title: Monitoring of Epstein-Barr virus load and killer T cells in patients with juvenile idiopathic arthritis treated with methotrexate or tocilizumab.
abstract: OBJECTIVE
  Methotrexate (MTX) is used for the treatment of polyarticular juvenile idiopathic arthritis (JIA), and an anti-interleukin-6 receptor monoclonal antibody (tocilizumab: TCZ) is also used and added for the treatment of intractable JIA. It has been reported that MTX might induce Epstein-Barr virus (EBV)-associated lymphoma, but the discussion about the effect of MTX and/or TCZ against reactivation of EBV in pediatric patients has been incomplete.
  
  
  METHODS
  The EBV loads in four polyarticular JIA and three systemic arthritis JIA patients treated with MTX and/or TCZ, and the percentage of EBV-specific killer T cells (EBV-CTLs) in some patients were prospectively monitored.
  
  
  RESULTS
  No patients had EBV-associated symptoms during the observation period. EBV loads in all patients were not significantly increased, and the levels of EBV loads were the same as EBV-seropositive healthy children following the administration of MTX and/or TCZ. EBV-CTLs were detectable during the observation period, but some patients had slightly low levels of EBV-CTLs.
  
  
  CONCLUSIONS
  Treatment with MTX and/or TCZ did not severely affect EBV load and prevent induction of EBV-CTLs in JIA patients.
authors.affiliation: a Department of Pediatrics , Kochi Medical School, Kochi University , Nankoku, Kochi , Japan.
authors.forename: Mikiya
authors.initials: M
authors.lastname: Fujieda
authors.affiliation: b Department of Pediatrics , Graduate School of Medicine, Hirosaki University , Aomori , Japan , and.
authors.forename: Kazushi
authors.initials: K
authors.lastname: Tsuruga
authors.affiliation: a Department of Pediatrics , Kochi Medical School, Kochi University , Nankoku, Kochi , Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Sato
authors.affiliation: a Department of Pediatrics , Kochi Medical School, Kochi University , Nankoku, Kochi , Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kikuchi
authors.affiliation: a Department of Pediatrics , Kochi Medical School, Kochi University , Nankoku, Kochi , Japan.
authors.forename: Wataru
authors.initials: W
authors.lastname: Tamaki
authors.affiliation: a Department of Pediatrics , Kochi Medical School, Kochi University , Nankoku, Kochi , Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Ishihara
authors.affiliation: a Department of Pediatrics , Kochi Medical School, Kochi University , Nankoku, Kochi , Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Yamamoto
authors.affiliation: a Department of Pediatrics , Kochi Medical School, Kochi University , Nankoku, Kochi , Japan.
authors.forename: Taku
authors.initials: T
authors.lastname: Oishi
authors.affiliation: b Department of Pediatrics , Graduate School of Medicine, Hirosaki University , Aomori , Japan , and.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tanaka
authors.affiliation: c Department of Microbiology , Kochi Medical School, Kochi University , Nankoku, Kochi , Japan.
authors.forename: Masanori
authors.initials: M
authors.lastname: Daibata
mesh_terms: D000293:Adolescent; D061067:Antibodies, Monoclonal, Humanized / Q000009:adverse effects* / Q000494:pharmacology / Q000627:therapeutic use; D001171:Arthritis, Juvenile / Q000188:drug therapy* / Q000821:virology; D002648:Child; D002675:Child, Preschool; D005260:Female; D004854:Herpesvirus 4, Human / Q000302:isolation & purification*; D006801:Humans; D008223:Lymphoma / Q000175:diagnosis* / Q000209:etiology / Q000821:virology; D008297:Male; D008727:Methotrexate / Q000009:adverse effects* / Q000494:pharmacology / Q000627:therapeutic use; D013601:T-Lymphocytes / Q000187:drug effects; D019562:Viral Load; D055815:Young Adult
chemical_list: D061067:Antibodies, Monoclonal, Humanized; C502936:tocilizumab; D008727:Methotrexate
keywords: Epstein–Barr virus; Juvenile idiopathic arthritis; Killer T cells; Methotrexate; Tocilizumab