Monitoring of Epstein–Barr virus load and killer T cells in patients with juvenile idiopathic arthritis treated with methotrexate or tocilizumab

Abstract

Objectives: 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.

Conclusion: Treatment with MTX and/or TCZ did not severely affect EBV load and prevent induction of EBV-CTLs in JIA patients.

Keywords:

• Epstein–Barr virus
• Juvenile idiopathic arthritis
• Killer T cells
• Methotrexate
• Tocilizumab

Acknowledgments

The authors would like to thank Ai Uchida for her important and skillful technical assistance.

Conflict of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.