NOD2 and infection: In the other hand, the continuous stimulation of NOD2 with muramyl peptide could tolerize macrophages previously stimulated with either TLR2 or 4 [184, 185]; therefore, defective tolerizing proteins such as NOD2 could induce a perpetual inflammatory status despite; in this case, the threat of infection (i.e., bacterial invasion) is not real (Figure 4).