The Impact of Targeted Therapy on Microorganism in Patients With Psoriasis

Background: Psoriasis is a chronic, immunologically-mediated, inflammatory skin disease and targeted therapies e.g. tumor necrosis factor (TNF)-α and TH-17 antagonists have become increasing important agents in the management of psoriasis. TNF, interleukin-17 (IL-17) and TH-17 play major roles in defense against infection. Large-scaled clinical trials and post-marking surveillance had shown these agents may increase susceptibility to infections. Most studies evaluate the reactivation of tuberculosis but the influence of targeted therapies on the viral infection has not been extensively investigated. TNF-α has been shown to contribute to the killing of cytomegalovirus (CMV)- and human papillomaviruses (HPV)-infected cells. Additionally, recent studies have shown a high prevalence of HPV DNA in psoriatic skin and increased HPV5 antibodies in patients with psoriasis. The prevalence of HPV in the skin was also affected by therapeutic modalities, such as psoralen-ultraviolet A (PUVA). Several case reports in which CMV, Epstein-Barr virus (EBV) and HPV infection complicated therapy with TNF-α antagonists have been reported. However, the study investigated the effect of TNF-α antagonists and other biologics on reactivation of latent viruses is limited. Only two studies investigated the short-term effect of infliximab on reaction of herpesviruses in patients of rheumatoid arthritis and Crohn's disease. The high prevalence of combination use of immunosuppressants, such as methotrexate alongside with TNF-α antagonists in these patients is different from patients with psoriasis. Additionally, various bacterium and fungi, such as Staphylococcus aureus, Malassezia are associated with provocation and/or exacerbation of psoriasis and recent studies had shown IL-17 is essential for the immune response to common fungus Candida albicans. Aim: The aim of this study is to prospectively investigate the effect of target therapies (TNF-α, TH-17 antagonist, IL-17 antagonists, tofacitin