Background: Psoriasis is a common chronic immunologic disease which shares common inflammatory pathways to other disease like diabetes, cardiovascular disease, and irritable bowel disease. Ustekinumab is a human monoclonal antibody that reduces the expression of interleukin-12 and interleukin-23, the key inflammatory cells of the pathology of psoriasis.
Main observation: Four patients with severe chronic plaque type psoriasis who were not responding well to conventional systemic therapy were included in the ustekinumab treatment. The study revealed good clinical response with at least PASI 75 response at week 12, and long-term clearing of psoriatic lesions was observed.
Conclusion: Ustekinumab represents an effective alternative for the management of psoriasis; despite being used as a shortterm treatment, it still shows efficacy on recalcitrant psoriasis.

Keywords: Psoriasis, Ustekinumab, Biologic agents