FPR1 and vasculitis: To determine whether plasma-mediated neutrophil activation was dependent on fMET in vasculitis, neutrophils were pre-treated with cyclosporine H. Blocking FPR1 with cyclosporine H reduced the capacity for plasma to induce neutrophil activation and ROS production in both HC and plasma from patients with vasculitis (p<0.01, Fig. 4A).