Response to: Correspondence on “Hyperleukocytosis in a neuroblastoma patient after treatment with natural killer T cells expressing a GD2-specific chimeric antigen receptor and IL-15” by Ataca Atilla and Atilla - Amy N Courtney; Gengwen Tian; Leonid S Metelitsa; Andras Heczey (Journal for ImmunoTherapy of Cancer)