Epstein-Barr virus-specific antibody titers in seven Alaskan natives before and after diagnosis of nasopharyngeal carcinoma

Epstein-Barr virus antibodies and the risk of associated malignancies: review of the literature

Epstein-Barr virus (EBV), a ubiquitous herpes virus that infects 90% of humans by adulthood, is linked to the development of various cancers, including nasopharyngeal carcinoma, gastric cancer, Burkitt lymphoma, non-Hodgkin lymphoma (NHL), and Hodgkin lymphoma. We reviewed the literature published since 1980 regarding an association between antibodies against EBV proteins and the risk of EBV-associated malignancies. Immunoglobulin A antibody levels that are elevated before diagnosis have consistently been associated with the risk of nasopharyngeal carcinoma, and patients with Hodgkin lymphoma have significantly higher immunoglobulin G antibody levels than disease-free controls. However, the link between the immune response to EBV and other EBV-associated malignancies was less clear. Although evidence of an association between the risk of Burkitt lymphoma and immunoglobulin G antibodies was consistent for available studies, the sample sizes were limited. Evidence for a link between antibodies against EBV and risk of either gastric cancer or NHL was inconsistent. Future investigations should account for tumor EBV status because only 7%-10% of gastric tumors and select NHL subtypes are related to EBV infection. Comparing differences in the associations between the humoral immune response to EBV and disease risk across cancers may help elucidate how this ubiquitous virus contributes to distinct tumors globally.

Fluctuations of epstein-barr virus serological antibodies and risk for nasopharyngeal carcinoma: a prospective screening study with a 20-year follow-up

Background

The impact of variation of Epstein-Barr virus (EBV) antibody titers before the development of nasopharyngeal carcinoma (NPC) is still unclear. We analyzed the fluctuations of antibodies against EBV before histopathological diagnosis to assess the risk of NPC and aimed to provide a reliable basis for screening in high risk populations.

Methods

This study was based on a population-based screening program in Sihui County in Guangdong Province of China. A total of 18,986 subjects were recruited in 1987 and 1992, respectively. Baseline and repeated serological tests were performed for IgA antibodies against EBV capsid antigen (VCA/IgA) and early antigen (EA/IgA). Follow-up until the end of 2007 was accomplished through linkage with population and health registers. Cox proportional hazards regression model was used to estimate the relative risk of NPC in association with EBV antibodies. Time-dependent receiver operating characteristic curve (ROC) analysis was used to further evaluate the predictive ability.

Results

A total of 125 NPCs occurred during an average of 16.9 years of follow-up. Using baseline information alone or together with repeated measurements, serological levels of VCA/IgA and EA/IgA were significantly associated with increased risks for NPC, with a striking dose-response relationship and most prominent during the first 5 years of follow-up. Considering the fluctuant types of serological titers observed during the first three tests, relative risk was highest among participants with ascending titers of EBV VCA/IgA antibodies with an adjusted hazard ratio (HR) of 21.3 (95% confidence interval [CI] 7.1 to 64.1), and lowest for those with decreasing titers (HR = 1.5, 95% CI 0.2 to 11.4), during the first 5 years of follow-up. Time-dependent ROC analysis showed that VCA/IgA had better predictive performance for NPC incidence than EA/IgA.

Conclusion

Our study documents that elevated EBV antibodies, particularly with ascending titers, are strongly associated with an increased risk for NPC.

Native early antigen of Epstein-Barr virus, a promising antigen for diagnosis of nasopharyngeal carcinoma

The Epstein-Barr virus (EBV) early antigen (EA) complex consists of multiple proteins with relevance for diagnosis of acute, chronic and malignant EBV related diseases, including nasopharyngeal carcinoma (NPC). In a recent study, it was found that the molecular diversity of EBV-specific IgG and IgA antibody responses in NPC patients and demonstrated that these reflect independent B-cell triggering leading to distinct EBV antigen-recognition profiles. The fine-specificity of NPC-related IgG and IgA responses was explored further against defined recombinant and synthetic EBV-EA antigens using immunofluorescence, immunoblot and ELISA techniques and determined their diagnostic value in a large panel of sera from NPC (n = 154), non-NPC tumor patients (n = 133), acute mononucleosis patients (n = 70) and healthy EBV carriers (n = 259). Individual recombinant EBV-EA markers yielded sensitivity/specificity values not exceeding 86%, whereas selected EA-specific peptide epitopes were rather poorly recognized by IgG and IgA antibodies in NPC sera. Surprisingly, we found that a "low salt" native EA-protein extract reproducibly prepared from purified nuclei of EA-induced HH514 cells, and containing characteristic EA(D)-polypeptides, such as p47-54 (BMRF1), p138 (BALF2), p55-DNAse (BGLF5), and p65-TK (BXLF1), but without viral capsid (VCA) or nuclear antigen (EBNA) reactivity, gave highest sensitivity (90.4%) and specificity (95.5%) values for NPC diagnosis in both IgG and IgA ELISA. The data support further the notion that EBV-EA reactive IgG and IgA antibodies in NPC patients are directed against distinct conformational and-in part-linear epitopes on EBV-specific proteins, barely recognized in other EBV-related syndromes. The use of a defined native EBV EA-specific antigen opens the way to further improve serological diagnosis of NPC.

In vivo real-time diagnosis of nasopharyngeal carcinoma in situ by contact rhinoscopy

BACKGROUND

Nasopharyngeal dysplasia or nasopharyngeal carcinoma in situ (NPCIS) lesions have rarely been reported. Timely diagnosis of the preinvasive lesion may improve prognosis. Contact endoscopy has been documented to accurately differentiate normal cells of the nasopharynx from malignant cells and allows a real-time diagnosis of primary and recurrent nasopharyngeal carcinoma (NPC) in a clinical setting. However, the role of contact endoscopy in the diagnosis of NPCIS is unknown.

METHODS

The superficial cells of the nasopharynx in a patient with NPCIS were examined in vivo under local anaesthesia by use of a contact rhinoscope. The contact endoscopic findings were correlated with the histologic findings of the biopsy.

RESULTS

The atypical cells of the lesion were magnified and visualized under contact endoscopy. Histopathologic analysis of the biopsied tissue confirmed the presence of NPCIS staining positively for Epstein-Barr virus (EBV)-encoded RNA (EBER). No cell-free EBV DNA was detected in the sera of the patient.

CONCLUSIONS

Contact endoscopy can accurately identify the atypical cells of a tiny preinvasive lesion in the nasopharynx in a clinical setting, which may not be evident in routine imaging examination.

Nasopharyngeal carcinoma in situ (NPCIS)--pathologic and clinical perspectives

BACKGROUND

Dysplasia or carcinoma in situ lesions (NPCIS) of the nasopharynx have rarely been reported. The prevalence, biologic behavior, and the transformation period of the pure preinvasive lesions have not been fully explained.

METHODS

All cases of NPCIS were retrospectively reviewed during the period between 1990 and 2000. The clinical features of all cases were studied. The biopsy samples were examined using light microscopy and in situ hybridization (ISH) for EBV-encoded RNA (EBER). The sera taken before and after the transformation were analyzed for anti-viral capsid antigen (VCA) EBV titers and circulating cell-free EBV DNA concentration.

RESULTS

Three cases of NPCIS were identified. Two of the three cases subsequently developed into invasive NPC after initial presentation. The interval of transformation varied from 40 to 48 months. In all three cases, the specimens showed abnormal findings on light microscopy and positive staining for EBER. Elevated anti-VCA titers were present in two of the preinvasive lesions. No cell-free EBV DNA was detected in the sera of these patients during the preinvasive phase of the disease.

CONCLUSIONS

Preinvasive NPC is a rare but distinct entity. Its transformation period can be as long as 4 to 5 years. Elevated anti-VCA titers, in the presence of abnormal cells on light microscopy, should alert the pathologist to perform ISH EBER studies to diagnose this rare condition.

Tissue specific distribution of Epstein-Barr virus (EBV) BZLF1 gene variants in nasopharyngeal carcinoma (NPC) bearing patients

Using EBV BNLF1 gene polymorphism, we have recently shown that, in NPC bearing patients, lymphocytes and tumor cells of the same individual were infected by different viruses. It appeared as a rule that EBV infection was by multiple strains in these immunocompetent, HIV negative patients. Our data did not detect any evident association between tumor cells and a particular BNLF1 variant. In the present paper, we extend our analysis to the BZLF1 gene of the viruses present in different sites of the same patients. Only two main variants of the BZLF1 gene were identified. Despite this very weak polymorphism of this locus, our results entirely confirm the very frequent occurrence of multistrain infections in these patients, and the presence of different EBV strains in tumor cells and lymphocytes from the same individual. However, in contrast to our results concerning the BNLF1 gene, the BZLF1 variants appeared to be cell type specific, one being associated mainly with epithelial or tumor cells and the other with lymphocytes. The possible reasons for this distribution are discussed.

Infections as a major preventable cause of human cancer

Infections may be responsible for over 15% of all malignancies worldwide. Important mechanisms by which infectious agents may induce carcinogenesis include the production of chronic inflammation, the transformation of cells by insertion of oncogenes and inhibition of tumour suppressors, and the induction of immunosuppression. Common characteristics shared by infectious agents linked to malignancies are that they are persistent in the host, often highly prevalent in the host population and induce cancer after a long latency. The associations between a selection of infectious agents and malignancies are covered in detail.

Antibodies to the Epstein-Barr virus transactivator protein (ZEBRA) as a valuable biomarker in young patients with nasopharyngeal carcinoma

Epstein-Barr virus (EBV)-associated nasopharyngeal carcinoma (NPC) generally occurs in adults, especially in high-prevalence populations such as the Chinese and Eskimos. In Maghrebian populations, young patients affected with this malignancy represent 25% of the total NPC cases. In adults with NPC, relatively high titers of IgA antibodies to the EBV viral capsid antigen (VCA) and early antigen (EA) represent important markers. However, nearly 50% of young NPC patients are negative for IgA-anti-VCA and -EA or exhibit very low titers of these antibodies. We report here that 92% of sera from young NPC patients negative for IgA-EA and 89% of those negative for IgA-VCA were positive for IgG antibodies to the EBV transactivator protein (ZEBRA) at very high titers. Our results show that in young patients with NPC these antibodies represent the most reliable marker for diagnosis and prognosis, particularly when compared with conventional NPC markers, i.e., IgA-VCA (58%) and anti-EA (25%). The titers of IgG-ZEBRA antibodies increased along with lymph node involvement only in the young patient group, suggesting a prognostic value of this marker in this patient group.

Late effects of radiation on the human immune system: an overview of immune response among the atomic-bomb survivors

The studies of the late effects of atomic-bomb (A-bomb) radiation on the immune system were started about 20 years after the bombings in 1945. The most remarkable late effects of radiation are the functional and quantitative abnormalities of T and B cells in survivors exposed to high doses (> or = 1.0 Gy). Abnormalities of T-cell immunity include (1) a decreased proportion of CD3+ T cells in peripheral blood lymphocytes, particularly the proportion of CD4+ CD45RA+ naive T cells (study period 1987-91); (2) an increased frequency of CD4- and CD8- (double negative) alpha beta + T cells (1987-91); and (3) functional defects in T-cell responses to mitogens and alloantigens (1974-85). B-cell abnormalities include: (1) a significant increase in the proportion of B cells among peripheral lymphocytes (1987-91); (2) an increase in serum immunoglobulin A levels in females and immunoglobulin M and the incidence of rheumatoid factor in both sexes (1987-89); and (3) an increased level of anti-Epstein-Barr virus antibody titer (1987-90). In contrast, suggestive (0.05 < p < 0.1) or not significant (p > 0.1) dose effects were observed for the number and function of natural killer cells (1983-91), and benign monoclonal gammopathy (1979-87). In addition, studies initiated sooner after the bombing such as the incidence of autoimmune diseases (1958-87), systemic bacterial infections (1954-67), and granulocyte functions (1947-79) also show little dose-effects. Thus, A-bomb radiation induced the alteration of the balance/interaction between the T- and B-cell subsets--specifically, a decrease in the T-cell population and an increase in the B-cell population in the periphery.

A molecular study of EBV DNA and p53 mutations in nasopharyngeal carcinoma of Saudi Arab patients

Tumor biopsies obtained from 25 Saudi Arab patients with nasopharyngeal carcinoma (NPC) were examined for the presence of Epstein-Barr virus (EBV) DNA detected by the polymerase chain reaction (PCR) and for the incidence of p53 mutations screened by a combination of PCR, single strand conformation polymorphism (SSCP) and PCR-restriction fragment length polymorphism (PCR-RFLP). DNA sequencing was carried out to confirm the occurrence of p53 mutation. While 92% of the tumor specimens were found to carry EBV DNA, only 1/25 showed the incidence of a homozygous mutation at codon 248 of the p53 gene. The data showed that despite a high association of EBV infection with Saudi NPC, the frequency of p53 mutations was very low. Our results are consistent with the worldwide observation of infrequent p53 mutations in NPC.

IgA directed against early antigen of Epstein-Barr virus is no specific marker for the diagnosis of nasopharyngeal carcinoma

The aim of this study was to evaluate the significance and specificity of IgA directed against Epstein-Barr virus (EBV)-specific early antigens (EA) for the unequivocal diagnosis of nasopharyngeal carcinoma (NPC). Therefore, sera from patients with diseases other than NPC, selected on the basis of elevated antibody titres against EBV antigens, were compared to sera from NPC patients with regard to the presence of IgA directed against EBV viral capsid antigen (VCA-IgA) and IgA directed against EA (EA-IgA). Four hundred forty-seven out of 7,508 non-NPC sera tested showed high titres (> 512) of IgG directed against Epstein Barr viral capsid antigen (VCA-IgG) and positive VCA-IgA (> or = 32). Two hundred twenty-seven of these sera were compared to 51 VCA-IgA-positive sera from NPC patients regarding the titre of EA-IgA. 60.7% of VCA-IgA-positive NPC sera showed positive EA-IgA, however 33% of VCA-IgA-positive non-NPC patients also exhibited EA-IgA. This result demonstrates that EA-IgA is not specific for NPC and does not allow an unequivocal serological diagnosis of NPC in individual cases. It seems therefore to be of questionable use for screening programs in NPC low-risk areas. The data do not contradict the usefulness of this marker for monitoring of patients treated for NPC and for screening programmes in high-risk areas.

A positive correlation between the precursor frequency of cytotoxic lymphocytes to autologous Epstein-Barr virus-transformed B cells and antibody titer level against Epstein-Barr virus-associated nuclear antigen in healthy seropositive individuals

A limiting dilution analysis was established to determine the precursor frequency (PF) of cytotoxic lymphocytes against autologous B cells transformed with the Epstein-Barr virus (EBV). This method was found to detect mainly self-restricted T-cell activity and little non-self-restricted cytotoxicity. The mean PF in 21 healthy EBV-seropositive persons was 1.4 x 10(-3) (range: 0.03 x 10(-3) to 8.7 x 10(-3)) for peripheral blood mononuclear cells, whereas 4 samples of mononuclear cells obtained from umbilical cord blood had PFs below 0.007 x 10(-3). A positive correlation was observed between the PF and serum antibody titers against EBV-associated nuclear antigen among the seropositive persons.

Epstein-Barr virus carriage by nasopharyngeal carcinoma in situ

We studied the distribution of the EBV genome in tumour biopsies obtained from 42 patients with poorly differentiated or undifferentiated nasopharyngeal carcinoma (NPC) and 3 patients with well-differentiated NPC. Six carcinoma in situ (CIS) foci were seen in 5 tumour specimens. By in-situ hybridization, multiple copies of the EBV genome were detected in some of the tumour cells in 3 CIS lesions involving the full thickness of the mucosal epithelium, but without microinvasion, while the viral genome was present in the majority of the tumour cells contained in another 3 CIS lesions with microinvasion. In agreement with previous findings, poorly differentiated and undifferentiated carcinomas regularly carried the viral genome, the number of copies of which was similar to that seen in CIS, while some, but not all, of the tumour cells of the well-differentiated histological type carried the virus. The viral genome was otherwise rarely detected in other areas of the mucosal epithelium and, where present, the viral carriage was confined to a few epithelial cells, in which the viral genome contents were markedly lower than in tumour cells. These results suggest that EBV may first become associated with NPC at an early stage of the disease shortly after the tumour has been initiated.

Immunoglobulin A against viral capsid antigen of Epstein-Barr virus and indirect mirror examination of the nasopharynx in the detection of asymptomatic nasopharyngeal carcinoma

To evaluate the efficacy of population screening for early stage nasopharyngeal carcinoma (NPC) in southern China, the authors recruited 42,048 and 10,402 apparently healthy subjects residing in a high incidence and a low incidence area, respectively; all subjects were between the ages of 30 and 59 years. The subjects' serum specimens were tested for immunoglobulin (Ig) A antibody against viral capsid antigen (IgA/VCA) of Epstein-Barr virus (EBV). Of the subjects from the high incidence area, 2823 were found to be seropositive. In follow-up, they had yearly examinations of the nasopharynx by indirect mirror with or without biopsy; 41 were found to have histologically confirmed asymptomatic NPC during the first 2 years of follow-up. The tumors in most of these cases were localized and were at earlier stages than tumors of symptomatic cases of NPC seen in the same region before the screening. The yearly indirect mirror examination of the nasopharynx seems to have effectively identified most of the tumors at the stage of asymptomatic disease. The risk of harboring NPC was found to be different among the different sex and age subgroups of seropositive individuals. By limiting such screening to those who are at exceedingly high risk, the cost of the screening can be kept within the spending of the public health authority, and the effectiveness of the screening also is improved.

Epstein-Barr virus antibody patterns preceding the diagnosis of nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) patients have elevated IgG and IgA antibody titers against the Epstein-Barr viral capsid antigen (VCA) and the diffuse component of the early antigen complex (EA-D) at diagnosis. Several studies have implied that the presence of anti-VCA-IgA can be used as a screening marker for early NPC. To evaluate this further, we undertook a serologic case-control study based on four serum banks which together had specimens from over 240,000 persons. Seven cases of undifferentiated or poorly differentiated NPC were diagnosed in the period after serum collection ranging from 26 months to 154 months. Two controls per case matched on serum bank, age, sex, race, and date of serum collection were selected by a predetermined random process. For anti-VCA-IgG, the geometric mean titer for cases (88.3) was significantly higher than that for controls (75.5, P less than 0.05). The difference was greatest among the Asian patients. No significant differences were found for anti-VCA-IgA, anti-EA-D, and anti-EA-R or anti-EBNA. No time effects were evident when titers were plotted against time of blood collection preceding diagnosis. Our results do not suggest EBV activation in the period preceding NPC diagnosis, nor that detectable IgA antibody against VCA is a marker for early disease.

Viruses and cancer. Causal associations

This review first considered some general problems in establishing causal links between a virus and a human cancer and offered some guidelines in the pursuit of this objective. Second, it reviewed the current causal associations for several candidate oncogenic viruses in relation to the tumors with which they are associated. These include Epstein-Barr virus in relation to Burkitt's lymphoma, nasopharyngeal carcinoma, Hodgkin's disease, and non-Hodgkin's lymphoma; hepatitis B and C viruses in relation to hepatocellular carcinoma; human T-cell leukemia/lymphoma virus type 1 and atypical leukemia/lymphoma; and human papilloma viruses in relation to cervical carcinoma. For some, the causal relationship is strong: hepatitis B virus with hepatocellular carcinoma, and human T-cell leukemia/lymphoma virus with adult T-cell leukemia/lymphoma. For one, the causal relationship is moderate: Epstein-Barr virus with African Burkitt's lymphoma. For others it is incomplete or inconclusive: Epstein-Barr virus with Hodgkin's disease and non-Hodgkin's lymphoma, and hepatitis C virus with hepatocellular carcinoma. Current techniques do not permit an answer for some: human papilloma virus with cervical carcinoma.

Detection of subclinical nasopharyngeal carcinoma by fibreoptic endoscopy and multiple biopsy

Of 6054 people who had high titres of antibodies against the viral capsid antigen of Epstein-Barr virus but no symptoms or signs of nasopharyngeal carcinoma as assessed by conventional methods, 130 were randomly recruited and examined by fibreoptic endoscopy and biopsy of several sites of the nasopharynx. 7 cases of nasopharyngeal carcinoma were detected. The tumours were largely confined to the pharyngeal recess, which suggests that it is the area of the nasopharynx most prone to the development of the tumour. Tumour was found in both recesses in 1 subject, who also had evidence of transition from severe epithelial dysplasia to carcinoma in a sample from the left roof, which suggests that the disease was multifocal in origin. This study showed that endoscopy and biopsy of several sites of the nasopharynx are more effective than the conventional approach in the detection of subclinical nasopharyngeal carcinoma among seropositive individuals at high risk of the disorder.

Evaluation of monoclonal antibodies for the detection of exfoliative nasopharyngeal carcinoma cells

Exfoliative cells were aspirated from 15 patients suspected of having nasopharyngeal carcinoma (NPC) and showing the presence of lesions or other abnormalities in the nasopharynx. They were tested for binding with a 125I monoclonal antibody (MAb) (MA6) which is selectively reactive against human B lymphocytes and a variety of carcinomas. A positive result was obtained from 6/9 patients with, and from 0/5 patients without, histologically confirmed disease. One patient with eskimoma also gave a negative binding result. Cytology was specific but less sensitive, tumour cells being detected in 3 of the patients with confirmed disease. Immunocytology using MA6 was limited, like cytology, by poor recovery of the tumour cells and the results were in complete concordance with cytology. The other MAbs used were raised against carcinoembryonic antigen (CEA) and a carcinoma cell line (Ca2), respectively. The latter was not reactive against the NPC tumour cells while the CEA antibody was not sufficiently selective to be useful.

Inhibitory effect of retinoid (E5166) on cell growth and suppressive effect on Epstein-Barr virus early-antigen induction by n-butyrate in nasopharyngeal hybrid cells

The in vitro proliferation and colony-forming activity (plating efficiency) of Epstein-Barr virus (EBV) nuclear antigen-positive nasopharyngeal hybrid cells were inhibited by one of the retinoid, polyprenoic acid; E5166. It was dependent on retinoid concentration. Furthermore, an induction of EBV early antigen after treatment with 4 mM n-butyrate was markedly suppressed by E5166 and this was similar to the previously reported effects of retinoid acid on iododeoxyuridine (IUDR) and 12-O-tetra-decanoyl-phorbol-13-acetate (TPA) induction. These results support to lead a clinical application of E5166 for combination chemotherapy in patients with nasopharyngeal carcinoma.

Epstein-Barr virus-associated malignancies

The infectious aspects of cancer in humans were epidemiologically pioneered by Dr. David Burkitt through his observations of lymphomatous tumors seen in children in equatorial Africa. Years, later, the Epstein-Barr virus (EBV) was shown to be intimately associated with such tumors and is now recognized as a component of some B-cell lymphomas and nasopharyngeal carcinoma. Still the questions of an active, passive, or accessory role persist. The ability of this virus to cause immunosuppressive hemopoietic disturbances in individuals infected with EBV but not developing cancer raise questions about host susceptibility, host immune response, and possible coconspiring, infectious, oncogenic agents. Recent associations of EBV antibody found in diseases, such as squamous cell carcinoma of the head and neck and acquired immunodeficiency syndromes, point to its possible accessory role as an immunosuppressive agent. The ability of EBV to spread by extracellular and intracellular mechanisms demonstrates its variable infectious potential. Numerous EBV-transformed human cell lines attest to its ability to confer "immortality" with uncontrolled growth patterns. This review critically examines the association of EBV with various malignancies, the type of evidence which links it there, and the implications for further investigations and therapy.

Familial clustering of salivary gland carcinoma in Greenland

Salivary gland carcinoma (SGC) occurs at an increased frequency in the Eskimo population. In Greenland the incidence of SGC is 4.5-fold higher for men and 9-fold higher for women as compared with European incidence. The increased incidence is caused by low-differentiated carcinoma. Unusual familial clustering of SGC is reported among two families (five siblings). Peculiar aspects of racial and geographical distribution and possible role of genetic and environmental factors in the etiology of this relatively uncommon tumor are briefly discussed with special emphasis on the recently detected association between the Eskimos' SGC and the Epstein-Barr virus.

Detection of IgA antibodies to Epstein-Barr virus-associated antigens by ELISA

The detection of IgA antibodies to the Epstein-Barr virus (EBV)-associated viral capsid antigen (VCA) and early antigens (EA) is of diagnostic and prognostic importance for patients with nasopharyngeal carcinoma (NPC). An ELISA for the determination of serum IgG antibodies to these antigens has been developed which uses the double antibody method. 136 sera obtained from healthy donors and patients with non-EBV related tumors and lymphomas were tested by ELISA; only 3 sera, from patients with chronic lymphatic leukemia, hairy cell leukemia and Burkitt-like lymphoma, contained antibodies of IgA class to VCA and EA. Ninety-five sera from patients suspected of having NPC were tested. IgA anti-VCA was found in 28 sera (29.5%), 12 of which also contained IgA anti-EA. The assays described are suitable for diagnosis and follow-up of patients with EBV-associated nasopharyngeal carcinoma. Furthermore, isolated EA components may be tested for their reactivity with IgA antibodies, as was shown for the 60 kDa polypeptide associated with the EA complex.

Presence of elevated antibody titres to Epstein-Barr virus before Hodgkin's disease

Sera taken 12 and 21 months before the diagnosis of Hodgkin's disease in two patients showed higher antibody levels to several Epstein-Barr-virus (EBV) antigens than did sera from eight matched controls. In one case the titres of all EB antibodies except that to nuclear antigen were raised in a serum sample obtained 45 months after the diagnosis was made. Antibody levels to herpes simplex, cytomegalovirus, and varicella zoster viruses were normal in both cases. A third patient with histiocytic lymphoma had normal EBV and other herpes antibody titres in a serum sample taken 40 months before diagnosis.