Retinoic acid takes effector T cells to the gallows: P2X7, the molecular hangman.

Effector T-cell contraction is one of the primary means by which immune homeostasis in the peripheral tissues is reestablished following an inflammatory response. In this issue of Mucosal Immunology, Hashimoto-Hill et al.1 show that retinoic acid (RA) transcriptionally upregulates P2X7 primarily in effector T cells of the intestine sensitizing them to NAD-induced cell death (NICD); thus, demonstrating a previously unrecognized role of RA in effector T-cell contraction.