On the cover: The immunostained image shows donor CD4⁺ T cells (green) that infiltrated into the injured skin of CD28-deficient mice that developed systemic sclerosis–like chronic graft-versus-host disease. Host cells and nuclei were revealed with CD45.2 (red) and Hoechst 33342 (blue), respectively. This infiltration was due to regulatory T cell deficiency. Akieda, Y., E. Wakamatsu, T. Nakamura, Y. Ishida, S. Ogawa, and R. Abe. 2015. Defects in regulatory T cells due to CD28 deficiency induce a qualitative change of allogeneic immune response in chronic graft-versus-host disease. J. Immunol. 194: 4162–4174.