The LCs infiltrated in the inflamed psoriasis skin also produce the pro-inflammatory IL-23 cytokine in response to the TLR activation (TLR2 (Zymosan, a fungal PAMP), TLR4 and TLR7/TLR8) that further increases in the presence of TNF-α (Martini et al., 2017[126]; Sweeney et al., 2016[200]). This evidence concerns the gene TLR2 and psoriasis.