Transmission electron microscopy images of hematopoietic stem cells from 18‑month‑old wild‑type (left) and MLKL‑deficient (right) mice. The images were captured by Dr. Yuta Yamada and Dr. Masayuki Yamashita in collaboration with Dr. Yuji Watanabe and Dr. Hiroshi Sagara at Medical Proteomics Laboratory, The Institute of Medical Science, The University of Tokyo, Japan. Credit: Dr. Masayuki Yamashita from The University of Tokyo, Japan As people get older, their blood and immune systems gradually