aDivision of Hematology, Oncology, and Transplantation, Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota

bDivision of Hematology, Department of Medicine, University of North Carolina at Chapel Hill, Blood Research Center, Chapel Hill, North Carolina, USA

Correspondence to Erica M. Sparkenbaugh, PhD, University of North Carolina at Chapel Hill, 116 Manning Drive CB 7035, 8114 Mary Ellen Jones Bldg, Chapel Hill, NC 27599, USA. Tel: +1 919 962 9958; e-mail: [email protected]