Generalized pustular psoriasis (GPP) is a rare and yet potentially lethal clinical variant of psoriasis, characterized by the formation of sterile cutaneous pustules, neutrophilia, fever and features of systemic inflammation. We sequenced the exomes of five unrelated individuals diagnosed with GPP. Nonsynonymous, splice-site, insertion, and deletion variants with an estimated population frequency of <0.01 were considered as candidate pathogenic mutations. A homozygous c.338C>T (p.Ser113Leu) missense substitution of IL36RN was identified in two individuals, with a third subject found to be a compound heterozygote for c.338C>T (p.Ser113Leu) and a c.142C>T (p.Arg48Trp) missense substitution. IL36RN (previously known as IL1F5) encodes an IL-1 family receptor antagonist, which opposes the activity of the IL-36A and IL-36G innate cytokines. Homology searches revealed that GPP mutations alter evolutionarily conserved residues. Homozygosity for the c.338C>T (p.Ser113Leu) variant is associated with an elevated proinflammatory response following ex vivo stimulation with IL36A. These findings suggest loss of function of IL36RN as the genetic basis of GPP and implicate innate immune dysregulation in this severe episodic inflammatory disease, thereby highlighting IL-1 signaling as a potential target for therapeutic intervention.

BACKGROUNDThe oral Janus kinase 1 (JAK1) inhibitor abrocitinib, which reduces interleukin-4 and interleukin-13 signaling, is being investigated for the treatment of atopic dermatitis. Data from trials comparing JAK1 inhibitors with monoclonal antibodies, such as dupilumab, that block interleukin-4 receptors are limited. METHODSIn a phase 3, double-blind trial, we randomly assigned patients with atopic dermatitis that was unresponsive to topical agents or that warranted systemic therapy (in a 2:2:2:1 ratio) to receive 200 mg or 100 mg of abrocitinib orally once daily, 300 mg of dupilumab subcutaneously every other week (after a loading dose of 600 mg), or placebo; all the patients received topical therapy. The primary end points were an Investigator's Global Assessment (IGA) response (defined as a score of 0 [clear] or 1 [almost clear] on the IGA [scores range from 0 to 4], with an improvement of ≥2 points from baseline) and an Eczema Area and Severity Index-75 (EASI-75) response (defined as ≥75% improvement from baseline in the score on the EASI [scores range from 0 to 72]) at week 12. The key secondary end points were itch response (defined as an improvement of ≥4 points in the score on the Peak Pruritus Numerical Rating Scale [scores range from 0 to 10]) at week 2 and IGA and EASI-75 responses at week 16. RESULTSA total of 838 patients underwent randomization; 226 patients were assigned to the 200-mg abrocitinib group, 238 to the 100-mg abrocitinib group, 243 to the dupilumab group, and 131 to the placebo group. An IGA response at week 12 was observed in 48.4% of patients in the 200-mg abrocitinib group, 36.6% in the 100mg abrocitinib group, 36.5% in the dupilumab group, and 14.0% in the placebo group (P<0.001 for both abrocitinib doses vs. placebo); an EASI-75 response at week 12 was observed in 70.3%, 58.7%, 58.1%, and 27.1%, respectively (P<0.001 for both abrocitinib doses vs. placebo). The 200-mg dose, but not the 100-mg dose, of abrocitinib was superior to dupilumab with respect to itch response at week 2. Neither abrocitinib dose differed significantly from dupilumab with respect to most other key secondary end-point comparisons at week 16. Nausea occurred in 11.1% of the patients in the 200-mg abrocitinib group and 4.2% of those in the 100-mg abrocitinib group, and acne occurred in 6.6% and 2.9%, respectively. CONCLUSIONSIn this trial, abrocitinib at a dose of either 200 mg or 100 mg once daily resulted in significantly greater reductions in signs and symptoms of moderate-to-severe atopic dermatitis than placebo at weeks 12 and 16. The 200-mg dose, but not the 100-mg dose, of abrocitinib was superior to dupilumab with respect to itch response at week 2. Neither abrocitinib dose differed significantly from dupilumab with respect to most other key secondary end-point comparisons at week 16.

Summary Background Tralokinumab is a fully human monoclonal antibody that specifically neutralizes interleukin‐13, a key driver of atopic dermatitis (AD). Objectives To evaluate the efficacy and safety of tralokinumab in combination with topical corticosteroids (TCS) in patients with moderate‐to‐severe AD who were candidates for systemic therapy. Methods This was a double‐blind, placebo plus TCS controlled phase III trial. Patients were randomized 2 : 1 to subcutaneous tralokinumab 300 mg or placebo every 2 weeks (Q2W) with TCS as needed over 16 weeks. Patients who achieved an Investigator’s Global Assessment (IGA) score of 0/1 and/or 75% improvement in Eczema Area and Severity Index (EASI 75) at week 16 with tralokinumab were rerandomized 1 : 1 to tralokinumab Q2W or every 4 weeks (Q4W), with TCS as needed, for another 16 weeks. Results At week 16, more patients treated with tralokinumab than with placebo achieved IGA 0/1: 38·9% vs. 26·2% [difference (95% confidence interval): 12·4% (2·9–21·9); P = 0·015] and EASI 75: 56·0% vs. 35·7% [20·2% (9·8–30·6); P < 0·001]. Of the patients who were tralokinumab responders at week 16, 89·6% and 92·5% of those treated with tralokinumab Q2W and 77·6% and 90·8% treated with tralokinumab Q4W maintained an IGA 0/1 and EASI 75 response at week 32, respectively. Among patients who did not achieve IGA 0/1 and EASI 75 with tralokinumab Q2W at 16 weeks, 30·5% and 55·8% achieved these endpoints, respectively, at week 32. The overall incidence of adverse events was similar across treatment groups. Conclusions Tralokinumab 300 mg in combination with TCS as needed was effective and well tolerated in patients with moderate‐to‐severe AD.

Linked Comment: Jemec. Br J Dermatol 2019; 180:975. Plain language summary available online

Background The multi-morbid burden and use of systemic immunosuppressants in people with psoriasis may confer greater risk of adverse COVID-19 outcomes but data are limited. Objective Characterize the course of COVID-19 in psoriasis and identify factors associated with hospitalization. Methods Clinicians reported psoriasis patients with confirmed/suspected COVID-19 via an international registry, PsoProtect. Multiple logistic regression assessed the association between clinical/demographic characteristics and hospitalization. A separate patient-facing registry characterized risk-mitigating behaviours. Results Of 374 clinician-reported patients from 25 countries, 71% were receiving a biologic, 18% a non-biologic and 10% no systemic treatment for psoriasis. 348 (93%) fully recovered from COVID-19, 77 (21%) were hospitalized and nine (2%) died. Increased hospitalization risk was associated with older age (multivariable-adjusted OR 1.59 per 10 years, 95% CI 1.19-2.13), male sex (OR 2.51, 95% CI 1.23-5.12), non-white ethnicity (OR 3.15, 95% CI 1.24-8.03) and comorbid chronic lung disease (OR 3.87, 95% CI 1.52-9.83). Hospitalization was more frequent in patients using non-biologic systemic therapy than biologics (OR 2.84, 95% CI 1.31-6.18). No significant differences were found between biologic classes. Independent patient-reported data (n=1,626 across 48 countries) suggested lower levels of social isolation in individuals receiving non-biologic systemic therapy compared to biologics (OR 0.68, 95% CI 0.50-0.94). Conclusion In this international moderate-severe psoriasis case series, biologics use was associated with lower risk of COVID-19-related hospitalization than non-biologic systemic therapies, however further investigation is warranted due to potential selection bias and unmeasured confounding. Established risk factors (being older, male, non-white ethnicity, comorbidities) were associated with higher hospitalization rates. Clinical Implications We identify risk factors for COVID-19-related hospitalization in psoriasis patients, including older age, male sex, non-white ethnicity and comorbidities. Use of biologics was associated with lower hospitalization risk than non-biologic systemic therapies.

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Hidradenitis suppurativa (HS) is a debilitating chronic inflammatory skin condition of unclear etiology. It may segregate as an autosomal dominant trait, and heterozygous mutations in the γ-secretase genes NCSTN, PSENEN, and PSEN1 have recently been reported in a small number of multiplex kindreds and sporadic cases. These mutations highlight γ-secretase (an enzyme that has been extensively investigated in familial Alzheimer's disease) to have an integral role in cutaneous biology and, more specifically, in HS. In this article, we review the recent genetic data, how they inform disease pathogenesis, and the long-term implications in HS and related diseases.