Rapid response to secukinumab in a 5-year-old with deficiency of the interleukin-36 receptor antagonist (DITRA) with severe scalp and nail involvement

Increased neutrophil-derived IL-17A identified in generalized pustular psoriasis

Generalized pustular psoriasis (GPP) is considered to be a distinct clinical entity from psoriasis vulgaris (PV), with different clinical and histological manifestations. The pathogenesis of GPP has not been thoroughly elucidated, especially in those patients lacking interleukin (IL)36RN. In present study, we performed RNA sequence analysis on skin lesions from 10 GPP patients (4 with and 6 without IL36RN mutation) and 10 PV patients without IL36RN mutation. Compared with PV, significantly overexpressed genes in GPP patients were enriched in IL-17 signalling pathway (MMP1, MMP3, DEFB4A and DEFB4B, etc.) and associated with neutrophil infiltration (MMP1, MMP3, ANXA and SERPINB, etc.). GPP with IL36RN mutations evidenced WNT11 upregulation and IL36RN downregulation in comparison to those GPP without IL36RN mutations. The expression of IL-17A/IL-36 in skin or serum and the origin of IL-17A in skin were also investigated. IL-17A expression in skin was significantly higher in GPP than PV patients, whereas, there were no differences in skin IL-36α/IL-36γ/IL-36RA or serum IL-17A/IL-36α/IL-36γ between GPP than PV. Besides, double immunofluorescence staining of MPO/IL-17A or CD3/IL-17A further confirmed that the majority of IL-17A in GPP skin was derived from neutrophils, but not T cells. These data emphasized the role of neutrophil-derived IL-17A in the pathogenesis of GPP with or without IL36RN mutations. Targeting neutrophil-derived IL-17A might be a promising treatment for GPP.

Clinical advances in biological therapy for generalized pustular psoriasis: a review

INTRODUCTION

In 2022, U.S. Food and Drug Administration (FDA) approved the first biologics, intravenous spesolimab, for acute flare of generalized pustular psoriasis (GPP). The drug works by blocking IL-36 signaling, the key pathway of GPP. Among the known mutations causing GPP, IL36RN mutations are most common, and the presence of IL36RN mutations had been found to affect the clinical manifestations and treatment response of GPP.

AREAS COVERED

Literature search was conducted in PubMed, Embase and ClinicalTrials.gov for relevant studies discussing biologic treatment for GPP with special emphasis on larger studies, pediatric group, pregnant women, and the influence of IL36RN mutation on the effectiveness of biologics.

EXPERT OPINION

The approval of spesolimab for GPP flare treatment marks a new era. However, whether spesolimab will be placed as the treatment of choice remains unknown, considering its higher cost, lack of direct comparison with existing biologics, and uncertain effects on co-existing plaque-type psoriasis. However, the demonstration of numerically better efficacy for patients carrying pathogenic IL36RN mutations suggests the role of pharmacogenetics in the choices of GPP treatment. Future randomized studies are warranted to investigate the effectiveness and safety of biologics for GPP in pediatric and pregnant groups.

Cutaneous findings and treatments in deficiency of interleukin-36 receptor antagonist (DITRA): A review of the literature

Deficiency of the interleukin-36 receptor antagonist (DITRA) is a rare autoinflammatory disorder caused by mutations in the IL36RN gene. This mutation leads to a lack of functional interleukin-36 receptor antagonists (IL-36Ra), which results in an overactive immune system and chronic inflammation. Despite its rarity, numerous case series and individual reports in the literature emphasize the importance of recognizing and managing DITRA. Early identification of the cutaneous signs of DITRA is crucial for accurate diagnosis and timely administration of appropriate treatment. This review article provides a comprehensive overview of the current understanding of the cutaneous, non-cutaneous and histopathological manifestations of DITRA, with a focus on reported treatments. The disease typically presents in early childhood, although the age of onset can vary. Patients with DITRA exhibit recurrent episodes of skin inflammation, often with a pustular or pustular psoriasis-like appearance. Additionally, non-cutaneous manifestations are common, with recurrent fevers and elevated acute-phase reactants being the most prevalent. The exact prevalence of DITRA is unknown. Some cases of loss-of-function mutations in the IL36RN gene, considered a hallmark for diagnosis, have been identified in patients with familial generalized pustular psoriasis (GPP). Biological therapies with inhibition of IL-12/23 and IL-17 are promising treatment options; paediatric patients with DITRA have shown complete response with mild relapses. New and emerging biologic therapeutics targeting the IL-36 pathway are also of interest in the management of this rare autoinflammatory disorder.

Targeting IL-17A for the treatment of pustular psoriasis: a comprehensive review

INTRODUCTION

Pustular psoriasis (PP) is a rare subtype of psoriasis. Overall, the growing evidence - in particular for acute generalized PP (GPP) - supports that it is a separate entity with a specific pathogenetic pathway. Interleukin (IL)-17/T-helper 17 (Th17) axis involvement may play an important role in the pathophysiology of PP. Biologicals, often required to achieve clinical remission, have changed the treatment of PP.

AREAS COVERED

We provide the reader with an overview of all the available evidence on the use of the antibody-based therapy targeting IL-17A in patients with PP.

EXPERT OPINION

Although papers reported in this review do not provide definitive evidence (due to methodological limitations) to support the use of IL-17 inhibitors as potential first-line for the treatment of PP, based on our own experience and according to most of the reported literature, targeting IL-17A, may represent the best therapeutical approach in this peculiar clinical spectrum of psoriasis.