Biologic therapy for chronic spontaneous urticaria in pediatrics and adolescents: current landscape, challenges, and future perspectives.

INTRODUCTION: Chronic spontaneous urticaria (CSU) poses significant challenges, especially in pediatric and adolescent patients, impacting physical, emotional, and social well-being. Recent biologic breakthroughs offer promise, however, data on safety and efficacy in this population remain limited. AREAS COVERED: This review examines current biologic treatments in pediatrics and adolescents with CSU and explores the rapidly emerging landscape. EXPERT OPINION: Despite omalizumab's approval for allergic asthma in children since 2009, its delayed approval for CSU raises questions. Ligelizumab, a next-generation anti-IgE mAb, showed effectiveness in adults but lacks pediatric studies. CT-P39, a biosimilar to omalizumab, demonstrates promise, yet adolescent-specific outcomes are undisclosed. Dupilumab's recent approval for atopic dermatitis in children from 6 months onwards signifies progress. Expert opinion underscores the scarcity of controlled trials in pediatric and adolescent CSU, emphasizing the need for comprehensive studies. Age-specific data and collaboration are crucial for addressing research gaps and expanding indications for pediatric CSU treatment. The recently validated UAS7 parameter in children marks a milestone for prospective clinical trials. Despite challenges, the biology therapy outlook for pediatric and adolescent CSU is promising. Importantly, studies indicate that pediatric CSU is at least as prevalent as in adults, highlighting the need for approved treatments in this population.

Inflammatory cytokine levels and changes during omalizumab treatment in chronic spontaneous urticaria.

While several studies have examined the role of T cells and related cytokines in the development of chronic spontaneous urticaria (CSU), there is a limited amount of research focusing on the changes in cytokine levels during omalizumab treatment. The primary objective of this study was to investigate the inflammatory cytokine profile (including IL-4, IL-5, IL-10, IL-13, IL-17, IL-31, IL-33, and TNFα) among CSU patients undergoing to omalizumab treatment. Plasma levels of cytokines were measured using ELISA. Measurements were taken before CSU treatment, at the 3rd and 6th months of omalizumab treatment, and once in the control group. The severity of the patients' disease was assessed using the weekly Urticaria Activity Score(UAS7), and disease control was evaluated using the Urticaria Control Test(UCT). Thirty-one CSU patients and 56 age- and gender-matched healthy controls were included. Plasma levels of IL-4 and IL-33 were significantly lower in patients with CSU compared to healthy controls (p = 0.001; p = 0.038, respectively). During omalizumab treatment, IL-4 levels showed a significant increase in the 3rd month compared to baseline (p = 0.01), and IL-5 levels significantly decreased in the 6th month compared to both the 3rd month and baseline (6th month vs. baseline; p = 0.006, 6th month vs. 3rd month; p = 0.001). One potential mechanism of action for omalizumab may involve its regulatory effects on type 2 inflammatory cytokines in CSU patients. This finding partially explains the efficacy of anti-IL-4/13 treatments in chronic spontaneous urticaria. Further investigations on drugs targeting type 2 inflammatory cytokines in CSU are warranted.

PD-BAT: A novel approach of pooling basophil donors for expansion of commercial laboratory testing of Chronic Spontaneous Urticaria.

The type II autoimmune subtype of Chronic Spontaneous Urticaria (CSU) is characterized by the presence of IgG autoantibodies targeting IgE or the IgE high-affinity receptor (FcεRI) on mast cells and basophils. In evaluation of CSU patients, indirect basophil activation testing (BAT), has been utilized, involving the mixing of patient serum with heterologous peripheral blood donors, followed by flow cytometric assessment of basophil markers. However, the reliability of the indirect BAT results hinges on the quality of the donor basophils utilized. In this study, we introduce an innovative approach where multiple potential basophil donors undergo rigorous BAT characterization alongside control samples. By selecting and pooling donors with optimal performance, we significantly enhance the inter-assay reproducibility of the indirect BAT test.

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

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

Abnormalities in Gut Microbiota and Metabolism in Patients With Chronic Spontaneous Urticaria.

Background: Increasing evidence suggests that the gut microbiome plays a role in the pathogenesis of allergy and autoimmunity. The association between abnormalities in the gut microbiota and chronic spontaneous urticaria (CSU) remains largely undefined. Methods: Fecal samples were obtained from 39 patients with CSU and 40 healthy controls (HCs). 16S ribosomal RNA (rRNA) gene sequencing (39 patients with CSU and 40 HCs) and untargeted metabolomics (12 patients with CSU and 12 HCs) were performed to analyze the compositional and metabolic alterations of the gut microbiome in CSU patients and HCs. Results: The 16S rRNA gene sequencing results showed a significant difference in the ß-diversity of the gut microbiota, presented as the Jaccard distance, between CSU patients and HCs. No significant differences were found in the α-diversity of the gut microbiota between patients and HCs. At the phylum level, the major bacteria in the gut microbiome of patients with CSU were Firmicutes, Bacteroidetes, Proteobacteria, and Actinobacteria. At the genus level, Lactobacillus, Turicibacter, and Lachnobacterium were significantly increased and Phascolarctobacterium was decreased in patients with CSU. PICRUSt and correlation analysis indicated that Lactobacillus, Turicibacter, and Phascolarctobacterium were positively related to G protein-coupled receptors. Metabolomic analysis showed that α-mangostin and glycyrrhizic acid were upregulated and that 3-indolepropionic acid, xanthine, and isobutyric acid were downregulated in patients with CSU. Correlation analysis between the intestinal microbiota and metabolites suggested that there was a positive correlation between Lachnobacterium and α-mangostin. Conclusions: This study suggests that disturbances in the gut microbiome composition and metabolites and their crosstalk or interaction may participate in the pathogenesis of CSU.

What Basophil Testing Tells Us About CSU Patients - Results of the CORSA Study.

Basophil testing is the most effective single approach for diagnosing type-IIb autoimmune chronic spontaneous urticaria (TIIbaiCSU). A positive basophil test has been linked to long disease duration, higher disease activity, a poor response to antihistamines and omalizumab, and a better response to cyclosporine and fenebrutinib. As of now it is unclear what other features are connected to a positive basophil test in chronic spontaneous urticaria (CSU). We aimed to identify features of basophil test-positive CSU patients. We performed a cross-sectional study of 85 CSU patients. Basophil testing was done with the basophil activation test (BAT) and the basophil histamine release assay (BHRA). Data were analysed using SPSS: Student's t-test, Chi-square test, Odds Ratio, Spearman's correlation test. Of 85 CSU patients, 44% and 28% tested positive with the BAT and BHRA, respectively. These patients showed higher disease activity and impact, lower levels of disease control and total serum IgE, as well as higher rates of having a positive autologous serum skin test (ASST), angioedema, nocturnal symptoms, symptoms for >5 days/week, and thyroid autoantibodies. The ASST, by itself, was not a good predictor of basophil test results, but it predicted a positive basophil test in up to 100% of cases when combined with angioedema, thyroid autoantibodies or low IgE. In conclusion, a positive basophil test is linked to known features of TIIbaiCSU and novel characteristics including nocturnal symptoms. Further studies on basophil test-positive and -negative CSU patients can help to better understand CSU endotypes and to develop better management approaches.

A patient-oriented approach to long-term use of omalizumab in chronic spontaneous urticaria.

BACKGROUND: Omalizumab is an effective and safe treatment for antihistamine resistant chronic spontaneous urticaria (CSU), however, long-term efficacy and safety remains unclear. OBJECTIVE: To evaluate the efficacy and safety of omalizumab in CSU patients treated for long term and to identify long-term management strategies. METHODS: We retrospectively analyzed demographic characteristics, clinical features, laboratory parameters and treatment outcomes of 41 CSU patients who received omalizumab for at least 3 years. Treatment responses were evaluated with urticaria control test (UCT). Treatment safety was evaluated by comparing laboratory findings before and three years after omalizumab initiation as well as considering patients' adverse event reports. RESULTS: The patients (mean age 40.46 years; 63.4% women) received omalizumab for an average of 41.93 months (mean 31.68 injections/patient). The mean baseline UCT score was 5.56 and average number of injections to reach UCT score ≥12 was 3.3. Nine patients (22%) responded insufficiently to 300 mg/4 weeks omalizumab and required updosing. Thirty-eight patients (92.7%) could tolerate longer dose intervals (>4 weeks) and the dose interval was increased after a mean of 11.53 injections. There was no loss of efficacy of omalizumab. Sixteen patients (39%) had been retreated with omalizumab after a mean discontinuation time of 24 weeks. Five patients (12.2%) reported mild and transient adverse effects. Liver and renal function tests as well as full blood count before and after omalizumab were in normal ranges. CONCLUSION: For the long-term management of CSU, omalizumab is a safe and effective treatment which can be tailored according to patients' disease activity.

Serum level of hemokinin-1 is significantly lower in patients with chronic spontaneous urticaria than in healthy subjects.

BACKGROUND: We previously reported upregulation of expression of Mas-related G protein-coupled receptor X2 (MRGPRX2) on mast cells (MCs) in the skin of patients with severe chronic spontaneous urticaria (CSU). Serum levels of substance P (SP) were reportedly significantly elevated, in correlation with the severity of CSU. Hemokinin-1 (HK-1) reportedly induced histamine release from LAD2 cells via MRGPRX2. We aimed to investigate HK-1's role in CSU. METHODS: The concentrations of HK-1 and SP were measured using ELISAs. Skin- and synovium-derived cultured MCs were generated by culturing dispersed skin and synovial cells, respectively, with stem cell factor. MRGPRX2 expression in the MCs was reduced using a lentiviral shRNA silencing technique. RESULTS: Anti-SP Ab used in the SP ELISA showed 100% cross-reactivity to HK-1, but anti-HK-1 Ab showed 0% cross-reactivity to SP. The serum level of HK-1 was significantly lower in patients with CSU (n = 151) than in non-atopic healthy control (NC) subjects (n = 114). The EC50 of histamine release from MCs induced by HK-1 (5056 nM) was 12-fold higher than by SP (426 nM). Brief pretreatment of MCs with HK-1 at concentrations of 3.0-10 µM significantly reduced histamine release by 0.1 µM SP. However, brief incubation of MCs with HK-1 did not elicit rapid MRGPRX2 internalization. CONCLUSIONS: In NC subjects, high HK-1 concentrations may desensitize MGRPRX2-mediated MC activation, thereby preventing MC degranulation by SP.

Case Report: Omalizumab for Chronic Spontaneous Urticaria in Pregnancy.

Most chronic spontaneous urticaria (CSU) patients are female, and pregnancy can aggravate the disease activity of patients, but little is known about the efficacy and safety of omalizumab in pregnant CSU patients. We report two pregnant CSU patients treated with omalizumab and review the published information on omalizumab treatment during 11 pregnancies. The outcomes reported on patients with known pregnancies showed they had normal pregnancies and healthy babies as well as complete control of their CSU. The two new cases we reported support the view that omalizumab could be an effective and safe treatment option for pregnant and breastfeeding CSU patients. Further high-quality studies need to be carried out in order to obtain more information on the long-term efficacy and safety of the use of omalizumab during pregnancy in patients with chronic urticaria, including CSU.

Response of peripheral blood basophils in subjects with chronic spontaneous urticaria during treatment with omalizumab.

BACKGROUND: Treatment of patients with asthma or food allergy with omalizumab results in several consistent changes in circulating basophils. The multiple basophil phenotypes observed in patients with chronic spontaneous urticaria (CSU) present some unique attributes that may not respond in a similar fashion to patients with asthma or food allergy. As part of a clinical study on the therapeutic outcomes of omalizumab treatment in CSU, the basophil compartment was examined for changes in characteristics predicted by prior studies. OBJECTIVE: This study sought to examine the changes in basophil function and its relationship to auto-antibodies in serum during treatment with omalizumab. METHODS: At multiple time points before and during omalizumab treatment of patients with CSU, basophil surface IgE and FcεRI expression, cellular spleen tyrosine kinase (SYK) expression, IgE-mediated histamine release (HR), and the presence of auto-antibodies in serum were determined. RESULTS: Three basophil phenotypes were enumerated in the clinical study and used to group results in this basophil study: subjects with (1) basopenia, (2) normal basophil numbers with normal IgE-mediated HR, and (3) normal basophil numbers with poor HR. Basopenia was highly associated with the presence of auto-antibodies to unoccupied FcεRI and basophil numbers did not change during treatment. Likewise, subjects who are basopenic showed no changes in SYK expression or HR during treatment. In basophils of subjects who are nonbasopenic, increases in SYK expression and HR showed the expected inverse relationship to starting SYK and HR levels. Treatment with omalizumab resulted in similar kinetics for decreases in surface FcεRI and IgE in all 3 groups. CONCLUSIONS: A unifying interpretation of the results revolves around the presence of auto-antibodies to FcεRI in CSU. If present, basopenia and an absence of changes in basophils during omalizumab treatment are observed. If auto-antibodies are absent, the changes in the basophil compartment are consistent with prior studies of asthma and food allergy. These group differences also are related to efficacy of the treatment for clinical outcomes, as found in the parent clinical study.

Case Report: Refractory Chronic Spontaneous Urticaria Treated With Omalizumab in an Adolescent With Crohn's Disease.

Chronic spontaneous urticaria (CSU) is a mast cell-driven disease that is often associated with autoimmune or autoinflammatory conditions. Omalizumab is recommended in the treatment of refractory CSU in patients over 12 years of age who do not respond to four standard doses of antihistamines. Omalizumab blocks the mast cells' degranulation, thus interrupting the resulting inflammatory cascade driven by T-helper 2 (Th2) cytokines. The efficacy of omalizumab in controlling CSU and possible associated diseases has been studied in few patients so far. In particular, some case reports describe adults with CSU and concomitant inflammatory bowel diseases (IBD), such as Crohn's disease (CD) or ulcerative colitis (UC). Although the treatment of CD with anti-tumor necrosis factors-α (TNF-α) seems to be effective in controlling CSU, no cases of the utility of omalizumab in patients with both conditions have been described so far. At the moment, there is no evidence that the pathogenetic mechanisms underlying CD are linked to the same pathways that are inhibited by omalizumab for the treatment of CSU. We present the first pediatric case of refractory CSU and CD in which omalizumab led to CSU remission, even if the follow-up period was limited. In conclusion, our experience shows how CSU could be associated with CD and successfully treated with the monoclonal anti-IgE antibody in a patient on immunosuppressive therapy. However, more data is needed from a larger population.

Chronic urticaria and common variable immunodeficiency (CVID): an association to remember.

The patient is a 64-year-old Caucasian woman with idiopathic chronic urticaria who presented to her primary care physician's office with mucoid otitis media. Medical history was significant for hypertension, hyperlipidaemia, allergic rhinitis, pre-diabetes, gastro-oesophageal reflux, paroxysmal atrial fibrillation, chronic kidney disease, diverticulosis with prior diverticulitis and history of recurrent infections. Her chronic urticaria was initially treated with antibiotics, antihistamines and oral steroids, but later she developed refractory urticaria requiring dapsone with modest improvement. When she presented with mucoid otitis media, immunoglobulin levels were found to be decreased. The pneumococcal vaccine antibody challenge confirmed the diagnosis of common variable immunodeficiency (CVID). Her HIV test was negative. She was started on intravenous immunoglobulin infusions and her chronic urticaria stabilised.In patients with chronic urticaria refractory to treatment, especially with a history of recurrent infections, a diagnosis of CVID should be considered, regardless of HIV status.

Biomarkers of chronic spontaneous urticaria and their clinical implications.

Introduction: Chronic spontaneous urticaria (CSU) is a frequent disorder in which activation of effector cells and histamine release can be induced via several distinct pathogenetic mechanisms. Much work has been carried out to identify biomarkers useful for classifying CSU patients, and to predict their response to currently available treatments.Areas covered: The recent literature dealing with CSU biomarkers was screened in PubMed and Google Scholar using 'chronic spontaneous urticaria', 'biomarker', 'diagnosis', 'therapy' and 'treatment response' as key words. The characteristics found in relevant papers were divided into clinical and serological biomarkers of (a) clinical severity/disease activity, and (b) response to treatments.Expert opinion: A diagnostic biomarker for CSU is still missing. Most biomarkers described so far do not seem to possess sufficient specificity for this disease. Basopenia and the activation of the coagulation cascade might be biomarkers of disease activity and severity, but information available so far is insufficient to consider their routine use. Markers suggesting IgG-mediated autoimmunity (autologous serum skin test, basophil activation/histamine release assays, low total IgE) seem to identify patients less prone to respond to omalizumab but responsive to cyclosporine. In contrast, 'autoallergy' (i.e. the presence of IgE to autoallergens), which is often associated with elevated IgE levels seems to identify patients who will respond to omalizumab.

Correlations between disease activity, autoimmunity and biological parameters in patients with chronic spontaneous urticaria.

Summary: Background. Biomarkers of disease activity/severity and criteria of autoimmune chronic spontaneous urticaria (CSU) are still a matter of debate. Objective. To investigate possible correlations between clinical and biological markers and their associations with: 1) disease activity, 2) resistance to H1-antihistamines, 3) autoimmunity and 4) autologous serum skin test (ASST) in patients with CSU. To also analyze biological parameter modifications in patients with CSU treated with omalizumab. Materials and methods. Disease activity, H1-antihistamines response and presence of concomitant autoimmune disease were prospectively recorded in 95 patients with CSU. For 60 of them, ASST was performed. Broad biological analysis were performed. Results. C-reactive protein (CRP) serum levels were higher in H1-antihistamines unresponders (p less-than 0.0001) and in more active diseases (p = 0.033). D-dimer plasma levels were higher in H1-antihistamines unresponders (p = 0.008) and in patients with autoimmune status (concomitant autoimmune disease and/or with autoantibodies) (p = 0.016). Total immunoglobuline E (IgE) serum level was lower in patients with positive ASST. Blood basophil counts were lower in patients with CSU and especially in H1-antihistamines unresponders (p = 0.023), in patients with more active disease (p = 0.023), with positive ASST (p = 0.001), and with autoimmune status (p = 0.057). Conversely, under omalizumab, a decrease of CRP (p = 0.0038) and D-dimer serum/plasma levels (p = 0.0002) and an increase of blood basophil counts (p = 0.0023) and total IgE serum levels (p = 0.0007) were observed. Conclusions. This study brings additional evidences of interest to investigate IgE, D-dimer serum/plasma levels and basophil blood counts in patients with CSU as they could be correlated to disease activity, response to treatment and/or autoimmunity.

Peptic Ulcer Disease is Associated with Increased Risk of Chronic Urticaria Independent of Helicobacter pylori Infection: A Population-Based Cohort Study.

BACKGROUND: Some studies showed patients with chronic urticaria have a higher rate of peptic ulcer disease (PUD). Whether PUD is a risk factor for chronic urticaria is unclear. OBJECTIVE: The objective of this study was to evaluate the incidence of and risk factors for chronic urticaria in patients with PUD using the Taiwan National Health Insurance Research Database. METHODS: We conducted a retrospective nationwide cohort study of the period 2000-2012 and involving 11,901 patients with PUD who underwent Helicobacter pylori (HP) therapy (PUD + HP group) and an equal number of matched patients without HP infection (PUD - HP group). Furthermore, we enrolled 23,802 patients without PUD for comparison (non-PUD group). The Cox proportional hazards regression model was used to analyze chronic urticaria risk after adjusting for potential confounding factors. RESULTS: The mean ages of the three groups were around 50 years. Approximately 42.6% were female. Chronic urticaria incidences in the PUD + HP and PUD - HP groups were both significantly higher than that in the non-PUD group. The hazard ratios of chronic urticaria in the PUD + HP group and the PUD - HP group were 1.34 (95% confidence interval 1.09-1.64) and 1.45 (95% confidence interval 1.19-1.79), respectively. The risk difference became significant 2 years after patients with PUD had the HP infection tests and persisted till the end of follow-up. The risk increase was significant in patients with PUD who were female or aged 40-64 years. There was no difference in the risk comparison between PUD + HP and PUD - HP groups. CONCLUSIONS: Peptic ulcer disease, independent of HP infection, is associated with an increased chronic urticaria risk. Patients with PUD who were female or aged 40-64 years are more likely to have chronic urticaria.

Mas-related G protein-coupled receptor X2 and its activators in dermatologic allergies.

The Mas-related G protein-coupled receptor X2 (MRGPRX2) is a multiligand receptor responding to various exogenous and endogenous stimuli. Being highly expressed on skin mast cells, MRGPRX2 triggers their degranulation and release of proinflammatory mediators, and it promotes multicellular signaling cascades, such as itch induction and transmission in sensory neurons. The expression of MRGPRX2 by skin mast cells and the levels of the MRGPRX2 agonists (eg, substance P, major basic protein, eosinophil peroxidase) are upregulated in the serum and/or skin of patients with inflammatory and pruritic skin diseases, such as chronic spontaneous urticaria or atopic dermatitis. Therefore, MRGPRX2 and its agonists might be potential biomarkers for the progression of cutaneous inflammatory diseases and the response to treatment. In addition, they may represent promising targets for prevention and treatment of signs and symptoms in patients with skin diseases or drug reactions. To assess this possibility, this review explores the role and relevance of MRGPRX2 and its activators in cutaneous inflammatory disorders and chronic pruritus.