Upregulation of TNF-alpha and IL-3 expression in lesional and uninvolved skin in different types of urticaria

Key genes and immune infiltration in chronic spontaneous urticaria: a study of bioinformatics and systems biology

Background

Chronic spontaneous urticaria (CSU) is defined by the spontaneous occurrence of wheals and/or angioedema for >6 weeks. The pathogenesis involves skin mast cells, but the complex causes of their activation remain to be characterized in detail.

Objectives

To explore disease-driving genes and biological pathways in CSU.

Methods

Two microarray data sets, e.g., GSE57178 and GSE72540, with mRNA information of skin from CSU patients, were downloaded from the Gene Expression Omnibus (GEO) database. An integrated bioinformatics pipeline including identification of differentially expressed genes (DEGs), functional enrichment analysis, protein-protein interaction (PPI) network analysis, co-expression and drug prediction analysis, and immune and stromal cells deconvolution analyses were applied to identify hub genes and key drivers of CSU pathogenesis.

Results

In total, we identified 92 up-regulated and 7 down-regulated genes in CSU lesions. These were significantly enriched in CSU-related pathways such as TNF, NF-κB, and JAK-STAT signaling. Based on PPI network modeling, four genes, i.e., IL-6, TLR-4, ICAM-1, and PTGS-2, were computationally identified as key pathogenic players in CSU. Immune infiltration analyses indicated that dendritic cells, Th2 cells, mast cells, megakaryocyte-erythroid progenitor, preadipocytes, and M1 macrophages were increased in lesional CSU skin.

Conclusion

Our results offer new insights on the pathogenesis of CSU and suggest that TNF, NF-κB, JAK-STAT, IL-6, TLR-4, ICAM-1, and PTGS-2 may be candidate targets for novel CSU treatments.

Chronic Spontaneous Urticaria in Belgium: Deciphering the Clinical Profile and Treatment of Patients Visiting an Urban City Immunology Department

BACKGROUND

Chronic urticaria (CSU) is a chronic inflammatory mast cell-driven disorder of which reliable clinical data in Belgium are lacking. This study focusses on clinical characteristics of CSU patients presenting at an urban Immunology-Allergology department.

METHODS

Outpatients with CSU were included from 2018 to 2021. Clinical characteristics, Dermatology Life Quality Index (DLQI) and Urticaria activity score (UAS7) were collected by thorough anamnesis and questionnaires. Furthermore, patients underwent provocational testing, an autologous serum skin test (ASST) and a blood analysis.

RESULTS

The study included 49 CSU patients and 20 non-CSU subjects. CSU was distributed differently with age and sex, showing higher numbers in female patients below the age of 46 years. 67% of CSU patients had accompanying angioedema of which 9% were reported genital. CSU patients scored a mean 8/30 on their DLQI questionnaire. There was no significant difference in immunoglobulin E (IgE), C-reactive protein, and tryptase levels between CSU patients and controls. Oral glucocorticosteroids were prescribed in 23% of CSU patients during their disease course though only half of these patients had a severity grade 4 CSU. In 82% of the included CSU patients, Urticaria Control Test (UCT) scores were below 12. When we hypothetically considered low IgE levels and high IgG anti-thyroid peroxidase levels as differentiation marker for autoimmune (ai)CSU and non-aiCSU, we found that 4% of all included CSU patients could be considered aiCSU.

CONCLUSION

Generally, the inner-city population displayed the same clinical characteristics, as previous cohorts from Northern Europe. The relatively high rate of CSU patients receiving oral glucocorticosteroid treatment for their disease though not always classified as severe, underlines the need to train doctors of various specialties in the treatment algorithms of CSU. Furthermore, by looking at potential autoimmune characteristics, our findings open perspectives on the identification of new routinely used clinical parameters for the detection of aiCSU, a relatively small immunological subtype of CSU.

Involvement of CCL2 and CH25H Genes and TNF signaling pathways in mast cell activation and pathogenesis of chronic spontaneous urticaria

Chronic spontaneous urticaria (CSU), a mast cell-driven disease, substantially affects the quality of life. While genetics affect CSU susceptibility and severity, the specific genetic factors associated with mast cell activation in CSU remain elusive. We aimed to identify key genetic factors and investigate their roles in CSU pathogenesis. Two gene expression datasets from the Gene Expression Omnibus were merged and validated using principal component analysis and boxplots. The merged dataset was subjected to limma and weighted gene co-expression network analyses. Genes whose expression correlated highly with CSU were identified and analyzed using Gene Set Enrichment Analysis (GSEA), Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. As GSEA, GO, and KEGG analyses highlighted the importance of chemokine (C-C motif) ligand 2 (CCL2) and cholesterol 25-hydroxylase (CH25H) gene and tumor necrosis factor (TNF) signaling pathways in CSU; the three corresponding genes were knocked down in human mast cell line-1 (HMC-1), followed by incubation with thrombin to mimic CSU pathogenesis. CCL2, CH25H, and TNF knockdown reduced excitability and cytokine production in HMC-1. Our findings suggest that genes involved in the CCL2, CH25H, and TNF pathways play crucial roles in CSU pathogenesis, providing insights into potential therapeutic targets for CSU treatment.

Current and Emerging Therapies for Chronic Spontaneous Urticaria: A Narrative Review

Chronic spontaneous urticaria (CSU) is a condition in which wheals, angioedema, and pruritus occur spontaneously and recurrently for at least 6 weeks. The etiology of this disease is partially dependent on production of autoantibodies that activate and recruit inflammatory cells. Although the wheals can resolve within 24 h, symptoms have a significant detrimental impact on the quality of life of these patients. Standard therapy for CSU includes second-generation antihistamines and omalizumab. However, many patients tend to be refractory to these therapies. Available treatments such as cyclosporine, dapsone, dupilumab, and tumor necrosis factor alpha (TNFa) inhibitors have been used with success in some cases. Furthermore, various biologics and other novel drugs have emerged as potential treatments for this condition, and many more are currently under investigation in randomized clinical trials.

Chronic urticaria and the pathogenic role of mast cells

The signs and symptoms of chronic urticaria (CU) are caused by the activation and degranulation of skin mast cells (MCs). Recent studies have added to our understanding of how and why skin MCs are involved and different in CU. Also, novel and relevant mechanisms of MC activation in CU have been identified and characterized. Finally, the use of MC-targeted and MC mediator-specific treatments has helped to better define the role of the skin environment, the contribution of specific MC mediators, and the relevance of MC crosstalk with other cells in the pathogenesis of CU. Here, we review these recent findings and their impact on our understanding of CU, with a focus on chronic spontaneous urticaria (CSU). Also, we highlight open questions, issues of controversy, and unmet needs, and we suggest what studies should be performed moving forward.

A newly identified myokine: irisin, and its relationship with chronic spontaneous urticaria and inflammation

Chronic spontaneous urticaria (CSU) is an important dermatological disease involving severe itchy urticaria lesions and/or angioedema. Urticaria and angioedema occur in the community at a rate of 25-30%. Many factors, such as inflammation, have been implicated in the etiology of CSU. Irisin is a newly identified adipocytokine shown by research to exhibit anti-inflammatory properties in addition to its many other effects. The aim of the study was to investigate, for the first time in the literature, the significance of serum irisin levels in patients with CSU. Seventy-eight individuals were evaluated. The study group included 44 patients diagnosed with CSU, and the control group consisted of 34 healthy individuals. Serum samples were collected, and serum irisin, Interleukin-2 (IL-2), Interleukin-3 (IL-3), Tumor Necrosis Factor-alpha (TNF-α), and Interferon-ɣ (IF-ɣ) levels were determined using the enzyme-linked immunosorbent assay (ELISA) method. Irisin was studied for the first time in patients with CSU and exhibited a significantly higher level in the control group than in the patient group (p = 0.020). IL-2, IL-3, and IF-ɣ levels were higher in the CSU group than in the control group, although the results were not statistically significant. Only TNF-α results increased significantly. Correlation analysis was applied to determine the relationships between irisin and IF-ɣ and IL-3 levels. This revealed that the irisin parameter was significantly and positively correlated with IF-ɣ and IL-3 in patients with CSU (r = 0.518, p = 0.016 and r = 0.536, p = 0.022, respectively). This is the first report to evaluate irisin as an inflammatory biomarker in CSU. Irisin levels in patients with CSU were low, suggesting that irisin may pay a role in the pathogenesis of CSU and may be a marker showing the severity of the disease.

Myricetin alleviated immunologic contact urticaria and mast cell degranulation via the PI3K/Akt/NF-κB pathway

Immunologic contact urticaria (ICU) is characterized by the wheal and flare reaction from direct contact with a chemical or protein agent, which involves a type I hypersensitivity mediated by allergen-specific immunoglobulin E (sIgE). Myricetin (Myr), a bioactive flavonoid, exhibits antiinflammatory activities. Our results showed that treatment with Myr could alleviate ICU symptoms, including a decrease in the number of wheals and scratching, and inhibit ear swelling in the IgE/DNFB-induced mice. The serum level of IgE, histamine, interleukin (IL)-4, TNF-α, and MCP-1 were reduced in Myr-treated mice. Myr also attenuated mast cells (MCs) degranulation and H-PGDS, TSLP, IL-33, PI3K, Akt, and NF-κB mRNA levels in ICU model. The IgE-mediated anaphylaxis mouse models demonstrated anti-allergic effects of Myr. In vitro analysis showed that Myr reduced IgE-induced calcium (Ca²⁺ ) influx, suppressed degranulation, and chemokine release in LAD2 cells (human primary mast cells). Myr can significantly inhibited PLCγ1, Akt, NF-κB, and p38 phosphorylation. In conclusion, the study demonstrated that Myr alleviate ICU symptoms and inhibit mast cell activation via PI3K/Akt/NF-κB signal pathway.

S3 Guideline Urticaria. Part 1: Classification and diagnosis of urticaria - German-language adaptation of the international S3 Guideline

The lifetime prevalence of urticaria, a severe allergic disease, is almost 20%. It not only limits the quality of life of those affected, but also their general performance at work and in their daily activities. This publication is the first section of the Urticaria Guideline. It covers the classification and diagnosis of urticaria, taking into account the major advances in research into its causes, triggering factors and pathomechanisms. It also addresses strategies for the efficient diagnosis of the different subtypes of urticaria. This is crucial for individual, patient-oriented treatment, which is covered in the second part of the guideline, published separately. This German-language guideline was developed according to the criteria of the AWMF on the basis of the international English-language S3 guideline with special consideration of health system characteristics in the German-speaking countries. This first part of the guideline describes the classification of urticaria, distinguishing spontaneously occurring wheals (hives) and angioedema from forms of urticaria with inducible symptoms. Urticaria is defined as sudden onset of wheals, angioedema, or both, but is to be distinguished from conditions in which wheals occur as a short-term symptom, such as anaphylaxis. The diagnosis is based on (a limited number of) laboratory tests, but especially on medical history. In addition, validated instruments are available to measure the severity, activity and course of the disease.

Pathophysiology, Diagnosis, and Management of Chronic Spontaneous Urticaria: A Literature Review

Chronic spontaneous urticaria (CSU) is characterized by recurring wheals that last 6 weeks or longer without an identifiable cause. The estimated point prevalence of CSU worldwide is 1%. Furthermore, it has a significant impact on quality of life in both adults and pediatric patients and their families. Although it is most often a self-limited disease, some patients have urticaria refractory to first-line treatment: second-generation H1 antihistamines. In these patients, the use of targeted monoclonal antibodies is necessary. While omalizumab is the only Food and Drug Administration-approved monoclonal antibody for CSU, others, including ligelizumab, dupilumab, benralizumab, and several orally administered Bruton's tyrosine kinase inhibitors, are also promising therapeutics for reducing the morbidity of CSU. Novel therapies, among others discussed here, are rapidly being developed with new trials and therapeutics being released nearly monthly. Thus, we performed a scoping literature review of randomized controlled trials studying targeted therapies for CSU. We also discuss the pathophysiology, diagnosis, prognosis, and future research directions in CSU.

Monoclonal Antibodies in Treating Chronic Spontaneous Urticaria: New Drugs for an Old Disease

Background: H1-antihistamines (H1AH) represent the current mainstay of treatment for chronic spontaneous urticaria (CSU). However, the response to H1AH is often unsatisfactory, even with increased doses. Therefore, guidelines recommend the use of omalizumab as an add-on treatment in refractory CSU. This paved the way for the investigation of targeted therapies, such as monoclonal antibodies (mAbs), in CSU. Methods: A literature review was conducted including papers published between 2009 and 2022 and ongoing trials about the efficacy and safety of mAbs as treatment for CSU. Results: Twenty-nine articles, a trial with preliminary results, and seventeen ongoing or completed clinical trials on the use of mAbs in CSU were included. Randomized controlled trials (RCTs), meta-analysis, and real-life studies have proven the effectiveness and safety of omalizumab as a third-line treatment in refractory CSU. However, a percentage of patients remain unresponsive to omalizumab. Therefore, other mAbs, targeting different pathways, have been used off-label in case series and others are under investigation in RCTs. Most of them have showed promising results. Conclusions: Omalizumab remains the best choice to treat refractory CSU. Although results from other mAbs seem to be encouraging to achieve symptom control in refractory CSU, thus improving patients’ QoL, RCTs are needed to confirm their effectiveness and safety.

Evidence for histamine release in chronic inducible urticaria – A systematic review

Background

Chronic inducible urticaria (CIndU) constitutes a group of nine different CIndUs in which pruritic wheals and/or angioedema occur after exposure to specific and definite triggers. Histamine released from activated and degranulating skin mast cells is held to play a key role in the pathogenesis of CIndU, but evidence to support this has, as of yet, not been reviewed systematically or in detail. We aim to characterize the role and relevance of histamine in CIndU.

Methods

We systematically searched 3 electronic databases (PubMed, Scopus, and Embase) for studies that reported increased serum or skin histamine concentration (direct evidence) or in vitro or ex vivo histamine release (indirect evidence) following trigger exposure.

Results

An initial total of 3,882 articles was narrowed down to 107 relevant studies of which 52 were in cold urticaria, 19 in cholinergic urticaria, 14 in heat urticaria, 10 in contact urticaria, 7 each in solar urticaria and vibratory angioedema, 4 each in symptomatic dermographism and aquagenic urticaria, and 3 in delayed pressure urticaria. The results of our review support that histamine has a key pathogenic role in the pathogenesis of all CIndUs, but it is not the sole mediator as evidenced by the often poor relationship between the level of histamine and severity of symptoms and the variable clinical efficacy of H1-antihistamines.

Conclusions

Histamine released from skin mast cells is a key driver of the development of signs and symptoms and a promising therapeutic target in CIndU.

Plasma-derived exosomes in chronic spontaneous urticaria induce the production of mediators by human mast cells

Mast cell activation and inflammatory mediators play central roles in the pathogenesis of chronic spontaneous urticaria (CSU). The factors that induce mast cell activation in CSU are still largely unknown. Exosomes are extracellular vesicles that activate mast cells. Here, we enriched exosomes derived from the plasma of healthy volunteers and CSU patients with antihistamine sensitivity (EXs-CSU-S) or resistance (EXs-CSU-R) using ultracentrifugation. We then incubated these exosomes with HMC-1 human mast cells. Notably, EXs-CSU-S and EXs-CSU-R increased tryptase-1 expression; histamine production; inflammatory mediator production; and Toll-like receptor-2 (TLR-2), TLR-4, and phospho-mitogen-activated protein kinase (MAPK) levels in HMC-1 cells. These effects were more significant in the EXs-CSU-R group than in the EXs-CSU-S group. TLR-2, TLR-4, and MAPK inhibitors (CC-401, TAK-715, and SCH772984, respectively) reduced EXs-CSU-Stimulated production of inflammatory mediators in HMC-1 cells. Overall, exosomes in the plasma of patients with CSU were found to activate mast cells and elicit the production of multiple inflammatory mediators, partly via the TLR-2, TLR-4, and MAPK pathways. Additionally, EXs-CSU-R had more powerful mast cell-activating and histamine-release abilities. Thus, these exosomes may be involved in the pathogenesis of CSU with antihistamine resistance.

The Role of Crosstalk of Immune Cells in Pathogenesis of Chronic Spontaneous Urticaria

Chronic spontaneous urticaria (CSU) is defined as recurrent episodes of spontaneous wheal development and/or angioedema for more than six weeks and at least twice a week. The core link in the pathogenesis of CSU is the activation of mast cells, T cells, eosinophils, and other immune cells infiltrating around the small venules of the lesion. Increased vascular permeability, vasodilatation, and recruitment of inflammatory cells directly depend on mast cell mediators’ release. Complex regulatory systems tightly influence the critical roles of mast cells in the local microenvironment. The bias toward Th2 inflammation and autoantibodies derived from B cells, histamine expressed by basophils, and initiation of the extrinsic coagulation pathway by eosinophils or monocytes exerts powerful modulatory influences on mast cells. Cell-to-cell interactions between mast cells and eosinophils/T cells also are regulators of their function and may involve CSU’s pathomechanism. This review summarizes up-to-date knowledge regarding the crosstalk between mast cells and other immune cells, providing the impetus to develop new research concepts and treatment strategies for CSU.

Immunological signature of chronic spontaneous urticaria (Review)

Chronic urticaria (CU) is a condition characterized by intensely pruritic, edematous, erythematous papules lasting for more than 6 weeks. Over half of the cases have concomitant swelling of deeper tissues, known as angioedema. The socio-economic burden of the disease is significant. Unfortunately, patients with severe CU, refractory to conventional treatment, have limited and expensive therapeutic options. The pathogenesis of CU is not yet completely understood. Therefore, elucidating the pathophysiological mechanisms involved would potentially identify new therapeutic targets. It has been accepted in recent years that mast cells and their activation, followed by excessive degranulation represent the key pathophysiological events in chronic spontaneous urticaria (CSU). The triggering events and the complexity of the effector mechanisms, however, remain intensely debated topics with conflicting studies. One pathogenetic mechanism incriminated in chronic spontaneous urticaria is the response mediated by the high-affinity receptor for IgE (FcεRI) expressed on mast cells. Increasing recognition of chronic spontaneous urticaria as an autoimmune disease linked to the cytokine-chemokine network imbalance resulting from alteration of innate immune response is another pathogenetic explanation. It is likely that these different pathological mechanisms are more interconnected, both acting synergistically, rather than separately, to produce the clinical expression of CU. The discovery and understanding of pathogenic mechanisms represent the premise for the development of safe and effective immunomodulators and targeted biological treatment for severe, refractory CU.

The international EAACI/GA²LEN/EuroGuiDerm/APAAACI guideline for the definition, classification, diagnosis, and management of urticaria

This update and revision of the international guideline for urticaria was developed following the methods recommended by Cochrane and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) working group. It is a joint initiative of the Dermatology Section of the European Academy of Allergology and Clinical Immunology (EAACI), the Global Allergy and Asthma European Network (GA²LEN) and its Urticaria and Angioedema Centers of Reference and Excellence (UCAREs and ACAREs), the European Dermatology Forum (EDF; EuroGuiDerm), and the Asia Pacific Association of Allergy, Asthma and Clinical Immunology with the participation of 64 delegates of 50 national and international societies and from 31 countries. The consensus conference was held on 3 December 2020. This guideline was acknowledged and accepted by the European Union of Medical Specialists (UEMS). Urticaria is a frequent, mast cell-driven disease that presents with wheals, angioedema, or both. The lifetime prevalence for acute urticaria is approximately 20%. Chronic spontaneous or inducible urticaria is disabling, impairs quality of life, and affects performance at work and school. This updated version of the international guideline for urticaria covers the definition and classification of urticaria and outlines expert-guided and evidence-based diagnostic and therapeutic approaches for the different subtypes of urticaria.

Loratadine vs Rupatadine: Unearthing the Capital Choice in Chronic Idiopathic Urticaria (CIU) - A Randomized Controlled Trial

Background:

Chronic Idiopathic Urticaria (CIU) is a debilitating disease characterised by almost daily presence of urticarial symptoms like short-lived wheals, itching, and erythema for at least 6 weeks without an identifiable cause there by leading to impairment of quality of life of the patient.

Aim:

To evaluate the efficacy and safety of loratadine and rupatadine in chronic idiopathic urticaria.

Methods:

This is a prospective, randomized, single-blind, parallel arm study conducted to evaluate the efficacy and safety of loratadine and rupatadine in patients with CIU. The study was registered prospectively with Clinical Trial registry of India (CTRI/2017/05/008624). Institutional Ethics Committee clearance was obtained. Written informed consent was obtained from all the participants before enrolment into the trial. The study was conducted in the outpatient department of Dermatology, SRM Medical College, Kattankulathur, Tamil Nadu, India, during the period from June 2017 to August 2018. Patients with CIU enrolled into the study based on inclusion-exclusion criteria were given the intervention drugs; Loratadine 10 mg once daily or rupatadine10 mg once daily orally for 6 weeks.

Results:

Rupatadine is more efficacious than loratadine in the reduction of Total Leucocyte Count, Differential Count and Absolute Eosinophil Count, the key determinants of allergy. Rupatadine also produced better improvement in Total symptom Score, Dermatology Life Quality Index in patients with CIU.

Conclusion:

Analysis of all the parameters of efficacy and safety establishes the probable superiority of rupatadine over loratadine for the treatment of urticaria.

IL-3 in the development and function of basophils

The β common chain (βc) cytokine family includes granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3) and IL-5, all of which use βc as key signaling receptor subunit. GM-CSF, IL-3 and IL-5 have specific roles as hematopoietic growth factors. IL-3 binds with high affinity to the IL-3 receptor α (IL-3Rα/CD123) and then associates with the βc subunit. IL-3 is mainly synthesized by different subsets of T cells, but is also produced by several other immune [basophils, dendritic cells (DCs), mast cells, etc.] and non-immune cells (microglia and astrocytes). The IL-3Rα is also expressed by immune (basophils, eosinophils, mast cells, DCs, monocytes, and megacaryocytes) and non-immune cells (endothelial cells and neuronal cells). IL-3 is the most important growth and activating factor for human and mouse basophils, primary effector cells of allergic disorders. IL-3-activated basophils and mast cells are also involved in different chronic inflammatory disorders, infections, and several types of cancer. IL-3 induces the release of cytokines (i.e., IL-4, IL-13, CXCL8) from human basophils and preincubation of basophils with IL-3 potentiates the release of proinflammatory mediators and cytokines from IgE- and C5a-activated basophils. IL-3 synergistically potentiates IL-33-induced mediator release from human basophils. IL-3 plays a pathogenic role in several hematologic cancers and may contribute to autoimmune and cardiac disorders. Several IL-3Rα/CD123 targeting molecules have shown some efficacy in the treatment of hematologic malignancies.

Markers for the involvement of endothelial cells and the coagulation system in chronic urticaria: A systematic review

Chronic urticaria (CU) is a chronic inflammatory mast cell-driven disorder. Endothelial cells (ECs) contribute importantly to key features of CU. Several markers of EC (dys)function in CU have been reported, but have not yet been systematically reviewed. In this study, we systematically reviewed and categorized all published markers of EC functions in CU through a comprehensive search in Pubmed, The Cochrane Library, Web of Science, and SCOPUS using the following Mesh terms: CU AND pathogenesis AND (vasculopathy OR microangiopathy OR ECs OR marker). In total, 79 articles were selected and the identified biomarkers were categorized according to EC (dys)function in CU. The most frequent and consistently reported upregulated biomarkers in CU skin were adhesion molecules, TF, and P-selectin. The most frequently reported upregulated and reliable biomarkers in sera of CU patients were F1+2 for coagulation cascade involvement, D-dimers for fibrinolysis, and MMP-9 for vascular permeability. Emerging biomarkers described in the selected articles were endostatin, heat shock proteins, cleaved high molecular weight kininogen, and adipokines. This systematic review contributes to the pool of growing evidence for vascular involvement in CU where EC dysfunction is present in different aspects of cell survival, maintenance of vascular structure, and coagulation/fibrinolysis balance.

The Pathogenesis of Chronic Spontaneous Urticaria: The Role of Infiltrating Cells

Chronic spontaneous urticaria is characterized by a perivascular non-necrotizing cellular infiltrate around small venules of the skin. It consists primarily of CD4(+) lymphocytes, a prominence of the T helper (Th)2 subtype but also Th1 cells, with Th17 cell-derived cytokines elevated in plasma. There are also neutrophils, eosinophils, basophils, and monocytes. Chemokines derived from mast cells and activated endothelial cells drive the process. Although the role of the cellular infiltrate has not previously been addressed, each constituent can contribute to the overall pathogenesis. It is of interest that CSU responds to corticosteroid, yet, short-term steroids do not affect autoimmunity or degranulation of mast cells, and act on margination of cells along the endothelium and chemotaxis to enter the surrounding dermis. In this review, we address each cell's contribution to the overall inflammatory response, as it is currently understood, with a view toward development of therapeutic options that impede the function of critical cells and/or their secretory products.

Cold urticaria - What we know and what we do not know

Cold urticaria (ColdU) is a common form of chronic inducible urticaria characterized by the development of wheals, angioedema or both in response to cold exposure. Recent research and guideline updates have advanced our understanding and management of ColdU. Today, its pathophysiology is thought to involve the cold-induced formation of autoallergens and IgE to these autoallergens, which provoke a release of proinflammatory mediators from skin mast cells. The classification of ColdU includes typical and atypical subtypes. We know that cold-induced wheals usually develop on rewarming and resolve within an hour and that anaphylaxis can occur. The diagnosis relies on the patient's history and cold stimulation testing. Additional diagnostic work-up, including a search for underlying infections, should only be done if indicated by the patient's history. The management of ColdU includes cold avoidance, the regular use of nonsedating antihistamines and the off-label use of omalizumab. However, many questions regarding ColdU remain unanswered. Here, we review what is known about ColdU, and we present important unanswered questions on the epidemiology, underlying pathomechanisms, clinical heterogeneity and treatment outcomes. Our aim is to guide future efforts that will close these knowledge gaps and advance the management of ColdU.

Current and emerging pharmacotherapy for chronic spontaneous Urticaria: a focus on non-biological therapeutics

INTRODUCTION

Chronic spontaneous urticaria (CSU) refers to urticaria (wheals) or angioedema, which occur for a period of six weeks or longer without an apparent cause. The condition may impair the patient's quality of life.

AREAS COVERED

Treatment for CSU is mainly symptomatic. Both AAAAI/ACAAI practice parameters and EAACI/GA2LEN/EDF/WAO guidelines suggest CSU management in a stepwise manner. First-line therapy is with second-generation H₁-antihistamines. Treatment should be stepped up along the algorithm if symptoms are not adequately controlled. Increasing the dosage of second-generation H₁-antihistamines, with the addition of first-generation H₁-antihistamines, H₂ antagonist, omalizumab, ciclosporin A, or short-term corticosteroid may be necessary. New medications are being developed to treat refractory CSU. They include spleen tyrosine kinase inhibitor, Bruton tyrosine kinase inhibitor, prostaglandin D₂ receptor inhibitor, H₄-antihistamine, and other agents. The authors discuss these treatments and provide expert perspectives on the management of CSU.

EXPERT OPINION

Second-generation H₁-antihistamines remain the first-line therapeutic options for the management of CSU. For patients not responding to higher-dose H₁-antihistamines, international guidelines recommend the addition of omalizumab. Efficacy and safety data for newer agents are still pending. Large-scale, well-designed, randomized, double-blind, placebo-controlled trials will further provide evidence on the safety profile and efficacy of these agents in patients with CSU.

Successful treatment of delayed pressure urticaria with 300 mg of omalizumab every 14 days

Delayed pressure urticaria is a rare form of chronic inducible urticaria characterized by erythematous-painful plaques that develop in areas of the skin exposed to prolonged pressure. Its treatment is very difficult, and its response to antihistamines is variable. Cases of delayed pressure urticaria, which have been completely controlled with the use of omalizumab in recent years, have been reported.

Current and Potential Biologic Drugs for the Treatment of Chronic Urticaria

This article reviews biologic treatments that are currently applied for the treatment of severe chronic urticaria. Monoclonal anti-immunoglobulin E (omalizumab) is effective and safe in many patients, but accessibility and cost constitute barriers to its wider use. Questions on the optimal duration of the treatment and possible symptom recurrences after discontinuing the drug are still raised. A discussion is presented about several other biologics currently under investigation with potential to be incorporated in the near future in patients with severe chronic urticaria.

Chronic Spontaneous Urticaria: A Review of Pathological Mechanisms, Diagnosis, Clinical Management, and Treatment

Urticaria is a poorly understood and underestimated clinical condition characterised by the sudden onset of itchy wheals and/or angioedema, which usually resolve within 24 and 72 hours, respectively. It is generally classified as being acute (lasting <6 weeks) or chronic (continuous or intermittent for ≥6 weeks). Chronic urticaria can be further classified as chronic spontaneous urticaria (CSU) and chronic inducible urticaria, appearing in response to specific eliciting factors, such as heat, cold, or sun exposure, or following the application of pressure. Scientific advances have been made in the understanding of pathological mechanisms and treatment, especially associated with CSU. The exact pathological mechanism of how urticaria develops is still not yet fully understood, but the clinical implications on the patients’ quality of life are severe and have been associated with mental disorders and metabolic diseases. The diagnosis of urticaria is based on medical history and clinical manifestations. The treatment pathway begins with the administration of second-generation, nonsedating, nonimpairing histamine 1 receptor antihistamines and, in case of nonresponse, with new-generation biological drugs. The current review presents an update of the pathological mechanisms, diagnosis, clinical management, and treatment of CSU. It also focusses on the future implications of new-generation drugs and their effects on the clinical practice.

Delayed Pressure Urticaria: A Systematic Review of Treatment Options

BACKGROUND

Delayed pressure urticaria (DPU) is characterized by recurrent erythematous and often painful swelling after the skin is exposed to sustained pressure. Treatment is challenging. Antihistamines, the first-line and only approved treatment, are often not effective.

OBJECTIVE

To systematically review the treatment options for DPU.

METHOD

A literature search of electronic databases for all relevant articles published till April 29, 2019, was conducted using the search terms "delayed pressure urticaria" and "pressure urticaria." This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses recommendations.

RESULTS

Twenty-one studies (8 randomized controlled trials [RCTs], 10 retrospective cohort studies, and 3 open-label prospective studies) were included. Second-generation H₁ antihistamines (sgAHs) were effective in 3 RCTs. The combination of an sgAH and montelukast (2 RCTs) or an sgAH and theophylline (1 non-RCT) was more effective than the sgAH alone. The disease improved with omalizumab (4 non-RCTs), sulphones (3 non-RCTs), oral prednisolone (1 RCT and 2 non-RCTs), intravenous immunoglobulin (1 non-RCT), and gluten-free diet (1 non-RCT). There are no studies on updosing of antihistamines over standard dosage in DPU.

CONCLUSIONS

Overall, the quality of studies on DPU is low. Because of the lack of other evidence, antihistamines remain the first-line therapy. Updosing of sgAHs could be considered in patients with uncontrolled symptoms on the basis of the extrapolation of evidence from chronic spontaneous urticaria, even though there is no evidence of its efficacy over standard dosage. Addition of montelukast may be considered. Omalizumab or sulphones may be used in treatment-resistant patients. High-quality DPU studies should be conducted.

Chronic Urticaria: An Overview of Treatment and Recent Patents

Background:

Up to 1% of the general population in the USA and Europe suffer from chronic urticaria (CU) at some point in their lifetime. CU has an adverse effect on the quality of life.

Objective:

This study aims to provide an update on the epidemiology, pathogenesis, clinical manifesta-tions, diagnosis, aggravating factors, complications, treatment and prognosis of CU.

Methods:

The search strategy included meta-analyses, randomized controlled trials, clinical trials, reviews and pertinent references. Patents were searched using the key term “chronic urticaria” at the following links: www.google.com/patents, www.uspto.gov, and www.freepatentsonline.com.

Results:

CU is a clinical diagnosis, based on the episodic appearance of characteristic urticarial lesions that wax and wane rapidly, with or without angioedema, on most days of the week, for a period of six weeks or longer. Triggers such as medications, physical stimuli, and stress can be identified in 10 to 20% of cases. C-reactive protein/erythrocyte sedimentation rate, and complete blood cell count with differential are the screening tests that may be used to rule out an underlying disorder. The mainstay of therapy is reassurance, patient education, avoidance of known triggers, and pharmacotherapy. Second-generation H1 antihistamines are the drugs of choice for initial therapy because of their safety and efficacy profile. If satisfactory improvement does not occur after 2 to 4 weeks or earlier if the symptoms are intolerable, the dose of second-generation H1 antihistamines can be increased up to fourfold the manufacturer’s recom-mended dose (all be it off license). If satisfactory improvement does not occur after 2 to 4 weeks or earlier if the symptoms are intolerable after the fourfold increase in the dosage of second-generation H1 antihis-tamines, omalizumab should be added. If satisfactory improvement does not occur after 6 months or earli-er if the symptoms are intolerable after omalizumab has been added, treatment with cyclosporine and sec-ond-generation H1 antihistamines is recommended. Short-term use of systemic corticosteroids may be considered for acute exacerbation of CU and in refractory cases. Recent patents for the management of chronic urticaria are also discussed. Complications of CU may include skin excoriations, adverse effect on quality of life, anxiety, depression, and considerable humanistic and economic impacts. On average, the duration of CU is around two to five years. Disease severity has an association with disease duration.

Conclusion:

CU is idiopathic in the majority of cases. On average, the duration of CU is around two to five years. Treatment is primarily symptomatic with second generation antihistamines being the first line. Omalizumab has been a remarkable advancement in the management of CU and improves the quality of life beyond symptom control.

Emerging Biomarkers and Therapeutic Pipelines for Chronic Spontaneous Urticaria

Chronic spontaneous urticaria (CSU) is defined as the appearance of evanescent wheals, angioedema, or both, for at least 6 weeks. CSU is associated with intense pruritus and poor quality of life, with higher odds of reporting depression, anxiety, and sleep difficulty. As of yet, the assessment of the activity and course of the disease along with the response to several treatments in CSU are based purely on the patient's medical history and the use of the patient-reported outcomes. Recently, several reports have suggested that certain parameters could be considered as potential disease-related biomarkers. Moreover, with the advent of such biomarkers, newer biologic agents are coming forth to revolutionize the management of potential refractory diseases such as CSU. The purpose of this article is to review the most promising biomarkers related to important aspects of CSU, such as the disease activity, the therapeutic response, and the natural history of the disease, and discuss the mechanisms of action and therapeutic effectiveness of the latest agents available or currently under investigation for the management of antihistamine-refractory CSU. The knowledge of these features could have an important impact on the management and follow-up of patients with CSU.

How to Approach Chronic Inducible Urticaria

Chronic inducible urticaria (CIndU) is a group of chronic urticarias characterized by the appearance of recurrent wheals, recurrent angioedema or both, as a response to specific triggers. CIndU includes both physical (symptomatic dermographism, cold and heat urticaria, delayed pressure urticaria, solar urticaria, and vibratory urticaria) and nonphysical urticarias (cholinergic urticaria, contact and aquagenic urticaria). Here, we review the different forms of CIndU with an emphasis on symptomatic dermographism, cold urticaria, cholinergic urticaria, and delayed pressure urticaria. We discuss the clinical features, the diagnostic workup including provocation and threshold testing, and available treatment options.

New treatments for chronic urticaria

OBJECTIVE

Chronic urticaria (CU) is a common, heterogeneous, and debilitating disease. Antihistamines and omalizumab are the mainstay therapies of CU. Additional treatment options are needed. Here, we review the off and beyond label use of licensed drugs, novel treatments that are currently under development, and promising new targets.

DATA SOURCES

MEDLINE was searched for recent reports of the successful use of treatments in CU and promising targets for the development of novel treatment options. We also searched ClinicalTrials.gov for recent and ongoing randomized clinical trials in CU.

STUDY SELECTIONS

Relevant articles were selected and reviewed.

RESULTS

Omalizumab, the treatment of choice in patients with antihistamine-resistant chronic spontaneous urticaria (CSU), should be explored for use in chronic inducible urticaria in children younger than 12 years with CSU and at higher doses. The off-label use of dupilumab, reslizumab, mepolizumab, and benralizumab can be effective in CU. Ligelizumab and UB-221, 2 novel anti-IgE monoclonal antibodies, are in clinical trials for CU. Other promising drugs that are currently under development for CU are a chemoattractant receptor-homologous molecule expressed on T_H2 cell antagonist, a monoclonal antibody to Siglec-8 (AK002), Bruton tyrosine kinase inhibitors (fenebrutinib and Lou064), a spleen tyrosine kinase inhibitor, and dupilumab. Promising targets of future therapies include the Mas-related G-protein-coupled receptor X2; the histamine₄ receptor; C5a and its receptor; inhibitory mast cell receptors other than Siglec-8; interleukin 33, interleukin 25, and thymic stromal lymphopoietin, and stem cell factor.

CONCLUSION

Novel and better treatments for CU are very much needed. Some agents are in clinical trials already (eg, ligelizumab), and additional ones should be developed, making use of the many promising targets recently identified and characterized.

Tumor necrosis factor-alpha and Fas/Fas ligand signaling pathways in chronic spontaneous urticaria

Background

There is increasing evidence pointing to the important role of tumor necrosis factor-alpha (TNF-α), a key inflammatory and apoptotic mediator in urticarial inflammation. However, the role of the TNF-α system and Fas/Fas ligand (FasL) in the apoptosis-inducing pathways in chronic spontaneous urticaria (CSU), remain unclear.

Aim

To determine circulating concentrations of TNF-α, soluble TNF-α receptor type 1 and type 2 (sTNF-R1 and sTNF-R2, respectively) as well as soluble Fas (sFas) and FasL (sFasL) in CSU subjects.

Methods

Serum TNF-α, sTNF-R1, sTNF-R2, sFas, sFasL concentrations were measured using enzyme-linked immunosorbent assay in CSU subjects and in the healthy subjects.

Results

TNF-α concentrations were significantly higher in CSU subjects and moderate-to-severe CSU than in the controls, while there were no significant differences in TNF-α concentrations between subjects with mild CSU and the controls. sTNF-R1 and sTNF-R2 concentrations were significantly higher in all CSU and moderate-severe CSU subjects vs. the controls. Serum concentrations were also significantly higher in mild CSU vs. the controls, but not in moderate-severe CSU vs. mild CSU. No significant differences were observed in sFas and sFasL concentrations between CSU subjects and the healthy controls. Significant correlations were found between concentrations of TNF-α and its receptors, as well as sTNF-R1 and sTNF-R2, but not with the urticaria activity score (UAS). There was no relationship between TNF-α/sTNF-R1/sTNF-R2 and sFas/sFasL pathways in CSU.

Conclusions

CSU is associated with the activation of the TNF-α/receptors signaling pathway, marked by increased circulating concentrations of TNF-α, sTNF-R1 and sTNF-R2, which are related to each other in this disease. In contrast, the circulating sFas/FasL system is not up-regulated in CSU, and sFas/sFasL may not be a useful marker of the activity/severity of urticarial processes. Considering the lack of significant changes in sFas/sFasL (mainly reflecting systemic apoptosis) in CSU patients, it appears that elevated serum TNF-α concentrations are related to its pro-inflammatory function rather than an enhanced systemic apoptotic response in CSU.

Aeroallergen sensitization and associated comorbid diseases of an adult Filipino population with allergic rhinitis

Background

There is a large global variation in sensitization patterns to aeroallergens due to differences in climate, urbanization, and lifestyle. Knowledge of the most common inhalant allergens is important for appropriate prevention and management of allergic rhinitis (AR).

Objective

This study aims to provide data on aeroallergen sensitization patterns and associated comorbid diseases of adult Filipinos with AR.

Methods

Medical records of adult Filipinos seen in an Otolaryngology-Allergy Clinic from January 2011 to 2016 were reviewed. Inclusion criteria used was presence of clinically defined AR and positive skin test to at least one aeroallergen in the test panel. Demographics, comorbid conditions, and results of skin prick test were determined. Standard descriptive statistics were used for analysis.

Results

One hundred ninety-one adult patients were included in this study. Mean age was 38.8 years, and majority lived in an urban area (71.2%). Most patients exhibited polysensitization (97.4%). All exhibited sensitization to indoor and 86.9% to outdoor allergens. The most common indoor allergens were Dermatophagoides pteronyssinus (97.4%), Dermatophagoides farinae, (95.8%), cockroach (80.1%), and molds (72.8%). Bermuda (67%), Johnson grass (58.7%), and Acacia (58.2%) were the most common outdoor allergens. Urticaria (18.8%), dermatitis (16.8%), and asthma (11.5%) were the most common associated comorbid disease. Twelve percent of patients had more than one associated comorbid disease. Asthma + urticaria followed by asthma + dermatitis were the most common co-morbid combinations. One patient had three comorbid diseases: asthma + urticaria + rhinosinusitis.

Conclusion

Compared to earlier studies, aeroallergen sensitization patterns of Filipinos remain unchanged. This study also identifies for the first time, the associated comorbid diseases of AR in this population. Understanding these factors can guide treatment strategies to reduce disease burden.

The EAACI/GA²LEN/EDF/WAO guideline for the definition, classification, diagnosis and management of urticaria

This evidence- and consensus-based guideline was developed following the methods recommended by Cochrane and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) working group. The conference was held on 1 December 2016. It is a joint initiative of the Dermatology Section of the European Academy of Allergology and Clinical Immunology (EAACI), the EU-founded network of excellence, the Global Allergy and Asthma European Network (GA²LEN), the European Dermatology Forum (EDF) and the World Allergy Organization (WAO) with the participation of 48 delegates of 42 national and international societies. This guideline was acknowledged and accepted by the European Union of Medical Specialists (UEMS). Urticaria is a frequent, mast cell-driven disease, presenting with wheals, angioedema, or both. The lifetime prevalence for acute urticaria is approximately 20%. Chronic spontaneous urticaria and other chronic forms of urticaria are disabling, impair quality of life and affect performance at work and school. This guideline covers the definition and classification of urticaria, taking into account the recent progress in identifying its causes, eliciting factors and pathomechanisms. In addition, it outlines evidence-based diagnostic and therapeutic approaches for the different subtypes of urticaria.

Consensus Statement for the Diagnosis and Treatment of Urticaria: A 2017 Update

This article is developed by the Skin Allergy Research Society of India for an updated evidence-based consensus statement for the management of urticaria, with a special reference to the Indian context. This guideline includes updated definition, causes, classification, and management of urticaria. Urticaria has a profound impact on the quality of life and causes immense distress to patients, necessitating effective treatment. One approach to manage urticaria is by identification and elimination of the underlying cause(s) and/or eliciting trigger(s) while the second one is by treatment for providing symptomatic relief. This guideline recommends the use of second-generation nonsedating H1-antihistamines as the first-line treatment. The dose can be increased up to four times to meet the expected results. In case patients still do not respond, appropriate treatment options can be selected depending on the associated medical condition, severity of the symptoms, affordability of the drugs, and accessibility of modern biologics such as omalizumab.

Treatment of chronic spontaneous urticaria: Immunomodulatory approaches

This paper summarizes and reviews the mechanisms of action and data concerning efficacy of recommended treatments as well as other treatments that have been tested, independently of the outcomes, in the management of chronic spontaneous urticaria. Due to the central role of mast cells, basophils and histamine in the pathophysiology of this disease, H₁-antihistamines remain the first-line treatment. However, current knowledge about this complex disease, also recognizes an important role for T lymphocytes, B lymphocytes, and autoantibodies. Implications of these others mediators thus provide further targets for treatment. Indeed, agents previously used to treat other autoimmune and inflammatory diseases, have demonstrated efficacy in chronic spontaneous urticaria and are therefore potential therapeutic alternatives for antihistamine unresponsive patients.

Biologics and biomarkers for asthma, urticaria, and nasal polyposis

Many patients with allergic disorders continue to have uncontrolled symptoms despite new and better pharmacologic options. Novel biologic agents that target specific and critical pathophysiologic pathways have been developed to better manage these patients. The utility of biologic agents for the management of allergic diseases has been facilitated by recent advances in better characterizing patients, including identification of relevant biomarkers that predict clinical responsiveness. This has led to the ability to phenotype and endotype patients, allowing for a more rational approach to picking a specific biologic agent for a specific patient. In this review I focus on point-of-care biomarkers that enhance the usefulness of biologics to manage uncontrolled asthma, urticaria, and nasal polyposis. I discuss biologic agents already approved for the management of allergic and respiratory disorders and biologics currently in development or recently abandoned because of a lack of efficacy or intolerable side effects. The successes and failures of biologics in clinical trials have facilitated our ability to better understand which molecules and pathways are most important in the pathogenesis of allergic diseases and in the development of symptoms and impairment in individual patients.

The Expanding Field of Biologics in the Management of Chronic Urticaria

Chronic urticaria (CU) is the occurrence of urticaria with or without angioedema for at least 6 weeks. Management has traditionally involved antihistamines as first-line therapy with various alternative therapies for refractory cases. Largely based on the success of biologics for various diseases, this class of drugs has come to the forefront of medical research. The first and only Food and Drug Administration-approved biologic for the management of CU is omalizumab (humanized anti-IgE mAb). In the past decade, a substantial amount of research has been centered on the mechanism of action, efficacy, dosing, and safety of omalizumab. This review will focus on the data surrounding the management of CU with omalizumab, off-label use of other biologics for CU, and biologics currently under investigation for use in CU. We will also discuss management considerations and areas of interest for future research.

Looking forward to new targeted treatments for chronic spontaneous urticaria

The introduction of omalizumab to the management of chronic spontaneous urticaria (CSU) has markedly improved the therapeutic possibilities for both, patients and physicians dealing with this disabling disease. But there is still a hard core of patients who do not tolerate or benefit from existing therapies and who require effective treatment. Novel approaches include the use of currently available drugs off-licence, investigational drugs currently undergoing clinical trials and exploring the potential for therapies directed at pathophysiological targets in CSU. Off-licence uses of currently available drugs include rituximab and tumour necrosis factor inhibitors. Ligelizumab (anti-IgE), canakinumab (anti-IL-1), AZD1981 (a PGD2 receptor antagonist) and GSK 2646264 (a selective Syk inhibitor) are currently in clinical trials for CSU. Examples of drugs that could target potential pathophysiological targets in CSU include substance P antagonists, designed ankyrin repeat proteins, C5a/C5a receptor inhibitors, anti-IL-4, anti-IL-5 and anti-IL-13 and drugs that target inhibitory mast cell receptors. Other mediators and receptors of likely pathogenic relevance should be explored in skin profiling and functional proof of concept studies. The exploration of novel therapeutic targets for their role and relevance in CSU should help to achieve a better understanding of its etiopathogenesis.

Biologics in Chronic Urticaria

Chronic urticaria (CU) is defined as wheals, angioedema, or both, that last more than 6 weeks. Second-generation antihistamines are considered the first-line therapy for CU. Unfortunately, many patients will fail antihistamines and require alternative therapy, including immune response modifiers or biologics. Multiple biological agents have been evaluated for use in antihistamine-refractory CU, including omalizumab, rituximab, and intravenous immunoglobulin; omalizumab is the most efficacious. Because of the success of omalizumab, multiple new biologics that are directed at the IgE pathway are under investigation. This review summarizes the relevant data regarding the efficacy of biologics in antihistamine-refractory CU.

A Review of the Use of Infliximab to Manage Cutaneous Dermatoses

Background:

Infliximab is a chimeric monoclonal antibody that binds specifically to human tumor necrosis factor-alpha (TNF-α), decreasing the effect of the cytokine in inflammatory diseases.

Objective:

The aim of this study was to review the efficacy and safety of infliximab in the treatment of dermatological diseases.

Methods:

A MEDLINE search (1966–January 2003), using the keyword “infliximab” was performed to find relevant articles pertaining to the use of infliximab in dermatology.

Results:

Infliximab has been used in the following dermatological diseases: psoriasis, Behçet's disease, graft versus host disease, hidradenitis suppurativa, panniculitis, pyoderma gangrenosum, SAPHO (synovitis, acne, pustulosis, hyperostosis and osteitis) syndrome, sarcoidosis, subcorneal pustular dermatosis, Sweet's syndrome, toxic epidermal necrolysis, and Wegener's granulomatosis. There is a generally good safety profile for infliximab, which is similar to that when it is used to treat Crohn's disease and rheumatoid arthritis.

Conclusion:

Although not approved for use in dermatological diseases, there have been numerous reports of the efficacy of infliximab in cutaneous inflammatory diseases. The most promise lies in those diseases that have increased amounts of TNF-α in the cutaneous lesions, such as psoriasis.

Inducible urticaria: Case series and literature review

Inducible urticaria is a heterogeneous group of skin disorders characterized by the appearance of wheals, pruritus and/or angioedema, sometimes accompanied by systemic symptoms caused by innocuous stimuli (cold, heat, pressure, etc.). This group of disorders compromises people's quality of life and most of the literature in this regard comes from case reports and case series since its epidemiology has been poorly studied and some cases are very rare. The aim of this review is to show an up-to-date overview of the available literature for various types of inducible urticarias, always beginning with an illustrative case and then describing their pathophysiological mechanisms, clinical manifestations, and treatment.

Gene expression profiles in chronic idiopathic (spontaneous) urticaria

BACKGROUND

The pathophysiology of chronic idiopathic (spontaneous) urticaria (CIU) is poorly understood.

OBJECTIVE

We hypothesized that a study of gene expression in active lesions from patients with CIU would uncover unexpected associations.

METHODS

We enrolled eight patients with CIU and six healthy controls, and obtained 4 mm punch biopsy specimens of active lesions and unaffected skin of patients with CIU and of skin from normal controls. Routine histologic evaluation was performed, RNA was isolated, and gene expression data were assessed. Due to technical reasons, the final evaluation included six samples of lesional skin, six samples of nonlesional skin, and five samples of normal skin.

RESULTS

As expected, lesional skin had more inflammatory cells per high-powered field (mean ± SE, 96 ± 6) than did samples from nonlesional skin of the subjects with CIU (17 ± 2) (p < 0.01). Lesions of CIU showed significant upregulation of 506 genes and reduced expression of 51 genes. Those most upregulated were predominantly involved in cell adhesion (e.g., selectin E [SELE]), cell activation (e.g., CD69), and chemotaxis (e.g., CCL2). Twelve independent canonical pathways with p ≤ 0.001 were identified (including intracellular kinase pathways (RAs-related nuclear protein [RAN] and Janus activated kinase/interferon), cytokine signaling pathways (IL-9, IL10, and IFN), a strong inflammatory response (interferon, IL-9, IL-10, inducible nitric oxide synthase and glucocorticoid pathways) and increased cell proliferation (RAN signaling, cell cycle control, and tRNA charging).

CONCLUSIONS

This preliminary study describes a method to study gene activation in urticarial lesions and demonstrated a strong inflammatory response with a large variety of activated genes that are distinct from those reported with other dermatologic conditions.

Chronic urticaria in adults: state-of-the-art in the new millennium

Chronic urticaria has been explored in several investigative aspects in the new millennium, either as to its pathogenesis, its stand as an autoimmune or auto-reactive disease, the correlation with HLA-linked genetic factors, especially with class II or its interrelation with the coagulation and fibrinolysis systems. New second-generation antihistamines, which act as good symptomatic drugs, emerged and were commercialized over the last decade. Old and new drugs that may interfere with the pathophysiology of the disease, such as cyclosporine and omalizumab have been developed and used as treatments. The purpose of this article is to describe the current state of knowledge on aspects of chronic urticaria such as, pathophysiology, diagnosis and the current therapeutic approach proposed in the literature.

Role of biologics in intractable urticaria

Chronic urticaria (CU) is a common condition faced by many clinicians. CU has been estimated to affect approximately 0.5%-1% of the population, with nearly 20% of sufferers remaining symptomatic 20 years after onset. Antihistamines are the first-line therapy for CU. Unfortunately, nearly half of these patients will fail this first-line therapy and require other medication, including immune response modifiers or biologics. Recent advances in our understanding of urticarial disorders have led to more targeted therapeutic options for CU and other urticarial diseases. The specific biologic agents most investigated for antihistamine-refractory CU are omalizumab, rituximab, and intravenous immunoglobulin (IVIG). Of these, the anti-IgE monoclonal antibody omalizumab is the best studied, and has recently been approved for the management of CU. Other agents, such as interleukin-1 inhibitors, have proved beneficial for Schnitzler syndrome and cryopyrin-associated periodic syndromes (CAPS), diseases associated with urticaria. This review summarizes the relevant data regarding the efficacy of biologics in antihistamine-refractory CU.