Cytomegalovirus and Epstein-Barr virus subtypes—The search for clinical significance

Cytomegalovirus (CMV) as well as Epstein Barr virus (EBV) genomes include regions which show in part substantial polymorphisms. Characterization of several polymorphic regions led to the identification of various CMV and EBV subtypes. Within the last years there have been undertaken numerous efforts to find out whether the diverse subtypes differentially contribute to clinical manifestations. However, although some associations have been described so far between a certain virus subtype and the development of individual diseases these analyses were greatly complicated by the huge genomic background of CMV and EBV, by the large variety of individual host-virus relations and by differences in the geographic or demographic subtype distribution. In addition, it was shown meanwhile that a substantial proportion of virus infections is due to mixed infections with different subtypes. In this review we will give an overview of the current knowledge concerning the clinical significance of individual CMV and EBV subtypes, defined by characterization of selected polymorphisms. In addition, we also focus on recent analyses which show that infection with mixed virus subtype populations may be disadvantageous compared to single virus subtype infections.

Phenotype analysis by MUC2, MUC5AC, MUC6, and CD10 expression in Epstein-Barr virus-associated gastric carcinoma

BACKGROUND

Gastric marker mucins (MUC5AC and MUC6) and intestinal marker molecules (MUC2 and CD10) have been used to determine the cell lineage of epithelial cell of gastric carcinoma (GC).

METHODS

To clarify the characteristics of Epstein-Barr virus (EBV)-associated GC, 18 cases were immunohistochemically evaluated along with 56 cases of EBV-negative GC.

RESULTS

MUC2 expression was lower in EBV-associated GC: immunostaining grades 0, 1, 2, 3, and 4 were observed in 10, 6, 1, 1, and 0 cases of EBV-associated GC, respectively, and in 18, 11, 15, 6, and 6 cases of EBV-negative GC, respectively (P = 0.013). CD10 positivity (grades 2-4) in EBV-associated GC was 6%, significantly lower than in EBV-negative GC (34%) (P = 0.030). When phenotypes of GC were categorized by the combined positivities of gastric markers (either MUC5AC or MUC6) and intestinal markers (either MUC2 or CD10), EBV-associated GC included primarily null (44%) and gastric (39%) types, but EBV-negative GC comprised null (7%), gastric (30%), intestinal (27%), and mixed (36%) types. The age of patients with gastric types was significantly younger for both EBV-associated GC and EBV-negative GC cases.

CONCLUSIONS

Neoplastic epithelial cells of EBV-associated GC did not express MUC2 or CD10, and most of them were categorized as null or gastric types. EBV infection may occur in the epithelial cells of null or gastric phenotypes, which may be devoid of transdifferentiation potential toward intestinal phenotypes.

The high frequency of EBV infection in pediatric Hodgkin lymphoma is related to the classical type in Bahia, Brazil

Pediatric Hodgkin lymphoma (HL) occurring in developing regions is different from HL in industrialized countries due to the higher frequency of association with Epstein-Barr virus (EBV) infection. This infection is related to classical HL (cHL) but is virtually absent in nodular lymphocyte predominant HL (nLPHL). We studied the phenotype and the expression of EBV gene products in 90 pediatric cases by immunohistochemistry and in situ hybridization. EBV-positive tumor cells were found exclusively in cHL. The infection occurred with high frequency in all cHL subtypes, but it predominated in the mixed cellularity and lymphocyte depletion subtypes. These results reinforce the hypothesis that EBV plays a major role in the etiology of pediatric cHL in developing areas. Curiously, the frequency of EBV infection in HL was identical to the previously described for Burkitt's lymphoma in the same pediatric population. As both lymphomas have a postulated precursor cell in the germinal center (GC), the pattern of latently EBV-infected GC cells previously described in Bahia may be related to the development of these lymphomas.

Histological varieties of Epstein-Barr virus-related lymph node lesion resembling autoimmune disease-like clinicopathological findings in middle-aged and elderly patients: a study of six cases

Six cases were studied to further clarify clinicopathological findings of Epstein-Barr virus (EBV)-related lymph node lesions showing autoimmune disease-like clinicopathological findings (EBVAID) in middle-aged and elderly patients. The patients, four males and two females, ranged in age from 53 to 74 years, with a median age of 62 years. Clinically, they were characterized by systemic lymphadenopathy, "B"symptoms, polyclonal hypergammaglobulinemia, elevated serum lactate dehydrogenase and a transient presence of various autoantibodies, as well as an infrequent presence of atypical lymphocytosis in peripheral blood. Two cases were associated with idiopathic thrombocytopenic purpura. The clinical course was self-limiting. Histologically, three patterns could be delineated: pattern A, follicular hyperplasia with pronounced arborizing vasculature in the expanded paracortex (n=3); pattern B, follicular hyperplasia with pronounced interfollicular B-immunoblastic/plasma cell proliferation (n=2); and pattern C, paracortical hyperplasia containing numerous large transformed lymphocytes (n=1). In situ hybridization demonstrated a varying number of EBV-infected lymphocytes in the germinal center and in the interfollicular area. Polymerase chain reaction analysis demonstrated that neither clonal rearrangement of T-cell receptor gamma-chain nor immunoglobulin heavy-chain rearrangement was detected in the three cases examined. Although EBVAID appears to be rare in middle-aged and older adults, EBVAID exhibits histological variations and should be added to the differential diagnosis of various atypical or malignant lymphoproliferative disorders, in particular autoimmune-disease-associated lymphadenopathy and angioimmunoblastic T-cell lymphoma with a hyperplastic germinal center in middle-aged and elderly patients.

Clinicopathologic implications of tissue inhibitor of metalloproteinase-1-positive diffuse large B-cell lymphoma

The tissue inhibitor of metalloproteinase-1 (TIMP-1) is a stromal factor that promotes plasmablastic differentiation, and the survival of germinal center B-cells. The expression of TIMP-1 is known to be correlated with a subset of non-Hodgkin lymphoma at the mRNA level, and Epstein-Barr virus infection in vitro. To characterize TIMP-1(+) diffuse large B-cell lymphoma, TIMP-1 expression was investigated in tissue microarrays from 182 cases of de novo diffuse large B-cell lymphoma and compared with prognostic factors, immunophenotypes, and Epstein-Barr virus infection status. TIMP-1 was expressed not only in tumor cells themselves, in 14 of 182 cases (8%), designated as TIMP-1(+) diffuse large B-cell lymphoma, but also in stromal cells like fibroblasts and endothelial cells. In univariate analysis and hierarchical clustering, our findings suggest that TIMP-1 expression may represent a distinct subgroup. In multivariate analysis, TIMP-1(+) diffuse large B-cell lymphoma (n=14) was associated with unfavorable outcomes compared to TIMP-1(-) diffuse large B-cell lymphoma (n=168) (odds ratio=2.5, P=0.049). Together with TIMP-1 expression, age (greater than 60 years), the presence of B-symptoms, abnormal lactate dehydrogenase level, or more advanced stage (III/IV) was correlated with a poor overall survival. However, TIMP-1 expression in diffuse large B-cell lymphoma was not correlated with other prognostic factors including: clinical stage, international prognostic index score, and nongerminal center B-cell phenotype, as well as Epstein-Barr virus infection. Our results suggest that TIMP-1 expression may be an independent negative prognostic factor in patients with diffuse large B-cell lymphoma.

Posttransplant Lymphoproliferative Disorder in a Kidney-Pancreas Transplanted Recipient

Posttransplant lymphoproliferative disorders (PTLDs) are lymphoid proliferations or lymphomas that develop as a consequence of immunosuppression after solid organ or bone marrow transplantation and are mostly associated with an Epstein-Barr virus infection. The morphologic categories include different types of benign and malignant lymphoid proliferations. The majority of PTLDs is of B-cell origin with clonal rearrangements of the immunoglobulin genes. The PTLDs in solid organ transplants are reported to be either of host or of donor origin. Donor-related PTLDs frequently involve the allograft. We report a case of a 52-year-old woman recipient who developed simultaneously PTLDs in several organs 5 month after receiving a sex-mismatched renal and pancreas allograft. Immunosuppression regimen comprised antithymocyte globulin, tacrolimus, mycophenolate mofetil, and steroids. Pathologic features appeared as polymorphic PTLDs in the renal allograft, liver, and central nervous system (CNS). Molecular genetic studies revealed different clonal immunoglobulin heavy chain gene rearrangements in all 3 organs as determined by polymerase chain reaction (PCR). Epstein-Barr virus were detected by nested PCR and in situ hybridization in all 3 tumors. The PTLDs in liver and CNS were of host origin whereas the allograft kidney PTLD was found to originate from the male donor as shown by the simultaneous detection of female and male sex chromosomes by PCR and fluorescence in situ hybridization. The recipient died in consequence of the CNS involvement, after intracerebral hemorrhage with uncal and tonsillar herniation.

No association of primary adenocarcinomas of the small bowel with Epstein-Barr virus infection

Epstein-Barr Virus (EBV) infection is considered to play an etiologic role in human malignancies, including a subset of gastric and cardiac cancers. Adenocarcinomas of the small bowel comprise a very rare entity, with little knowledge about molecular properties and etiological aspects. We have investigated the prevalence of EBER expression (EBV-encoded small RNAs) in a series of small bowel adenocarcinomas (n=56) utilizing RNA in situ hybridization (EBER-RISH). The patients had undergone primary surgical resection at either the Technical University of Munich or at the University of Graz. A surgical series of 82 primary resected gastric (n=36) or cardiac (n=46) adenocarcinomas (TU Munich) was used as control group. None of the 56 small bowel carcinomas exhibited EBER expression whereas in the control group the rate of EBER expression accounted for 4.4% in the group of cardia carcinomas and 8.6% in the group of gastric cancers. These results indicate that EBV infection plays no etiologic role in primary small bowel adenocarcinomas.

Epstein–Barr virus infected natural killer cell lymphoma in a patient with hypersensitivity to mosquito bite

Hypersensitivity to mosquito bite (HMB) can occur in association with chronic Epstein-Barr virus (EBV) infection and natural killer (NK) cell leukaemia/lymphoma, which was named 'Tokura-Ishihara disease'. This disease is very rare and most previous reports have been documented in Japan. We present a patient who suffered from of pustules on skin, high fever, myalgia and multiple lymph node enlargements after mosquito bite from childhood. Recently, multiple lymph nodes were palpable on his both inguinal area. Peripheral blood smear (PBS) revealed many large granular lymphocytes and the skin lesion showed a dense dermal and subcutaneous infiltrate of lymphocytes. The lymph nodes and perinodal adipose tissue were infiltrated by atypical lymphoid cells in which EBER-positive signals were identified by in situ hybridization using EBV encoded RNA-1 probe. He was diagnosed as having Tokura-Ishihara disease and receives chemotherapy now. Here, we report a case of this disease with a precise pathological description on the lymph node biopsy.

Adoptive transfer of Epstein-Barr virus-specific cytotoxic T-lymphocytes for the treatment of angiocentric lymphomas

Angiocentric lymphoma, known as natural killer (NK)/T-cell non-Hodgkin's lymphoma, has been reported to be associated with the Epstein-Barr virus (EBV). We performed adoptive transfer of EBV-specific polyclonal T-cell lines in 3 patients with extranodal NK/T-cell lymphoma, nasal type, and evaluated the treatment for safety, immunologic reconstitution, and clinical outcomes. The tissue samples collected from the 3 patients were confirmed by polymerase chain reaction analysis to be EBV positive. In the cases of the first and second patients, EBV-transformed B-lymphoblastoid cell lines (LCLs) and T-cell lines were generated from peripheral lymphocytes of HLA-matched sibling donors. The third patient's T-cell lines were induced with autologous lymphocytes. Polyclonal T-cell infusion was carried out after high-dose radiotherapy because active relapsed disease remained in all of the patients. The first patient received 4 weekly infusions of 2 3 10(7) cells/m(2), and the second and third patients underwent treatment with 2 cycles of infusions of the same dosage. All T-cell lines showed >60% NK activity, cytotoxic T-lymphocyte (CTL) responses of >40% against autologous LCLs, and no CTL activity against patient-derived lymphoblasts. The level of cytotoxicity increased substantially in all patients after cell infusion. The 2 patients who received T-cell therapy twice had stabilized disease for more than 3 years. These safe treatments exhibited no severe inflammatory response, and no serious toxicity developed during T-cell therapy. Our findings demonstrate that adoptively transferred cells may provide reconstitution of EBV-specific CTL responses in patients with active relapsed angiocentric lymphoma. These results provide a rationale for the immunotherapy of angiocentric lymphoma.

Hodgkin lymphoma-like posttransplant lymphoproliferative disorder (HL-like PTLD) simulates monomorphic B-cell PTLD both clinically and pathologically

Although Hodgkin lymphoma-like posttransplantation lymphoproliferative disorder (HL-like PTLD) has been grouped with classic Hodgkin lymphoma type PTLD (HL-PTLD), controversy remains as to whether it is truly a form of HL or whether it should be more appropriately classified as a form of B-cell PTLD. Because only few cases of HL-like PTLD have been reported, their pathologic nature and clinical behavior have not been well defined. This report characterized 5 cases of HL-like PTLD with respect to their immunophenotype, EBV status, clonality, and clinical outcome. All of the patients were male, with ages ranging from 1.5 to 55 years at diagnosis. PTLD developed from 4 months to 6 years following solid organ transplantation (3 hearts, 1 kidney, 1 liver), and involved both nodal and extranodal sites. All were EBV-related (EBER+) with the large neoplastic cells CD20/CD79a positive but CD15 negative. Immunoglobulin gene rearrangements were detected in 3 of 5 tested. All patients were managed by initial reduction/withdrawal of immunosuppression, with 2 also receiving chemotherapy for non-HL. Three patients died of progressive disease within 2 to 3 months after diagnosis, 1 is alive and well 2 years later, and the fifth was disease free but died of unrelated causes (graft coronary disease) 2 years later. We conclude that, although HL-like PTLD morphologically simulates classic HL PTLD, there are important immunophenotypic, molecular genetic, and clinical differences, suggesting it is in fact most often a B-cell PTLD. Distinction between HL and HL-like PTLD may be important for clinical management and prognosis.

Epstein-Barr virus, cytokines, and inflammation: a cocktail for the pathogenesis of Hodgkin's lymphoma?

The association between chronic inflammation and cancer has been known for well over a century. However, direct evidence detailing the role of inflammation in carcinogenesis has been slow in forthcoming. A number of recent studies suggest that the gaps in our understanding of the molecular pathways bridging the link between inflammation and cancer are slowly beginning to close and that this relationship is more deep-rooted than had been previously believed. This review addresses the link between inflammation and Hodgkin's lymphoma (HL), a malignancy which has many features reminiscent of chronic inflammation. The role of Epstein-Barr virus (EBV) in the pathogenesis of HL is discussed, along with an outline of our current understanding of the cellular nature and development of Reed-Sternberg cells, the malignant cells of HL. The involvement of cytokines and chemokines as orchestrators of inflammation and vehicles for chemical cross-talk between the malignant cells and the reactive inflammatory infiltrate forms a major part of the review. It is suggested that chronic inflammation, triggered by factors such as EBV, is likely to contribute to tumor cell proliferation, progression, and inhibition of apoptosis. Furthermore, it is proposed that the pro-inflammatory transcription factor NF-kappaB plays a central role in many of these processes.

[Primary infection with Epstein-Barr virus in a 77-year-old patient with B symptoms and hepatitis -- a case report]

Epstein-Barr virus (EBV) infection has a prevalence of 90 % and is - depending on the immune status of the host - associated with a broad spectrum of clinical manifestations. By presenting a case report we would like to demonstrate an unusual clinical course of a primary infection with EBV in an elderly patient. A 77-year-old patient was admitted to hospital in reduced health condition because of a persisting bronchopulmonary infection with B symptoms. The patient had already been treated with antibiotics. Because of elevated liver enzymes, a liver biopsy was performed. Histopathology revealed moderate acute hepatitis with cholangitis und endothelialitis, pointing to an EBV-induced hepatitis. Serological examinations confirmed the diagnosis, revealing a primary infection with positive EBV VCA IgM and IgG. EBV PCR of the liver tissue was positive, viral genome could be demonstrated within lymphocytes. A short period later the patient was discharged to reconvalescence. This case report demonstrates an unusual primary infection with EBV at the age of 77 with atypical clinical symptoms and hepatitis. The relevance of EBV in the differential diagnosis of atypical infectious diseases with hepatitis of unknown aetiology is strengthened on taking data reports from the literature into consideration.

Fatal Epstein-Barr virus meningitis: an autopsy report

A 3-year-old Asian female presented with fever for 1 week and neck swelling for 1 day. Serology revealed a recent Epstein-Barr virus (EBV) infection. Late on the evening of admission, she developed confusion and would not follow commands. A CT scan showed diffuse cerebral edema and a cerebral flow scan demonstrated no blood flow to the brain. She was declared brain dead and expired on the following day. At autopsy, the brain weighted 1175 grams and grossly showed significant edema. Microscopically, the entire neuraxis revealed extensive leptomeningeal infiltrate of mainly CD8+ T lymphocytes, the majority of which expressed activated markers, HLA-DR and/or CD45RO, and monocytes/macrophages with intermixed numerous apoptotic/karyorrhectic nuclear fragments. These nuclear fragments were considered to be due to apoptosis of the expanded population of CD8+ T lymphocytes. Focal venulitis was noted. EBV-encoded small nuclear RNA in situ hybridization revealed positivity in the occasional lymphocytes. Interestingly, most intraparenchymal as well as leptomeningeal vascular endothelium showed HLA-DR immunoreactivity. This finding has been reported primarily in the acute inflammatory/demyelinating conditions, not in the viral meningitis/meningoencephalitis, and was thought to be related to cytokines due to widespread inflammation in our case. Massive edema secondary to severe EBV-meningitis can be fatal.

Pathogenic Link Between Hydroa Vacciniforme and Epstein-Barr Virus–Associated Hematologic Disorders

OBJECTIVES

To determine the pathogenic association of latent Epstein-Barr virus (EBV) infections with both typical hydroa vacciniforme (HV) and severe HV-like eruptions, and to survey the complications and outcomes of patients.

DESIGN

Case series.

PATIENTS

Twenty-nine patients with HV or severe HV-like eruptions.

INTERVENTIONS

In situ hybridization and immunostaining of biopsy specimens; extraction of DNA samples from cutaneous lesions and/or peripheral blood mononuclear cells for EBV DNA assay.

MAIN OUTCOME MEASURES

Clinicopathologic manifestations, hematologic findings, complications, and outcomes; presence of latent EBV infection.

RESULTS

T cells positive for EBV-encoded small nuclear RNA (EBER) were detected, to various degrees, in cutaneous infiltrates in 28 (97%) of 29 patients, including all 6 patients with definite HV with a positive phototest reaction, 11 of 12 patients with probable HV without evidence of photosensitivity, and all 11 patients with severe HV associated with systemic symptoms. In addition to EBER-positive T cells, many cytotoxic T lymphocytes expressing T-cell intracellular antigen 1 and granzyme B were present in the cutaneous lesions. Natural killer (NK) cells were absent or at a background level. The UV-induced cutaneous lesions showed histopathologic findings consistent with those of HV, containing many EBER-positive cells. Although no hematologic abnormalities were found in the definite and probable HV groups, the amounts of EBV DNA were increased in the peripheral blood mononuclear cells. By contrast, the severe HV group had markedly increased levels of EBV DNA associated with NK-cell lymphocytosis, and complications including chronic active EBV infection, hypersensitivity to mosquito bites, and hemophagocytic syndrome. Five patients with severe disease died of EBV-associated NK/T-cell lymphomas or hemophagocytic syndrome 2 to 14 years after onset.

CONCLUSION

Both typical and severe HV are included within the spectrum of cutaneous disorders mediated by EBV-infected T cells, and the severe HV group may have overt EBV-associated NK/T-cell lymphoproliferative disorders with a frequently fatal outcome.

The role of Epstein-Barr virus in acute and chronic hepatitis

BACKGROUND/AIMS

Epstein-Barr virus has a seroprevalence of more than 80% world wide and is known to be associated with hepatitis. However, little is known about the underlying pathogenesis and immunmechanisms and no standard diagnostic criteria to diagnose EBV-hepatitis are available.

METHODS

We collected liver biopsies (n=21) with the tentative diagnosis of EBV induced hepatitis according to pathological changes and traceable EBV genome by PCR. Correlation with serological data revealed acute in seven cases, convalescent in two cases, past EBV infection in six cases. Viral RNA was visualised by in situ hybridisation within nuclei of lymphocytes.

RESULTS

In seven of 68 liver biopsies with the diagnosis 'liver disease of unknown aetiology' EBV genome in the tissue was demonstrated indicating a possible role for EBV in the induction of hepatitis or a trapping of infected lymphocytes within the liver. In a control group of 20 EBV-seropositive patients with steatohepatitis EBV-DNA PCR of the liver tissue was negative. Immunohistochemistry identified CD3 and CD8 positive T-lymphocytes as the main lymphocytic infiltrate in EBV hepatitis.

CONCLUSIONS

EBV hepatitis should be taken into consideration in case of typical histopathological changes and a positive DNA PCR of liver biopsy. Serological confirmation of the diagnosis is inevitable.

Orale Epstein-Barr-Virus-assoziierte diffuse großzellige B-Zell-Lymphome bei HIV-negativen immunsupprimierten Patienten

BACKGROUND

Diffuse large B-cell lymphomas (DLBCL) are non-Hodgkin's lymphomas (NHL) and with a prevalence of 30-40% they comprise the most frequent NHL in adults. Although their etiology is still unknown, a virus induction, especially by the Epstein-Barr-virus (EBV), is the subject of discussion. Patients with congenital or acquired immunodeficiency are primarily afflicted. PATIENT 1: A 39-year-old female patient developed an EBV-associated DLBCL of the plasmablastic subtype in the maxillary alveolar ridge in the region of teeth 11 and 21 after 24 years of immunosuppressive therapy with azathioprine due to myasthenia gravis. Clinically the lesion presented as a localized acute necrotizing periodontitis that was resistant to symptomatic therapy. After polychemotherapy the disease is in complete remission until today. PATIENT 2: A 56-year-old male patient developed an EBV-associated DLBCL of immunoblastic variant of the right maxillary edentulous alveolar ridge in the posterior region 7 weeks after heart transplantation and immunosuppressive therapy with azathioprine and cyclosporine A. Clinically, a soft, nonpainful, swelling measuring 1.5x0.5x0.5 cm with a central ulceration was evident. The tumor was excised followed by local radiation therapy. No recurrence was noted during a 15-year-follow-up.

DISCUSSION

The presented clinical cases demonstrate the increased risk of occurrence of oral malignant B-cell lymphomas as adverse effects of immunosuppressive therapy. The demonstration of EBV in the tumor cells in both cases underlines the involvement of this virus in the pathogenesis of oral DLBCL arising in the setting of an immunodeficiency as has been shown previously in patients with HIV.

CONCLUSIONS

Due to the varying and often nonspecific clinical appearance of oral DLBCL, an early biopsy and work-up by an institute specialized in hematopathology is essential for diagnosis, because these tumors may disseminate in early stages.

Simultaneous occurrence of Hodgkin's lymphoma and Kaposi's sarcoma within the same lymph nodes of a non-AIDS patient

We report a case of simultaneous occurrence of Hodgkin's lymphoma and Kaposi's sarcoma within the same lymph nodes of a 61-year-old woman without human immunodeficiency virus (HIV) infection. Epstein-Barr virus (EBV) was detected in the Hodgkin cells and Reed-Sternberg cells by EBV LMP-1 immunostaining and Epstein-Barr virus encoded early RNA (EBER) in situ hybridization. In contrast, Kaposi's sarcoma cells were positive for human herpes virus 8. This case is documented because the occurrence of 2 independent tumors infected by 2 unrelated viruses within the same lymph nodes of a patient without HIV infection has rarely been observed.

Epstein-Barr virus-associated post-transplant lymphoproliferative disease with central nervous system involvement after unrelated allogeneic hematopoietic stem cell transplantation

Post-transplant lymphoproliferative disorders (PTLD) represent an heterogeneous group of abnormal lymphoid proliferation related to Epstein-Barr virus (EBV) reactivation that arise early after allogeneic hematopoietic stem cell transplant (HSCT). PLTD with central nervous system (CNS) involvement has been reported in few cases. We describe the case of a 31-year-old-man who developed an EBV-related PTLD with CNS involvement 2 months after an allogeneic unrelated HSCT for acute myeloid leukemia in first complete remission who was successfully treated with rituximab, cidofovir and intrathecal infusion of methotrexate and methylprednisolone.

Postreplicative Mismatch Repair Factors Are Recruited to Epstein-Barr Virus Replication Compartments

The mismatch repair (MMR) system, highly conserved throughout evolution, corrects nucleotide mispairing that arise during cellular DNA replication. We report here that proliferating cell nuclear antigen (PCNA), the clamp loader complex (RF-C), and a series of MMR proteins like MSH-2, MSH-6, MLH1, and hPSM2 can be assembled to Epstein-Barr virus replication compartments, the sites of viral DNA synthesis. Levels of the DNA-bound form of PCNA increased with progression of viral productive replication. Bromodeoxyuridine-labeled chromatin immunodepletion analyses confirmed that PCNA is loaded onto newly synthesized viral DNA as well as BALF2 and BMRF1 viral proteins during lytic replication. Furthermore, the anti-PCNA, -MSH2, -MSH3, or -MSH6 antibodies could immunoprecipitate BMRF1 replication protein probably via the viral DNA genome. PCNA loading might trigger transfer of a series of host MMR proteins to the sites of viral DNA synthesis. The MMR factors might function for the repair of mismatches that arise during viral replication or act to inhibit recombination between moderately divergent (homologous) sequences.

EBV+ lymphoepithelial carcinoma of the parotid gland in Mexican Mestizo patients with chronic autoimmune diseases

Lymphoepithelial carcinomas of the salivary gland are rare tumors constantly associated with Epstein-Barr virus (EBV) and mainly identified in Asiatic and Greenlander population. Four cases have been described in Caucasians, only two with EBV infection. We describe two cases of parotid gland lymphoepithelial carcinomas in Mexican mestizo women in which chronic latent EBV infection was documented by immunohistochemistry and in situ hybridization. One patient had primary Sjögren's syndrome and the other systemic lupus erythematosus of six and three years of evolution, respectively. Epithelial neoplastic cells showed latency pattern II (LMP1+, EBNA-2-, EBER+) with a dense inflammatory infiltrate composed mainly by CD8+ T lymphocytes. Follow-up excluded nasopharyngeal involvement in both patients. This report expands the ethnic groups in which salivary lymphoepithelial carcinomas associated with chronic latent EBV infection have been described, and illustrates for the first time its association with autoimmune diseases in two women living in a region non-endemic for this unusual neoplasm.

Follicular dendritic cell tumor of the liver associated with Epstein-Barr virus

Follicular dendritic cell tumors are an uncommon neoplasm. About half of all cases occur in the lymph nodes, especially in the neck region. Follicular dendritic cell tumors of the liver are even rarer. In this article we report a case of a hepatic follicular dendritic cell tumor. A 30-year-old female was noted to have a hepatic mass 6 cm in size in segment 6. The patient underwent a right lobectomy of the liver. Microscopically, the lesion was an admixture of spindle cells and inflammatory cells, chiefly lymphocytes, plasma cells, histiocytes and a few neutrophils. The spindle cells were arranged in a wavy pattern, with a vague cellular border and eosinophilic cytoplasm. These tumor cells were immunoreactive to CD21 and CD68. The test for Epstein-Barr virus (EBV)-encoded nuclear RNAs using in situ hybridization was also positive. Although hepatic follicular dendritic cell tumors appear similar to conventional inflammatory pseudotumors in terms of histology, they should be regarded as a clonal proliferation of follicular dendritic cells. In contrast to follicular dendritic cell tumors in extrahepatic areas, hepatic follicular dendritic cell tumors have a strong association with EBV and a greater inflammatory component and are more prevalent in females.