On behalf of the ASBMT Committee on Education, we are pleased to continue our monthly self-directed learning quiz "Basic Principles and Practices of Hematopoietic Cell Transplantation and Cell Therapy – Question and Answer Approach” for fellows in training, highlighting HCT and cell therapy topics. Answers to each question appear with evidence-based “non-exhaustive” peer-review commentary. Our aim is to provide you with a credible and freely available educational resource. Questions generated and reviewed by Syed Abutalib, MD, Mark R. Litzow, MD, and William A. Wood, MD.