NOD2 and Crohn disease: Finally, although no specific signal transduction pathways activated by NLRs in MCs have been reported, the in vivo relevance of those receptors on MCs function has started to be characterized, for example, an important increase on NOD2+ positive MCs was observed in colonic mucosal biopsies from Crohn ́s disease (CD) patients compared to those obtained from ulcerative colitis patients or control biopsies [113], and IFNγ-treated human MCs showed an increase in NOD2 expression.