Benralizumab promotes eosinophil (Eos) apoptosis by macrophage (Mac) cytotoxicity through the tumour necrosis factor (TNF)/TNF receptor 1 (TNFR1) pathway. Human eosinophils were pre-treated with 10 nM of indicated antibodies, then labelled and co-incubated with macrophages and natural killer (NK) cells in the presence of PO-PRO-1 for 6 h. a) Quantification of TNFR1-induced expression in eosinophils in the presence and absence of macrophages and NK cells, represented as percentage of total CD66b+ Siglec-8+ cells (n=4). b) TNFR1 expression was compared with TNF receptor 2 (TNFR2) in apoptotic Caspase-3/7+ (Casp3/7) eosinophils in the presence and absence of macrophages and NK cells, represented as percentage of total CD66b+ Siglec-8+ cells (n=3). c, d) Reduction of apoptotic eosinophils, as assessed by c) PO-PRO-1 and JC-10 green mitochondrial membrane potential assay and d) cytochrome c, after inhibition of TNF and TNFR1 in the presence of indicated antibodies, macrophages and NK cells (n=4). Data are mean±sem. Two-way ANOVA with Tukey's multiple comparisons. *: p<0.05; ****: p<0.0001, benralizumab versus controls (isotype or parent fucosylated anti-interleukin-5 receptor α (PF anti-IL-5Rα)). ++++: p<0.0001, Eos+Mac+NK versus Eos+Mac. #: p<0.05; ##: p<0.01; ####: p<0.0001, blocking antibodies+benralizumab versus benralizumab. Statistical values are presented in supplementary table S2.