Presence of EBV-DNA sequences in nasopharyngeal cells of individuals without IgA-VCA antibodies

Epstein-Barr virus-specific adoptive immunotherapy for recurrent, metastatic nasopharyngeal carcinoma

BACKGROUND

Early-stage and intermediate-stage nasopharyngeal cancer (NPC) generally carry a good prognosis, but for patients with recurrent, metastatic disease, options are limited. In the current study, the authors present a phase 1/2 study to evaluate the efficacy of Epstein-Barr virus (EBV)-stimulated cytotoxic T-lymphocyte (EBV-CTL) immunotherapy in this patient population.

METHODS

Screening for patients with active, recurrent, metastatic EBV-associated NPC began in February 2007, and the study was closed to accrual in January 2012. After informed consent was obtained, patients had their blood drawn to initiate manufacturing of the EBV-CTL product. During product manufacturing, patients were placed on interim standard-of-care chemotherapy, and only after disease progression on the interim chemotherapy did patients receive investigational immunotherapy. Patients were restaged every 2 months until disease progression and then followed for survival.

RESULTS

A total of 28 patients were enrolled, and 21 patients were treated. There was 1 complete response achieved, and at the time of last follow-up, the patient had been in remission for >8 years since treatment. The median progression-free survival was 2.2 months, and the median overall survival was 16.7 months. Two other patients, after failing EBV-CTL immunotherapy, unexpectedly demonstrated strong responses to the chemotherapy regimens they had previously failed. Patient EBV viral load and EBV-CTL specificity for tumor-associated viral antigens did not appear to correlate with clinical response.

CONCLUSIONS

A durable response was observed with EBV-CTL immunotherapy, but the overall response rate for patients with recurrent, metastatic NPC was low. Further research is necessary to increase the efficacy of EBV-specific immunotherapy in patients with incurable NPC, and to characterize mechanisms for refacilitation to chemotherapy. Cancer 2017;123:2642-50. © 2017 American Cancer Society.

Improved Accuracy of Detection of Nasopharyngeal Carcinoma by Combined Application of Circulating Epstein–Barr Virus DNA and Anti-Epstein–Barr Viral Capsid Antigen IgA Antibody

Background: Circulating Epstein–Barr viral (EBV) DNA and anti-EBV capsid antigen IgA (IgA VCA) represent two of the most sensitive peripheral blood markers of nasopharyngeal carcinoma (NPC), but direct comparative studies of these two markers are lacking.

Methods: The sensitivities and specificities of IgA-VCA and EBV DNA for diagnosis of NPC were determined in 139 new cases of NPC and 178 healthy individuals, respectively. EBV DNA was also assessed in 36 healthy family members identified as having false-positive IgA-VCA results at a screening clinic. EBV DNA was measured by a real-time quantitative PCR assay with a detection limit of 60 copies/mL. IgA-VCA was measured by semiquantitative indirect immunofluorescent method; a titer ≥1/10 was taken as positive.

Results: The sensitivities of EBV DNA and IgA-VCA for diagnosis of NPC were 95% (95% confidence interval, 91–98%) and 81% (73–87%), respectively. The combined marker panel had an overall sensitivity (positive result by either marker) of 99%. The concentrations of both markers showed dependence on cancer stage. The specificities of EBV DNA and IgA-VCA were 98% (96–99%) and 96% (91–98%), respectively. Among 36 healthy family members with false-positive IgA-VCA results, three-fourths had undetectable EBV DNA, whereas the others had increased EBV DNA concentrations that were significantly lower than in NPC patients.

Conclusions: For diagnosis of NPC, EBV DNA identifies almost all false-negative IgA-VCA cases and gives a 99% diagnostic sensitivity when combined with IgA-VCA. In the screening setting, EBV DNA identifies three-fourths of false-positive IgA-VCA cases. The selective application of EBV DNA in an IgA-VCA-based screening protocol could improve screening accuracy with only moderate increases in cost.

Cell-to-cell contact as an efficient mode of Epstein-Barr virus infection of diverse human epithelial cells

We show clear evidence for direct infection of various human epithelial cells by Epstein-Barr virus (EBV) in vitro. The successful infection was achieved by using recombinant EBV (Akata strain) carrying a selective marker gene but without any other artificial operations, such as introduction of the known EBV receptor (CD21) gene or addition of polymeric immunoglobulin A against viral gp350 in culture. Of 21 human epithelial cell lines examined, 18 became infected by EBV, as ascertained by the detection of EBV-determined nuclear antigen (EBNA) 1 expression in the early period after virus exposure, and the following selection culture easily yielded a number of EBV-infected clones from 15 cell lines. None of the human fibroblasts and five nonhuman-derived cell lines examined was susceptible to the infection. By comparison, cocultivation with virus producers showed approximately 800-fold-higher efficiency of infection than cell-free infection did, suggesting the significance of direct cell-to-cell contact as a mode of virus spread in vivo. Most of the epithelial cell lines infectable with EBV were negative for CD21 expression at the protein and mRNA levels. The majority of EBV-infected clones established from each cell line invariably expressed EBNA1, EBV-encoded small RNAs, rightward transcripts from the BamHI-A region of the virus genome, and latent membrane protein (LMP) 2A, but not the other EBNAs or LMP1. This restricted form of latent viral gene expression, which is a central issue for understanding epithelial oncogenesis by EBV, resembled that seen in EBV-associated gastric carcinoma and LMP1-negative nasopharyngeal carcinoma. The results indicate that direct infection of epithelial cells by EBV may occur naturally in vivo, and this could be mediated by an unidentified, epithelium-specific binding receptor for EBV. The EBV convertants are viewed, at least in terms of viral gene expression, as in vitro analogs of EBV-associated epithelial tumor cells, thus facilitating analysis of an oncogenic role(s) for EBV in epithelial cells.

Epstein-Barr virus DNA in nasopharyngeal carcinomas from Chinese patients in Hong Kong

AIMS

To investigate the presence of Epstein-Barr virus (EBV) in cases of nasopharyngeal carcinoma (NPC) in Chinese patients living in Hong Kong.

METHODS

Nasopharyngeal biopsy specimens, formalin fixed and paraffin wax embedded, from 24 patients, eight with undifferentiated nasopharyngeal carcinoma, eight with well differentiated squamous carcinoma, and eight showing normal tissue histology, were analysed for the presence of Epstein-Barr virus (EBV) DNA by slot-blot hybridisation on extracted unamplified DNA, and also after amplification of EBV specific sequences by the polymerase chain reaction (PCR).

RESULTS

DNA slot-blot analysis showed viral DNA in all the undifferentiated, five of the well differentiated tumours, and none of the normal biopsy specimens. PCR studies confirmed positivity in the eight undifferentiated tumours, but six of the well differentiated tumours and three of the normal biopsy specimens showed viral DNA by this method, illustrating its greater sensitivity.

CONCLUSIONS

EBV genome is present in appreciable copy number in most cases of well differentiated NPC in Chinese patients in Hong Kong.

EBV genome and immunoglobulin gene rearrangement in the differential diagnosis of nasopharyngeal carcinoma and lymphoma

Head and neck tumors include nasopharyngeal carcinoma (NPC) and lymphoma. The differential diagnosis of these tumors is based on histology, immunocytochemical staining, and EBV serology. In rare cases it might be difficult to distinguish between NPC and lymphoma in HE section or biopsies. DNA hybridization with cloned EBV and human immunoglobulin gene fragments allows the detection of EBV-related sequences and immunoglobulin gene rearrangements. The presence of EBV genome supports the diagnosis of NPC or EBV related BL, while rearrangement of immunoglobulin genes points to B-cell lymphoma. The diagnosis in 11 patients suspected of head and neck tumors was carried out by hybridization of DNA extracted from the tumors and assayed with cloned EBV and IgHCJ DNA probes. One patient proved to have EBV-associated BL based on positive hybridization with EBV probes and immunoglobulin rearrangement, presenting a unique hybridization with cloned EBV DNA BamHI W fragment, with bands of 3.2 and 3.9 kb. BL was confirmed in this patient by demonstration of c-myc rearrangement. A second patient was negative in hybridization with EBV, and positive for immunoglobulin rearrangement, and therefore was diagnosed as having B-cell lymphoma. In seven patients NPC was confirmed by hybridization with EBV-DNA probes. In two patients, both NPC and B-cell lymphomas were excluded.

Association of the Epstein-Barr virus with lymphoepithelioma of the thymus

A 30-year-old woman with the histologic diagnosis of lymphoepithelioma of the thymus is reported on. Investigation of Epstein-Barr serology showed evidence of infection, and Southern blot analysis showed the presence of the viral genome in the tumor specimen. The patient achieved complete remission after treatment with combination chemotherapy, autologous bone marrow transplant, and radiotherapy. These findings suggest that lymphoepithelioma of the thymus may have a viral pathogenesis similar to that of nasopharyngeal carcinoma.

The differentiated form of nasopharyngeal carcinoma contains Epstein-Barr virus DNA

Immunologic studies of Epstein-Barr virus (EBV) have implicated EBV in undifferentiated and partially differentiated, non-keratinizing nasopharyngeal carcinoma (NPC). Patients with the well-differentiated, keratinizing form of NPC have EBV serologic patterns similar to those of control populations. In addition, viral DNA has not been detected in the differentiated tumors using viral cRNA probes to DNA immobilized on filters. In this study we have tested for EBV DNA using recombinant DNA probes to Southern blots of DNA from 33 NPC specimens. The 24 undifferentiated and 4 partially differentiated specimens generally contained a relatively high number of EBV genome equivalents, while the 5 well-differentiated NPC all contained detectable EBV, but at low copy number. The viral DNA from one of the well-differentiated specimens was cloned into a cosmid vector. Five recombinant clones representing the fused viral termini were obtained, indicating the presence of episomal, intracellular DNA in the tumor. These findings indicate that all histologic subsets of NPC contain EBV DNA.

Epstein-Barr viral serology in nasopharyngeal carcinoma patients in the USSR and Cuba, and its value for differential diagnosis of the disease

Serological responses to Epstein-Barr virus (EBV)-associated antigens were studied in nasopharyngeal carcinoma (NPC) patients in 2 countries non-endemic for the disease: the USSR (77 cases) and Cuba (55 cases). Two age- and sex-matched control groups were available, one consisting of patients with other head-and-neck tumours (OHNT) (171 from the USSR and 56 from Cuba), and the other of normal individuals (blood donors) (83 from the USSR and 80 from Cuba). Unlike the control groups, NPC patients from both countries had high levels of IgG and IgA antibodies, similar to those seen in patients from endemic areas. The only difference between NPC patients in the USSR and those in Cuba was lower (2-2.5 fold) anti-VCA IgG and IgA antibody titres. Using one-factor and multi-factor statistical methods the diagnostic value of different titres of EBV-specific IgG and IgA antibodies and their combinations for NPC patients (in the USSR) was evaluated. It was found that with simple mathematical analysis of EBV-specific antibody titres a differential diagnosis of NPC could be made to a significance level of 90%. The data obtained demonstrated the importance and reliability of EBV serology in the diagnosis of NPC in areas of low incidence of the disease.

Evidence that respiratory tract is major reservoir for Epstein-Barr virus

Exfoliated cells harvested from bronchial washings of 53 patients with suspected bronchogenic carcinoma were tested by means of DNA dot hybridisation using the cloned large internal repeat (IR) sequence of Epstein-Barr virus (EBV) genome as a probe. 25 of these patients gave positive results. Since the patients had diseases that were not related to the virus, this finding suggests that the lower respiratory tract is a major reservoir for EBV. Attempts at cellular localisation of the virus revealed only an occasional cell which harboured the viral genome or expressed viral capsid antigens. These cells could not account for the quantity of the viral DNA detected in bronchial washings. Moreover, patients had similar profiles of serum EBV antibodies whether they were positive or negative for EBV DNA by dot hybridisation. These findings are compatible with a state of viral latency in which cells harbour a low copy number of the viral genome. Viral expression rarely occurs in these cells, which seem to elicit a minimum host immune response. If it is assumed that each latently infected cell harbours a maximum of approximately 30 EBV genomes (which is the lower limit of detection by the in-situ hybridisation method used in this study), the findings suggest that a considerable proportion of the exfoliative cells from the lower respiratory tract, of the order of 0.1-16%, harbour latent EBV.