Regulating the regulator: Bhlhe40 directly keeps IL-10 in check.

In this issue of JEM, two complementary manuscripts by Huynh et al. (https://doi.org/10.1084/jem.20171704) and Yu et al. (https://doi.org/10.1084/jem.20170155) demonstrate that the transcription factor Bhlhe40 acts as a repressor of IL-10 production during infection with Mycobacterium tuberculosis or Toxoplasma gondii. Deletion of Bhlhe40 in both cases resulted in chronic infection and increased pathogen load as a consequence of increased IL-10 production.