title: Tocilizumab masks the clinical symptoms of systemic juvenile idiopathic arthritis-associated macrophage activation syndrome: the diagnostic significance of interleukin-18 and interleukin-6.
abstract: Macrophage-activation syndrome (MAS) is a potentially life-threatening complication of systemic juvenile idiopathic arthritis (s-JIA). Tocilizumab (TCZ), a humanized anti-IL-6 receptor monoclonal antibody, is an effective cytokine inhibitor for the treatment of s-JIA. We described the clinical courses of five cases of MAS during TCZ therapy and demonstrated the need for monitoring serum interleukin (IL)-18 and IL-6 concentrations. Clinical symptoms of patients with s-JIA receiving TCZ were apparently mild compared to those not receiving TCZ. Furthermore, serum CRP concentrations never increased during TCZ therapy, even in MAS. Serum IL-6 concentrations increased during s-JIA flare-up and with the complication of infection. Serum IL-18 concentrations increased persistently before the other measures of disease activity. The clinical symptoms of MAS and s-JIA could be masked during TCZ therapy; hence, monitoring serum concentrations of IL-18 and IL-6 is recommended for the evaluation of disease activity in s-JIA and to detect the complication of infection.
authors.affiliation: Department of Pediatrics, School of Medicine, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Japan. shimizum@staff.kanazawa-u.ac.jp
authors.forename: Masaki
authors.initials: M
authors.lastname: Shimizu
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Nakagishi
authors.forename: Kazuko
authors.initials: K
authors.lastname: Kasai
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Yamasaki
authors.forename: Mari
authors.initials: M
authors.lastname: Miyoshi
authors.forename: Syuji
authors.initials: S
authors.lastname: Takei
authors.forename: Akihiro
authors.initials: A
authors.lastname: Yachie
mesh_terms: D000293:Adolescent; D061067:Antibodies, Monoclonal, Humanized / Q000494:pharmacology* / Q000627:therapeutic use; D001168:Arthritis / Q000188:drug therapy* / Q000276:immunology; D002648:Child; D005260:Female; D006801:Humans; D008262:Macrophage Activation / Q000187:drug effects*; D008297:Male
chemical_list: D061067:Antibodies, Monoclonal, Humanized; C502936:tocilizumab