Group | Evaluation |
---|---|
Group 1 | Patients in which MAS could be confirmed on the basis of changes in laboratory findings similar to those for MAS observed in general patients with sJIA who did not receive TCZ treatment. |
3 events in 3 patients, definitive MAS. | |
Group 2 | Patients in which MAS was probable despite insufficient laboratory data. |
12 events in 11 patients, probable MAS. | |
Group 3 | Patients with confirmed EB-VAHS. |
2 events in 2 patients, EB-VAHS. | |
Group 4 | Patients in which early intervention resulted in improvement or resolution, but without any confirmed typical changes in laboratory findings, or patients with other potential causes such as infections or hemolytic uremic syndrome. |
8 events in 8 patients, possible MAS or non-MAS. |
The JIA Committee classified the 25 events of MAS or related events into the following 4 groups for ease of understanding: Group 1, definitive MAS; Group 2, probable MAS; Group 3, EB-VAHS; Group 4, possible or non-MAS. Including overlaps, 2 events in 1 patient were classified into Groups 1 and 2, and another 2 events in 1 patient were classified into Group 2. MAS: macrophage activation syndrome; TCZ: tocilizumab; sJIA: systemic juvenile idiopathic arthritis; EB-VAHS: Epstein-Barr virus–associated hemophagocytic syndrome.