Plasmablastic lymphomas with light chain restriction – plasmablastic extramedullary plasmacytomas?

J Oral Pathol Med (2010) 39 : 435–439 Background: It is diagnostically difficult to differentiate plasmablastic lymphomas (PBLs) from plasma cell neoplasms with plasmablastic differentiation. Plasmablastic lymphomas are currently classified as ‘PBL of the oral mucosa’ and ‘PBL with plasmacytic differentiation’. Methods: Forty‐five cases of PBL were retrieved from the Departments of Oral Pathology of the Universities of Pretoria and Limpopo, South Africa. Clinical features and HIV status were recorded and each case was classified as ‘PBL of the oral mucosa type’ or as ‘PBL with plasmacytic differentiation’. Immunohistochemistry included: CD45, CD3, CD20, CD79a, CD38, CD138, MUM1, Ki‐67 and kappa and lambda light chains. Positivity was recorded based on the percentage of positive staining cells as focal (5–20%); intermediate (20–70%) or diffuse (>70%). In situ hybridization was performed for Epstein–Barr virus (EBV) and HHV‐8. Results were recorded as positive or negative. Results: All cases showed some degree of plasmacytic differentiation. All were negative for CD20 with reactive T cells detected with CD3. Diffuse and strong positive staining was found with Ki‐67 and MUM1, but variable immunoreactivity was found with CD79a, CD45, CD38 and CD138. Twenty cases (47%) showed light chain restriction. Epstein–Barr virus was detected in 44/45 cases and HHV‐8 in none. Conclusions: The morphological classification of PBLs is not valid as all cases showed some degree of plasmacytic differentiation. We propose that PBLs with light chain restriction be reclassified as ‘plasmablastic extramedullary plasmacytomas’ and managed accordingly. The rest represents true PBLs. The true nature of these neoplasms as an entity should be further investigated with molecular and genetic studies.     

Epstein–Barr virus in the pathogenesis of oral cancers

Epstein–Barr virus (EBV) is a ubiquitous gamma‐herpesvirus that establishes a lifelong persistent infection in the oral cavity and is intermittently shed in the saliva. EBV exhibits a biphasic life cycle, supported by its dual tropism for B lymphocytes and epithelial cells, which allows the virus to be transmitted within oral lymphoid tissues. While infection is often benign, EBV is associated with a number of lymphomas and carcinomas that arise in the oral cavity and at other anatomical sites. Incomplete association of EBV in cancer has questioned if EBV is merely a passenger or a driver of the tumorigenic process. However, the ability of EBV to immortalize B cells and its prevalence in a subset of cancers has implicated EBV as a carcinogenic cofactor in cellular contexts where the viral life cycle is altered. In many cases, EBV likely acts as an agent of tumor progression rather than tumor initiation, conferring malignant phenotypes observed in EBV‐positive cancers. Given that the oral cavity serves as the main site of EBV residence and transmission, here we review the prevalence of EBV in oral malignancies and the mechanisms by which EBV acts as an agent of tumor progression.     

Epstein-Barr virus: Biology and disease

Epstein—Barr virus is a human herpes virus which, whilst found as a widespread asymptomatic infection, is also associated with certain tumours of lymphoid and epithelial origin including Burkitt's lymphoma (BL), immunoblastic lymphoma (IBL), Hodgkin's Disease (HD) and nasopharyngeal carcinoma (NPC). A unique characteristic of EBV is its ability to infect and transform primary resting B lymphocytes in vitro into permanently growing lymphoblastoid cell lines (LCLs); this effect is associated with constitutive expression of a limited set of viral genes. Interestingly, the pattern of EBV gene expression observed in LCLs in vitro is also a feature of IBLs, a tumour associated with immunosuppression. The other EBV associated tumours display a more restricted pattern of EBV latent protein expression. B cell lines can be activated in vitro into the virus replicative cycle, where a large number of viral genes associated with EBV DNA replication and virus assembly are synthesised. Whilst EBV can be detected in throat washings from seropositive individuals, the only in vivo situation where full virus replication can be reliably observed is hairy leukoplakia (HL), a benign lesion of lingual epithelium frequently found in AIDS patients. Thus, the relative contribution of lymphoid cells and epithelial cells to latent EBV infection/persistence vs replication in vivo remains controversial. Recent studies suggest that HL represents a focus of EBV replication in the absence of a truly latent infection and this supports the contention that EBV persistence resides in the lymphoid compartment. These aspects together with the role of EBV in oral diseases and the effect of certain EBV genes on the control of epithelial cell growth and differentiation will be discussed.     

Quantitative analysis of association between herpesviruses and bacterial pathogens in periodontitis

Background and Objective: The development of human periodontitis may depend upon cooperative interactions among herpesviruses, specific pathogenic bacteria and tissue‐destructive inflammatory mediators. This study sought to identify associations among human cytomegalovirus, Epstein–Barr virus and six putative periodontopathic bacteria in periodontitis lesions. Material and Methods: Fifteen periodontitis patients (nine with aggressive periodontitis and six with chronic periodontitis) and 15 periodontally normal subjects were included in the study. In each study subject, a microbiological sample was collected, using a curette, from the deepest periodontal probing depth of the dentition. A real‐time TaqMan® polymerase chain reaction assay was employed to determine the subgingival counts of human cytomegalovirus, Epstein–Barr virus, Porphyromonas gingivalis, Tannerella forsythia, Prevotella intermedia, Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum and Campylobacter rectus. Statistical analysis was performed using the Student's t‐test, the Pearson correlation coefficient test and the single variable logistic regression test for odds ratio‐based risk calculation. Results: Human cytomegalovirus was detected in eight periodontitis lesions and in one normal periodontal site, Epstein–Barr virus was detected in nine periodontitis lesions and in two normal periodontal sites, and the study bacteria were detected in 6–15 periodontitis lesions and in 1–11 normal periodontal sites. Correlations were found between counts of human cytomegalovirus and Epstein–Barr virus, between counts of human cytomegalovirus and P. gingivalis, T. forsythia and C. rectus, and between counts of Epstein–Barr virus and P. gingivalis and T. forsythia. Human cytomegalovirus and Epstein–Barr virus counts were also positively associated with the level of periodontal attachment loss, probing pocket depth and gingival bleeding on probing. Conclusion: This study confirmed that periodontal human cytomegalovirus and Epstein–Barr virus are associated with major periodontopathic bacteria and with the severity of periodontal disease. The finding of abundant herpesviruses in periodontitis lesions redefines the pathogenic paradigm of the disease. Understanding the interplay between herpesviruses and specific bacterial species in the pathogenesis of periodontitis may form the basis for new approaches to preventing, reducing or delaying tissue breakdown from periodontal infections.     

Viruses in pulp and periapical inflammation: a review

The presence of viruses in endodontic disease has been studied in the last decade. Their presence is associated with periapical radiolucency and with clinical findings, such as pain. The aim of this review is to analyze the scientific evidence currently published about viruses in pulp and periapical inflammation, and its possible clinical implications. A literature review was carried out using the Medline/Pubmed database. The search was performed, in English and Spanish, using the following keyword combinations: virus AND endodontic; virus AND periapical; virus AND pulpitis; herpesvirus AND periapical; papillomavirus AND periapical. We subsequently selected the most relevant studies, which complied with the search criterion. A total of 21 articles were included, of which 18 detected the present of viruses in the samples. In 3 of the studies, viral presence was not found in the samples studied. The Epstein–Barr virus was found in about 41 % of cases compared to controls, in which it was present in about 2 %. The main association between viruses and endodontic pathosis is between Cytomegalovirus and Epstein–Barr virus; these are found in 114 of the 406 samples of different endodontic pathosis. Some evidence supports that the Epstein–Barr virus is present in a significant number of endodontic diseases, without exact knowledge of their action in these diseases.     

Fusobacterium nucleatum Binding to Complement Regulatory Protein CD46 Modulates the Expression and Secretion of Cytokines and Matrix Metalloproteinases by Oral Epithelial Cells

Background: Periodontitis is a chronic inflammatory disease that results in the destruction of the supporting tissues of the teeth. Gingival epithelial cells are an important mechanical barrier and participate in the host inflammatory response to periodontopathogens. The aim of the present study is to investigate the capacity of Fusobacterium nucleatum to bind to the complement regulatory protein CD46 expressed by oral epithelial cells and to determine the impact of the binding on the gene expression and protein secretion of interleukin (IL)‐6, IL‐8, and matrix metalloproteinase (MMP)‐9 by oral epithelial cells. Methods: Binding of recombinant human CD46 to the surface of F. nucleatum was demonstrated by immunologic assays. After stimulation of oral epithelial cells with F. nucleatum, gene expression was determined by real‐time polymerase chain reaction analysis while protein secretion was monitored by enzyme‐linked immunosorbent assays. Results: Heat and protease treatments of bacterial cells reduced CD46 binding. F. nucleatum–bound CD46 mediated the cleavage of C3b in the presence of factor I. Stimulating oral epithelial cells with F. nucleatum at a multiplicity of infection of 50 resulted in a significant upregulation of the gene expression and protein secretion of IL‐6, IL‐8, and MMP‐9 by oral epithelial cells. However, pretreating the epithelial cells with an anti‐CD46 polyclonal antibody attenuated the production of IL‐6, IL‐8, and MMP‐9 in response to F. nucleatum. Such an inhibitory effect was not observed with non‐specific antibodies. Conclusions: The present study demonstrates that F. nucleatum can bind the complement regulatory protein CD46. The interaction of F. nucleatum with epithelial cell surface CD46 may contribute to increasing the levels of proinflammatory mediators and MMPs in periodontal sites and consequently modulate tissue destruction.     

Shedding dynamics of Epstein-Barr virus: A type 1 carcinogen

Epstein Barr virus (EBV) is one of the ubiquitous viral carcinogens found in humans and successfully infects more than 90% of the world population. The spectrum of EBV-related pathology ranges from asymptomatic primary infection to grave B- and T-cell malignancies. EBV triggers lymphoproliferative disorders after allogeneic stem cell transplantation, which contributes to higher mortality rates. Although the transmission of EBV primarily occurs from an infected host to a naive host through viral shedding from the oropharynx, increasing evidence points to considerable amount of shedding in other anatomical sites such as cervix, anal mucosa, breast milk and respiratory tract. It is impossible to eradicate the prevalence of EBV-related malignancies and other pathologies without preventing viral shedding. However, a detail analysis of the multifaceted nature of EBV shedding is not available in the literature. Thus, this review focuses on elucidating the key elements of the shedding dynamics of this carcinogenic virus.     

Assessment of SARS-CoV-2 entry in gingival epithelial cells expressing CD147

SARS-CoV-2, the causative agent of the debilitating COVID-19, is mainly transmitted by first infecting nose and lung epithelial cells. The mouth is also believed to be a viral portal site since certain types of oral epithelial cells were shown to express ACE2 receptor. However, it is unclear whether oral epithelial cells are directly infected by SARS-CoV-2. In this study, we addressed whether epithelial cells of the oral gingiva were susceptible to infection. Interestingly, we found that KRT5+ and KRT18+ gingival epithelial cells do not express ACE2 but highly express TMPRSS2 and Furin as well as CD147, which was proposed to be an alternative receptor for SARS-CoV-2. However, using SARS-CoV-2 pseudoviruses containing the spike protein, we observed that gingival epithelial cells were not susceptible to infection due to the lack of ACE2 expression and the inability of CD147 to mediate viral entry. These results strongly suggest that epithelial cells from the gingiva are not susceptible to SARS-CoV-2 and CD147 is not a receptor for the SARS-CoV-2 virus. The susceptibility of oral cells from other oral structures under healthy and pathological conditions still needs to be confirmed to better understand the role of the oral cavity in COVID-19 infection and transmission.     

Human cytomegalovirus in peripheral giant cell granuloma

Background:  The peripheral giant cell granuloma is a relatively common non-neoplastic inflammatory lesion of gingiva, but the etiopathogeny remains unknown. This study aimed to evaluate the importance of human cytomegalovirus and Epstein–Barr virus in a peripheral giant cell granuloma of a 47-year-old female.
Methods:  The lesion was studied clinically, histopathologically, immunologically and virologically using established procedures.
Results:  The gingival growth was located at the mesial surface of the maxillary left canine having a vital pulp. The mass was 12 × 21 mm in size and exhibited a smooth surface with no evidence of fluctuation on palpation. An excisional biopsy revealed giant cells in a fibrohistiocytic stroma with areas of haemorrhage. Serum protein levels and lymphocyte subsets were within normal limits, except CD3⁺ and CD4⁺ cells were below normal ranges. Polymorphonuclear leukocytes expressed p150,95 (CD11c/CD18) and CXCR-2 receptors within normal ranges, but the CXCR1 receptor showed decreased density, and CD15 were below normal range. A virological sample of the tooth surface adjacent to the gingival swelling yielded 7.6 × 10³ copy-counts of cytomegalovirus and 4.3 × 10³ copy-counts of Epstein–Barr virus.
Conclusions:  The clinical and histological findings were consistent with the diagnosis of peripheral giant cell granuloma. Cytomegalovirus has the potential to induce multinucleated giant cells, and the possibility that the virus contribute to the development of peripheral giant cell granuloma merits further study.     

Plasmablastic lymphoma of the oral cavity in an HIV-positive patient: a case report and review of literature

Plasmablastic lymphoma (PBL) of the oral cavity is an uncommon, recently described B-cell derived lymphoma that is most commonly seen in patients with human immunodeficiency virus (HIV) infections. The authors report a rare case of PBL in the oral cavity of a 40-year-old man with HIV. The lymphoma cells were positive for leukocyte common antigen, CD79a, CD138, Epstein–Barr virus (EBV) and kappa light chain restriction and negative for CD20, CD3, S100, HMB45 and cytokeratins. The lesion regressed after treatment with local radiotherapy and systemic chemotherapy. The features of this rare disease are summarized based on a comprehensive review of the epidemiological, clinical and immunohistochemical findings of previously reported cases.     

The expression of the Epstein-Barr virus nuclear antigen (EBNA-I) in oral hairy leukoplakia

OBJECTIVE: Oral hairy leukoplakia (OHL) is characterised by the presence of a replicative Epstein-Barr virus (EBV) in the superficial layers of the epithelium. There is some doubt, however, whether this reflects activation of a latent infection of the basal epithelial cells. EBV latency is associated with the expression of the viral gene product EBNA-I and the aim of this study was to investigate EBNA-I expression in OHL. METHODS: 22 biopsies of clinically suspicious OHL and three cases of normal mucosa were available as fresh frozen or paraffin embedded material. EBNA-I was detected immunocytochemically using a rat monoclonal antibody (IH4-I) following microwave irradiation. Lytic EBV infection was confirmed by the identification of the BZLF-I protein. RESULTS: 16 of the 22 cases displayed focal replicative EBV meeting the criteria for OHL, and in 13 of these, EBNA-I expression was restricted to the nuclei of epithelial cells in the upper layers of the epithelium. EBNA-I expression was absent from the basal cells in all cases and in the nine BZLF-I negative mucosal biopsies. CONCLUSION: These findings suggest that lytic EBV infection in OHL is not the result of activation of a latent infection of basal cells and suggests a role for EBNA-I, not only in latent EBV infection, but also in virus replication.     

Increased Expression of Interleukin (IL)‐35 and IL‐17, But Not IL‐27, in Gingival Tissues With Chronic Periodontitis

Background: Interleukin (IL)‐35 plays an important role in immune regulation through the suppression of effector T‐cell populations, including T‐helper 17 (Th17) cells. Although Th17 cells and IL‐17 are involved in the pathogenesis of periodontitis, the level of IL‐35 in inflamed periodontal tissues is unclear. Here, IL‐35, IL‐17, and IL‐27 production/expression in gingival crevicular fluid (GCF) and human gingival tissue were investigated. Methods: GCF samples were collected from buccal (mesial, center, and distal) sites of teeth from patients with chronic periodontitis (CP) and healthy controls and were analyzed by enzyme‐linked immunosorbent assay for IL‐35 (periodontitis, n = 36; healthy, n = 30) and IL‐17 (periodontitis, n = 16; healthy, n = 13). Gingival tissue, including sulcus/pocket epithelium and underlying connective tissue, was collected from an additional 10 healthy participants and 10 patients with CP and were analyzed by quantitative polymerase chain reaction (qPCR) for Epstein Barr virus‐induced gene 3 (EBI3), IL12A, and IL17A. IL27p28 was also tested by qPCR. Results: IL‐35 and IL‐17 were significantly higher in GCF from patients with periodontitis than healthy participants (P <0.01, P <0.05, respectively). In both healthy participants and those with periodontitis, positive correlations were found among IL‐35 and probing depth and clinical attachment level (CAL) as well as between IL‐17 and CAL. EBI3, IL12A (components of IL‐35), and IL17A messenger RNA expression levels were significantly higher in inflamed gingival tissue than in healthy control tissues (P <0.05). IL27p28 was not detected in any sample, suggesting that IL‐27 is not produced in large quantities in periodontal tissue. Conclusion: IL‐35 and IL‐17, but not IL‐27, may play important roles in the pathogenesis of periodontitis.     

Histological analysis of epithelial stem cells during induced pluripotent stem cell-derived teratoma development

ObjectiveInduced pluripotent stem (iPS) cells can differentiate into a variety of cell types and can form teratomas when transplanted in vivo. The purpose of the present study was to investigate the developmental processes and features of epithelial tissues, and the existence of epithelial stem/progenitor cells in iPS cell-derived teratomas.Materials and methodsiPS cell-derived teratomas formed by subcutaneous injection into immuno-deficient mice were extracted at 7-day intervals up to 21 day interval. Paraffin-embedded tissue sections were evaluated by H&E staining and immunohistochemistry for specific markers of three germ layer cell types and epithelial stem cells in oral tissues.ResultsDuring iPS cell-derived teratoma development, ectodermal cells emerged first, followed by the appearance of mesodermal and endodermal cells. The teratomas contained various types of epithelia, including epithelial masses, pseudostratified epithelium, simple epithelium and stratified epithelium. As teratoma development progressed, the epithelia matured. p63 and K14 were strongly expressed in epithelial masses and in the basal layer of pseudostratified and stratified epithelium. CD49f was expressed in all types of epithelia observed, and intense expression was observed in both the basal layer and luminal surface of pseudostratified and stratified epithelium.ConclusionsiPS cell-derived teratoma is a useful model for study of epithelial development, and it may provide significant information regarding oral epithelial tissue regeneration.     

Oral Epstein–Barr virus-positive mucocutaneous ulcer: gingival presentation of a benign lymphoproliferative lesion

Epstein–Barr virus-positive mucocutaneous ulcer (EBVMCU) is a benign lymphoproliferative lesion related to iatrogenic or age-related immunosuppression in patients with prior Epstein–Barr virus (EBV) infection. Although the clinical presentation may resemble malignant disease, the course of EBVMCU is indolent, and regression is expected when immunosuppression is reduced. We present a case of EBVMCU in the gingiva of a 59-year-old male patient with long-standing pemphigus vulgaris. The initial presentation was suspicious for oral cavity cancer, which was ruled out by biopsy. After reduction of immunosuppression, the ulceration regressed and an area of exposed necrotic bone remained. Complete healing was achieved after sequestrectomy and primary closure with a local gingival flap.     

Human cytomegalovirus and Epstein‐Barr virus type 1 in periodontal abscesses

Objectives: Recent studies have linked herpesviruses to severe types of periodontal disease, but no information exists on their relationship to periodontal abscesses. The present study determined the presence of human cytomegalovirus (HCMV) and Epstein‐Barr virus type 1 (EBV‐1) in periodontal abscesses and the effect of treatment on the subgingival occurrence of these viruses. Material and methods: Eighteen adults with periodontal abscesses participated in the study. Subgingival samples were collected from each patient with sterile curettes from an abscess‐affected site and a healthy control site. HCMV and EBV‐1 were identifed by polymerase chain reaction at the time of the abscess and at 4 months after surgical and systemic doxycycline therapy. Results: HCMV was detected in 66.7% of periodontal abscess sites and in 5.6% of healthy sites (P = 0.002). EBV‐1 occurred in 72.2% of abscess sites but not in any healthy site (P < 0.001). HCMV and EBV‐1 co‐infection was identified in 55.6% of the abscess sites. Posttreatment, HCMV and EBV‐1 were not found in any study site. Conclusions: HCMV and EBV‐1 genomes are commonly found in periodontal abscesses. These data favor a model in which a herpesvirus infection of the periodontium impairs the host defense and serves as a platform for the entrance of bacterial pathogens into gingival tissue with subsequent risk of abscess development.     

Chemokine receptor expression in HIV-positive persons with oropharyngeal candidiasis

OBJECTIVE: In HIV+ persons with reduced CD4+ T cells, oropharyngeal candidiasis (OPC) is often associated with the accumulation of CD8+ T cells at the epithelial/lamina propria interface within the lesion together with increased tissue-associated cytokines and chemokines. Despite this reactivity, a dysfunction in the ability of the CD8+ cells to reach the organism at the outer epithelium is postulated. The purpose of this study was to examine chemokine receptors present in the OPC lesions for a potential role in susceptibility to infection. METHODS: Biopsies taken from buccal mucosa of HIV- persons, healthy mucosa of HIV+ OPC- persons, and OPC lesions were processed for protein immunohistochemical staining or RNA analysis by real-time PCR and Superarray. RESULTS: There was little change in expression of chemokine receptors at the protein or RNA level between OPC+ and OPC- tissue. At the protein level, increases occurred in OPC+ persons only if associated with CD8 cells. In the Superarray, of the 22 chemokine receptor mRNAs expressed, c. 90% remained unchanged (< 1.0-fold change) between HIV- and HIV+ tissue and between HIV+ OPC- and HIV+ OPC+ tissue. CONCLUSION: Tissue-associated chemokine receptor expression does not appear to contribute to the dysfunction in cellular migration associated with susceptibility to OPC.     

Class II β‐tubulin is a novel marker for human tonsillar M cells and follicular dendritic cells

J Oral Pathol Med (2010) 39 : 533–539 Objective: Membranous (M) cell of the human palatine tonsil is an antigen entry site for mucosal infection, but its location is obscure in histological sections. Recently, a microarray analysis has demonstrated that clusterin, annexin A5, CD44, MMP14, and β‐tubulin are candidate genes of M cell marker in mice. Among these genes, we here describe class II β‐tubulin as a new marker for human tonsillar M cells and follicular dendritic cells (FDCs), and present its usefulness for diagnosis of angioimmunoblastic T‐cell lymphomas (AILTs). Materials and methods: Immunohistochemistry and Western blotting for class II β‐tubulin were performed using 81 cases of lymphoid, gastrointestinal and thyroid tissues, and an FDC cell line, respectively. Double immunostaining with clusterin and class II β‐tubulin were carried out. Results: Class II β‐tubulin localized the M cells and FDCs in the palatine tonsils (10/10, 100%) and adenoids (10/10, 100%). It was colocalized with clusterin in the palatine tonsils. However, class II β‐tubulin staining did not identify intestinal M cells in the intestines. Immunoblot analysis revealed that class II β‐tubulin expression was upregulated in HK cells, a normal FDC cell line. Class II β‐tubulin immunostaining highlighted hyperplastic FDC meshworks in all AILTs (14/14, 100%). Conclusion: Class II β‐tubulin is a specific histochemical marker for human tonsillar M cells and FDCs. Thus, class II β‐tubulin immunostaining may be useful to identify tonsillar M cells and to diagnose FDC proliferative lesions such as AILT.