小宮根 真弓

The interleukin (IL)-1 superfamily upregulates immune responses and maintains homeostasis between the innate and adaptive immune systems. Within the IL-1 superfamily, IL-36 plays a pivotal role in both innate and adaptive immune responses. Of the four IL-36 isoforms, three have agonist activity (IL-36α, IL-36β, IL-36γ) and the fourth has antagonist activity (IL-36 receptor antagonist [IL-36Ra]). All IL-36 isoforms bind to the IL-36 receptor (IL-36R). Binding of IL-36α/β/γ to the IL-36R recruits the IL-1 receptor accessory protein (IL-1RAcP) and activates downstream signalling pathways mediated by nuclear transcription factor kappa B and mitogen-activated protein kinase signalling pathways. Antagonist binding of IL-36Ra to IL-36R inhibits recruitment of IL-1RAcP, blocking downstream signalling pathways. Changes in the balance within the IL-36 cytokine family can lead to uncontrolled inflammatory responses throughout the body. As such, IL-36 has been implicated in numerous inflammatory diseases, notably a type of pustular psoriasis called generalized pustular psoriasis (GPP), a chronic, rare, potentially life-threatening, multisystemic skin disease characterised by recurrent fever and extensive sterile pustules. In GPP, IL-36 is central to disease pathogenesis, and the prevention of IL-36-mediated signalling can improve clinical outcomes. In this review, we summarize the literature describing the biological functions of the IL-36 pathway. We also consider the evidence for uncontrolled activation of the IL-36 pathway in a wide range of skin (e.g., plaque psoriasis, pustular psoriasis, hidradenitis suppurativa, acne, Netherton syndrome, atopic dermatitis and pyoderma gangrenosum), lung (e.g., idiopathic pulmonary fibrosis), gut (e.g., intestinal fibrosis, inflammatory bowel disease and Hirschsprung's disease), kidney (e.g., renal tubulointerstitial lesions) and infectious diseases caused by a variety of pathogens (e.g., COVID-19; Mycobacterium tuberculosis, Pseudomonas aeruginosa, Streptococcus pneumoniae infections), as well as in cancer. We also consider how targeting the IL-36 signalling pathway could be used in treating inflammatory disease states.

Plaque psoriasis (PsO) is a chronic immune-mediated inflammatory disease with skin lesions accompanied by an inflammation-related comorbidity risk. The development of various oral drugs and biologics for PsO has provided increasing systemic treatment options for patients with PsO, and the guidance regarding the use of biologics and PsO treatment schemes are widespread in Japan. However, no comprehensive guidelines regarding systemic drug use are available, and the current treatment patterns of systemic drugs for PsO in Japan remain unclear. We conducted a retrospective chart review to clarify the current treatment patterns of systemic drugs for PsO. We enrolled 114 patients who started systemic drugs for PsO between January 2017 and December 2020 at four institutes, with a mean follow-up of 37.2 months. The mean disease duration was 7.8 (standard deviation 9.5) years at the systemic drug initiation. Of all the patients, 78.1% started with oral drugs (phosphodiesterase [PDE] 4 inhibitors 56.1%. calcineurin inhibitors 14.0%. vitamin A derivatives 7.9%), whereas 21.9% started with biologics (interleukin [IL]-17 inhibitors 9.6%. tumor necrosis factor inhibitors 7.0%. IL-23 inhibitors 3.5%. IL-12/23 inhibitors 1.8%). Oral drugs had shorter drug persistence than biologics: the 12-month persistence of the oral drugs vitamin A derivative, calcineurin inhibitor, and PDE4 inhibitor, was 35.5%, 25.8%, and 60.1%, respectively, compared with that of the biologics IL-23 and IL-17 inhibitors, which was 85.6% and 84.7%, respectively. During the study period, the incidence of treatment changes was 59.1/100 patient-years. Lack of efficacy was the most common reason for treatment changes from monotherapy (34.1%). This retrospective medical chart review allowed us to understand the real-world, long-term treatment patterns of systemic drugs for PsO and the relationships between the reasons for treatment changes and subsequent treatment selection, indicating that there is still room for improvement in the appropriate use of systemic drugs for PsO in Japan.

Psoriasis is an immune-mediated chronic inflammatory disease that predominantly affects the skin and joints. Systemic therapies are required for patients with moderate-to-severe psoriasis, and biologics can provide significant symptomatic improvement. Computed tomography (CT) analysis is recommended before and after biologic therapy to exclude the possibility of comorbid infections and malignancies; incidental findings are often detected in asymptomatic patients. In this study, we analyzed the common incidental findings on CT in 227 patients with psoriasis on biologic therapy and 219 living-kidney transplant donors at our hospital. Incidental findings on CT were observed in 176 (77.5%) patients with psoriasis. The most common were fatty liver (82 patients, 36.1%), urolithiasis (54 patients, 23.8%), pulmonary lesions (47 patients, 20.7%), gallstones or postoperative gallstones (38 patients, 16.7%), liver cysts (36 patients, 15.9%), renal cysts (33 patients, 14.5%), and colonic diverticulum (22 patients, 9.7%), which were observed in 38 (17.4%), eight (3.7%), 68 (31.1%), 12 (5.5%), 58 (26.5%), 88 (40.2%), and 10 (4.6%) donors, respectively. The prevalence of fatty liver, urolithiasis, gallstones, and postoperative gallstones was significantly higher in patients with psoriasis. Multivariate logistic regression showed that psoriasis was a risk factor for fatty liver disease, urolithiasis, and gallstones. Currently, incidental findings on CT in patients with psoriasis have not been well studied. The results of this survey will lead to increased awareness of the incidental findings on CT as a complication of psoriasis.

This is the English version of Japanese guidance for the use of oral Janus kinase (JAK) inhibitors (JAK1 and tyrosine kinase 2 [TYK2] inhibitors) in the treatments of psoriasis. Several cytokines, such as interleukin (IL)-6, IL-7, IL-12, IL-21, IL-22, IL-23, interferon (IFN)-α, and IFN-γ, are involved in the pathogenesis of psoriasis (including psoriatic arthritis). As oral JAK inhibitors hinder the JAK-signal transducers and activators of transcription signal transduction routes involved in the signal transduction of these cytokines, they may be effective for the treatment of psoriasis. JAK has four types: JAK1, JAK2, JAK3, and TYK2. Regarding the use of oral JAK inhibitors for the treatment of psoriasis in Japan, indications of the JAK1 inhibitor upadacitinib were extended also to psoriatic arthritis in 2021, and the use of the TYK2 inhibitor deucravacitinib for plaque-type psoriasis, pustular psoriasis, and erythrodermic psoriasis became covered by health insurance in 2022. This guidance was developed for board-certified dermatologists who specialize in the treatment of psoriasis and to promote the proper use of oral JAK inhibitors. In the package inserts and guides for appropriate use, upadacitinib and deucravacitinib are classified as a "JAK inhibitor" and a "TYK2 inhibitor", respectively, and it is possible that there may be differences in safety between the two drugs. The safety of these drugs will be evaluated for the future by the postmarketing surveillance for molecularly targeted drugs for psoriasis of the Japanese Dermatological Association.