TNF and psoriasis: In addition to TNF-α antagonists such as infliximab (a chimeric monoclonal antibody composed of a human IgG1 constant region and a murine variable region), etanercept (a soluble TNFR, made of two extracellular domains of the human TNFR2 fused to the Fc fragment of human IgG1), or adalimumab (a human monoclonal antibody), a new drug (ustekinumab), an antibody targeting the common p40 subunit of IL-23 and IL-12, has been introduced in the therapeutic management of psoriasis [30, 31].