Epstein-Barr virus in Hodgkin disease. Relation to age and subtype

Inflammatory marker testing in primary care in the year before Hodgkin lymphoma diagnosis: a UK population-based case-control study in patients aged ≤50 years

BACKGROUND

Proinflammatory conditions are associated with increased risk of Hodgkin lymphoma, although the neoplastic process per se often induces an inflammatory response.

AIM

To examine pre-diagnostic inflammatory marker test use to identify changes that may define a 'diagnostic window' for potential earlier diagnosis.

DESIGN AND SETTING

This was a matched case-control study in UK primary care using Clinical Practice Research Datalink data (2002-2016).

METHOD

Primary care inflammatory marker test use and related findings were analysed in 839 Hodgkin lymphoma patients and 5035 controls in the year pre-diagnosis. Poisson regression models were used to calculate monthly testing rates to examine changes over time in test use. Longitudinal trends in test results and the presence/absence of 'red-flag' symptoms were examined.

RESULTS

In patients with Hodgkin lymphoma, 70.8% (594/839) had an inflammatory marker test in the year pre-diagnosis versus 16.2% (816/5035) of controls (odds ratio 13.7, 95% CI = 11.4 to 16.5, P<0.001). The rate of inflammatory marker testing and mean levels of certain inflammatory marker results increased progressively during the year pre-diagnosis in Hodgkin lymphoma patients while remaining stable in controls. Among patients with Hodgkin lymphoma with a pre-diagnostic test, two-thirds (69.5%, 413/594) had an abnormal result and, among these, 42.6% (176/413) had no other 'red-flag' presenting symptom/sign.

CONCLUSION

Increases in inflammatory marker requests and abnormal results occur in many patients with Hodgkin lymphoma several months pre-diagnosis, suggesting this period should be excluded in aetiological studies examining inflammation in Hodgkin lymphoma development, and that a diagnostic time window of appreciable length exists in many patients with Hodgkin lymphoma, many of whom have no other red-flag features.

State of the Art and Future Challenges in Multiple Sclerosis Research and Medical Management: An Insight into the 5th International Porto Congress of Multiple Sclerosis

The 5th International Porto Congress of Multiple Sclerosis took place between the 14th and 16th of February 2019 in Porto, Portugal. Its intensive programme covered a wide-range of themes-including many of the hot topics, challenges, pitfalls and yet unmet needs in the field of multiple sclerosis (MS)-led by a number of well-acknowledged world experts. This meeting review summarizes the talks that took place during the congress, which focussed on issues in MS as diverse as the development and challenges of progressive MS, epidemiology, differential diagnosis, medical management, molecular research and imaging tools.

Epstein-Barr virus and Hodgkin lymphoma in Jordan

BACKGROUND AND OBJECTIVES

This study aims to examine the possible association of Epstein-Barr virus (EBV) in Classical Hodgkin lymphoma (cHL) and to shed light on the epidemiology of Hodgkin lymphoma (HL) in Jordan.

PATIENTS AND METHODS

We examined 100 consecutive cases of HL for the presence of EBV in tumor cells by immunohistochemistry for latent membrane protein-1 (LMP-1). We collected patient data on age, sex and histologic subtype. We reviewed the pathological findings in each case and confirmed diagnosis.

RESULTS

Nodular lymphocyte predominant HL was diagnosed in 6% of the cases and these were negative for EBV LMP-1. Of the 94 cases of cHL, 65% were males, the most common subtype was nodular sclerosis (NS), representing 70% of the cases, and 45.7% of cHL (43% of all HL) cases were positive for EBV LMP-1. The positive cases were significantly related to age: ⩽15 years and >51 years (p: 0.009 and 0.014 respectively), male gender (p: 0.03) and mixed cellularity (MC) subtype (p: <0.0001). In line with other developing countries, there also appears to be a trend towards a decreasing association of EBV with cHL and a subtype switch from MC to NS in Jordan.

CONCLUSION

The epidemiology of HL in Jordan and some developing countries is approaching that of developed countries.

Comparison of three methods for the detection of Epstein-Barr virus in Hodgkin's lymphoma in paraffin-embedded tissues

The percentage rate of Epstein-Barr virus (EBV)-positive cases of Hodgkin's lymphoma (HL) ranges between 20 and 70% in various studies worldwide. To further explore the definite rate in China, three methods, including immunohistochemistry for EBV latent membrane protein 1 (LMP1), in situ hybridization (ISH) for EBV-encoded RNA (EBER)-1 and polymerase chain reaction (PCR) for EBV BamHI‑W fragment, were employed to detect EBV in 59 cases of HL in China using paraffin-embedded tissue samples. Our results revealed that the PCR method presented the highest (44/59, 74.6%) detection rate among the three methods. The other two methods identified 66.1% (39/59, LMP1) and 67.8% (40/59, EBER1 ISH) EBV-positive results, respectively. Three samples were positive for LMP1 but negative when using EBER1 ISH, while another four samples were EBER1-positive but LMP1-negative. Of the four major histopathological subtypes of HL, the lymphocyte predominant (LR) subtype is the one most frequently associated with EBV, followed by the mixed cellularity (MC), nodular sclerosis (NS) and lymphocyte depletion (LD) subtypes. Our results also indicated the seldomly reported fact that EBV-positive cases in children were more numerous than those of adults with HL.

Epstein-Barr virus and Hodgkin's lymphoma in Cairo, Egypt

Fifty-five consecutive cases of Hodgkin's lymphoma (HL), collected between 1996 and 1998 from Cairo, Egypt, were histologically subtyped, phenotyped, and then studied for the presence of Epstein-Barr virus (EBV). We used immunohistochemical stains for EBV latent membrane protein 1 (LMP-1) and in situ hybridization stains for EBV-encoded small RNA (EBER-1) transcripts. Forty-five cases (82%) had classic HL (cHL), and ten cases (18%) had nodular lymphocyte predominant HL (NLPHL), with each group expressing its typical phenotype. LMP-1 stains were positive in 63% and 0% of cHL and NLPHL cases, respectively. EBER-positive Reed-Sternberg cells and variants were also present in 62% and 0% of each group, respectively. The cHL cases showed variable EBER positivity: nodular sclerosis, 58%; mixed cellularity, 100%; lymphocyte depletion, 100%; and unclassifiable, 67%. Our findings are similar to those from other developing countries and point towards a pathogenic role of EBV in cHL.

Utility of fascin and JunB in distinguishing nodular lymphocyte predominant from classical lymphocyte-rich Hodgkin lymphoma

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) and lymphocyte-rich classical Hodgkin lymphoma (LRCHL), although clinically and morphologically similar, differ biologically and in prognosis. Immunolabeling of Reed-Sternberg (RS) cells in LRCHL and lymphocytic and/or histiocytic variants (L&H cells) in NLPHL is often required to help distinguish between the 2 variants. Our aim was to evaluate fascin (a distinct 55-kd actin-bundling protein) and JunB (an activator protein-1 family transcription factor) to differentiate NLPHL from LRCHL. A total of 35 archival cases of NLPHL (n = 24) and LRCHL (n = 11) from adults and children were studied. Slides were reviewed for all cases and clinical, morphologic, and immunohistochemical features were evaluated. Each case was immunostained for fascin and JunB, and immunoreactivity of RS cells, L&H cells, and background lymphocytes were recorded. Whereas occasional L&H cells were weakly positive for fascin in 3 out of 24 (12.5%) cases of NLPHL, RS cells in LRCHL were positive for fascin in 11 out of 11 (100%) cases with a strong cytoplasmic staining pattern. JunB was positive in 10 out of 24 (41.7%) of NLPHL cases, and 11 out of 11 (100%) of LRCHL cases, showing a stippled and/or diffuse nuclear staining pattern. In addition to L & H Cells, JunB also stained small background lymphocytes, particularly in areas of progressively transformed germinal centers of NLPHL. Either stains when tested alone, if negative, or with rare L&H cell weak positivity for fascin, is indicative of NLPHL. The L&H cells of NLPHL cases were negative for concomitant staining in 24 out of 24 (100%) cases. Concomitant positive staining of classic RS cells for fascin and JunB was found in 11 out of 11 (100%) of LRCHL cases. Although fascin positivity alone supports the diagnosis of LRCHL, concomitant positivity offers stronger support and is less likely to lead to a false conclusion if aberrant fascin staining were to be encountered in a case of NLPHL. Staining for fascin and JunB provides a basis for distinguishing NLPHL from LRCHL and offers an alternative to other antibody profiles.

Expression of Epstein-Barr virus in Hodgkin lymphoma in a population of United Arab Emirates nationals

Hodgkin lymphoma (HL) shows wide geographic variation in histological subtypes and in its association with the Epstein-Barr virus (EBV). HL has three main epidemiological patterns (I, II and III). Type I pattern, which is prevalent in developing countries, shows a relatively high incidence in male children, a low incidence in the third decade and a second peak of high incidence in older age groups. Type III, which is usually seen in developed countries, is characterised by a low rate in children and a pronounced initial peak in young adults. The third pattern (Type II), which is described in many Asian countries, is intermediate and reflects a transition between types I and III. In this pattern there is both a childhood and a third decade peak. The proportion of EBV positive HL is low in industrialised countries, high in non-industrialised countries and intermediate in early-industrialised countries. Reports from the Arabian Gulf and Middle East are few. The aim of this study is to determine the epidemiology of HL in a population of United Arab Emirates (UAE) nationals, an early industrialised country in the Arabian Gulf, and to delineate the extent of its association with EBV. In total, 88 cases of HL were diagnosed in native patients during the period 1988 through 2004 at Tawam hospital. Forty-five paraffin blocks were available for this study. Five-micrometer sections were prepared and stained with hematoxylin and eosin and the immunohistochemical streptavidin-biotin methods for CD45, CD3, CD20, CD15 and CD30. Other sections were examined for the presence of EBV using the immunohistochemical streptavidin-biotin method for the latent membrane protein 1 and in situ hybridisation for EBV encoded RNA to determine the prevalence of EBV in Hodgkin cells and its possible role in the pathogenesis of HL. Nodular sclerosis (NS) subtype was the most common type of HL among UAE nationals followed by mixed cellularity (MC), lymphocytic predominant (LP), unclassified, lymphocytic depletion (LD) and lymphocyte rich (LR) subtypes, respectively. EBV was seen in 17 of 45 (38%) cases of HL and was predominately seen in the MC subtype followed by NS, LD and LR subtypes, respectively. EBV was more frequently expressed in HL in the pediatric age group than the adult age group. These data indicate that the epidemiology of HL in a native population of the UAE is suggestive of a type II epidemiologic pattern in terms of age distribution, and histopathologic subtypes, whereas the frequency of EBV expression is more suggestive of a type III epidemiologic pattern. The significant association between EBV and HL that we have found further strengthens the suggestion that all cases of HL should be assessed for EBV status, because its presence may have a significant impact on prognosis and response to therapy.

Association between Epstein-Barr virus and Hodgkin's lymphoma in Belgium: a pathological and virological study

The association between Epstein-Barr virus (EBV) and classical Hodgkin's lymphoma (cHL) varies according to the geographic location. In this work we sought to characterize EBV involvement in a series of 111 cHL cases diagnosed in Belgium. The overall prevalence of EBV infection detected by in situ hybridization in Reed-Sternberg cells was 33%. EBV positivity correlated with older age at diagnosis (>54 years; p = 0.01), mixed cellularity subtype (p = 0.000001), male gender (p = 0.004) and tended to be associated with higher clinical stage (III/IV; p = 0.02). The molecular features of the virus in EBV-positive cHL were studied by comparison with a series of reactive tonsils. A 30-bp deletion within the LMP-1 gene was in 15/28 (53.6%) EBV-positive cHL cases, and in 41.7% of reactive tonsil samples. This variant did not correlate with any clinical or pathological feature. The EBV strain was type A in all cHL and reactive samples.

Association of Hodgkin's lymphoma with Epstein Barr virus infection

The role of Epstein Barr virus (EBV) in the onset of Hodgkin's lymphoma has been a subject of ongoing research. However, confirmation of EBV oncogenic involvement was not possible due to the small number of neoplastic cells characteristic for this type of tumor. Presence of EBV infection in neoplastic and non-neoplastic cells was analyzed in 81 cases of Hodgkin's lymphoma. In neoplastic cells, using an immunohistochemical method, latent membrane protein 1 (LMP1) was found in 33,3% of cases, while in situ hybridization results demonstrated the presence of EBER RNA in 48,1% of the cases. EBER RNA was found in non-neoplastic lymphocytes in 38,3% of cases. EBV is most frequently associated with Hodgkin's lymphoma in the first and seventh decade of life, specifically the nodular sclerosis subtype. No apparent difference was observed in the association of Hodgkin's lymphoma with EBV between genders, or in relation to clinical stage of the disease and average age of the patient. However, association with childhood age is significantly greater in comparison to adults. EBV associated disease shows a significantly greater prevalence in T lymphocytes. Slightly more abundant are cytotoxic T lymphocytes, which are also more frequently in contact with Reed-Sternberg cells, although there is no difference in number and positioning of histiocytes. Variations between the data on the association of EBV with Hodgkin's lymphoma among studies from different parts of the world suggest that factors of age, gender, ethnic background and social status might present biological modifiers of EBV influence on the pathogenesis of this neoplasm. The differences in non-neoplastic infiltrate EBV+ and EBV- lymphoma indicate the effect of the virus on the immune interaction of tumor and host in this disease.

HHV-6 and EBV DNA quantitation in lymph nodes of 86 patients with Hodgkin's lymphoma

Human herpesvirus (HHV-6) and Epstein-Barr virus (EBV), are two ubiquitous human herpesviruses which share many common features although they belong to different sub-families. In particular, both viruses are found in lymph nodes of patients suffering from Hodgkin's lymphoma. The aim of this study was to detect and to quantify independently HHV-6 and EBV by a real-time PCR in lymph nodes from 86 patients with Hodgkin's lymphoma. EBV quantitative method was compared with LMP-1 protein detection among the same samples. EBV genome was detected for 61.6% of the patients (53/86) and the highest prevalence of this virus was observed in Hodgkin's lymphoma with mixed-cellularity histopathological type (80%). In contrast to that, HHV-6 genome was detected for 79.1% of the patients (68/86) and was most observed in the nodular-sclerosis group (83.6%). Among the 68 HHV-6 positive samples, 63 belonged to the B subtype. A large number of biopsies (47.7%) were positive for both viruses whereas a little number (7%) was negative for both. EBV quantitation and LMP-1 immunohistochemistry were correlated statistically but this latter technique was less sensitive. Among the nodular-sclerosis patients, HHV-6-/EBV+ patients were significatively older than HHV-6+/EBV- patients. Patients infected dually had higher values of quantitation for each virus than those positive for one virus. Data of the clinical follow-up obtained by diagnosis and during the treatment of 83 patients, were correlated with the virological findings.

Pathobiology of Classical Hodgkin Lymphoma

The World Health Organization has acknowledged the malignant nature of classical Hodgkin lymphoma (cHL), which encompasses four histological subtypes. The diagnosis of cHL is based on the detection of malignant Hodgkin and Reed-Sternberg cells (HRSC) confirmed by immunophenotyping and the detection of growth patterns specific to each histological subtype. The pathologic HRSC arise from germinal center or immediate postgerminal cells that lack detectable immunoglobulin/B-cell antigen receptor expression, with a consequent loss of B-cell identity; very few cHL cases are of T-cell origin. To escape apoptosis, which normally occurs in B cells with nonfunctioning antigen receptor machinery, HRSC develop concurrent antiapoptotic mechanisms by activation of nuclear factor-kappaB or are rescued by Epstein-Barr virus infection. HRSC are characterized by a variable and inconstant immunophenotype, with a remarkable loss of lineage-specific cell antigens and expression of antigens of other cell lineages. The master plan of B-cell identity in HRSC is disturbed not only at the immunoglobulin expression level, but also at the transcriptional factor level. HRSC are further characterized by profound cell cycle deregulation with futile replication, multinucleation and poly- and aneuploidy. Here, we review pathobiological aspects of cHL with respect to lymphomagenesis and routine diagnostics.

Association between the Epstein-Barr virus and Hodgkin's lymphoma in the North-Eastern part of Hungary: effects on therapy and survival

This retrospective study included 109 patients with Hodgkin's lymphoma (HL; 45 females, 64 males). In 47 of the 109 HL patients (43%), immunohistochemical analysis of their formalin-fixed, paraffin-embedded histologic samples revealed Epstein-Barr virus (EBV) by latent membrane protein (LMP) 1. The highest virus association (50%) was found with the mixed cellularity histologic subtype, especially in patients aged 11-20 and >50 years. Virus positivity in nodular sclerosis was 35% (negative cases accumulated in patients aged 15-30 years). Regarding clinical stages, histologic subtypes, general symptoms, treatments employed and response to treatment, the EBV-positive group was not significantly different from the virus-negative group. During the mean follow-up time of 83 months (9-300 months), the overall or event-free survival of EBV-negative patients was more favorable than that of EBV-positive patients, although the difference was not significant (p = 0.16 and p = 0.24, respectively). EBV infection may be involved in the pathogenesis of HL in our Hungarian study cohort, but it does not significantly affect clinical symptoms, therapeutic results or complete and event-free survival of HL patients.

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.

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.

Longer failure-free survival interval of Epstein-Barr virus-associated classical Hodgkin's lymphoma: a single-institution study

We analyzed Epstein-Barr virus association in classical Hodgkin's lymphoma from a single center in Austria with special emphasis on the latent membrane protein1 gene configuration and clinical outcome. All 119 (65 male, 54 female) patients were treated from 1974 to 1999 in the Division of Hematology and Oncology at the Department of Internal Medicine, University of Innsbruck, Austria. The mean follow-up time was 122 months (range, 3-333 mo). Epstein-Barr virus was examined by latent membrane protein1 immunohistochemistry and by in situ hybridization for Epstein-Barr virus-encoded early ribonuclein acid transcripts. For assessment of the Epstein-Barr virus subtype (A/B) and latent membrane protein1 gene configuration, the polymerase chain reaction was employed. Fifty-four reactive tonsils were used as the control population. These results as well as clinical parameters such as age, gender, tumor stage, risk factors, and B symptoms were correlated with failure-free and overall survival. Latent membrane protein1 was detected in 31/119 (26%) classical Hodgkin's lymphoma, and Epstein-Barr virus subtyping was successful in 19 of the 31 virus-infected classical Hodgkin's lymphoma cases, as well as in 28 of 54 reactive tonsils. Subtype A was observed in all classical Hodgkin's lymphoma patients and in 26/28 (93%) tonsils. The 30-base pair latent membrane protein1 gene deletion was found in only 4/31 (13%) Epstein-Barr virus-associated classical Hodgkin's lymphoma as well as in 20/54 (37%) reactive tonsils. Patients with Epstein-Barr virus-associated classical Hodgkin's lymphoma showed a significantly longer mean time to first relapse of 99 months, as compared with 49 months for the Epstein-Barr virus-negative cases (P <.02), and were more frequent in those aged >45 years (P <.04). Epstein-Barr virus-associated classical Hodgkin's lymphoma were predominantly of the mixed-cellularity subtype and occurred more frequently in male patients, in patients with Stage III and IV, and in patients with B symptoms as well as risk factors. However, overall survival did not correlate with Epstein-Barr virus association. The 30-base pair latent membrane protein1 gene deletion had no influence on overall survival and failure-free survival time. Although the number of patients with this specific mutation was low, it further shows that an increased oncogenic potential of the latent membrane protein1 deletion variant is unlikely. This large single-center study demonstrates a low prevalence of Epstein-Barr virus positivity in classical Hodgkin's lymphoma in western Europe. In accordance with results of similar studies, the presence of Epstein-Barr virus has a beneficial effect on the length of failure-free survival despite the higher frequency of risk factors such as higher tumor stage or advanced age.

Epstein-Barr virus expression in Hodgkin's lymphoma in Kuwait

The epidemiology of Hodgkin's lymphoma (HL) shows wide geographic variation in histological subtypes and in its association with the Epstein-Barr virus (EBV). The proportion of EBV positive HL is low in industrialized countries, high in non-industrialized countries and intermediate in early-industrialized countries. Reports from the Persian Gulf and Middle East are very limited. The aim of this study was to determine the epidemiology of HL in Kuwait, an early-industrialized country in the Persian Gulf, and to delineate the extent of its association with EBV. We reviewed 134 cases of HL for histological classification and demographic data. 107 cases were examined for the presence of EBV using immunohistochemistry (IHC) for the latent membrane protein I (LMPI) and in-situ hybridization (ISH) for EBVencoded RNA (EBER). 70.4% of the patients were males and 29.6% were females. The male: female ratio was 2.4:1. The mean age was 30.6 years (range, 4-71 years). Mixed cellularity HL (MCHL) was the most common subtype (45.5%), followed by nodular sclerosis (37.3%), nodular lymphocyte predominant (6.7%), lymphocyte rich (3%) and lymphocyte depletion (3%). 4.5% of cases were unclassifiable. EBV expression was seen in 56%, was significantly higher in MCHL, in children, and in males. Our findings suggest that the frequency of EBV expression in HL in Kuwait is similar to other early-industrialized countries. Further research from other countries in the Persian Gulf and the Middle East should shed more light on the epidemiology of HL and its relation to EBV in this region.

Viruses and Hodgkin disease: no evidence of novel herpesviruses in non-EBV-associated lesions

The Epstein-Barr virus (EBV) is associated with a proportion of cases of Hodgkin disease (HD) and this association is believed to be causal. Epidemiological studies suggest that an infectious agent is involved in the aetiology of young adult HD, however, cases in this age group are less likely to have EBV-associated disease than cases diagnosed in early childhood or older adult years. Molecular studies have failed to find a consistent association between HD and other candidate viruses, and the aetiology of non-EBV-associated cases remains obscure. We looked for evidence of herpesvirus infection in samples of non-EBV-associated HD using a highly sensitive, degenerate PCR assay. Despite exhaustive sequence analysis of PCR products, no novel herpesviruses were identified. These results suggest that it is extremely unlikely that a novel herpesvirus is involved in the pathogenesis of non-EBV-associated HD.

Hodgkin disease in adult and juvenile groups from two different geographic regions in Brazil: characterization of clinicopathologic aspects and relationship with Epstein-Barr virus infection

We analyzed clinicopathologic data, immunophenotype, and Epstein-Barr virus (EBV) status in 96 cases of Hodgkin disease (HD) in juveniles (younger than 20 years) and adults (20 years or older) from 2 distinctive states in Brazil. We studied 34 juvenile (group 1) and 16 adult (group 2) cases from Ceara and 31 juvenile (group 3) and 15 adult (group 4) cases from São Paulo. Ceara has a socioeconomic profile similar to a developing country; São Paulo is in better economic condition. Mixed cellularity (MC) was the major histologic subtype among groups 1 (22 [65%]), 3 (21 [68%]), and 4 (7 [47%]); nodular sclerosis (NS) was more frequent in group 2 (8 [50%]). EBV infection was observed in 61 cases (64%), including the following (among others): group 1, MC, 22 (65%) and NS, 4 (12%); group 2, NS, 3 (19%) and MC, 2 (12%); group 3, MC, 16 (52%) and NS, 1 (3%); and group 4, MC, 7 (47%). There was predominance of EBV+ HD cases in group 1 compared with group 3. HD in Brazilian patients is highly associated with EBV infection, but geographic differences reflect histologic subtypes and age distribution.

Epstein-Barr virus (EBV) in Chinese pediatric Hodgkin disease: Hodgkin disease in young children is an EBV-related lymphoma

BACKGROUND

The Epstein-Barr virus (EBV) is thought to be involved in the pathogenesis of some Hodgkin disease (HD) cases. EBV may be associated particularly with childhood HD, a disease rare in the West compared with developing countries. In this study, a large series of Chinese pediatric HD cases has been examined to determine the age-specific prevalence of EBV.

METHODS

Paraffin sections from 104 pediatric and 52 adult Chinese HD cases were examined for EBV-RNA (EBERs) and EBV latent membrane protein-1.

RESULTS

Most pediatric cases arose in boys and showed an histology of mixed cellularity. Prominent interfollicular involvement was seen frequently in the childhood cases. EBV was identified in tumor cells in 113 of 156 (72%) HD cases but was more frequent in pediatric cases (93 of 104; 89%) compared with adult cases (20 of 52; 38%) (P < 0.01; chi-square test). EBV was found in 86 out of 91 (95%) cases in children aged 3-10 years and in 7 out of 13 (54%) cases in children aged 11-14 years (P < 0.01; chi-square test). The virus was less frequent in cases in young adults than in old adults, although this trend was not significant (P > 0.05; chi-square test). Pediatric HD was associated with EBV irrespective of histologic subtype. In adults, EBV was associated more frequently with mixed cellularity than with other subtypes.

CONCLUSION

To the authors' knowledge, this is to date the largest series of pediatric HD cases studied for EBV. Study findings provided further evidence that HD is etiologically heterogeneous. The authors believe that pediatric HD now should be regarded as a distinctive EBV-related lymphoma.

Current treatment of Hodgkin's disease

In spite of the fact that Hodgkin's disease (HD) remains still an enigma its management and treatment yield a cure rate of about 80% of all patients. However, this management has two limits: on one side favourable cases which should not be overtreated because of unacceptable side-effects, and on the other side very unfavourable cases which should be treated differently because of a very high rate of failure and/or relapse. Then it becomes necessary to precise as thoroughly as possible these two limits in order to choose the adequate treatment for the patient. Prognostic factors based on patient and disease characteristics allow a relatively exact classification of favourable and unfavourable cases. This distinction in two prognostic groups has therapeutic implications in terms of chemotherapy (regimen, duration) and radiotherapy (extension, doses). Other specific situations have to be considered, e.g. pediatric cases, pregnancy, old age and HIV-infected patients who need an adapted management according to very different situations.

Variation in the frequency of Epstein-Barr virus-associated Hodgkin's disease with age

A number of studies in developed countries have reported variation in the frequency of Epstein-Barr virus (EBV)-associated Hodgkin's disease (HD) with age. A 'three disease' model for HD that incorporates the EBV association, histological subtype of HD and age has recently been proposed. In this model, Hodgkin's disease of childhood and older adults is commonly EBV-associated and of mixed cellularity type, whereas young adult HD is generally not EBV-associated and is usually characterised by nodular sclerosis disease. A case series of HD diagnosed in the West Midlands between 1981 and 1997, inclusive, was used to investigate the applicability of the 'three disease' model. In situ hybridisation for the EBV early RNAs (EBERs) was used to determine the presence of EBV in the malignant Hodgkin/Reed-Sternberg cells. In contrast to the 'three disease' model, nodular sclerosis was the predominant subtype in each of the age groups within the case series. In addition, overall there was little variation in EBV-positive rates across the age ranges examined. However, when females were analysed separately, older women (45+ years) were significantly more likely to have EBV-positive disease than their younger counterparts (<45 years). In summary our results do not generally support the 'three disease' model.

Improved prognosis of Epstein-Barr virus associated childhood Hodgkin's lymphoma: study of 47 South African cases

AIM

To study the distribution of Hodgkin's lymphoma in South African children and report the incidence of Epstein-Barr virus (EBV) as regards age, race, sex, and histological subtype; to investigate whether EBV is relevant to survival.

METHODS

Immunohistochemistry (IHC) and in situ hybridisation (ISH) to detect EBV were performed on 47 South African children with classical Hodgkin's lymphoma, ranging in age from 3 to 14 years and coming from different ethnic backgrounds. The correlation between the presence of the virus and clinical outcome was assessed.

RESULTS

The nodular sclerosing subtype predominated, comprising 89% of cases; the remaining 11% were of the mixed cellularity subtype. EBV was present in 68%. Full clinical data were available for 36 cases; EBV positive patients presented with less aggressive symptoms at diagnosis and had a significantly longer median survival than EBV negative patients.

CONCLUSIONS

The distribution of EBV in South African childhood Hodgkin's lymphoma follows a pattern intermediate to that of industrialised and non-industrialized countries. Furthermore, our data suggest that there is an association between poor prognosis and the non-detection of EBV products in South African childhood Hodgkin's lymphoma.

Epstein-Barr virus expression in Hodgkin's disease: Correlation with histologic subtypes and T and B lymphocyte distribution

BACKGROUND

The pathogenesis of Hodgkinâs disease (HD) has been linked to Epstein-Barr virus (EBV). Some histologic subtypes show a high level of viral expression. These include mixed cellularity (MCHD) and nodular sclerosis (NSHD) subtypes. Grade II NSHD is a more aggressive variant of HD. Lymphocyte predominant (LPHD) is a B cell lymphoproliferative disorder that has not been associated with EBV expression. Infiltrating lymphocytes in HD are predominantly T lymphocytes, with a minor component of B lymphocytes. In the current study, EBV expression was tested in cases of HD in relation to histologic subtypes. An attempt was made at correlating EBV expression with T and B lymphocyte distribution in lymph nodes involved by HD.

METHOD

Formalin-fixed paraffin-embedded tissue from 62 cases of HD were tested for EBV mRNA expression, using the EBER-1 probe and in situ hybridization. T and B lymphocyte distribution and their ratios were evaluated using antibodies to T and B lymphocytes (UCHL-1 [CD45 RO] and CD 20, respectively), and the immunoperoxidase technique.

RESULTS

The cases were seen in 38 male and 24 female patients, with an age range of 3 to 72 years (median 25 years). There were 30 cases of grade I and 15 cases of grade II NSHD, 9 cases of MCHD and 8 cases of LPHD. EBV mRNA expression was seen in 29 cases (46%). This expression was seen in 8 cases of grade I NSHD (26%), 13 cases of grade II NSHD (86%) and 8 cases of MCHD (88%). None of the cases of LPHD showed viral expression. T to B lymphocyte ratios in EBV-positive cases ranged from 1/6 to 8/1, and ranged from 2/1 to 20/1 in EBV-negative cases (P=0.06). Nine of the 29 positive cases (31%) showed equal T/B lymphocyte ratios (n=4), or predominance of B lymphocytes (n=5). None of the EBV-negative cases showed predominance of B lymphocytes.

CONCLUSION

Our study confirms previously reported findings of the prevalence of EBV expression in MCHD and NSHD. Our findings also suggest that EBV expression may be more commonly seen in aggressive forms of HD. Decreased numbers of T lymphocytes in these aggressive subtypes may suggest that a process of more profound T lymphocyte depletion is occurring in these cases, leading to uncontrolled EBV replication and more aggressive disease.

Lack of involvement of known oncogenic DNA viruses in Epstein-Barr virus-negative Hodgkin's disease

Epstein-Barr virus (EBV) is associated with around one-third of cases, but young adult cases are rarely EBV associated. In this study, known oncogenic DNA viruses, including human adenoviruses, papovaviruses and the human herpesviruses-6 (HHV-6) and -8 (HHV-8) were not detected in Hodgkin's disease lesions. These results suggest that an as yet unidentified infectious agent is involved in the pathogenesis of non-EBV-associated Hodgkin's disease.

An immunohistochemical analysis of Reed-Sternberg-like cells in posttransplantation lymphoproliferative disorders: the possible pathogenetic relationship to Reed-Sternberg cells in Hodgkin's disease and Reed-Sternberg-like cells in non-Hodgkin's lymphomas and reactive conditions

The aim of this study was to assess the incidence and immunophenotype of Reed-Sternberg-like (R-S-like) cells in the setting of posttransplantation lymphoproliferative disorders (PTLD). Twenty-eight formalin-fixed, paraffin-embedded cases (17 renal and 11 heart/heart-lung PTLDS) were analyzed for the presence of typical binucleate cells with inclusionlike nucleoli--the Reed-Sternberg phenotype. An immunohistochemical evaluation for the following markers was performed: CD3, CD20, CD79a, CD15, CD30, CD45, EBV-LMP-1, and vimentin. Monoclonality was assessed by staining for light chain restriction. Eleven cases contained R-S-like cells (9 renal and 2 heart/heart-lung PTLD). All 11 cases were positive for CD45 (LCA), EBV-LMP-1, and vimentin. Ten of 11 cases were CD20/CD79a positive, one case being of a null immunophenotype. Nine cases expressed CD30, whereas 0 of 11 were positive for CD15. In nine cases, expression of both kappa and lambda light chains was present; the remaining two cases failed to express either light chain. This study shows that the R-S-like cells encountered in PTLD have an activated B cell immunophenotype, are invariably EBV-LMP-1 positive, are often CD30 positive, and are CD15 negative. This latter immunophenotypic feature separates R-S-like cells from the R-S cells seen in Hodgkin's disease. The strong staining for EBV-LMP-1 in R-S-like cells also indicates a strong association between EBV-LMP and the R-S morphological phenotype in the context of PTLDs.

Epstein-Barr virus in Hodgkin's disease: more than just an innocent bystander

Several lines of evidence suggest that the Epstein-Barr virus (EBV) is an important factor in the pathogenesis of Hodgkin's disease (HD). This Editorial focuses on two pathogenic mechanisms probably influenced by the presence of EBV in the Hodgkin and Reed-Sternberg (H-RS) cells: resistance of the H-RS cells to apoptosis; and escape of H-RS cells from a cytotoxic T lymphocyte (CTL) mediated immune response. In addition, data are summarized implicating the latent membrane protein 1 (LMP1) as the most likely EBV-encoded protein responsible for this putative EBV-mediated pathogenic effect. It is known that, using conventional therapy regimens, the presence of EBV bears little influence on clinical presentation and treatment outcome of HD. However, the differences in regulation of both apoptosis and immune escape mechanisms between EBV+ and EBV- cases may be important determinants of the success of immunotherapy to treat Hodgkin's disease. Thus, clarification of these mechanisms will be essential to the development of successful immunotherapeutic strategies in Hodgkin's disease.

Epstein-Barr virus-associated Hodgkin's disease: epidemiologic characteristics in international data

Hodgkin's disease (HD) has long been suspected to have an infectious precursor, and indirect evidence has implicated Epstein-Barr virus (EBV), a ubiquitous herpesvirus, as a causal agent. Recent molecular studies using EBER in situ hybridization or latency membrane protein-I (LMP-I) immunohistochemistry have identified EBV latent infection in up to 50% of HD tumors. However, the epidemiologic features of these cases have not been examined in detail. To explore the epidemiology of EBV-positive HD so as to understand the role of EBV in HD etiology more clearly, this project accumulated patient data from 14 studies that had applied these EBV assays to HD tumors. With information on age at diagnosis, sex, ethnicity, histologic subtype, country of residence, clinical stage and EBV tumor status from 1,546 HD patients, we examined risk for EBV-positive disease using logistic regression. Forty percent of subjects had EBV-positive tumors, and EBV prevalence varied significantly across groups defined by the study variables. Odds ratios (OR) for EBV-associated HD were significantly elevated for Hispanics vs. whites (OR = 4.1), mixed cellularity vs. nodular sclerosis histologic subtypes (OR = 7.3, 13.4, 4.9 for ages 0-14, 15-49, 50+ years), children from economically less-developed vs. more-developed regions and young adult males vs. females (OR = 2.5). These findings suggest that age, sex, ethnicity and the physiologic effects of poverty may represent biologic modifiers of the EBV association and confirm that this association is strongly but variably linked to histologic subtype. The data augment biologic evidence that EBV is actively involved in HD pathogenesis in some cases but describe epidemiologic complexity in this process.

Epstein Barr virus in Argentine pediatric Hodgkin's disease

Since Hodgkin's disease (HD) is an heterogeneous condition with diverse histological and epidemiological subgroups, it seemed worthwhile to investigate the Argentine pediatric pattern. Moreover, the presence of Epstein Barr virus (EBV) infection occurs at different ages depending on the development status of the country. Thus, it was interesting to assess the relation between EBV and HD in the Argentine pediatric population. The age distribution profile of our pediatric HD patients showed a peak in early childhood which declined towards adolescence, closely resembling EBV infection pattern. Male:female ratio of the studied population was 3.2:1 and the histological subtype distribution disclosed that mixed cellularity HD (MCHD) was the most common, an epidemiological profile shared with other developing countries. Fifty percent of assessed HD cases were associated with EBV, showing a significantly higher prevalence in the 3-6 years-old group, indicating a non-random distribution. EBV was also present in most of MCHD cases and in some nodular lymphocyte predominance HD (nLPHD) but entirely absent in nodular sclerosis HD (NSHD). Both EBV subtypes, namely EBV-1 and EBV-2, were detected in studied HD cases. EBV-HD association in the Argentine pediatric population reveals typical epidemiological features indicating EBV as the aetiologic agent or, alternatively as a cofactor in a considerable percentage of such HD cases.

Hodgkin's disease and lymphoproliferations resembling Hodgkin's disease in patients receiving long-term low-dose methotrexate therapy

Recently, it has been shown that patients with rheumatologic diseases who are treated with methotrexate can develop immunosuppression-associated lymphoproliferative disorders. Although a variety of lymphoproliferations have been described in the setting of methotrexate therapy, only rare cases of Hodgkin's disease (HD) have been reported. In this study, we provide a more complete characterization of the spectrum of lymphoproliferations that resemble HD or show features diagnostic of HD that occur in patients receiving long-term low-dose methotrexate therapy. Eight patients were receiving methotrexate for various disorders. Four cases were considered to represent lymphoproliferations resembling HD; the other four cases were diagnosed as HD because they showed diagnostic morphologic and immunophenotypic features. All three patients with lymphoproliferations resembling HD on whom follow-up was available experienced tumor regression with methotrexate withdrawal or with methotrexate withdrawal and steroids; none of these three patients required further therapy. All three patients with HD on whom follow-up was available are alive and free of disease following chemotherapy or radiation therapy. In two of these patients, the tumor persisted or progressed despite discontinuation of methotrexate with observation; the third patient received chemotherapy at the same time methotrexate was stopped. Our findings indicate that a spectrum of lymphoproliferations resembling HD or diagnostic of HD can occur in patients receiving long-term low-dose methotrexate therapy. Recognition of these lymphoproliferative disorders is clinically important because a subset of these neoplasms will completely resolve with discontinuation of methotrexate, thereby obviating the need for chemotherapy or radiation therapy.

Epstein-Barr virus in tumours

The Epstein-Barr virus (EBV) is the best characterized human virus known to infect most people all over the world. In most cases, primary infection with EBV is asymptomatic and the virus persists life-long without causing any disease. The availability of sensitive detection methods, however has led to the identification of a wide array of EBV-associated disease entities. Although nearly 9000 publications have been written since the first description of this virus in 1964, many questions concerning its function and infection patterns remain unanswered. The direct involvement of EBV in the pathogenesis of a disease has only been established for infectious mononucleosis and lymphoproliferative disorders in the setting of congenital or acquired immunodeficiency. Extensive investigations on the role of EBV infection in the pathogenesis of all other EBV-associated lymphoid and epithelial proliferations have led to the conclusion that EBV is not the primary causative agent but it can promote tumour development. Since the early steps in neoplastic development are difficult to assess, further studies are required to clarify the precise role of EBV infection. Furthermore, the clinical significance of the presence of EBV in neoplasia is largely unknown.

The epidemiology of Hodgkin's disease

Much of the epidemiological heterogeneity of HD incidence reflects the behaviour of the NS subtype, at least in the USA. Incidence variation across races (except Asians) and time periods is most marked in this subtype. In young adults with HD, there is compelling evidence for social class modification of risk consistent with an infectious aetiology; limited data suggest that this effect occurs within the NS subtype, but considerable evidence indicates that it does not primarily involve EBV infection. Findings from familial aggregation studies and HLA associations point to inherited susceptibility to this subtype. Despite little sex difference for NS in young adulthood in the latest incidence data, parity nevertheless appears to be protective against this subtype for women. Therefore, the greater increase for females than males in the incidence of young-adult NS in recent years may reflect the impact of population trends towards later childbearing and lower parity. This change, as well as the concomitant smaller family sizes and growing affluence, could explain part of the burgeoning incidence of NS in young adults in the USA. These observations suggest that NS in young adults constitutes a separate disease, probably of infectious origin. The incongruous occurrence of this subtype in older adults, and the presence of EBV in some NS cases, could reflect heterogeneity within NS, for example, representing features of the cellular phase of NS (Cozen et al, 1992; Medeiros and Greiner, 1995). For the non-NS subtypes, many of the factors that predict risk of NS may also be relevant. Patterns of social class determinants in children and older adults, the age groups at risk for MC, support involvement of an infectious precursor given intense exposure, and EBV is a likely candidate, based on its high prevalence in these groups. However, little aetiological research has been directed explicitly at the non-NS subtypes. Considerable effort has gone into exploring an infectious aetiology of HD. Recently, this line of investigation has moved beyond social class determinants to molecular epidemiological studies of EBV and, to a lesser degree, other potentially involved viruses. The roles of genetic susceptibility and sex hormones also represent promising areas for exploration, particularly in their possible interaction with infectious agents and other environmental factors. Ultimately, clearer epidemiological understanding of HD will be aided by more precise classification of this disease at the molecular level.

Hodgkin's disease: old and recent clinical concepts

The diagnosis of Hodgkin's disease (HD) is still primarily based on the histopathologic criteria presented by Lukes et al in 1965. Over the past three decades, however, advances in immunohistochemistry, molecular studies, and virologic findings have provided evidence that HD exhibits significant heterogeneity. Whereas the nodular sclerosis subtype is the major subset of the "classic" disease, it has become evident that the nodular, lymphocytic predominance subtype may represent a minor distinct subset, and possibly a distinct disease entity. Furthermore, there is strong evidence that the mixed cellularity subtype may be an Epstein-Barr virus-related disorder. Finally, based on phenotypic and genotypic features, the existence of a "continuum" between a fraction of HD cases, including the lymphocytic depletion subtype, and CD30-positive anaplastic large cell lymphomas has been suggested.

Phenotypic modulation of Hodgkin and Reed-Sternberg cells by Epstein-Barr virus

Expression of the Epstein-Barr virus (EBV) gene product LMP1 is found in tumour cells in varying proportions of Hodgkin's disease (HD) cases. It is not clear which cellular genes are influenced by EBV in HD. A total of 387 HD cases were tested for differences among LMP1-positive and -negative cases with respect to age, sex, histotype and immunophenotypic parameters (CD2, CD3, CD4, CD15, CD19, CD20, CD21, CD22, CD23, CD25, CD30, CD43, CD45RA, CD45R0, CD70, HLA-DR, T-cell receptor beta-chain, and p53 expression). Comparison of patient age and sex as well as distribution of histotype and tumour cell immunophenotype with published data suggests that the cases in this study are representative of the spectrum of HD in developed countries. LMP1 expression was found in 131/387 HD cases (36.4 per cent) with non-homogeneous distribution among HD histotypes, the mixed cellularity type (HDmc) being most frequently EBV-associated (71/129 cases, 55 percent). No relationship was found to age and sex. Significant phenotypic differences were restricted to the HDmc histotype, where the tumour cells expressed the activation marker CD30 in a larger proportion, and CD20 in a smaller proportion, when harbouring EBV. These results suggest that EBV may influence the tumour cell phenotype in HD.

Neoplastic cells of Hodgkin's disease show differences in EBV expression between Kenya and Italy

The Epstein-Barr Virus (EBV) has been implicated in the pathogenesis of Hodgkin's disease (HD). However, the association of EBV with this disease varies greatly from series to series and from country to country. Epidemiological studies have shown differences in HD occurring in different parts of the world. In particular, it has been reported that HD in developing countries differs from HD in Western countries in terms of epidemiological, pathological and clinical characteristics. These discrepancies among populations suggest an interaction with environmental factors and a direct role of different etiological agents. At present, there are no data on the frequency of association of EBV with HD in equatorial Africa. In this study, a large series of HD cases have been collected at the University of Nairobi, Kenya, and at the Universities of Bologna and Siena, Italy. The cases have been reviewed and classified according to the REAL Classification and the presence of EBV has been assessed by in situ hybridization (ISH). A statistical difference in EBV expression was found between HD from Kenya and HD from Italy. EBV-positive neoplastic cells were detected in 92% of Kenyan cases, whereas only 48% of Italian cases showed EBER1/2 positivity in the neoplastic cells. Our results suggest that, in Kenya, EBV plays a more direct role in the pathogenesis of HD, as it does for endemic Burkitt lymphoma.

Morphologic differences between latent membrane protein-1 (LMP-1)-positive and negative tumour cells in Epstein-Barr virus (EBV)-related childhood Hodgkin's disease. A morphometric study

The values of five cellular morphometric parameters (longest and shortest cytoplasmic axis, cellular circumference, area and roundness coefficient) were compared between 20 Latent Membrane Protein 1 (LMP-1)-positive and an equal number of LMP-1-negative Reed-Sternberg and Hodgkin (HRS) cells for each of 13 cases of Hodgkin's disease (HD) occurring in children (aged 3-15 years); the presence of Epstein-Barr virus (EBV) encoded EBER mRNAs had previously been detected in all cases using RNA in situ hybridisation (RISH), while the presence of LMP-1 was immunohistochemically detected using the alkaline phosphatase-antialkaline phosphatase (APAAP) method. The longest and shortest axis, circumference and area were larger in LMP-1-positive than in LMP-1 negative HRS cells, while the roundness coefficient of LMP-positive HRS cells was smaller than that of LMP-1 negative cells. All differences were statistically highly significant when univariate (paired comparisons) t-test were used. Multivariate analysis (Hotelling's T2 test) showed all differences (except the roundness coefficient) to be significant both at the 5% and 1% level of significance. These results provide a numerical basis for the alteration brought by the expression of LMP-1 in the cellular skeleton of tumour (HRS) cells in EBV-related childhood HD cases.

A pathologic study of Hodgkin's disease in Korea and its association with Epstein-Barr virus infection

BACKGROUND

The incidence of Hodgkin's disease (HD) in Korea and other Asian countries is much lower than in western countries and its association with the Epstein-Barr virus has not been well characterized.

METHODS

We evaluated the clinical, morphologic, and immunohistochemical features of 87 patients with Hodgkin's disease and also analyzed patients for Epstein-Barr virus (EBV) using in situ hybridization for EBV DNA, RNA, and latent membrane protein (LMP1).

RESULTS

There were 68 males and 19 females, with a mean age of 38 years. Mixed cellularity was the most prevalent subtype. Expression of EBV RNA (EBER:EBV-encoded RNA) was detected in 60 of 87 cases (69%): 1 of 1 (100%) with lymphocyte predominance, nodular; 4 of 7 (57%) with lymphocyte predominance, diffuse; 10 of 17 (59%) with nodular sclerosis; 38 of 51 (75%) with mixed cellularity; and 7 of 11 (64%) with lymphocyte depletion. Positivity was higher in advanced clinical stages; 4 of 7 patients (57%) with Stage I; 6 of 12 patients (50%) with Stage II: 7 of 9 patients (75%) with Stage III; and 5 of 5 patients (100%) with Stage IV HD EBV DNA was detected in 9 of 25 cases tested (36%). LMP1 was seen in 39 of 87 cases (45%). EBER and LMP1 positivity were higher in children and older adults than in adults aged between 15-50 years. Immediate early mRNAs (BHLF:Bam H-fragment, lower strand frame) was seen in a single patient.

CONCLUSIONS

HD in Korea showed a high incidence of mixed cellularity subtype and a high prevalence of EBV. EBV was detected in all subtypes, including a case of nodular lymphocytic predominance, and in all age groups, and showed correlation with mixed cellularity subtype and higher clinical stage. The expression of EBER and LMP were more frequently seen in children and older adults, suggesting a lowered immune surveillance in those age groups or a different pathophysiology of HD among different age groups.

The role of Epstein-Barr virus in Hodgkin's disease from different geographical areas

Recent studies have suggested that Epstein-Barr virus (EBV) may play a role in the aetiology of Hodgkin's disease. To determine the role of EBV in childhood Hodgkin's disease in different geographical areas, immunohistochemical staining and in situ hybridisation were used to analyse latent membrane protein 1 (LMP 1) and small nuclear non-transcribed RNAs (EBER-1) respectively. Testing for EBV within the Reed-Sternberg and Hodgkin's cells was carried out in childhood Hodgkin's disease from 10 different countries. The proportion of LMP 1 positive cases varied significantly, being 50% of cases from the United Kingdom (38/75), South Africa (9/18), Egypt (7/14), and Jordan (8/16), 60% from the United Arab Emirates (6/10), 70% from Australia (11/16), 81% from Costa Rica (34/42), 88% from Iran (7/8), 90% from Greece (20/22), and 100% of the 56 cases from Kenya. A sensitive polymerase chain reaction based EBV strain typing technique was established using archival tissues. EBV strain type 1 was shown to be predominant in childhood Hodgkin's disease from the United Kingdom, South Africa, Australia, and Greece. Type 2 was predominant in Egypt. EBV strain types 1 and 2 were both detected in some cases of childhood Hodgkin's disease in the United Kingdom, Costa Rica, and Kenya. The high incidence of EBV and the presence especially in developing countries of dual infection with both strain types 1 and 2 may reflect socioeconomic conditions leading to malnutrition induced immunological impairment. The possibility of HIV infection also needs to be explored.

Epidemiology of EBV and Hodgkin's lymphoma

The incidence of Hodgkin's disease shows marked heterogeneity with respect to age, gender, race, geographical locale, social class and histological subtype. The Epstein-Barr virus (EBV) is associated with a proportion of cases, approximately 40% in developed countries, and there is a body of evidence which suggests that mixed cellularity Hodgkin's disease is more likely to be EBV-associated than nodular sclerosis Hodgkin's disease. This study investigates the relationship between EBV and both age and histological subtype. We confirm the above subtype distribution and that childhood and older adult cases are more likely to be EBV-associated than young adult cases. Young adult nodular sclerosis cases are rarely EBV-associated providing further evidence that this is a separate disease entity. The results of this study support the multiple aetiology hypothesis which suggests that Hodgkin's disease in different age groups has different aetiologies. The epidemiology of Hodgkin's disease and studies investigating the distribution of EBV-associated cases are reviewed.

Down-regulation of Epstein-Barr virus nuclear antigen 1 in Reed-Sternberg cells of Hodgkin's disease

AIMS

To demonstrate Epstein-Barr virus (EBV) encoded nuclear antigen 1 (EBNA-1) gene expression in EBV associated disorders using a new monoclonal antibody (1H4-1) on routinely processed tissues.

METHODS

The pressure cooker antigen retrieval method was used for the immunohistochemical demonstration of EBNA-1 gene expression in formalin fixed, EBV positive tissues from Hodgkin's disease, infectious mononucleosis, HIV associated non-Hodgkin's lymphomas, post-transplant lymphomas, and undifferentiated nasopharyngeal carcinoma (NPC). EBV encoded EBNA-2, latent membrane protein 1 (LMP-1) and BZLF-1 gene expression was also examined using commercially available monoclonal antibodies.

RESULTS

Of the 34 EBER in situ hybridisation positive cases of Hodgkin's disease examined, none expressed EBNA-1 in the Reed-Sternberg cells. These cells were nevertheless strongly LMP-1 positive in all cases. Strong EBNA-1 staining was seen in all cases of EBER positive HIV associated non-Hodgkin's lymphoma (five of five), nasopharyngeal carcinoma (five of five), infectious mononucleosis (three of three), and post-transplant lymphoma (one of one). These cases also expressed LMP-1, EBNA-2 and BZLF-1, but at differing levels.

CONCLUSION

The pressure cooker antigen retrieval procedure is a sensitive and reliable adjunct to immunohistochemistry, especially with antibodies which are otherwise ineffective on routinely processed tissues. The EBNA-1 gene is not expressed at detectable levels in the malignant cells of Hodgkin's disease, but is consistently expressed in other EBV associated disorders. This finding has important implications for the role of EBNA-1 in the biology of EBV.