The poor response to IL-10 of the patients’ leukocytes does not appear to be associated with the early-onset colitis seen in patients with AR IL-10, IL-10RA, or IL-10RB deficiencies (Engelhardt and Grimbacher, 2014; Engelhardt et al., 2013; Glocker et al., 2009; Glocker et al., 2011), possibly because of residual TYK2-independent responses to IL-10. Here, IL10 is linked to colitis.