Macrophage Activation Syndrome in Patients with Systemic Juvenile Idiopathic Arthritis under Treatment with Tocilizumab.
OBJECTIVE
To identify macrophage activation syndrome (MAS) in patients with systemic juvenile idiopathic arthritis (sJIA) undergoing tocilizumab (TCZ) treatment, and to confirm laboratory marker changes and responses to treatment in patients with MAS receiving TCZ.


METHODS
In Japan, 394 patients with sJIA were registered in an all-patient registry surveillance of TCZ as of January 15, 2012. TCZ (8 mg/kg) was administered every 2 weeks to patients with sJIA. MAS, hemophagocytic lymphohistiocytosis, or Epstein-Barr virus-associated hemophagocytic syndrome (EB-VAHS) was reported in 23 of these patients (25 events). The Safety Evaluation Committee of Tocilizumab for JIA reviewed these cases and clinically evaluated the data and laboratory findings using their own therapeutic experience. Events were categorized into 4 groups: definitive MAS, probable MAS, EB-VAHS, and non-MAS.


RESULTS
The committee's review revealed 3 events of definitive MAS in 3 patients, 12 events of probable MAS in 11 patients, 2 events of EB-VAHS in 2 patients, and 8 events of non-MAS in 8 patients. There were 2 patients who developed 2 events: 2 events in 1 patient were classified into definitive MAS and probable MAS, and 2 events in another patient were classified into probable MAS. In patients with definitive or probable MAS, common clinical manifestations and laboratory findings of MAS were observed. Changes in laboratory data observed in patients with EB-VAHS were similar to those observed in patients with MAS.


CONCLUSION
These results suggest that the clinical/laboratory features in the course of MAS appear to be similar among patients regardless of whether TCZ is administered. Similarities in the pathophysiological background of MAS and EB-VAHS were also suggested.
['Yokota|Shumpei|S|', 'Itoh|Yasuhiko|Y|', 'Morio|Tomohiro|T|', 'Sumitomo|Naokata|N|', 'Daimaru|Kaori|K|', 'Minota|Seiji|S|']
D000293:Adolescent D000328:Adult D061067:Antibodies, Monoclonal, Humanized D018501:Antirheumatic Agents D001171:Arthritis, Juvenile D002648:Child D002675:Child, Preschool D005260:Female D006801:Humans D055501:Macrophage Activation Syndrome D008297:Male D012042:Registries D055815:Young Adult
MACROPHAGE ACTIVATION SYNDROME JUVENILE IDIOPATHIC ARTHRITIS TOCILIZUMAB INFECTION-ASSOCIATED HEMOPHAGOCYTIC SYNDROME INTERLEUKINS POSTMARKETING PRODUCT SURVEILLANCE