Autoimmune chronic spontaneous urticaria

Genetic Variants Leading to Urticaria and Angioedema and Associated Biomarkers

Advances in next generation sequencing technologies, as well as their expanded accessibility and clinical use over the past 2 decades, have led to an exponential increase in the number of identified single gene disorders. Among these are primary atopic disorders-inborn errors of immunity resulting in severe allergic phenotypes as a primary presenting feature. Two cardinal aspects of type I immediate hypersensitivity allergic reactions are hives and angioedema. Mast cells (MCs) are frequent primary drivers of these symptoms, but other cells have also been implicated. Even where MC degranulation is believed to be the cause, mediator-induced symptoms may greatly vary among individuals. Angioedema-particularly in the absence of hives-may also be caused by hereditary angioedema conditions resulting from aberrant regulation of contact system activation and excessive bradykinin generation or impairment of vascular integrity. In these patients, swelling can affect unpredictable locations and fail to respond to MC-directed therapies. Genetic variants have helped delineate key pathways in the etiology of urticaria and nonatopic angioedema and led to the development of targeted therapies. Herein, we describe the currently known inherited and acquired genetic causes for these conditions, highlight specific features in their clinical presentations, and discuss the benefits and limitations of biomarkers that can help distinguish them.

Positive Basophil Tests Are Linked to High Disease Activity and Other Features of Autoimmune Chronic Spontaneous Urticaria: A Systematic Review

BACKGROUND

Chronic spontaneous urticaria (CSU) is believed to be Autoimmune (aiCSU) (type IIb CSU) in at least 8% of patients, associated with mast cell-activating IgG autoantibodies. Basophil tests such as the basophil activation test (BAT) and basophil histamine release assay (BHRA) are considered the best single tests for an aiCSU diagnosis. To date, the strength of associations among a positive BAT and/or BHRA (BAT/BHRA+) and CSU features, patient demographics, and response to treatment remains poorly characterized.

OBJECTIVE

To evaluate the strength of current evidence on basophil tests as parameters for CSU characteristics.

METHODS

We performed a systematic literature search and review to assess the relationship between BAT/BHRA+ and clinical and laboratory parameters of CSU. Of 1,058 records found in the search, 94 studies were reviewed by experts in urticaria and 42 were included in the analysis.

RESULTS

In CSU patients, BAT/BHRA+ showed a strong level of evidence for an association with high disease activity and low levels of total IgE. A weak level of evidence was shown for the association of BAT/BHRA+ and the presence of angioedema, and basopenia.

CONCLUSIONS

Our results suggest that aiCSU defined by BAT/BHRA+ is more active or severe and is linked to other aiCSU markers such as low total IgE/basopenia. Basophil tests should be standardized and implemented in routine clinical care to improve the diagnosis and treatment of patients with aiCSU.

How Infection and Vaccination Are Linked to Acute and Chronic Urticaria: A Special Focus on COVID-19

Since more than a century ago, there has been awareness of the connection between viral infections and the onset and exacerbation of urticaria. Our knowledge about the role of viral infection and vaccination in acute and chronic urticaria improved as a result of the COVID-19 pandemic but it has also highlighted knowledge gaps. Viral infections, especially respiratory tract infections like COVID-19, can trigger the onset of acute urticaria (AU) and the exacerbation of chronic urticaria (CU). Less frequently, vaccination against viruses including SARS-CoV-2 can also lead to new onset urticaria as well as worsening of CU in minority. Here, with a particular focus on COVID-19, we review what is known about the role of viral infections and vaccinations as triggers and causes of acute and chronic urticaria. We also discuss possible mechanistic pathways and outline the unmet needs in our knowledge. Although the underlying mechanisms are not clearly understood, it is believed that viral signals, medications, and stress can activate skin mast cells (MCs). Further studies are needed to fully understand the relevance of viral infections and vaccinations in acute and chronic urticaria and to better clarify causal pathways.

The correlation between Th17/Treg immune dysregulation and the disease severity in chronic spontaneous urticaria patients

OBJECTIVE

Chronic spontaneous urticaria (CSU) has a profound impact on the sleep quality, productivity and overall quality of life of affected individuals. This study aimed to investigate the correlation between serum Th17/Treg immune dysregulation and the severity of CSU in patients.

METHODS

Clinical baseline data of 120 CSU patients and matched healthy controls were recorded. The pruritus level, disease severity, and quality of life of CSU patients were assessed using the visual analogue scale, weekly Urticaria Activity Score and chronic urticaria quality of life questionnaire, respectively. The Th17/Treg cell ratio was detected by flow cytometry. ELISA was used to measure the levels of serum Th17 cytokines (IL-17, IL-21) and Treg cytokines (TGF-β1, IL-35). Pearson's correlation analysis was conducted to examine the associations between these indicators.

RESULTS

No significant differences were identified in terms of sex, age, and BMI between the two groups. However, CSU patients exhibited a significant increase in the Th17 cell ratio, as well as the elevated serum levels of TGF-β1, IL-17 and, IL-21. Conversely, the proportion of Treg cells and the levels of IL-35 were remarkably decreased in CSU patients. Peripheral blood Th17 cells were negatively correlated with Treg cells. The severity of pruritus, life quality, and disease severity in CSU patients were positively correlated to Th17 cell ratio, and inversely correlated with Treg cell proportion.

CONCLUSIONS

A positive correlation was found between the percentage of peripheral blood Th17 cell in CSU patients and the pruritus level, life quality, and disease severity. In constrast, there was a negative correlation between the proportion of peripheral blood Treg cells and these clinical parameters.

Efficacy of Second-Line Treatments in Chronic Urticaria Refractory to Standard Dose Antihistamines

PURPOSE

The prevalence of chronic urticaria (CU) is increasing worldwide, and it imposes a major burden on patients. Few studies have evaluated the efficacy of second-line treatments of CU, particularly for patients being considered for costly third-line treatments such as omalizumab. We compared the efficacy and safety of second-line treatments of CU refractory to standard doses of nonsedating H₁-antihistamines (nsAHs).

METHODS

This 4-week, prospective, randomized, open-label trial divided patients into 4 treatment groups: 4-fold updosing of nsAHs, multiple combination of 4 nsAHs, switching to other nsAHs, and adjunctive H₂-receptor antagonist. The clinical outcomes included urticaria control status, symptoms, and rescue medication use.

RESULTS

This study included 109 patients. After 4 weeks of second-line treatment, urticaria was well-controlled, partly controlled, and uncontrolled in 43.1%, 36.7%, and 20.2% of patients, respectively. Complete control of CU was achieved in 20.4% of patients. Among the patients with high-dose nsAHs, the proportion with well-controlled status was higher compared to the patients who received standard doses (51.9% vs. 34.5%, P = 0.031). No significant difference was observed in the proportion of well-controlled cases between the updosing and combination treatment groups (57.7% vs. 46.4%, P = 0.616). However, increasing the dose of nsAHs 4-fold was associated with a higher rate of complete symptom control compared to multiple combination treatment with 4 nsAHs (40.0% vs. 10.7%, P = 0.030). Logistic regression analysis confirmed the higher efficacy of updosing of nsAHs for complete control of CU compared to the other treatment strategies (odds ratio, 0.180; P = 0.020).

CONCLUSIONS

In patients with CU refractory to standard doses of nsAHs, both updosing of nsAHs 4-fold and multiple combination treatment with 4 nsAHs increased the rate of well-controlled cases without causing significant adverse effects. Updosing of nsAHs is more effective for complete CU control than combination treatment.

Basophil Characteristics as a Marker of the Pathogenesis of Chronic Spontaneous Urticaria in Relation to the Coagulation and Complement Systems

Chronic spontaneous urticaria (CSU) is a common skin disorder characterized by daily or almost daily recurring skin edema and flare with itch and pruritus anywhere on the body for more than 6 weeks. Although basophil- and mast cell-released inflammatory mediators, such as histamine, play important roles in the pathogenesis of CSU, the detailed underlying mechanism is not clear. Since several auto-antibodies, IgGs which recognize IgE or the high-affinity IgE receptor (FcεRI) and IgEs against other self-antigens, are detected in CSU patients, they are considered to activate both mast cells in the skin and basophils circulating in the blood. In addition, we and other groups demonstrated that the coagulation and complement system also contribute to the development of urticaria. Here, we summarized the behaviors, markers and targets of basophils in relation to the coagulation-complement system, and for the treatment of CSU.

Urticaria and basophils

Chronic spontaneous urticaria (CSU) is a common skin disease without an etiology in the vast majority of cases. The similarity of symptoms and pathology to allergen-induced skin reactions supports that skin mast cell IgE receptor activation is also involved in CSU. Accumulating evidence also supports a role for blood basophils in disease expression. Blood basopenia is noted in active CSU disease with the recruitment of blood basophils to skin lesion sites. Blood basophils further display altered IgE receptor mediated degranulation patterns in two phenotypes that improve in remission. In active CSU subjects, changes in IgE receptor signaling molecule expression levels accompany the altered degranulation function in blood basophils. The success of therapies targeting IgE in CSU patients have also shown that altered blood basophil phenotypes and enumeration have potential use as a disease biomarker.

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.

Characteristics of immune response profile in patients with immediate allergic and autoimmune urticarial reactions induced by SARS-CoV-2 vaccines

Severe allergic reactions following SARS-COV-2 vaccination are generally rare, but the reactions are increasingly reported. Some patients may develop prolonged urticarial reactions following SARS-COV-2 vaccination. Herein, we investigated the risk factors and immune mechanisms for patients with SARS-COV-2 vaccines-induced immediate allergy and chronic urticaria (CU). We prospectively recruited and analyzed 129 patients with SARS-COV-2 vaccine-induced immediate allergic and urticarial reactions as well as 115 SARS-COV-2 vaccines-tolerant individuals from multiple medical centers during 2021-2022. The clinical manifestations included acute urticaria, anaphylaxis, and delayed to chronic urticaria developed after SARS-COV-2 vaccinations. The serum levels of histamine, IL-2, IL-4, IL-6, IL-8, IL-17 A, TARC, and PARC were significantly elevated in allergic patients comparing to tolerant subjects (P-values = 4.5 × 10^-5-0.039). Ex vivo basophil revealed that basophils from allergic patients could be significantly activated by SARS-COV-2 vaccine excipients (polyethylene glycol 2000 and polysorbate 80) or spike protein (P-values from 3.5 × 10^-4 to 0.043). Further BAT study stimulated by patients' autoserum showed positive in 81.3% of patients with CU induced by SARS-COV-2 vaccination (P = 4.2 × 10^-13), and the reactions could be attenuated by anti-IgE antibody. Autoantibodies screening also identified the significantly increased of IgE-anti-IL-24, IgG-anti-FcεRI, IgG-anti-thyroid peroxidase (TPO), and IgG-anti-thyroid-related proteins in SARS-COV-2 vaccines-induced CU patients comparing to SARS-COV-2 vaccines-tolerant controls (P-values = 4.6 × 10^-10-0.048). Some patients with SARS-COV-2 vaccines-induced recalcitrant CU patients could be successfully treated with anti-IgE therapy. In conclusion, our results revealed that multiple vaccine components, inflammatory cytokines, and autoreactive IgG/IgE antibodies contribute to SARS-COV-2 vaccine-induced immediate allergic and autoimmune urticarial reactions.

Early warning signs of thyroid autoantibodies seroconversion: A retrospective cohort study

BACKGROUND

Serum anti-thyroid peroxidase antibody (anti-TPO) and anti-thyroglobulin antibody (anti-Tg) levels are key indicators for the diagnosis of autoimmune diseases, especially autoimmune thyroiditis. Before the thyroid autoantibodies turn from negative to positive, it is unknown whether any clinical indicators in the body play a warning role.

PURPOSE

To establish an early prediction model of seroconversion to positive thyroid autoantibodies.

METHODS

This retrospective cohort study collected information based on clinical laboratory data. A logistic regression model was used to analyse the risk factors associated with a change in thyroid autoantibodies to an abnormal status. A machine-learning approach was employed to establish an early warning model, and a nomogram was used for model performance assessment and visualisation. Receiver operating characteristic (ROC) curves, calibration curves, and decision curve analyses were used for internal and external validation.

RESULTS

Logistic regression analysis revealed that albumin to globulin ratio, triglyceride levels, and Glutamic acid levels among liver function and some metabolism-related indicators, high density lipoprotein C among metabolism-related indicators, and cystatin C among renal function indicators were all risk factors for thyroid antibody conversion (P<0.05). In addition, several indicators in the blood count correlated with thyroid conversion (P<0.05). Changes in the ratio of free thyroxine to free triiodothyronine were a risk factor for positive thyroid antibody conversion (OR_fT4/fT3=1.763; 95% confidence interval 1.554-2.000). The area under the curve (AUC) of the early warning model based on the positive impact of clinical laboratory indicators, age, and sex was 0.85, which was validated by both internal (AUC 0.8515) and external (AUC 0.8378) validation.

CONCLUSIONS

The early warning model of anti-TPO and anti-Tg conversion combined with some clinical laboratory indicators in routine physical examination has a stable warning efficiency.

Thyroid Autoimmunity in CSU: A Potential Marker of Omalizumab Response?

The response of severe chronic spontaneous urticaria (CSU) to omalizumab largely depends on the autoimmune or autoallergic endotype of the disease. Whether thyroid autoimmunity may predict omalizumab response along with total IgE in CSU is still unclear. Three hundred and eighty-five patients (M/F 123/262; mean age 49.5 years; range 12-87 years) with severe CSU were studied. Total IgE levels and thyroid autoimmunity (levels of anti-thyroid peroxidase [TPO] IgG) were measured before omalizumab treatment. Based on the clinical response, patients were divided into early (ER), late (LR), partial (PR) and non (NR) responders to omalizumab. Thyroid autoimmunity was detected in 92/385 (24%) patients. Altogether, 52%, 22%, 16% and 10% of patients were ER, LR, PR and NR to omalizumab, respectively. Response to omalizumab was not associated with thyroid autoimmunity (p = 0.77). Conversely, we found a strongly positive association between IgE levels and omalizumab response (p < 0.0001); this association was largely driven by early response (OR = 5.46; 95% CI: 2.23-13.3). Moreover, the predicted probabilities of early response strongly increased with increasing IgE levels. Thyroid autoimmunity alone cannot be used as a clinical predictor of omalizumab response. Total IgE levels remain the only and most reliable prognostic marker for omalizumab response in patients with severe CSU.

Consecutive injections of low-dose interleukin-2 improve symptoms and disease control in patients with chronic spontaneous urticaria

PURPOSE

To describe the effectiveness and tolerability of low-dose interleukin (IL)-2 in treating patients with chronic spontaneous urticaria (CSU) refractory to H₁-antihistamines.

METHODS

This retrospective study included CSU patients who received treatment with at least one cycle of IL-2, injected intramuscularly at a dose of 1.0 million international units daily for 7 consecutive days, after failing treatment with H₁-antihistamines. Patients were followed up for ≥12 weeks.

RESULTS

Of the 15 patients, 7 (46.7%) and 11 (73.3%) achieved complete response at Week 2 and Week 12, respectively. The mean change of urticaria control test (UCT) and weekly urticaria activity score (UAS7) from baseline was 6.6 (95% CI, 4.2 to 8.9) and - 16.9 (95% CI, -24.0 to -9.8), respectively, at Week 12. Local injection-site reactions were the most common adverse events. No serious adverse events were reported.

CONCLUSION

Low-dose IL-2 treatment improves symptoms and disease control for CSU patients refractory to H₁-antihistamines.

Chronic spontaneous urticaria: Focus on pathophysiology to unlock treatment advances

Chronic spontaneous urticaria (CSU) is a debilitating skin disease characterized by intensely itchy wheals, angioedema, or both. Symptoms recur spontaneously, on a near-daily basis, over >6 weeks; many patients experience flare-ups over several years and, consequently, reduced quality of life. Differences between the inflammatory profiles of the skin of CSU patients (wheals and nonlesional sites) and healthy controls indicate that key drivers such as mast cells, eosinophils, and basophils interact, release vasoactive mediators, and prime the skin, leaving patients predisposed to symptoms. Many cytokines and chemokines involved in these inflammatory networks and their corresponding intracellular signaling cascades have been identified. These insights informed the development of therapies such as omalizumab, dupilumab, and Bruton's tyrosine kinase (BTK) inhibitors, marking a renewed focus on pathogenesis in CSU clinical research. Despite progress, current therapies provide symptomatic control but do not appear to redress the inflammatory balance in the skin permanently. A deeper understanding of CSU pathogenesis will permit a more targeted approach to developing novel treatments with curative intent. Here, we review what is known about the pathogenesis of CSU and consider how this can be used to identify rational targets to improve patient care further.

Combined microbiome and metabolome analysis of gut microbiota and metabolite interactions in chronic spontaneous urticaria

Background

The pathogenesis of chronic spontaneous urticaria (CSU) is unclear, and it turned out to be involved in biological processes, such as autoimmunity, autoallergy, inflammation, and coagulation. The gut microbiota plays an important role in immune and inflammatory diseases. However, the relationship between chronic spontaneous urticaria and the gut microbiota remains unknown.

Methods

The stool and serum samples were taken from 15 CSU patients and 15 normal controls. Changes in the composition of gut microbiota and serum metabolism in CSU patients and normal controls were analyzed by 16S ribosomal RNA (rRNA) gene sequencing and untargeted metabolomics.

Results

The results of 16S rRNA gene sequencing showed that compared with normal controls, CSU patients had increased α-diversity of gut microbiota and significant differences in β-diversity. At the phylum level, the relative abundance of Firmicutes increased and the relative abundance of Bacteroidetes and Proteobacteria decreased in CSU patients compared with healthy controls. At the genus level, six kinds of bacteria were significantly enriched in CSU patients and five in normal controls. Metabolomic analysis revealed altered levels of metabolites such as unsaturated fatty acids and purines. Correlation analysis of gut microbiota and metabolites showed that Lachnospira was negatively correlated with arachidonic acid, and Gemmiger was also negatively correlated with (±)8-HETE.

Conclusion

This study suggests that changes in gut microbiota and metabolites may play a role in immune and inflammatory pathways in the pathogenesis of CSU patients.

IgG and IgE Autoantibodies to IgE Receptors in Chronic Spontaneous Urticaria and Their Role in the Response to Omalizumab

Background: Chronic spontaneous urticaria (CSU) is defined as the recurrence of unprovoked transient wheals and itch for more than 6 weeks. Currently, there is an unmet need concerning response prediction in CSU. The present study investigated biomarkers of type I and type IIb autoimmunity as potential predictors of response to omalizumab in CSU. Materials and methods: Differences in levels of IgG and IgE autoantibodies targeting the high- and low-affinity IgE receptors (FcεRI and FcεRII, respectively), as well as spontaneous and specifically triggered leukotriene C (LTC)4 release by basophils from the investigated subjects, were evaluated in 18 consecutive, prospectively enrolled CSU patients and 18 age- and sex-matched, healthy non-atopic controls. Results: The patients with CSU had higher levels of anti-FcεRI IgE (542 (386.25-776.5) vs. 375 (355-418), optical density (OD), p = 0.008), and IgG (297 (214.5-431.25) vs. 193.5 (118-275) OD, p = 0.004) autoantibodies relative to the controls. Simultaneous anti-FcεRI IgG and IgE positivity (i.e., both autoantibody levels above the respective cut-offs) was recorded only in late- and non-responders (3/8 and 1/2, respectively). Discussion: Significantly higher anti-FcεRI IgE autoantibody levels were found in the CSU patients as compared to the controls, supporting FcεRI as an autoallergic target of IgE (autoallergen) in the complex pathophysiological scenario of CSU. The co-occurrence of anti-FcεRI IgG and IgE autoantibodies was documented only in late- and non-responders, but not in early ones, crediting the co-existence of autoimmune and autoallergic mechanisms as a driver of late/poor response to omalizumab.

Urticaria and Angioedema: Understanding Complex Pathomechanisms to Facilitate Patient Communication, Disease Management, and Future Treatment

Chronic spontaneous urticaria (CSU) is primarily a T2-dominant disease with a complex genetic background. Skin mast cell activation can be induced not only via the IgE-FcεRI axis but also from several other distinct mechanisms, molecules, and receptors involved in CSU onset, persistence, and exacerbation. These include autoallergy, autoimmunity, central or peripheral neuroimmune dysregulation, activation of both extrinsic and intrinsic coagulation pathways, and microbial infections. Besides mast cells, recent reports suggest the active and direct involvement of basophils and eosinophils. Several biological characteristics or biomarkers have been linked with CSU's known endotypes and may help forecast therapeutic responses. The introduction of biologic therapy for CSU has been a major advance in the last 10 years. The cornerstone of angioedema (AE) pathogenesis is increased vascular permeability and plasma leakage into the deeper dermis and subcutis, either mediated by histamine or bradykinin (BK). C1-inhibitor deficiency, hereditary or acquired, is the primary cause of BK-mediated AE due to increased plasma BK concentration. Other complex conditions have been identified, with some likely involving contact system dysregulation and other putative mechanisms related to vascular endothelial dysfunction. The approval of multiple hereditary-AE-specific therapies for both prevention and acute attacks has revolutionized treatment of this disease. Any new knowledge of the pathogenesis of CSU and AE offers the opportunity to improve patient information, physician-patient communication, prediction of therapeutic responses, selection of precise tailor-made treatment for each patient, and exploration of novel treatment options for those who do not achieve disease control with current medications.

Biologics for chronic spontaneous urticaria: toward a personalized treatment

INTRODUCTION

Chronic spontaneous urticaria (CSU) is characterized by the recurrent occurrence of short-lived wheals with or without angioedema for more than 6 weeks. Although its pathogenesis is not completely defined, several mechanisms seem involved, including autoimmunity and autoallergy with complement and coagulation activation. Various biologics are currently available or under investigation to counteract different CSU pathomechanisms.

AREAS COVERED

The recent literature dealing with biologics in the treatment of CSU was screened and analyzed; the different treatments were divided into anti-IgE and other than anti-IgE biologics. The latter were subdivided according to their target mechanisms.

EXPERT OPINION

Biologic drugs exert their effects in a very precise and specific manner. A majority of patients (arguably those with type I disease) respond to anti-IgE treatment. Others, possibly with type IIa disease, show a slow response to anti-IgE drugs. Things are much more complicated in anti-IgE-refractory patients. Some respond well to nonspecific immune suppressors, such as corticosteroids and cyclosporin suggesting that an immune-mediated pathogenic mechanism, not involving the high-affinity IgE receptor, is probably active. Several ongoing studies are evaluating biologics and small molecules counteracting other pathomechanisms, including anti-receptor biologics, Bruton tyrosine kinase (BTK) inhibitors, mast cell targets, and specific cytokines.

An update on anaphylaxis and urticaria

Notable scientific developments have taken place in the field of anaphylaxis and urticaria in recent years; they are highlighted in this review. Case-control studies, genome-wide association studies, and large omics analyses have promoted further insights into not only the underlying genetics but also the biomarkers of both anaphylaxis and urticaria. New evidence regarding IgE-dependent and non-IgE-dependent mechanisms of anaphylaxis and urticaria, including the Mas-related G protein-coupled receptor (MRGPR [formerly MRG]) signaling pathway, has been gained. Putative elicitors of anaphylactic reactions in the context of coronavirus disease 2019 (COVID-19) vaccination and impact of the COVID-19 pandemic on the management and course of chronic urticaria have been reported. Clinical progress has also been made regarding the severity grading and risk factors of anaphylaxis, as well as the distinction of phenotypes and elicitors of both diseases. Furthermore, novel treatment approaches for anaphylaxis and subtypes of urticaria have been assessed, with different outcome and potential for a better disease control or prevention.

Do Antinuclear Antibodies Influence the Clinical Features of Chronic Spontaneous Urticaria?: A Retrospective Cohort Study

Background

Antinuclear antibody (ANA) is often used as a screening test for autoimmune comorbidities in patients with chronic spontaneous urticaria (CSU). However, the relationship of ANA status and the clinical course of the disease have not been fully described.

Objectives

To compare clinical features of CSU patients who are positive and negative for ANA.

Methods

This was a retrospective cohort study that enrolled CSU patients attending the Urticaria Clinic at Siriraj Hospital from 2013 to 2019. Demographics, clinical characteristics, laboratory investigations, and treatments were collected until July 2021. All patients were investigated for ANA. Clinical feature data was compared between CSU patients with positive ANA and negative ANA groups using the 2-sample t-test and the Mann-Whitney U test for quantitative variables. The chi-squared test or Fisher's exact test was conducted to explore the association of qualitative variables. Disease relapse and remission were analysed via Kaplan-Meier survival analysis.

Results

Of 323 CSU patients, 31% had positive ANA. There were no significant differences in disease severity or impairment in quality of life. Patients with a positive ANA test had significantly lower prevalence of allergic rhinitis (p = .048) and significantly higher level of erythrocyte sedimentation rate (p = 0.007). Kaplan-Meier survival analysis showed that 2% of ANA positive CSU patients achieved remission status after one year and 28% did so after five years. There was no statistically significant difference in time to remission and time to relapse between ANA-positive and negative groups.

Conclusion

Positive ANA in CSU patients could not indicate the differences in main disease characteristics from the ANA-negative CSU patients. Investigation for ANA may be useful in CSU patients who are suspected of having autoimmune diseases.

Comorbidities of Chronic Urticaria: A glimpse into a complex relationship

Chronic Urticaria (CU) is a chronic inflammatory, predominantly mast cell-driven disease, characterized by the development of wheals and/or angioedema for more than 6 weeks. It affects approximately 1%-5% of the total population worldwide and imposes a substantial burden on health-related quality of life, significantly affecting patients' daily life. The economic impact on the health system is also not negligible, with an estimated cost per patient per year of approximately 2.000 $ in the United States. Although the underlying pathophysiology is not fully explored, autoimmune mechanisms have been proposed, including type I ("autoallergy" by means of autoantibodies to self-antigens) and type IIb (autoimmunity). Atopic, autoimmune, and psychiatric disorders are prevalent comorbidities in both children and adults with Chronic Spontaneous Urticaria (CSU). Although malignancies, cardiovascular diseases and other comorbidities have also been reported as associated diseases in patients with CSU, data remain scarce. It is still unknown whether the aforementioned comorbidities share common pathophysiological mechanisms with specific endotypes of CSU. The current review aims to overview current data on comorbidities of CU, and furthermore to comment on the potential linked pathways underlying these diseases.

Prevalence, predictors, and clinical relevance of α-gal sensitization in patients with chronic urticaria

Background

Little is known about α‐gal (galactose‐α‐1,3‐galactose) sensitization in patients with chronic urticaria (CU). The aim of this study was to examine the prevalence, predictors and clinical relevance of α‐gal sensitization in patients with CU.

Methods

Two consecutive cohorts of newly referred patients with CU from a primary care allergology practice and a tertiary hospital dermatology department, plus a control group with allergic disease, but not CU, from the allergology practice, were interviewed and screened for α‐gal sensitization (serum specific‐IgE ≥0.35 KU/L).

Results

Of 733 patients included, 21 (5.6%) and 11 (3.9%) of CU patients from private practice and hospital, respectively, were α‐gal sensitized. In total, 8 patients (38.1% of sensitized patients, and 2.1% of all CU patients) from private practice, and 2 patients (18.2% of sensitized patients, and 0.7% of all CU patients) from hospital, had clinically relevant α‐gal allergy. In private practice, male sex (47.6 vs. 24.7%), p = 0.020, obesity (33.3 vs. 23.6%), p = 0.302, and frequency of angioedema (61.9 vs. 51.4%), p = 0.350; and in hospital, male sex (72.7 vs. 27.9%), p = 0.003, and high total immunoglobulin E (median 168 vs. 70.5 KU/L), p = 0.022 were associated with α‐gal sensitization.

Conclusion

α‐gal sensitization is observed in a small fraction of CU patients with only few patients experiencing clinically relevant sensitization. Certain patients, particularly from primary care, may constitute a relevant population for aimed testing.

Urticaria

Urticaria is an inflammatory skin disorder that affects up to 20% of the world population at some point during their life. It presents with wheals, angioedema or both due to activation and degranulation of skin mast cells and the release of histamine and other mediators. Most cases of urticaria are acute urticaria, which lasts ≤6 weeks and can be associated with infections or intake of drugs or foods. Chronic urticaria (CU) is either spontaneous or inducible, lasts >6 weeks and persists for >1 year in most patients. CU greatly affects patient quality of life, and is linked to psychiatric comorbidities and high healthcare costs. In contrast to chronic spontaneous urticaria (CSU), chronic inducible urticaria (CIndU) has definite and subtype-specific triggers that induce signs and symptoms. The pathogenesis of CSU consists of several interlinked events involving autoantibodies, complement and coagulation. The diagnosis of urticaria is clinical, but several tests can be performed to exclude differential diagnoses and identify underlying causes in CSU or triggers in CIndU. Current urticaria treatment aims at complete response, with a stepwise approach using second-generation H1 antihistamines, omalizumab and cyclosporine. Novel treatment approaches centre on targeting mediators, signalling pathways and receptors of mast cells and other immune cells. Further research should focus on defining disease endotypes and their biomarkers, identifying new treatment targets and developing improved therapies.