Tocilizumab-induced anaphylaxis in patients with adult-onset Still's disease and systemic juvenile idiopathic arthritis: a case-based review.

The benefits afforded by tocilizumab (TCZ) in patients with adult-onset Still's disease (AOSD) and systemic juvenile idiopathic arthritis (SJIA) have been described in previous studies. However, few reports have evaluated severe hypersensitivity reactions (HSRs) to TCZ in patients with AOSD or SJIA. We describe three instances of TCZ-induced anaphylactic reactions in AOSD/SJIA patients, and review relevant prior reports on patients with various rheumatic diseases. Two of our cases exhibited shock and cardiovascular collapse; TCZ was discontinued in all three cases. All events occurred within 20 min of TCZ infusion, after at least three prior infusions, indicating an IgE-mediated mechanism and previous sensitization to TCZ. In all three cases, mild HSRs had been observed about 1 month before the anaphylactic events, but pre-medication with antihistamines and corticosteroids failed to prevent anaphylaxis. All three cases had active AOSD or SJIA disease, and were refractory to other immunosuppressive agents. It is essential to be aware that severe anaphylaxis to TCZ can develop in patients with active refractory AOSD or SJIA, and to be cautious when medicating certain patients. Anaphylaxis is a serious condition that can be fatal; TCZ infusion should not be re-challenged via pre-medication in patients who exhibited mild HSRs before TCZ without desensitization.