This evidence‐ and consensus‐based guideline on the treatment of psoriasis vulgaris was developed following the EuroGuiDerm Guideline and Consensus Statement Development Manual. The first part of the guideline includes general information on the scope and purpose, health questions covered, target users and strength/limitations of the guideline. Suggestions for disease severity grading and treatment goals are provided. It presents the general treatment recommendations as well as detailed management and monitoring recommendations for the individual drugs. The treatment options discussed in this guideline are as follows: acitretin, ciclosporin, fumarates, methotrexate, adalimumab, apremilast, brodalumab, certolizumab pegol, etanercept, guselkumab, infliximab, ixekizumab, risankizumab, secukinumab, tildrakizumab and ustekinumab.

Biological therapy became available for psoriasis with the introduction of alefacept at the beginning of this century. Up to then, systemic treatment options comprised small molecule drugs, targeting the immune system in a non-specific manner. The first biologics targeted T-cell activation and migration and served as an alternative to small molecules. However, significant improvement in outcome was first accomplished with the introduction of tumor necrosis factor-α inhibitors that were already approved for other inflammatory disorders, including rheumatic diseases. Along with the progress in understanding psoriasis pathogenesis, highly targeted and effective therapies have since developed with the perspective not only to improve but to clear psoriasis. These accomplishments enable future achievement of advanced goals to individualize treatment best suited for each patient. Mechanistic studies with patients treated with the new highly targeted biologics may guide us towards these goals. This review offers an overview of biologics developed for psoriasis and illustrate a historical progress in the treatment of this common chronic inflammatory skin condition.

This evidence‐ and consensus‐based guideline on the treatment of psoriasis vulgaris was developed following the EuroGuiDerm Guideline and Consensus Statement Development Manual. The second part of the guideline provides guidance for specific clinical and comorbid situations such as treating psoriasis vulgaris patient with concomitant psoriatic arthritis, concomitant inflammatory bowel disease, a history of malignancies or a history of depression or suicidal ideation. It further holds recommendations for concomitant diabetes, viral hepatitis, disease affecting the heart or the kidneys as well as concomitant neurological disease. Advice on how to screen for tuberculosis and recommendations on how to manage patients with a positive tuberculosis test result are given. It further covers treatment for pregnant women or patients with a wish for a child in the near future. Information on vaccination, immunogenicity and systemic treatment during the COVID‐19 pandemic is also provided.

Background: IkBz plays a key role in psoriasis by mediating IL-17A-driven effects, but the molecular mechanism by which IL-17A regulates IkBz expression is not clarified. Objective: We sought to explore the molecular transformation in patients with psoriasis during anti-IL-17A (secukinumab) treatment with a focus on IkBz. Methods: The study was an open-label, single-arm, single-center secukinumab treatment study that included 14 patients with plaque psoriasis. Skin biopsy specimens and blood samples were collected on days 0, 4, 14, 42, and 84 and processed for microarray gene expression analysis. Furthermore, in vitro experiments with human keratinocytes and synovial fibroblasts were conducted. Results: Secukinumab improved clinical scores and histologic psoriasis features. Moreover, secukinumab altered the skin transcriptome. The major transcriptional shift appeared between day 14 and day 42 after treatment initiation, although 80 genes were differentially expressed already at day 4. Expression of nuclear factor of kappa light polypeptide gene enhancer in B cells inhibitor (IkB) z (NFKBIZ, the gene encoding IkBz) was reduced already after 4 days of treatment in the skin. NFKBIZ expression correlated to Psoriasis Area and Severity Index score, and NFKBIZ mRNA levels in the skin decreased during anti-IL-17A treatment. Moreover, specific NFKBIZ signature genes were significantly altered during anti-IL-17A treatment. Finally, we identified NF-kB activator 1 (Act1), p38 mitogen-activated protein kinase (MAPK), Jun NH2-terminal kinase (JNK), and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) as key signaling pathways in NFKBIZ/IkBz regulation. Conclusion: Our results define a crucial role for IkBz in the antipsoriatic effect of secukinumab. Because IkBz signature genes were regulated already after 4 days of treatment, this strongly indicates that IkBz plays a crucial role in the antipsoriatic effects mediated by anti-IL-17A treatment. (J Allergy Clin Immunol 2020;145:379-90.)

IL-37 broadly suppresses inflammation in various disease models. However, studies of the regulation and role of IL-37 in psoriasis are limited and contradictive. Using transcriptome analysis, PCR, protein determination, and immunofluorescence, we demonstrated marked downregulation of IL-37 in biopsies from human lesional psoriasis skin compared with paired samples of nonlesional skin. Immunofluorescence analysis showed that IL-37 was localized to stratum granulosum of the epidermis. TNF-a stimulation of normal human epidermal keratinocytes led to increased IL37 expression through a p38 MAPK-mediated mechanism, whereas IL-17A, IL-17C, IL-17F, and IL-22 acted suppressively. Intradermal injection with recombinant human IL-37 into imiquimod-induced psoriasis skin of C57BL/6J mice demonstrated a trend toward a protective effect, however NS. Altogether, these results demonstrate that IL-37 is downregulated in human lesional psoriasis skin. This may be a consequence of the loss of stratum granulosum, but key cytokines in the development of psoriasis also seem to contribute to this downregulation. ImmunoHorizons, 2020, 4: 754-761.