1. Medical Scientist Training Program, Perelman School of Medicine of the University of Pennsylvania, Philadelphia, PA 19104, USA.
2. Department of Pathology and Laboratory Medicine, Perelman School of Medicine of the University of Pennsylvania, Philadelphia, PA 19104, USA.
3. Department of Medicine, Perelman School of Medicine of the University of Pennsylvania, Philadelphia, PA 19104, USA.
4. Department of Biomedical Sciences, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA 19104, USA.