RA) cells remained unchanged. Progression to AIDS resulted in an overall loss of absolute CD8+ T cells, though the percentages of CD8+ HLA-DR+ and CD8+ S6F1+ remained elevated. In contrast to patients in the late stages of disease, anti-HIVgag CTL activity, following in vitro stimulation, was present in most HIV+ asymptomatic subjects and was associated with an expansion of CD8+ HLA-DR+ and CD8+ CD45RO+ cells. The absence of CTL activity was associated with a reduced ability of these populations to expand in vitro and with a significant loss of peripheral CD4+ T cells, independent of clinical stage. We suggest that CD8+ expressing HLA-DR+ CD45RO+ and S6F1+ play an important role in anti-HIV cytotoxicity.

Chronic active Epstein-Barr virus infection, an AIDS-Co-Factor or predominant infection?

Chronic Active Epstein-Barr Virus is associated with Epstein-Barr Virus 2B (EBNA2B) and AIDS and possibly a widespread clinical syndrome. Provocative conclusions regarding their association are noted.

Immunophenotypical alterations in a subset of patients with common variable immunodeficiency (CVID)

We investigated the expression of surface molecules on lymphocytes from 20 patients with CVID and 40 healthy subjects. Lymphocytes were analysed by dual colour flow cytometry. We identified a subset of patients (8 of 20) characterized by low CD4/CD8 ratio (less than 1.1), expansion of T cells co-expressing the activation marker HLA-DR and significant increase in CD8+ T cells co-expressing CD57. Expression of the adhesion molecules LFA-3 (CD58) and ICAM-1 (CD54) was significantly increased in this subgroup. In addition, within the CD4+ T cells the percentage of CD29+ (memory) cells was increased, while the CD45RA and LAM-1 (Leu-8) antigens were depressed. These results indicate that in a subgroup of CVID patients T cells are activated in vivo and the CD57+CD8+ lymphocyte subpopulation, supposed to comprise functional suppressor T cells, is expanded. We suggest a chronic viral infection in these patients, but it is not clear whether this is primary or secondary to the underlying defect.

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.

Viruses and the blood

Haematological syndromes attributed to viruses demonstrate geographical variations in incidence and great dependence on host factors. Severe haematological disease is the exception rather than the rule in dengue virus infection, and probably depends at least in part on the host immune response to the virus. The increased incidence of hepatitis-associated aplasia in east Asia may reflect distribution of an infectious agent, an environmental toxin, or genetic predisposition, but probably represents some combination of these factors. Agents with apparently universal distribution, such as parvovirus B19 and Epstein-Barr virus, are associated with bone marrow failure only in a very narrow range of hosts. These examples teach us that viral causes cannot automatically be excluded from the differential diagnosis of syndromes whose occurrence is rare or apparently sporadic. Further investigation of these syndromes should include more detailed characterization of host factors, particularly immunological characteristics, and possible infectious and toxic cofactors which are associated with morbidity.

Proliferative response of mononuclear cells from HIV-infected patients to B-cell mitogens: effects of lymphocyte subset frequency, T-cell defects and prostaglandins

Proliferative responses of mononuclear cells from patients seropositive for human immunodeficiency virus to B-cell mitogens are severely depressed compared with those of controls. The role of several immunoregulatory phenomena was analyzed. Experimental results show that addition of exogenous lymphokines to cultures increases responses to anti-mu and SAC. Addition of indomethacin to cultures greatly increases the SAC response and causes a smaller increase in the pokeweed mitogen (PWM) response. When both exogenous lymphokines and indomethacin are present in cultures, responses of patients' cells to all three mitogens are positively correlated with the percentage of CD4+ T cells and negatively correlated with the percentage of CD8+ T cells. Responses to anti-mu and SAC are also positively correlated with the percentage of B cells in these cultures. On the basis of these correlations between B-cell responses and lymphocyte subset frequency, patients' B-cell responses can be mathematically corrected to estimate the responsiveness of the B cells in the presence of normal numbers of CD4+ and CD8+ cells. These corrected responses for all three mitogens are virtually identical to control responses. Furthermore, responses of enriched B-cell populations from HIV+ subjects and normal controls to SAC were not significantly different when assays were performed in the presence of indomethacin and exogenous lymphokines. These results suggest that B cells from HIV+ patients are inherently normal in their responsiveness to B-cell mitogens. The depressed function is imposed upon them as a result of the abnormal frequency of lymphocyte subsets in the blood, by increased prostaglandin production, and deficient lymphokine production.

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.

Epstein-Barr virus (EBV) recombinants: use of positive selection markers to rescue mutants in EBV-negative B-lymphoma cells

The objective of these experiments was to develop strategies for creation and identification of recombinant mutant Epstein-Barr viruses (EBV). EBV recombinant molecular genetics has been limited to mutations within a short DNA segment deleted from a nontransforming EBV and an underlying strategy which relies on growth transformation of primary B lymphocytes for identification of recombinants. Thus, mutations outside the deletion or mutations which affect transformation cannot be easily recovered. In these experiments we investigated whether a toxic drug resistance gene, guanine phosphoribosyltransferase or hygromycin phosphotransferase, driven by the simian virus 40 promoter can be recombined into the EBV genome and can function to identify B-lymphoma cells infected with recombinant virus. Two different strategies were used to recombine the drug resistance marker into the EBV genome. Both utilized transfection of partially permissive, EBV-infected B95-8 cells and positive selection for cells which had incorporated a functional drug resistance gene. In the first series of experiments, B95-8 clones were screened for transfected DNA that had recombined into the EBV genome. In the second series of experiments, the transfected drug resistance marker was linked to the plasmid and lytic EBV origins so that it was maintained as an episome and could recombine with the B95-8 EBV genome during virus replication. The recombinant EBV from either experiment could be recovered by infection and toxic drug selection of EBV-negative B-lymphoma cells. The EBV genome in these B-lymphoma cells is frequently an episome. Virus genes associated with latent infection of primary B lymphocytes are expressed. Expression of Epstein-Barr virus nuclear antigen 2 (EBNA-2) and the EBNA-3 genes is variable relative to that of EBNA-1, as is characteristic of some naturally infected Burkitt tumor cells. Moreover, the EBV-infected B-lymphoma cells are often partially permissive for early replicative cycle gene expression and virus replication can be induced, in contrast to previously reported in vitro infected B-lymphoma cells. These studies demonstrate that dominant selectable markers can be inserted into the EBV genome, are active in the context of the EBV genome, and can be used to recover recombinant EBV in B-lymphoma cells. This system should be particularly useful for recovering EBV genomes with mutations in essential transforming genes.

Expression of CD45R0 (UCHL1) by CD4+ and CD8+ T cells as a sign of in vivo activation in infectious mononucleosis

CD45R0 (UCHL1), a member of leucocyte common antigen family, is expressed largely on previously activated or memory T cells. We examined CD45R0 expression of T cell subpopulations in patients with Epstein-Barr virus (EBV) induced infectious mononucleosis (IMN) as a sign of in vivo activation. Consistent with the notion that activated CD8+ T cells expand in acute IMN; the majority of CD8+ T cells in patients with acute IMN expressed CD45R0 to the similar extent to HLA-DR expression. Most CD4+ T cells in these patients also demonstrated marked expression of CD45R0 as well as HLA-DR antigens, compared with age-matched controls. Expression of CD45R0 by CD4+ T cells in patients with acute IMN was more notable than their HLA-DR expression. While predominant CD8+ T cells resulted in decreased percentages of CD4+ T cells, CD4+ T cells expressing CD45R0 were shown to be significantly elevated in absolute number. The results suggest that both CD4+ and CD8+ T cells may be activated by stimulation with EBV infection. The appearance of two T cell subpopulations expressing CD45R0 in acute IMN implies their immunoregulatory roles in the control of EBV-infected cells.

Composite response of naive T cells to stimulation with the autologous lymphoblastoid cell line is mediated by CD4 cytotoxic T cell clones and includes an Epstein-Barr virus-specific component

We have approached the challenge of generating a primary T cell response to Epstein-Barr virus (EBV) in vitro by stimulating naive T cells with the autologous EBV-transformed lymphoblastoid cell line (LCL), a rich source of EBV-associated cytotoxic T lymphocyte (CTL) epitopes. Responsive T cells from three EBV-seronegative donors were cloned in agarose, phenotyped for T cell markers by flow cytometry, and their cytotoxic properties analyzed in the 51Cr release assay. Most clones (greater than 95%) expressed the CD4 phenotype and 59% of these clones showed cytotoxic properties. The dominant CTL response was specific for FCS-associated epitopes presented by FCS-grown autologous LCL target cells and was restricted by class II HLA antigens. Other clonal components included: (i) an EBV-specific response by HLA-restricted CD4 CTL clones that did not discriminate between A- and B-type EBV transformants; (ii) an EBV-specific response by an HLA-restricted CD4 CTL clone that discriminated between A- and B-type transformants, and (iii) a nonspecific cytotoxic response by CD3+,4+,8-, CD3+,4-,8-, and CD3-,4-,8- clones that were broadly allotypic or restricted to the lysis of K562 target cells. The EBV-specific CTL clones did not lyse the autologous EBV-negative B or T cell blasts and their specificity patterns of lysis were supported by the cold target competition data. These studies highlight the role of CD4 CTL in the establishment in vitro of a primary immune response to a human virus.

Severe chronic EBV infection associated with specific EBV immunodeficiency and an EBNA+ T-cell lymphoma containing linear, EBV DNA

A patient with severe chronic Epstein-Barr virus (EBV) infection (CEBVI) of 6 years duration developed an EBV+ T-cell lymphoma. To determine whether the development of the T-cell tumor was linked to EBV, we studied this patient's EBV-specific immune response and her T-cell tumor tissue for evidence of EBV infection. Peripheral blood lymphocytes from this patient were systematically studied for immune function and response to EBV. Tumor tissue was examined for EBV genome and for evidence of EBV replication. This patient failed to develop anti-EBV nuclear antigen (EBNA) antibodies and had decreased mitogen responsiveness. Her T-cells showed a broad suppression of both autologous and allogeneic B-cells, which was coincident with clinical hypoimmunoglobulinemia. A selective cytotoxic T-cell defect toward autologous EBV-infected B lymphoblasts, which could not be corrected by the addition of lymphokine-mediated T-cell help, was also documented. A lymph node biopsy taken 5 years after her clinical presentation revealed lymph node architecture completely effaced by a diffuse CD3+, CD4+, Ia+, CR2+ T-cell lymphoma containing EBNA and linear, replicating EBV DNA. Select CEBVI patients with humoral and combined cellular aberrations in the immune response to EBV may be predisposed to the development of EBV+ T-cell tumors.