Development of an anticomplement immunoenzyme test for detection of EB virus nuclear antigen (EBNA) and antibody to EBNA

Risk of lymphoid neoplasia after cardiothoracic transplantation. a cohort study of the relation to Epstein-Barr virus

BACKGROUND

Organ transplantation is associated with a greatly increased risk of Epstein-Barr virus (EBV)-associated lymphoproliferative disease (LPD), which is often fatal. There has been little epidemiological analysis, however, of the risk factors for LPD in transplant patients and none on whether the risks of non-EBV-associated lymphoid neoplasms are also increased.

METHODS

The risk of lymphoid neoplasia was assessed in a cohort of 1563 patients who underwent cardiothoracic transplantation at Harefield Hospital, UK from 1980 to 1994 and were followed until December 1995. EBV antibody was assessed in the patients before transplantation, and lymphoid neoplasms were assessed for EBV RNA and latent EBV gene expression.

RESULTS

Thirty cases of LPD occurred during follow-up. One lymphoma of unknown EBV status occurred. There were also six cases of EBV-negative non-Hodgkin's lymphoma (EBV-negative NHL), a highly significant excess over expectations from the general population rates of NHL (standardized incidence ratio 10.2 [95% confidence interval, 4.6-22.8]). The risk of LPD was significantly 10-fold raised in individuals who were EBV seronegative before transplantation; independently of this, it decreased steeply with age at transplantation and was greatest in the first year after transplantation. The risk was significantly raised in young seronegative recipients if the donor was older than the recipient. EBV-negative NHL occurred entirely in men 45 years old and older who were EBV seropositive before transplantation, and risk was not related to duration since transplantation.

CONCLUSIONS

The risk factors found for LPD accord with EBV etiology and with greater hazard from primary infection than from reactivation. A second non-Hodgkin's lymphoid neoplasm, not related to EBV, seems also to be a consequence of transplantation and immunosuppression but is unlikely to be due to first infection by a ubiquitous agent. Its etiology and prevention need investigation separately from LPD.

Establishing a KSHV+ Cell Line (BCP-1) From Peripheral Blood and Characterizing Its Growth in Nod/SCID Mice

Kaposi's sarcoma-associated herpesvirus (KSHV or HHV8) sequences are present in primary effusion lymphomas (PEL). KSHV+cell lines have been established from such lymphomas. Here we report the first description of the establishment of a KSHV+, EBV− cell line (BCP-1) from the peripheral blood of a patient with PEL. Using this cell line and a KSHV+, EBV+ PEL cell line (HBL-6) previously established from ascitic fluid, we investigated whether in nonobese diabetic/severe combined immunodeficiency disease (Nod/SCID) mice tumors representing PEL can be established. When injected intravenously (IV) into Nod/SCID mice, BCP-1 and HBL-6 infiltrated organs, with only occasional macroscopic tumor formation. Intraperitoneal injections (ip) led to the development of ascites and diffuse infiltration of organs, without obviously solid lymphoma formation, resembling the diffuse nature of human PEL. To investigate a possible mechanism for the peculiar phenotype of PEL, we examine the presence of adhesion molecules and homing markers on PEL cells before and after growing in mice. Both BCP-1 and HBL-6 cells lack expression of important cytoadhesion molecules including CD11a and CD18 (LFA1 α and β chains), CD29, CD31, CD44, CD54 (ICAM-1), and CD62L and E (L and E selectins).

Establishing a KSHV+ Cell Line (BCP-1) From Peripheral Blood and Characterizing Its Growth in Nod/SCID Mice

Kaposi's sarcoma-associated herpesvirus (KSHV or HHV8) sequences are present in primary effusion lymphomas (PEL). KSHV+cell lines have been established from such lymphomas. Here we report the first description of the establishment of a KSHV+, EBV− cell line (BCP-1) from the peripheral blood of a patient with PEL. Using this cell line and a KSHV+, EBV+ PEL cell line (HBL-6) previously established from ascitic fluid, we investigated whether in nonobese diabetic/severe combined immunodeficiency disease (Nod/SCID) mice tumors representing PEL can be established. When injected intravenously (IV) into Nod/SCID mice, BCP-1 and HBL-6 infiltrated organs, with only occasional macroscopic tumor formation. Intraperitoneal injections (ip) led to the development of ascites and diffuse infiltration of organs, without obviously solid lymphoma formation, resembling the diffuse nature of human PEL. To investigate a possible mechanism for the peculiar phenotype of PEL, we examine the presence of adhesion molecules and homing markers on PEL cells before and after growing in mice. Both BCP-1 and HBL-6 cells lack expression of important cytoadhesion molecules including CD11a and CD18 (LFA1 α and β chains), CD29, CD31, CD44, CD54 (ICAM-1), and CD62L and E (L and E selectins).

Analysis of the T-cell micro-environment in Epstein-Barr virus-related post-transplantation B lymphoproliferative disease

Epstein-Barr virus (EBV) post-transplantation B lymphoproliferative disease (BLPD) may undergo regression after immunosuppression withdrawal and restoration of EBV-specific cytotoxic T-cell (CTL) activity in the immunocompromised allografted host. The presence of morphologically normal T cells in the BLPD micro-environment may influence tumour behaviour in vivo. In this immunopathological study, the phenotype and the number of T cells and other immunoregulatory cells have been investigated in seven primary and four recurrent BLPD biopsies from nine solid organ transplant recipients. BLPD with either viral lymphadenopathic or polymorphic lymphoma appearances was found to contain sizeable T-cell populations, mainly of memory/helper (TCR alpha/beta +, CD3+, CD4+, CD45RO+) type. Cytotoxic (TCR alpha/beta +, CD3, CD8+, Tia-1+) T cells were strikingly low in all samples. Low CD28 and CD25 expression suggested that secondary signals for functional and sustained T-cell activation may be deficient in these tumours. No close correlation was found between the degree of T-cell infiltration and clinical outcome, although appreciably higher number of CD8+ T cells were detected in three BLPD tumours showing prolonged clinical remission after treatment. While some level of EBV-specific T-cell function may be present in untreated BLPD, the overall findings of this study suggest that the nature of T-cell infiltrates may reflect a response to immunosuppressive therapy rather than to EBV infection per se. The possibility that a local EBV-specific T-cell response is generated in BLPD undergoing regression after treatment needs to be investigated.

Analysis of the tumorigenic potential of common marmoset lymphoblastoid cells expressing a constitutively activated c-myc gene

The respective roles of Epstein-Barr virus (EBV) and c-myc in the pathogenesis of endemic Burkitt's lymphoma (BL) are unclear. In order to help resolve the question whether constitutive expression of the c-myc gene in an EBV-immortalised B cell is sufficient to induce a tumorigenic phenotype, B cells from a common marmoset (Callithrix jacchus) were immortalised with EBV, transfected with a constitutively activated c-myc gene and inoculated into the host animals. Despite the cell line transfected with c-myc displaying enhanced growth characteristics, in vitro and in vivo experiments demonstrated that this was not sufficient to induce a tumorigenic phenotype. This supports our previous findings with EBV-immortalised human B cells transfected with an activated c-myc gene (Hotchin et al., 1990).

Bcl-2 proto-oncogene expression in Epstein-Barr-virus-associated nasopharyngeal carcinoma

The bcl-2 proto-oncogene product inhibits apoptosis. Increased levels of bcl-2 protein are associated with prolonged B-cell survival and have been demonstrated in a high proportion of follicular B-cell lymphoma. Recent studies have shown that bcl-2 protein expression in B cells immortalized by Epstein-Barr virus (EBV) in vitro is up-regulated by the EBV-latency-associated antigen, latent membrane protein (LMP) 1. The epithelial malignancy, undifferentiated nasopharyngeal carcinoma (UNPC), has a well-established association with EBV and the tumour cells characteristically display a restricted latent viral phenotype including LMP 1. This study has investigated the relationship between the presence of EBV DNA, EBV phenotypic profiles and bcl-2 protein expression in conventionally processed and cryopreserved samples of NPC using in situ hybridization, immunocytochemical and immunoblotting techniques. bcl-2 was detected in most (80%) samples of UNPC as well as in 1/3 samples of keratinizing NPC and 2/2 samples of nasopharyngeal adenocarcinoma. However, no close correlation was found between the presence of EBV DNA, and profiles for LMP 1 and bcl-2 protein expression in 45 UNPC. In addition, bcl-2 protein was shown to be selectively expressed in the basal compartment of normal nasopharyngeal epithelia. bcl-2 protein expression has not been reported previously in malignant tumours of epithelial origin. The findings in this study implicate a role for bcl-2 both in normal keratinocyte differentiation and in the pathogenesis of epithelial malignancy.

Immunocytochemical detection of antibodies to Epstein-Barr virus nuclear antigen by a streptavidin-biotin-complex assay

An immunocytochemical staining for the detection of antibody to Epstein-Barr virus nuclear antigen in cell smears was developed by using a three-dimensional complex of streptavidin and biotin labeled with horseradish peroxidase as the detector system. The presence of antibody against Epstein-Barr virus nuclear antigen was revealed by a dark staining of the nuclei of Raji cells. A significant correlation was found between the titers obtained with our assay and titers obtained by anticomplement immunofluorescence on 110 serum samples. Our assay did not require an Epstein-Barr virus-negative serum source for fresh complement and gave a permanent record of the reaction that could easily be observed under an ordinary light microscope.

Expression of HLA-DR antigens in nasopharyngeal carcinoma: an immunohistological analysis of the tumour cells and infiltrating lymphocytes

A panel of conventional and monoclonal antibodies was used to examine the immunohistological characteristics of malignant epithelial cells and infiltrating lymphocytes in frozen sections of nasopharyngeal carcinoma (NPC) biopsies from 10 Tunisian patients. Three main categories of cells were identified. (1) Tumour cells which were positive for Epstein-Barr nuclear antigen, HLA-ABC and keratin determinants. In most samples, the tumour cells also expressed variable amounts of HLA-DR antigens. The presence of HLA-DR antigens has not been previously reported in NPC and may be a contributory factor in effecting the transfer of Epstein-Barr virus to the epithelial cells. (2) Infiltrating lymphocytes which were mainly composed of T inducer (T4+) and T suppressor/cytotoxic (T8+) cells although one sample contained predominantly immature T cells expressing the HTA-I+ cortical thymocyte phenotype. Few B cells or natural killer cells were demonstrated. (3) Large HTA-I+ dendritic cells which were invariably present within the tumour masses. These were morphologically and phenotypically similar to antigen presenting Langerhans cells which are usually located in the skin but also found in other epithelial sites. These cells may be a residual population from the normal nasopharynx or represent part of a specific immunological response to the presence of Epstein-Barr virus in the epithelial cells.

Serological mass survey for early detection of nasopharyngeal carcinoma in Wuzhou City, China

A serological mass survey was carried out in Wuzhou City of the Guangxi Autonomous Region, China. Sera were collected from 12,932 persons between the ages of 40 and 59. The positive rate of VCA/IgA antibody-positive person was 5.3%, but no EA/IgA antibody was found in sera from VCA/Iga-negative persons. Thirteen and nine nasopharyngeal carcinoma (NPC) patients were detected from the VCA/Iga and EA/IgA antibody-positive persons, respectively. With the present combination method the detection rate of NPC for 12,932 persons was 100.5/100,000 and for 680 VCA/IgA antibody-positive persons it was 1,900/100,000. Thus, the rate was twice and 37 times higher, respectively, than the annual incidence rate of NPC in persons of the same age group from 1975-1978 in Wuzhou City. Of 13 NPC patients, 9 were in stage I (70%) and 4 in stage II (30%). Therefore, it is possible to reduce the mortality rate of NPC in Wuzhou City by radiotherapy of NPC patients in the early stage of the disease. The present results further suggest that EB virus is closely associated with NPC.