IL-33 potentiates histaminergic itch.

BACKGROUND: Itch is a common symptom that can greatly diminish quality of life. Histamine is a potent endogenous pruritogen, and while antihistamines are often the first-line treatment for itch, in conditions like chronic spontaneous urticaria (CSU), many patients remain symptomatic while receiving maximal doses. Mechanisms that drive resistance to antihistamines are poorly defined. OBJECTIVES: Signaling of the alarmin cytokine IL-33 in sensory neurons is postulated to drive chronic itch by inducing neuronal sensitization to pruritogens. Thus, we sought to determine if IL-33 can augment histamine-induced (histaminergic) itch. METHODS: Itch behavior was assessed in response to histamine after IL-33 or saline administration. Various stimuli and conditional and global knockout mice were utilized to dissect cellular mechanisms. Multiple existing transcriptomic data sets were evaluated, including single-cell RNA sequencing of human and mouse skin, microarrays of isolated mouse mast cells at steady state and after stimulation with IL-33, and microarrays of skin biopsy samples from subjects with CSU and healthy controls. RESULTS: IL-33 amplifies histaminergic itch independent of IL-33 signaling in sensory neurons. Mast cells are the top expressors of the IL-33 receptor in both human and mouse skin. When stimulated by IL-33, mouse mast cells significantly increase IL-13 levels. Enhancement of histaminergic itch by IL-33 relies on a mast cell- and IL-13-dependent mechanism. IL-33 receptor expression is increased in lesional skin of subjects with CSU compared to healthy controls. CONCLUSIONS: Our findings suggest that IL-33 signaling may be a key driver of histaminergic itch in mast cell-associated pruritic conditions such as CSU.

Dupilumab in patients with chronic spontaneous urticaria (LIBERTY-CSU CUPID): Two randomized, double-blind, placebo-controlled, phase 3 trials.

BACKGROUND: Chronic spontaneous urticaria (CSU) is a chronic inflammatory disease characterized by recurrent pruritic wheals (hives) and/or angioedema. Patients with CSU could remain symptomatic despite standard-of-care H1 antihistamines (H1-AH) or anti-IgE (omalizumab) treatment. Dupilumab blocks IL-4/IL-13 signaling and is approved for multiple type 2/atopic indications. OBJECTIVE: We conducted two phase 3, randomized, placebo-controlled, double-blind trials comparing dupilumab with placebo in patients with symptomatic CSU despite H1-AH. METHODS: In LIBERTY-CSU CUPID Study A, patients were omalizumab-naive (n = 138, aged ≥6 years). In Study B, patients were omalizumab-intolerant/incomplete responders (n = 108, aged ≥12 years). The primary end point was either change from baseline over 7 days in the Urticaria Activity Score (UAS7) or Itch Severity Score (ISS7) at week 24, with the other as a key secondary end point, depending on regional regulatory requirements. Studies were pooled for safety assessment. RESULTS: In Study A, UAS7 and ISS7 improved with dupilumab versus placebo (difference -8.5 [95% CI, -13.2 to -3.9; P = .0003] and -4.2 [95% CI, -6.6 to -1.8; P = .0005]). In Study B, tested at α = 0.043 after interim analysis, UAS7 improved (difference -5.8 [95% CI, -11.4 to -0.3; P = .0390]), with a numerical trend in ISS7 (difference -2.9 [95% CI, -5.7 to -0.07; nominal P = .0449, not significant]). Pooled safety data were consistent between dupilumab and placebo and with the known dupilumab safety profile. CONCLUSIONS: Dupilumab reduced urticaria activity by reducing itch and hives severity in omalizumab-naive patients with CSU uncontrolled with H1-AH. Although the primary end point for Study B was not met, dupilumab effects were small in patients who were omalizumab-intolerant/incomplete responders.

Remibrutinib demonstrates favorable safety profile and sustained efficacy in chronic spontaneous urticaria over 52 weeks.

BACKGROUND: Remibrutinib (LOU064), an oral, highly selective Bruton tyrosine kinase inhibitor, offers fast disease control in patients with chronic spontaneous urticaria (CSU) who remain symptomatic despite treatment with second-generation H1 antihistamines. It is currently in phase 3 development for CSU. OBJECTIVE: We sought to evaluate long-term safety and efficacy of remibrutinib in patients with CSU inadequately controlled with H1 antihistamines. METHODS: In this phase 2b extension study, patients who completed the core study and had a weekly Urticaria Activity Score (UAS7) ≥16 at the beginning of the extension study received remibrutinib 100 mg twice daily for 52 weeks. The primary objective was to assess long-term safety and tolerability. Key efficacy end points included change from baseline in UAS7 and proportion of patients with complete response to treatment (UAS7 = 0) and well-controlled disease (UAS7 ≤6) at week 4 and over 52 weeks. RESULTS: Overall, 84.3% (194/230) of patients entered the treatment period and received ≥1 doses of remibrutinib. The overall safety profile of remibrutinib was comparable between the extension and core studies. Most treatment-emergent adverse events were mild to moderate and considered unrelated to remibrutinib by investigators. The 3 most common treatment-emergent adverse events by system organ class were infections (30.9%), skin and subcutaneous tissue (26.8%), and gastrointestinal disorders (16.5%). At week 4 and 52, mean ± SD change from baseline in UAS7 was -17.6 ± 13.40 and -21.8 ± 10.70; UAS7 = 0 (as observed) was achieved in 28.2% and 55.8% and UAS7 ≤6 (as observed) was achieved in 52.7% and 68.0% of patients, respectively. CONCLUSIONS: Remibrutinib demonstrated a consistent favorable safety profile with fast and sustained efficacy for up to 52 weeks in patients with CSU.

BTK signaling-a crucial link in the pathophysiology of chronic spontaneous urticaria.

Chronic spontaneous urticaria (CSU) is an inflammatory skin disorder that manifests with itchy wheals, angioedema, or both for more than 6 weeks. Mast cells and basophils are the key pathogenic drivers of CSU; their activation results in histamine and cytokine release with subsequent dermal inflammation. Two overlapping mechanisms of mast cell and basophil activation have been proposed in CSU: type I autoimmunity, also called autoallergy, which is mediated via IgE against various autoallergens, and type IIb autoimmunity, which is mediated predominantly via IgG directed against the IgE receptor FcεRI or FcεRI-bound IgE. Both mechanisms involve cross-linking of FcεRI and activation of downstream signaling pathways, and they may co-occur in the same patient. In addition, B-cell receptor signaling has been postulated to play a key role in CSU by generating autoreactive B cells and autoantibody production. A cornerstone of FcεRI and B-cell receptor signaling is Bruton tyrosine kinase (BTK), making BTK inhibition a clear therapeutic target in CSU. The potential application of early-generation BTK inhibitors, including ibrutinib, in allergic and autoimmune diseases is limited owing to their unfavorable benefit-risk profile. However, novel BTK inhibitors with improved selectivity and safety profiles have been developed and are under clinical investigation in autoimmune diseases, including CSU. In phase 2 trials, the BTK inhibitors remibrutinib and fenebrutinib have demonstrated rapid and sustained improvements in CSU disease activity. With phase 3 studies of remibrutinib ongoing, it is hoped that BTK inhibitors will present an effective, well-tolerated option for patients with antihistamine-refractory CSU, a phenotype that presents a considerable clinical challenge.

Biomarkers predicting the controller dose of omalizumab in patients with chronic spontaneous urticaria.

BACKGROUND: Clinical trials showed the efficacy of 300 mg/4 weeks of omalizumab (OMA) during 6 months in patients with severe chronic spontaneous urticaria (CSU). Nevertheless, in real life, many patients require higher doses and/or longer treatment. This study assesses the real-life performance of OMA in severe CSU and identifies factors associated with the response. METHODS: CSU patients eligible for OMA were recruited prospectively. Clinical data and a blood test were collected before OMA initiation. Urticaria Activity Score 7 (UAS7) was calculated at baseline and every 3 months during OMA treatment. CSU control was defined as UAS7 <7 points. This work was partially sponsored by OMA manufacturer. RESULTS: Eighty-nine adults (19.1% males) with severe CSU were recruited. Median duration of CSU prior to OMA initiation was 2 years, and median severity by UAS7 at baseline was 24 points (range 10-42 points). OMA controlled 94.4% of patients, but 17.9% of responders required doses >300 mg/4 weeks. A blood basophil count >20 cells/µL (OR 13.33; 95% CI 3.32-52.63; p < .001) and the absence of hypothyroidism (OR 3.65; 95% CI 0.78-16.95; p = .099) were identified as predictive factors to achieve control with 300 mg/4 weeks. Twelve patients were able to stop OMA during the study (responders in remission, RR). RR had received OMA for a median of 29 months (12-53 months). Conversely, 32 patients had been on OMA for >29 months at the end of the study (active responders, AR). AR had received OMA for a median of 45 months (30-100 months). There were no significant differences in clinical or analytical factors between RR and AR patients. CONCLUSIONS: Low blood basophil count and the presence of hypothyroidism might serve as biomarkers for the controller dose of OMA in severe CSU patients.

Efficacy and safety of on-demand versus daily rupatadine in chronic spontaneous urticaria: A randomized trial.

BACKGROUND: Non-sedating H1 -antihistamines (nsAH) are the most commonly used treatment for chronic spontaneous urticaria (CSU). Many patients use them as on-demand (OD) therapy rather than a maintenance treatment. Here, we compared OD versus daily maintenance treatment with the nsAH rupatadine, assessed the efficacy of rupatadine updosing, and investigated potential long-term disease-modifying effects. METHODS: This multicenter, randomized study consisted of 2 weeks of screening, 8 weeks of double-blind treatment, and 6 weeks of treatment-free follow-up (OD allowed). Adult patients were randomized to 10 mg rupatadine OD or 10 mg rupatadine daily. At Week 4, if patients did not have a complete response, they switched from 10 to 20 mg rupatadine daily or underwent sham updosing (patients on 10 mg rupatadine OD). The primary aim was to compare CSU disease activity at the end of follow-up between daily versus OD. Additionally, we assessed the efficacy of rupatadine updosing. Major outcomes were disease activity, CSU-related quality of life (QoL), and disease control. RESULTS: At Week 4, disease activity and QoL significantly improved in daily versus OD-treated patients. Updosing of rupatadine did not improve the mean disease activity, but the number of complete responders increased during updosing from 5% to 22%. At the end of follow-up, the disease activity of patients treated OD versus daily was not significantly different. CONCLUSIONS: Daily rupatadine treatment significantly improved CSU disease activity and QoL during treatment versus OD treatment but not after discontinuation of rupatadine, indicating the benefits of a daily maintenance nsAH schedule.

Disease modification in chronic spontaneous urticaria.

Chronic spontaneous urticaria (CSU) is a debilitating, inflammatory skin condition characterized by infiltrating immune cells. Available treatments are limited to improving the signs and symptoms. There is an unmet need to develop therapies that target disease-driving pathways upstream of mast cell activation to inhibit or delay the progression of CSU and associated comorbidities. Here, we aim to define disease modification due to a treatment intervention and criteria that disease-modifying treatments (DMTs) must meet in CSU. We have defined disease modification in CSU as a favorable treatment-induced change in the underlying pathophysiology and, therefore, the disease course, which is clinically beneficial and enduring. A DMT must fulfil the following criteria: (1) prevents or delays the progression of CSU, (2) induces long-term, therapy-free clinical remission, which is the sustained absence of CSU signs and symptoms without the need for treatment, and (3) affects the underlying mechanism of CSU, as demonstrated by an effect on disease-driving signals and/or a biomarker. DMTs in CSU should slow disease progression, achieve long-lasting disease remission, target disease-driving mechanisms, reduce mast cell-activating IgE autoantibodies, target cytokine profile polarization, and normalize the gut microbiome and barrier. Treating CSU at the immune system level could provide valuable alternatives to pharmacotherapy in CSU management. Specific DMTs in CSU are yet to be developed, but some show potential benefits, such as inhibitors of Bruton's Tyrosine Kinase, IL-4 and IL-13. Future therapies could prevent CSU signs and symptoms, achieve long-term clinical benefits after discontinuing treatment, and prevent associated concomitant disorders.

In chronic spontaneous urticaria, increased Galectin-9 expression on basophils and eosinophils is linked to high disease activity, endotype-specific markers, and response to omalizumab treatment.

BACKGROUND: Galectin-9 (Gal-9) has been implicated in allergic and autoimmune diseases, but its role and relevance in chronic spontaneous urticaria (CSU) are unclear. OBJECTIVES: To characterize the role and relevance of Gal-9 in the pathogenesis of CSU. METHODS: We assessed 60 CSU patients for their expression of Gal-9 on circulating eosinophils and basophils as well as T cell expression of the Gal-9 receptor TIM-3, compared them with 26 healthy controls (HCs), and explored possible links with disease features including disease activity (urticaria activity score, UAS), total IgE, basophil activation test (BAT), and response to omalizumab treatment. We also investigated potential drivers of Gal-9 expression by eosinophils and basophils. RESULTS: Our CSU patients had markedly increased rates of circulating Gal-9+ eosinophils and basophils and high numbers of lesional Gal-9+ cells. High rates of blood Gal-9+ eosinophils/basophils were linked to high disease activity, IgE levels, and BAT negativity. Serum levels of TNF-α were positively correlated with circulating Gal-9+ eosinophils/basophils, and TNF-α markedly upregulated Gal-9 on eosinophils. CSU patients who responded to omalizumab treatment had more Gal-9+ eosinophils/basophils than non-responders, and omalizumab reduced blood levels of Gal-9+ eosinophils/basophils in responders. Gal-9+ eosinophils/basophils were negatively correlated with TIM-3+TH17 cells. CONCLUSION: Our findings demonstrate a previously unrecognized involvement of the Gal-9/TIM-3 pathway in the pathogenesis CSU and call for studies that explore its relevance.

Characteristics and Clinical Significance of Atopy in Chronic Spontaneous Urticaria: A Cross-Sectional Observational Study.

INTRODUCTION: Atopy is an important and non-negligible clinical phenomenon in chronic spontaneous urticaria (CSU). However, the characteristics and clinical significance of atopy in patients with CSU have not been fully described. This study aimed to analyze the characteristics and clinical significance of atopy in patients with CSU. METHODS: A descriptive cross-sectional design was used. The study enrolled 176 patients with CSU. All enrolled patients underwent total IgE, specific IgE, and autologous serum skin tests (ASSTs). The relationships between atopy, the demographic and clinical data of patients with CSU, and the response to ASST were analyzed in detail; the distribution of allergens in atopic CSU was also analyzed. RESULTS: Atopy was confirmed in 48.9% of patients with CSU. Patients with atopic CSU were more likely than patients with non-atopic CSU to have dermatographism (57.0% vs. 41.1%, p < 0.05), history of urticaria (37.2% and 18.9%, respectively; p < 0.01), angioedema (39.5% and 24.4%, respectively; p < 0.05), and anaphylaxis (7/86 and 1/90, respectively; p < 0.05). Atopy was not associated with ASST response, disease duration, or response to antihistamine treatment in patients with CSU, nor was it associated with the urticaria activity score (UAS7), chronic urticaria quality of life questionnaire (CU-Q2oL), or pruritus visual analog scale (VAS) scores (all p < 0.05). The most common allergen in patients with atopic CSU was dust mites, followed by animal food allergens, tree/grass pollen, and cockroaches. CONCLUSIONS: Although larger prospective studies are needed to confirm these results, our study found atopy occurred in nearly half of patients with CSU, and preliminarily links atopy to CSU, suggesting it as a potential risk factor for angioedema, anaphylaxis, and recurrent urticaria, mirroring allergen patterns in other allergic disease.

Atopy and Response to Omalizumab Treatment in Chronic Spontaneous Urticaria.

INTRODUCTION: The possible influence of sensitization to aeroallergens on omalizumab response in chronic spontaneous urticaria (CSU) has been insufficiently investigated. This study's aim was to investigate atopy's influence on omalizumab response in CSU patients. METHOD: Retrospective study of CSU patients followed at a Portuguese Urticaria Center of Reference and Excellence (UCARE), treated with omalizumab for at least 6 months, between 2015 and 2022. At T0, all patients underwent quantification of specific immunoglobulin E (IgE) for total extract of most prevalent aeroallergens (ImmunoCAP Thermo Fisher Scientific®) and were divided in 2 groups, according to their response to omalizumab during the first 16 weeks of treatment: responders (R) (UAS7 <7) versus partial (PR) (UAS7 = 7-15) and nonresponders (UAS7 >15). R were further classified as fast (FR) (4-6 weeks) and slow responders (SR) (12-16 weeks). Total serum IgE, circulating eosinophil, and basophil counts were compared between groups at T0. p < 0.05 was considered statistically significant (SPSS® v25.0). RESULTS: Ninety-six patients (80% female) were studied, mean age 49 ± 14 years. Median CSU duration pre-omalizumab was 3 (0.6-20) years and mean omalizumab treatment duration was 3.7 ± 2.3 years. 38 (40%) had concomitant chronic inducible urticaria and 72 (75%) angioedema. Based on positive results of the specific IgE assay, 35 patients (36%) were considered atopic. Most patients (n = 30; 86%) were sensitized to house dust mites (HDM) (Dermatophagoides farinae = 28, Dermatophagoides pteronyssinus = 27, Blomia tropicalis = 19, Lepidoglyphus destructor = 17), followed by pollens (n = 12; 34%) (mixture of grasses = 10, Olea europaea = 7, Parietaria officinalis = 6), epithelia (n = 9; 26%) (dog = 8, cat = 7), and fungi (Alternaria alternata = 4; 11%). Eight patients (23%) were monosensitized to HDM and 4 (11%) to pollens. No significant association was found between aeroallergen sensitization and CSU duration, concomitant chronic inducible urticaria, or angioedema. Atopic patients featured significantly higher levels of baseline total serum IgE than nonatopic (469 vs. 94 U/mL, respectively; p = 0.0009). Mean baseline counts of eosinophils and basophils were not significantly different between atopic and non-atopic, respectively: eosinophils (128 vs. 121/mm3) and basophils (26 vs. 28/mm3). Regarding response to omalizumab, most patients (58; 60%) were responders: FR - 46 (79%); SR - 12 (21%). There was no significant association between aeroallergen sensitization and omalizumab response or speed of response. CONCLUSIONS: As far as we know, this is the first study exploring the influence of atopy sensitization pattern on omalizumab response in CSU. According to our results, presence of atopy/sensitization pattern does not influence omalizumab response in CSU patients.

Predicting the Speed of Response to Omalizumab in Chronic Spontaneous Urticaria.

INTRODUCTION: Two distinct chronic spontaneous urticaria (CSU) endotypes, IgE-mediated autoallergic and IgG-mediated autoimmune, were defined based on the response patterns to omalizumab. However, the coexistence of IgE and IgG autoantibodies in a subset of patients might complicate the prediction of the treatment outcomes. This study aimed to evaluate the effectiveness and safety of omalizumab in CSU patients, focusing on the factors predicting the response patterns. METHODS: This was a retrospective cross-sectional single-center study investigating CSU patients treated with omalizumab for at least 6 months between September 2015 and February 2023. Patients were evaluated regarding demographics, clinical findings, baseline laboratory parameters, treatment outcomes, and side effects. Early and late responders were defined depending on the time for response, within or after 3 months, respectively. RESULTS: Among 82 patients, 75 (91.5%) responded to omalizumab during the first 6 months, classified as early (n = 51) and late responders (n = 24). The IgG anti-thyroid peroxidase (anti-TPO)/total IgE ratio was an independent predictor for determining the speed of response (p < 0.05). Of 29 patients who discontinued omalizumab, 19 (65.5%) experienced relapse with a good response to retreatment (n = 18/19, 94.7%). Early responders relapsed more frequently than late responders (77.3% vs. 28.6%) (p < 0.05). Only mild side effects were observed in a minority of patients (n = 8/82, 9.8%). CONCLUSION: Omalizumab is an effective and safe treatment in CSU. The IgG anti-TPO/total IgE ratio seems a valuable tool to predict the early and late responders, the former having a higher possibility of relapse upon drug withdrawal.

Time-course and dose-effect of omalizumab in treating chronic idiopathic urticaria/chronic spontaneous urticaria.

PURPOSE: Several studies have shown that subcutaneous injections of omalizumab can treat chronic idiopathic/spontaneous urticaria (CIU/CSU) patients by only assessing the efficacy on specific endpoints. This study aimed to quantitatively analyze different doses of omalizumab in CIU/CSU and compare it with ligelizumab. METHODS: Literature searches were performed in PubMed, Embase, and Web of Science databases. A model-based meta-analysis (MBMA) was utilized to develop a model incorporating time since the initiation of treatment and dose for omalizumab, with the change from baseline in Urticaria Activity Score (CFB-UAS7) as the primary efficacy endpoint. The time-course and dose-effect relationship throughout the omalizumab treatment period was analyzed, and the findings were compared with those of the investigational ligelizumab. RESULTS: The model equation for the CFB-UAS7 was established as E = -Emax × time/(ET50 + time) × (b0 + b1 × dose). The estimated values of the model parameters E max , ET 50 , b 0 , and b 1 were -1.16, 1.26 weeks, -9.90, and -0.0361 mg-1, respectively. At week 12 after the first dose, the model-predicted CFB-UAS7 for 150 mg and 300 mg of omalizumab were -16.0 (95% CI, -17.2 to -14.8) and -21.7 (95% CI, -22.9 to -20.5), respectively. In the PEARL-1 trial, the CFB-UAS7 for 72 mg and 120 mg of ligelizumab were -19.4 (95% CI, -20.7 to -18.1) and -19.3 (95% CI, -20.6 to -18.0), respectively. In the PEARL-2 trial, these values were -19.2 (95% CI, -20.5 to -17.9) and -20.3 (95% CI, -21.6 to -19.0), respectively. CONCLUSION: Omalizumab showed a significant dose-dependent effect in the treatment of CSU. Both 72 mg and 120 mg ligelizumab might have the potential to outperform 150 mg (but not 300 mg) omalizumab.

Paediatric indications and dosing guidance for advanced targeted treatments in Australia.

As with adults, paediatric patients may benefit from a number of advanced targeted therapies for inflammatory skin disease. This brief report aims to be an accessible reference tool with respect to regulatory approval and reimbursement of these treatments within Australia.

A Practical Guide to Using Biologics in Pediatric Dermatology.

Psoriasis, hidradenitis suppurativa (HS), atopic dermatitis (AD), and chronic spontaneous urticaria (CSU), are common, immune-mediated, chronic, inflammatory skin diseases that can affect the pediatric population. While there is adequate evidence supporting the use of biologics in pediatric patients, concerns regarding safety and efficacy amongst healthcare providers are not uncommon. However, new emerging evidence in this population highlights the safety of biologic therapy, making it crucial to review and establish a practical guide for their use. This article describes a methodological framework for initiating biologics in the management of pediatric psoriasis, HS, AD, and CSU, with a special focus on baseline work-up, monitoring, dosing, and considerations in this population.

The autologous serum skin test (ASST) predicts the response to anti-IgE treatment in Chronic Spontaneous Urticaria patients: a prospective study.

Summary: Background. Chronic spontaneous urticaria (CSU), characterized by recurrent itchy wheals and angioedema for > 6 weeks, is a quite common disease that may heavily impair the quality of life. Omalizumab, an anti-IgE mAb, has much improved the management of CSU but patients' response to the drug may vary and predictive markers are still largely missing. We investigated the predictive value of the autologous serum skin test (ASST) on omalizumab response. Methods. 15 patients with severe CSU eligible for omalizumab treatment were prospectively studied submitting them to ASST and to complete blood count, D-dimer, anti-thyroid peroxidase antibodies, and total IgE measurement before the start of the treatment. Results. 14/15 (93%) responded brilliantly to omalizumab at 3 months assessment. 7 responded in less than 1 month ("early responders") and 7 only after multiple administrations ("late responders"). Of 9 patients scoring positive on ASST, 7 (78%) were late, and 2 (22%) early responders to omalizumab (p = 0.021). Of 6 patients scoring negative on ASST, 5 were early omalizumab responders and 1 did not respond. The PPV and NPV of the ASST for a "late" response to omalizumab were 78% and 100%, respectively. Total IgE were significantly higher in early responders. Conclusions. Although larger prospective studies are needed to confirm these results, this study confirms previous retrospective investigations that the positive ASST appears to predict a slow response to omalizumab in CSU patients.

A genome-wide association study of chronic spontaneous urticaria risk and heterogeneity.

BACKGROUND: Chronic spontaneous urticaria (CSU) is a dermatologic condition characterized by spontaneous, pruritic hives and/or angioedema that persists for 6 weeks or longer with no identifiable trigger. Antihistamines and second-line therapies such as omalizumab are effective for some CSU patients, but others remain symptomatic, with significant impact on quality of life. This variable response to treatment and autoantibody levels across patients highlight clinically heterogeneous subgroups. OBJECTIVE: We aimed to highlight pathways involved in CSU by investigating the genetics of CSU risk and subgroups. METHODS: We performed a genome-wide association study (GWAS) of 679 CSU patients and 4446 controls and a GWAS of chronic urticaria (CU)-index, which measures IgG autoantibodies levels, by comparing 447 CU index-low to 183 CU index-high patients. We also tested whether polygenic scores for autoimmune-related disorders were associated with CSU risk and CU index. RESULTS: We identified 2 loci significantly associated with disease risk. The strongest association mapped to position 56 of HLA-DQA1 (P = 1.69 × 10-9), where the arginine residue was associated with increased risk (odds ratio = 1.64). The second association signal colocalized with expression-quantitative trait loci for ITPKB in whole blood (Pcolocalization = .997). The arginine residue at position 56 of HLA-DQA1 was also associated with increased risk of CU index-high (P = 6.15 × 10-5, odds ratio = 1.86), while the ITKPB association was not (P = .64). Polygenic scores for 3 autoimmune-related disorders (hypothyroidism, type 1 diabetes, and vitiligo) were associated with CSU risk and CU index (P < 2.34 × 10-3, odds ratio > 1.72). CONCLUSION: A GWAS of CSU identified 2 genome-wide significant loci, highlighting the shared genetics between CU index and autoimmune disorders.

Unveiling chronic spontaneous urticaria pathophysiology through systems biology.

BACKGROUND: Chronic spontaneous urticaria (CSU) is a rare, heterogeneous, severely debilitating, and often poorly controlled skin disease resulting in an itchy eruption that can be persistent. Antihistamines and omalizumab, an anti-IgE mAb, are the only licensed therapies. Although CSU pathogenesis is not yet fully understood, mast cell activation through the IgE:high-affinity IgE receptor (FcεRI) axis appears central to the disease process. OBJECTIVE: We sought to model CSU pathophysiology and identify in silico the mechanism of action of different CSU therapeutic strategies currently in use or under development. METHODS: Therapeutic performance mapping system technology, based on systems biology and machine learning, was used to create a CSU interactome validated with gene expression data from patients with CSU and a CSU model that was used to evaluate CSU pathophysiology and the mechanism of action of different therapeutic strategies. RESULTS: Our models reflect the known role of mast cell activation as a central process of CSU pathophysiology, as well as recognized roles for different therapeutic strategies in this and other innate and adaptive immune processes. They also allow determining similarities and differences between them; anti-IgE and Bruton tyrosine kinase inhibitors play a more direct role in mast cell biology through abrogation of FcεRI signaling activity, whereas anti-interleukins and anti-Siglec-8 have a role in adaptive immunity modulation. CONCLUSION: In silico CSU models reproduced known CSU and therapeutic strategies features. Our results could help advance understanding of therapeutic mechanisms of action and further advance treatment research by patient profile.

Serum Concentration of IL-5 Receptor (IL-5R) and Associations with Disease Severity in Patients with Chronic Spontaneous Urticaria (CSU) and Atopic Dermatitis (AD).

The immunological pathogenesis of atopic dermatitis (AD) and chronic spontaneous urticaria (CSU) has not been fully elucidated yet. The aim of our research was to assess the serum concentration of interleukin-5 receptor (IL-5R) in relation to the disease activity and pruritus intensity in adult patients with AD and CSU. This pilot study included 45 participants (15 patients with AD, 15 patients with CSU, and 15 healthy controls). Blood samples were taken to examine the serum levels of IL-5R using the enzyme-linked immunosorbent assay (ELISA) test. The Scoring Atopic Dermatitis (SCORAD) index, the Urticaria Activity Score (UAS7), and the Visual Analogue Scale (VAS) were used to assess the disease activity and the pruritus intensity, respectively. Obtained results revealed that the IL-5R concentration was significantly higher in patients with CSU than in patients with AD and in the controls (p = 0.038). There was a positive correlation between the IL-5R level and the SCORAD index in patients with AD (r = -0.9, p = 0.047), which was not found for the CSU activity by UAS7 and with the pruritus severity by VAS in both examined groups of patients. Our findings underscore higher serum levels of IL-5R among CSU and AD patients, which may highlight its functional role in the pathogenesis of these diseases. In contrast, IL-5R might not be fully useful in reflecting the severity of symptoms. Although our results are promising, this study should be conducted on a larger cohort of patients.

The effectiveness of omalizumab therapy in patients with chronic spontaneous urticaria: the experience of a single-centre study in Poland.

Introduction: Omalizumab, which is a recombinant, humanised anti-immunoglobulin-E antibody, is the only approved drug for antihistamine refractory chronic spontaneous urticaria (CSU). It has been reported that it is an effective and safe drug, but the data about long-term effectiveness are still lacking. Aim: To perform a retrospective analysis of the patients with CSU treated with omalizumab at the dermatology department to assess effectiveness of omalizumab therapy in the single centre in Poland. Material and methods: A two-and-a-half-year retrospective analysis of patients with CSU undergoing the therapy with omalizumab was conducted. Patients' data were analysed for many factors such as age, gender, severity indexes (UAS7, DLQI), duration and effects of the treatment used. Results: Sixty-one patients with CSU have been treated with omalizumab in the drug program. The number of female patients - 42 (68.9%) significantly dominated over the number of male patients - 19 (31.1%). The mean UAS7 during the first course of treatment declined from 33.2 to 2.8, during the second from 30.9 to 1.7 and during the third 32.7 to 2.5. In case of DLQI the mean scores decrease from 18 to 2.1 in the first cycle, from 16.9 to 1.9 in the second and from 18.6 to 1.1 in the third. Conclusions: Our study confirmed that omalizumab is an effective medicine in a long-term treatment which improves a physical as well as psychological condition of the patients with antihistamine-resistant CSU. To our knowledge, it is the first study in Poland that presents omalizumab effectiveness during three courses of treatment.

Levels of serum inflammatory cytokines and their correlations with disease severity in patients with chronic spontaneous urticaria.

Introduction: Inflammation is crucial in the pathogenesis of chronic spontaneous urticaria (CSU). Investigating the correlation between levels of serum inflammatory cytokines (SICs) and the severity of CSU is of great significance for understanding the disease mechanism and finding effective treatment strategies. Aim: In this context, this work was developed. Material and methods: This work involved a researchy group (Res group) of 114 patients with CSU and a control group (Ctrl group) of 100 healthy individuals. SICs including leukotriene B4 (LTB4), leukotriene C4 (LTC4), interleukin (IL) 4 (IL-4), IL-17, IL-31, and tumor necrosis factor-γ (TNF-γ), of patients in different groups were measured and compared. Furthermore, the correlations between each SIC and pruritus severity, duration of pruritus, urticaria activity, and quality of life (QOL) were compared among the patients in different groups. Results: The Res group exhibited higher levels of LTB4, LTC4, IL-4, IL-17, and IL-31 but lower levels of TNF-γ. Great differences (p < 0.05) were found in IL-4, IL-17, and IL-31 among the patients with different pruritus severity, and positive correlations were observed between IL-17 and IL-31 levels and urticaria activity in the patients (p < 0.05). Additionally, levels of IL-4 and IL-31 exhibited a positive association to QOL scores in the patients, with obvious differences (p < 0.05). Conclusions: IL-4, IL-17, and IL-31 showed the strongest correlation with the severity of CSU, which may be attributed to their involvement in immune, inflammatory, and pruritic reactions, exacerbating the disease condition.