Shifting paradigms in the immunology of atopic dermatitis

Allergen-specific immunotherapy improves alopecia totalis in a severe atopic dermatitis patient

House dust mite (HDM) is the most common allergen exacerbating atopic dermatitis (AD), and allergen-specific immunotherapy (AIT) using HDM exhibited significant improvements in previous studies. Alopecia can occur as a complication of AD. Alopecia totalis (AT), a severe form of alopecia areata (AA), does not respond well to treatment and the chance of full recovery is less than 10%. For extensive hair loss, topical immunotherapy such as diphenylcyclopropenone (DPCP) is used as the first-line treatment. However, since DPCP is a kind of contact allergen, it has the potential to exacerbate AD. A 38-year-old man with AD and AA visited our clinic with symptoms worsening from 3 months ago. Although taking oral methylprednisolone (8 mg/day) and cyclosporine (100 mg/day) for 3 months, he has lost over 90% of his hair and the Eczema Area and Severity Index (EASI) was 43. Total serum immunoglobulin E (IgE) levels were 4454 kU/L (normal <100 kU/L) and the specific IgE levels for Dermatophagoides pteronyssinus and Dermatophagoides farinae following ImmunoCAP® were 20.8 and 37.4 kU/L, respectively. This patient did not respond well to previous treatment and was reluctant to use long-term steroids, so subcutaneous AIT using HDM was administered along with oral cyclosporine (100 mg/day). Topical tacrolimus was also applied to the AD lesions throughout the body. To reduce itching, nonsedative antihistamines were used if necessary. Hair loss was almost completely improved 1 year after the AIT initiation and the skin lesions of AD also improved (EASI 2.4). The specific IgE levels for D. pteronyssinus and D. farinae were 3.73 and 7.16 kU/L, respectively. Herein, we report a patient with promising results following AIT for AT with severe AD. In severe alopecic patients with AD refractory to conventional treatment, including immunosuppressants, AIT could be considered as a treatment option.

Activated Protein C Protects against Murine Contact Dermatitis by Suppressing Protease-Activated Receptor 2

Atopic dermatitis (AD) is a chronic inflammatory skin disease associated with excessive inflammation and defective skin barrier function. Activated protein C (APC) is a natural anticoagulant with anti-inflammatory and barrier protective functions. However, the effect of APC on AD and its engagement with protease activated receptor (PAR)1 and PAR2 are unknown. Methods: Contact hypersensitivity (CHS), a model for human AD, was induced in PAR1 knockout (KO), PAR2KO and matched wild type (WT) mice using 2,4-dinitrofluorobenzene (DNFB). Recombinant human APC was administered into these mice as preventative or therapeutic treatment. The effect of APC and PAR1KO or PARKO on CHS was assessed via measurement of ear thickness, skin histologic changes, inflammatory cytokine levels, Th cell phenotypes and keratinocyte function. Results: Compared to WT, PAR2KO but not PAR1KO mice displayed less severe CHS when assessed by ear thickness; PAR1KO CHS skin had less mast cells, lower levels of IFN-γ, IL-4, IL-17 and IL-22, and higher levels of IL-1β, IL-6 and TGF-β1, whereas PAR2KO CHS skin only contained lower levels of IL-22 and IgE. Both PAR1KO and PAR2KO spleen cells had less Th1/Th17/Th22/Treg cells. In normal skin, PAR1 was present at the stratum granulosum and spinosum, whereas PAR2 at the upper layers of the epidermis. In CHS, however, the expression of PAR1 and PAR2 were increased and spread to the whole epidermis. In vitro, compared to WT cells, PAR1KO keratinocytes grew much slower, had a lower survival rate and higher para permeability, while PAR2KO cells grew faster, were resistant to apoptosis and para permeability. APC inhibited CHS as a therapeutic but not as a preventative treatment only in WT and PAR1KO mice. APC therapy reduced skin inflammation, suppressed epidermal PAR2 expression, promoted keratinocyte growth, survival, and barrier function in both WT and PAR1KO cells, but not in PAR2KO cells. Conclusions: APC therapy can mitigate CHS. Although APC acts through both PAR1 and PAR2 to regulate Th and mast cells, suppression of clinical disease in mice is achieved mainly via inhibition of PAR2 alone. Thus, APC may confer broad therapeutic benefits as a disease-modifying treatment for AD.

Advances in Atopic Dermatitis in 2019-2020: Endotypes from skin barrier, ethnicity, properties of antigen, cytokine profiles, microbiome, and engagement of immune cells

Key research advances in atopic dermatitis (AD) suggest the complexity of its endotypes. A comprehensive serum biomarker panel revealed at least four types of AD. Some represent classic TH2-dominant AD with filaggrin mutations commonly reported in Europeans, a simultaneously activated multipolar axes of cytokines often reported in Asians, and an intrinsic type characterized by TH2-inferiority. Innate lymphoid cells, including NK cells, NKT cells, and fibroblasts, play a role in AD development and heterogeneity. Here, we discuss the endotypes of AD from the perspective of antigen types (hapten vs. protein antigens), barrier function, and a novel set of immune cells. Endotypic stratification of AD may lead to the development of customized therapeutic strategies in the future.

Safety and efficacy of upadacitinib in combination with topical corticosteroids in adolescents and adults with moderate-to-severe atopic dermatitis (AD Up): results from a randomised, double-blind, placebo-controlled, phase 3 trial

BACKGROUND

Systemic therapies are typically combined with topical corticosteroids for the management of moderate-to-severe atopic dermatitis. Upadacitinib is an oral Janus kinase (JAK) inhibitor with greater inhibitory potency for JAK1 than JAK2, JAK3, or tyrosine kinase 2 that is being tested for atopic dermatitis. We aimed to assess the efficacy and safety of upadacitinib plus topical corticosteroids compared with placebo for the treatment of moderate-to-severe atopic dermatitis.

METHODS

In this randomised, double-blind, placebo-controlled, phase 3 trial (AD Up) adults (aged 18-75 years) and adolescents (aged 12-17 years) with chronic atopic dermatitis that was moderate to severe (≥10% of body surface area affected, Eczema Area and Severity Index [EASI] score of ≥16, validated Investigator's Global Assessment for atopic dermatitis [vIGA-AD] score of ≥3, and weekly average Worst Pruritus Numerical Rating Scale score of ≥4 at baseline) were enrolled at 171 clinical centres across 22 countries in the Asia-Pacific region, Europe, the Middle East, North America, and Oceania. Patients were randomly assigned (1:1:1) to receive upadacitinib 15 mg, upadacitinib 30 mg, or placebo once daily, all in combination with topical corticosteroids for 16 weeks. Randomisation was done using an interactive response technology system, stratified by baseline disease severity, geographical region, and age. Study investigators, study site personnel, and patients were masked to study treatment. The coprimary endpoints were the proportion of patients who had achieved at least a 75% reduction in EASI score from baseline (EASI-75) and the proportion of patients who had achieved a vIGA-AD response (defined as a vIGA-AD score of 0 [clear] or 1 [almost clear] with ≥2 grades of improvement from baseline) at week 16. Efficacy was analysed in the intention-to-treat population and safety was analysed in all patients who received at least one dose of study drug. This study is registered with ClinicalTrials.gov, NCT03568318, and is active, but not recruiting.

FINDINGS

Between Aug 9, 2018, and Dec 20, 2019, 901 patients were randomly assigned to receive upadacitinib 15 mg plus topical corticosteroids (n=300), upadacitinib 30 mg plus topical corticosteroids (n=297), or placebo plus topical corticosteroids (n=304). At week 16, the proportion of patients who had achieved EASI-75 was significantly higher in the upadacitinib 15 mg plus topical corticosteroid group (194 [65%] of 300 patients) and the upadacitinib 30 mg plus topical corticosteroids group (229 [77%] of 297 patients) than the placebo group (80 [26%] of 304 patients; adjusted difference in EASI-75 response rate vs placebo, 38·1% [95% CI 30·8-45·4] for the upadacitinib 15 mg group and 50·6% [43·8-57·4] for the upadacitinib 30 mg group; p<0·0001 for both doses). The proportion of patients who had achieved a vIGA-AD response at week 16 was significantly higher in the upadacitinib 15 mg plus topical corticosteroid group (119 [40%] patients) and upadacitinib 30 mg plus topical corticosteroid group (174 [59%] patients) than the placebo group (33 [11%] patients; adjusted difference in vIGA-AD response vs placebo, 28·5% [22·1-34·9] for the upadacitinib 15 mg group and 47·6% [41·1-54·0] for the upadacitinib 30 mg group; p<0·0001 for both doses). During the double-blind period, upadacitinib 15 and 30 mg were well tolerated in combination with topical corticosteroids. The most frequently reported treatment-emergent adverse events (≥5% in any treatment group) were acne, nasopharyngitis, upper respiratory tract infection, oral herpes, elevation of blood creatine phosphokinase levels, headache, and atopic dermatitis. The incidence of acne was higher in the upadacitinib 15 mg (30 [10%] of 300 patients) and upadacitinib 30 mg (41 [14%] of 297 patients) groups than the placebo group (six [2%] of 304 patients). The incidence of adverse events leading to discontinuation of study drug (four [1%] patients in the upadacitinib 15 mg plus topical corticosteroids group, four [1%] patients in the upadacitinib 30 mg plus topical corticosteroids group, and seven [2%] patients in the placebo plus topical corticosteroids group) and serious adverse events (seven [2%] patients, four [1%] patients, and nine [3%] patients) were similar among treatment groups. No deaths were reported in any treatment group.

INTERPRETATION

Upadacitinib plus topical corticosteroids was well tolerated and superior to placebo plus topical corticosteroids. Upadacitinib as combination therapy had a positive benefit-risk profile in adults and adolescents with moderate-to-severe atopic dermatitis.

FUNDING

AbbVie.

Nomenclature and clinical phenotypes of atopic dermatitis

Atopic dermatitis is a heterogeneous disease and resists classification. In this review, we discuss atopic dermatitis nomenclature and identify morphologic phenotypes, which will facilitate correct diagnoses and development of treatment strategies. We support using the term 'atopic dermatitis' rather than eczema, because it describes the allergic background and inflammation ('itis') as drivers of the disease. Atopic dermatitis has many morphologic manifestations that vary by topographic area affected, age, or race and require consideration in differential diagnosis. Different phenotypes based on morphology and topographic location, ethnicity, and age are discussed. A better-defined phenotype identification for atopic dermatitis will facilitate earlier and correct diagnosis of this complex condition and inform selection of the most appropriate treatment choice in an era in which targeted therapies may generate more individualized patient care.