CD4 and colitis: Although nociceptor-expressed TRPV1 is essential to the generation of inflammatory thermal pain (Julius, 2013), CD4+ T cells were also reported to express functional TRPV1 which was shown to play a pro-inflammatory role in a mouse model of colitis (Bertin et al., 2014), which is in marked contrast to TRPA1 activation of which was shown to attenuate colitis (Bertin et al., 2017).