On the cover: Seven-month-old mice with a Treg-specific deficiency of Helios (Helios^fl/fl × Foxp3^YFP-Cre) exhibit enlarged spleens and the presence of numerous germinal centers. The spleen was stained for CD4 (green), IgD (blue), and GL7 (red). Image credit: Sundar Ganesan, Biological Imaging Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD. Sebastian, M., M. Lopez-Ocasio, A. Metidji, S. A. Rieder, E. M. Shevach, and A. M. Thornton. 2016. Helios controls a limited subset of regulatory T cell functions. J. Immunol. 196: 144–155.