Successful Amplified-Natural-Killer Cell (ANK) Therapy Administered to a Patient with Smoldering Adult T-Cell Leukemia in Acute Crisis

Abstract

Adult T-cell leukemia (ATL) is an indolent leukemia caused by type 1 human T-cell leukemia virus (HTLV-1). A variety of therapeutic interventions via immunological approaches have been attempted. ATL cells express costimulatory molecules of natural killer (NK) cells, and a new modality—amplified NK (ANK) cell treatment—was administered here to a patient with ATL. A 70-year-old female presenting with ringworm infection received a diagnosis of smoldering ATL in 2004. Monitoring of soluble IL-2 receptors (sIL-2Rs) in the serum showed disease exacerbation in 2007, associated with the enlargement of lymph nodes and formation of a skin tumor. NK cells were amplified by in vitro cell culture methods. To avoid cytokine release syndrome, 2–5 × 108 cells were administered with each injection. A total of 15 injections from 12 November 2007 to 15 February 2008 were administered to this patient. This case showed drastic downregulation of sIL-2R, resulting in the induction of complete remission, which lasted for >5 years. This is the first report of treatment of a patient with ATL using ANK cell therapy. More attempts of this therapy will enhance our insight into the appropriate application of this new therapy to clinically diverse patients.