title: Epstein-Barr virus, methotrexate, and lymphoma in patients with rheumatoid arthritis and primary Sjögren's syndrome: case series.
abstract: OBJECTIVE
  Rheumatoid arthritis (RA) and primary Sjögren's syndrome (SS) are associated with an increased risk of lymphoma. Epstein-Barr virus (EBV), a ubiquitous herpes virus, has been linked etiologically to lymphoma in patients with RA and primary SS. Recently, methotrexate (MTX) has also been linked to the development of these lymphomas. We investigated the frequency of EBV in lymphoma tissue of patients with RA and primary SS and the association of MTX with lymphomagenesis.
  
  
  METHODS
  Twenty-three patients with RA and 9 with primary SS with a history of lymphoma were identified by writing to all Arthritis Foundation member rheumatologists in Washington State. Formalin fixed, paraffin embedded tissue blocks were then requested from pathology laboratories. Lymph nodes from 5 RA patients without lymphoma were also studied. In situ hybridization using a biotinylated EBER-1 oligonucleotide probe was used to detect EBV in tissue sections. Positive and negative laboratory controls were used to ensure procedural integrity.
  
  
  RESULTS
  Specimens from 21 RA patients were obtained, with 2 subsequently excluded due to specimen quality. Specimens from 6 patients with primary SS were obtained. In situ hybridization for EBV was positive in 5/19 (26%) RA patients and 1/6 patients with primary SS. In the nonmalignant lymph nodes no patient showed EBV. One primary SS and 12 RA patients were known to be taking MTX at the time of lymphoma diagnosis. Of the EBV positive RA lymphoma patients, 4/5 were receiving MTX at the time of diagnosis. These results show that EBV is present in lymphoma tissue of some patients with RA and very few with primary SS.
  
  
  CONCLUSIONS
  EBV is over-represented in the lymphomas of patients with RA, but whether MTX plays a role in predisposing patients with RA and primary SS to the development of lymphoma, perhaps by influencing behavior of EBV, remains unclear.
authors.affiliation: VA Puget Sound Health Care System, Seattle Division, Washington 98108, USA.
authors.forename: T M
authors.initials: TM
authors.lastname: Dawson
authors.forename: G
authors.initials: G
authors.lastname: Starkebaum
authors.forename: B L
authors.initials: BL
authors.lastname: Wood
authors.forename: R F
authors.initials: RF
authors.lastname: Willkens
authors.forename: A M
authors.initials: AM
authors.lastname: Gown
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018501:Antirheumatic Agents / Q000627:therapeutic use*; D001172:Arthritis, Rheumatoid / Q000150:complications / Q000188:drug therapy / Q000473:pathology*; D020031:Epstein-Barr Virus Infections / Q000150:complications / Q000473:pathology*; D005260:Female; D004854:Herpesvirus 4, Human / Q000302:isolation & purification* / Q000472:pathogenicity; D006801:Humans; D016867:Immunocompromised Host; D017403:In Situ Hybridization; D008198:Lymph Nodes / Q000473:pathology / Q000821:virology; D008223:Lymphoma / Q000473:pathology* / Q000821:virology; D008297:Male; D008727:Methotrexate / Q000627:therapeutic use*; D008875:Middle Aged; D012367:RNA, Viral / Q000032:analysis; D012859:Sjogren's Syndrome / Q000150:complications / Q000188:drug therapy / Q000473:pathology*
chemical_list: D018501:Antirheumatic Agents; C099537:Epstein-Barr virus encoded RNA 1; D012367:RNA, Viral; D008727:Methotrexate