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

Abstract

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.