title: Expression of epstein-barr virus encoded nuclear antigen 1 in benign and malignant tissues harbouring EBV.
abstract: OBJECTIVE
  To determine levels of expression of Epstein-Barr virus (EBV) nuclear antigen 1 (EBNA1) in benign and malignant tissues harbouring EBV in relation to EBNA1 promoter usage.
  
  
  METHODS
  Expression of EBNA1 was investigated by means of immunohistochemistry using a mixture of two EBNA1 specific monoclonal antibodies, 1H4-1 and 2B4-1. The presence of EBV was detected by EBER1/2 RNA in situ hybridisation. Detection of promoter specific EBNA1 transcripts was by RT-PCR analysis.
  
  
  RESULTS
  EBNA1 positive cells were detected in all 20 EBV associated B cell lymphomas, 18 of which had arisen in immunocompromised patients; in eight of nine EBV associated T cell lymphomas; in 11 of 27 EBV positive cases of Hodgkin's disease; and in reactive lymphoid tissue harbouring EBV, including four cases of infectious mononucleosis. A diffuse EBNA1 staining pattern was observed in most of the EBV associated B cell lymphomas and was comparable with the EBER1/2 staining pattern. In the T cell lymphomas the number of EBNA1 positive cells was usually considerably less than the number of EBER1/2 positive ones. RT-PCR analysis revealed that in tumours with restricted EBNA1 expression-that is, T cell lymphomas and Hodgkin's disease lesions, EBNA1 transcripts were usually generated only by the F/Q promoter, whereas in B cell lymphomas EBNA1 transcripts were usually generated by both the C/W and F/Q promoters.
  
  
  CONCLUSIONS
  EBNA1 is expressed in all types of tissue harbouring EBV, but the level of expression varies greatly. This may be the result of differential promoter usage.
authors.affiliation: Department of Pathology, Free University Hospital, Amsterdam, The Netherlands.
authors.forename: J J
authors.initials: JJ
authors.lastname: Oudejans
authors.forename: D F
authors.initials: DF
authors.lastname: Dukers
authors.forename: N M
authors.initials: NM
authors.lastname: Jiwa
authors.forename: A J
authors.initials: AJ
authors.lastname: van den Brule
authors.forename: F A
authors.initials: FA
authors.lastname: Grässer
authors.forename: P C
authors.initials: PC
authors.lastname: de Bruin
authors.forename: A
authors.initials: A
authors.lastname: Horstman
authors.forename: W
authors.initials: W
authors.lastname: Vos
authors.forename: J
authors.initials: J
authors.lastname: van Gorp
authors.forename: J M
authors.initials: JM
authors.lastname: Middeldorp
authors.forename: C J
authors.initials: CJ
authors.lastname: Meijer
mesh_terms: D000956:Antigens, Viral / Q000378:metabolism*; D004854:Herpesvirus 4, Human / Q000235:genetics / Q000276:immunology*; D006689:Hodgkin Disease / Q000821:virology; D006801:Humans; D016867:Immunocompromised Host; D007150:Immunohistochemistry; D007244:Infectious Mononucleosis / Q000821:virology*; D008223:Lymphoma / Q000276:immunology / Q000821:virology*; D016393:Lymphoma, B-Cell / Q000276:immunology / Q000821:virology; D016399:Lymphoma, T-Cell / Q000821:virology; D011401:Promoter Regions, Genetic / Q000502:physiology; D014158:Transcription, Genetic
chemical_list: D000956:Antigens, Viral