In addition, blockade of IL-23 signaling using a monoclonal antibody (ustekinumab) against the p40 subunit of IL-12 and IL-23 has been shown to be effective in Crohn's disease, psoriasis and psoriatic arthritis with results similar to those seen when blocking IL-6 or TNFα [81, 82, 86]. Here, TNF is linked to psoriasis.