Author's Reply to Oka and Colleagues. - Nagai K; Tsuchida K; Ishihara N; Minagawa N; Ichien G; Yamada S; Hirose D; Michiwaki H; Kanayama HO; Doi T; Minakuchi J (Therapeutic apheresis and dialysis : official peer-reviewed journal of the International Society for Apheresis, the Japanese Society for Apheresis, the Japanese Society for Dialysis Therapy, 2018)