Pardeo M, Wang J, Ruperto N, et al. - Researchers examined if patients with systemic juvenile idiopathic arthritis (sJIA) and polyarticular-course juvenile idiopathic arthritis (pcJIA) treated with tocilizumab (TCZ) display increased the risk for infection in correlation with neutropenia. From two phase 3 trials of intravenous TCZ in sJIA (n = 112; ClinicalTrials.gov, NCT00642460) and pcJIA (n = 188; ClinicalTrials.gov, NCT00988221), data up to week 104 were pooled. In 25.0% and 5.9% of sJIA and pcJIA patients, respectively, absolute neutrophil count decreased to grade ≥ 3; the decreases were transient. Transient neutropenia in patients with JIA treated with TCZ was not identified to be associated with an increased number of infections. Patients with sJIA but not patients with pcJIA displayed a positive correlation of young age and methotrexate use with neutropenia.