Leukotriene receptor antagonists as add-on therapy to antihistamines for urticaria: a systematic review and meta-analysis of randomized clinical trials.

BACKGROUND: The benefits and harms of adding antileukotrienes to H1-antihistamines for the management of urticaria (hives, itch, and/or angioedema) remain unclear. OBJECTIVE: We sought to systematically synthesize the treatment outcomes of antileukotrienes in combination with H1-antihistamines versus H1-antihistamines alone for acute and chronic urticaria. METHODS: As part of updating American Academy of Allergy, Asthma & Immunology and American College of Allergy, Asthma, and Immunology Joint Task Force on Practice Parameters urticaria guidelines, we searched MEDLINE, Embase, CENTRAL, LILACS, WPRIM, IBECS, ICTRP, CBM, CNKI, VIP, Wanfang, FDA, and EMA databases from inception to December 18th, 2023 for randomized controlled trials (RCTs) evaluating antileukotrienes and H1-antihistamines versus H1-antihistamines alone in patients with urticaria. Paired reviewers independently screened citations, extracted data, and assessed risk of bias. Random effects models pooled effect estimates for urticaria activity, itch, wheal, sleep, quality of life, and harms. The GRADE approach informed certainty of evidence ratings. Open Science Framework registration: https://osf.io/h2bfx/. RESULTS: Thirty-four RCTs enrolled 3,324 children and adults. Compared to H1-antihistamines alone, the combination of a leukotriene receptor antagonist (LTRA) with H1-antihistamines probably modestly reduces urticaria activity (mean difference: -5.04, 95%CI -6.36 to -3.71; 7-day Urticaria Activity Score) with moderate certainty. We made similar findings for itch and wheal severity, and quality of life. Adverse events were probably not different between groups (moderate certainty), however, no RCT reported on neuropsychiatric adverse events. CONCLUSION: Among patients with urticaria, adding LTRAs to H1-antihistamines probably modestly improves urticaria activity with little to no increase in overall adverse events. The added risk of neuropsychiatric adverse events in this population with LTRAs is small and uncertain.

Efficacy and Safety of Systemic Corticosteroids for Urticaria: A Systematic Review and Meta-Analysis of Randomized Clinical Trials.

BACKGROUND: Short courses of adjunctive systemic corticosteroids are commonly used to treat acute urticaria and chronic urticaria flares (both with and without mast cell-mediated angioedema), but their benefits and harms are unclear. OBJECTIVE: To evaluate the efficacy and safety of treating acute urticaria or chronic urticaria flares with versus without systemic corticosteroids. METHODS: We searched the MEDLINE, EMBASE, CENTRAL, CNKI, VIP, Wanfang, and CBM databases from inception to July 8, 2023, for randomized controlled trials of treating urticaria with versus without systemic corticosteroids. Paired reviewers independently screened records, extracted data, and appraised risk of bias with the Cochrane 2.0 tool. We performed random-effects meta-analyses of urticaria activity, itch severity, and adverse events. We assessed certainty of the evidence using the Grading of Recommendations Assessment, Development and Evaluations (GRADE) approach. RESULTS: We identified 12 randomized trials enrolling 944 patients. For patients with low or moderate probability (17.5%-64%) to improve with antihistamines alone, add-on systemic corticosteroids likely improve urticaria activity by a 14% to 15% absolute difference (odds ratio [OR], 2.17, 95% confidence interval [CI]: 1.43-3.31; number needed to treat [NNT], 7; moderate certainty). Among patients with a high chance (95.8%) for urticaria to improve with antihistamines alone, add-on systemic corticosteroids likely improved urticaria activity by a 2.2% absolute difference (NNT, 45; moderate certainty). Corticosteroids may improve itch severity (OR, 2.44; 95% CI: 0.87-6.83; risk difference, 9%; NNT, 11; low certainty). Systemic corticosteroids also likely increase adverse events (OR, 2.76; 95% CI: 1.00-7.62; risk difference, 15%; number needed to harm, 9; moderate certainty). CONCLUSIONS: Systemic corticosteroids for acute urticaria or chronic urticaria exacerbations likely improve urticaria, depending on antihistamine responsiveness, but also likely increase adverse effects in approximately 15% more.

Functional human skin explants as tools for assessing mast cell activation and inhibition.

Mast cells are activated through a variety of different receptors to release preformed granules and mediators synthesized de novo. However, the physiology and function of mast cells are not fully understood. Traditional studies of mast cell activation in humans have utilized cultures of tissue-derived mast cells including CD34+ progenitor cells or well-characterized commercially available cell lines. One limitation of these methods is that mast cells are no longer in a natural state. Therefore, their applicability to human skin disorders may be limited. Human skin explant models have been utilized to investigate the short-term effects of cell mediators, drugs, and irritants on skin while avoiding the ethical concerns surrounding in vivo stimulation studies with non-approved agents. Nonetheless, few studies have utilized intact human tissue to study mast cell degranulation. This "Methods" paper describes the development and application of an intact skin explant model to study human mast cell activation. In this manuscript, we share our protocol for setting up ex vivo human skin explants and describe the results of stimulation experiments and techniques to minimize trauma-induced histamine release. Skin explants were generated using de-identified, full-thickness, non-diseased skin specimens from plastic and reconstructive surgeries. Results were reproducible and demonstrated FcɛRI- and MRGPRX2-induced mediator release which was inhibited with the use of a BTK inhibitor and QWF, respectively. Thus, this explant model provides a quick and accessible method of assessing human skin mast cell activation and inhibition.

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

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

Efficacy and safety of ligelizumab in adults and adolescents with chronic spontaneous urticaria: results of two phase 3 randomised controlled trials.

BACKGROUND: Many patients with chronic spontaneous urticaria (CSU) do not achieve complete control of their symptoms with current available treatments. In a dose-finding phase 2b study, ligelizumab improved urticaria symptoms in patients with H1-antihistamine (H1-AH) refractory CSU. Here, we report the efficacy and safety outcomes from two ligelizumab phase 3 studies. METHODS: PEARL-1 and PEARL-2 were identically designed randomised, double-blind, active-controlled and placebo-controlled parallel-group studies. Patients aged 12 years or older with moderate-to-severe H1-AH refractory CSU were recruited from 347 sites in 46 countries and randomly allocated in a 3:3:3:1 ratio via Interactive Response Technology to 72 mg ligelizumab, 120 mg ligelizumab, 300 mg omalizumab, or placebo, dosed every 4 weeks, for 52 weeks. Patients allocated to placebo received 120 mg ligelizumab from week 24. The primary endpoint was change-from-baseline (CFB) in weekly Urticaria Activity Score (UAS7) at week 12, and was analysed in all eligible adult patients according to the treatment assigned at random allocation. Safety was assessed throughout the study in all patients who received at least one dose of the study drug. The studies were registered with ClinicalTrials.gov, NCT03580369 (PEARL-1) and NCT03580356 (PEARL-2). Both trials are now complete. FINDINGS: Between Oct 17, 2018, and Oct 26, 2021, 2057 adult patients were randomly allocated across both studies (72 mg ligelizumab n=614; 120 mg ligelizumab n=616; 300 mg omalizumab n=618, and placebo n=209). A total of 1480 (72%) of 2057 were female, and 577 (28%) of 2057 were male. Mean UAS7 at baseline across study groups ranged from 29·37 to 31·10. At week 12, estimated treatment differences in mean CFB-UAS7 were as follows: for 72 mg ligelizumab versus placebo, -8·0 (95% CI -10·6 to -5·4; PEARL-1), -10·0 (-12·6 to -7·4; PEARL-2); 72 mg ligelizumab versus omalizumab 0·7 (-1·2 to 2·5; PEARL-1), 0·4 (-1·4 to 2·2; PEARL-2); 120 mg ligelizumab versus placebo -8·0 (-10·5 to -5·4; PEARL-1), -11·1 (-13·7 to -8·5; PEARL-2); 120 mg ligelizumab versus omalizumab 0·7 (-1·1 to 2·5; PEARL-1), -0·7 (-2·5 to 1·1; PEARL-2). Both doses of ligelizumab were superior to placebo (p<0·0001), but not to omalizumab, in both studies. No new safety signals were identified for ligelizumab or omalizumab. INTERPRETATION: In the phase 3 PEARL studies, ligelizumab demonstrated superior efficacy versus placebo but not versus omalizumab. The safety profile of ligelizumab was consistent with previous studies. FUNDING: Novartis Pharma.

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.

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.

56-year-old male with HIV and sudden cardiac arrest.

A 56-year-old man with well-controlled human immunodeficiency virus, anxiety, depression, and hypercholesterolemia developed acute urticaria, lip angioedema, and respiratory distress after consumption of a cheeseburger, French fries, lemonade, and ibuprofen. He was evaluated in the emergency department and, during admission, developed asystole, diaphoresis, pallor, and a brief episode of posturing that was treated with two doses of epinephrine. Results of the initial workup with electrocardiogram, troponin, complete blood cell count, and comprehensive metabolic panel were normal. He was subsequently evaluated by an allergist for further recommendations.

Effects of combination treatment with tezepelumab and allergen immunotherapy on nasal responses to allergen: A randomized controlled trial.

BACKGROUND: Thymic stromal lymphopoietin (TSLP) has been shown to play a central role in the initiation and persistence of allergic responses. OBJECTIVE: We evaluated whether tezepelumab, a human monoclonal anti-TSLP antibody, improved the efficacy of subcutaneous allergen immunotherapy (SCIT) and promoted the development of tolerance in patients with allergic rhinitis. METHODS: We conducted a double-blind parallel design trial in patients with cat allergy. A total of 121 patients were randomized to receive either intravenous tezepelumab plus subcutaneous cat SCIT, cat SCIT alone, tezepelumab alone, or placebo for 52 weeks, followed by 52 weeks of observation. Nasal allergen challenge (NAC), skin testing, and blood and nasal samples were obtained throughout the study. RESULTS: At week 52, the NAC-induced total nasal symptom scores (TNSS) (calculated as area under the curve [AUC0-1h] and as peak score [Peak0-1h] during the first hour after NAC) were significantly reduced in patients receiving tezepelumab/SCIT compared to SCIT alone. At week 104, one year after stopping treatment, the primary end point TNSS AUC0-1h was not significantly different in the tezepelumab/SCIT group compared to SCIT alone, while TNSS Peak0-1h was significantly lower in those receiving combination treatment versus SCIT. Transcriptomic analysis of nasal epithelial samples demonstrated that treatment with the combination of SCIT/tezepelumab, but neither monotherapy, caused persistent downregulation of a gene network related to type 2 inflammation that was associated with improvement in NAC responses. CONCLUSIONS: Inhibition of TSLP augments the efficacy of SCIT during therapy and may promote tolerance after a 1-year course of treatment. (ClinicalTrials.gov NCT02237196).

Biological screening of a unique drug library targeting MRGPRX2.

Background: Allergic drug reaction or drug allergy is an immunologically mediated drug hypersensitivity reaction (DHR). G-protein coupled receptors (GPCRs) are common drug targets and communicate extracellular signals that initiate cellular responses. Recent evidence shows that GPCR MRGPRX2 is of major importance in IgE-independent pseudo-allergic DHRs based on the suspected interactions between many FDA-approved peptidergic compounds and MRGPRX2. Objective: Our aim was to uncover novel MRGPRX2-selective and -potent agonists as drug candidates responsible for clinical features of pseudo-allergic DHRs. Methods: We conducted a primary high-throughput screening (HTS), coupled with mutagenesis targeting the MRGPRX2 N62S mutation, on a panel of 3,456 library compounds. We discovered pharmacologically active hit compounds as agonists of the MRGPRX2 protein according to high degrees of potency evaluated by the calcium response and validated by the degranulation assay. Using the molecular tool Forge, we also characterized the structure-activity relationship shared by identified hit compounds. Results: The alternative allele of single nucleotide polymorphism rs10833049 (N62S) in MRGPRX2 demonstrated loss-of-function property in response to substance P and antineoplastic agent daunorubicin hydrochloride. We applied a unique assay system targeting the N62S mutation to the HTS and identified 84 MRGPRX2-selective active hit compounds representing diverse classes according to primary drug indications. The top five highly represented groups included fluoroquinolone and non-fluoroquinolone antibiotics; antidepressive/antipsychotic; antihistaminic and antineoplastic agents. We classified hit compounds into 14 clusters representing a variety of chemical and drug classes beyond those reported, such as opioids, neuromuscular blocking agents, and fluoroquinolones. We further demonstrated MRGPRX2-dependent degranulation in the human mast cell line LAD2 cells induced by three novel agonists representing the non-fluoroquinolone antibiotics (bacitracin A), anti-allergic agents (brompheniramine maleate) and tyrosine-kinase inhibitors (imatinib mesylate). Conclusion: Our findings could facilitate the development of interventions for personalized prevention and treatment of DHRs, as well as future pharmacogenetic investigations of MRGPRX2 in relevant disease cohorts.

Pharmacokinetic equivalence of CT-P39 and reference omalizumab in healthy individuals: A randomised, double-blind, parallel-group, Phase 1 trial.

BACKGROUND: CT-P39 is being developed as a biosimilar of reference omalizumab. This study aimed to assess the pharmacokinetic equivalence of CT-P39 to European Union-approved and United States-licensed reference omalizumab (EU- and US-omalizumab, respectively). METHODS: This two-part, randomised, parallel-group, double-blind Phase 1 trial (NCT04018313) was conducted in healthy individuals with a total immunoglobulin E (IgE) level ≤100  international units (IU)/ml at screening. In part 2, described herein, participants were randomised (1:1:1) to receive a single 150 mg subcutaneous dose of CT-P39, EU-omalizumab, or US-omalizumab. The primary endpoint was pharmacokinetic equivalence in terms of area under the concentration-time curve (AUC) from time zero to the last quantifiable concentration (AUC0-last ), AUC from time zero to infinity (AUC0-inf ), and maximum serum concentration (Cmax ). Equivalence was concluded if 90% confidence intervals (CIs) of the geometric least-squares means ratios were contained within the predefined 80%-125% equivalence margin. Additional pharmacokinetic parameters, pharmacodynamics, safety, and immunogenicity were also evaluated. RESULTS: Overall, 146 participants were randomised (CT-P39, N = 47; EU-omalizumab, N = 49; US-omalizumab, N = 50). For all primary pharmacokinetic parameters, 90% CIs for pairwise treatment comparisons were within the 80%-125% equivalence margin, demonstrating pharmacokinetic equivalence. Decreases in free IgE and increases in total IgE serum concentrations were comparable across groups. CT-P39 was well tolerated. Safety endpoints were comparable across groups: there were no treatment-related serious adverse events, deaths, or discontinuations due to treatment-emergent adverse events. CONCLUSIONS: CT-P39 was well tolerated and demonstrated pharmacokinetic equivalence with EU-omalizumab and US-omalizumab following administration of a single dose in healthy individuals.

Existing and Investigational Medications for Refractory Chronic Spontaneous Urticaria: Safety, Adverse Effects, and Monitoring.

Treatment of chronic spontaneous urticaria (CSU) is responsive to H1 antihistamines administered up to four times the recommended US Food and Drug Administration dose in approximately 50% of patients. However, when patients do not respond to these first-line agents, evidence-based guidelines using Grading of Recommendations, Assessment, Development, and Evaluations methodology have provided direction for second- and third-line treatments that can effectively treat patients with CSU. Some patients remain refractory to these advanced treatments; therefore, alternative treatments with a lower certainty of evidence may be necessary. Regardless of the therapies used to treat CSU patients, it is essential for clinicians to be knowledgeable about the mechanism of action, efficacy, and safety and monitoring recommendations of the treatments prescribed. This review provides a comprehensive review of the adverse effects and monitoring recommendations for agents in use for CSU treatment as well as those currently undergoing investigation for CSU treatment.

Diversity, Disparities, and the Allergy Immunology Pipeline.

Disparities in health outcomes in under-represented racial and ethnic minority groups are evident in allergic/immunologic diseases and have been most completely described in asthma. The last 2 decades have not led to any substantive improvement in these disparities, with under-represented minorities (URMs) receiving worse care in several quality measures. Increasing physician workforce diversity is one strategy to improve access to care and address the health disparity problem because URM physicians more often choose to both work in clinical settings and pursue research that benefits underserved communities.

Short-Term Subcutaneous Allergy Immunotherapy and Dupilumab are Well Tolerated in Allergic Rhinitis: A Randomized Trial.

BACKGROUND: Subcutaneous immunotherapy (SCIT) has been proven as an effective therapy against some allergens for seasonal allergic rhinitis (SAR) patients unresponsive to intranasal corticosteroids and/or antihistamines but carries risk of systemic allergic reactions. Dupilumab blocks the shared receptor component for interleukin-4 and interleukin-13, key and central drivers of type 2 inflammation in multiple diseases. OBJECTIVE: To evaluate the efficacy and safety of SCIT+dupilumab vs SCIT alone. METHODS: This phase 2a, multicenter, double-blind, placebo-controlled parallel-group study conducted in 103 adults with grass pollen-induced SAR (NCT03558997) randomized patients 1:1:1:1 to SCIT, dupilumab (300 mg every 2 weeks), SCIT+dupilumab, or placebo. SCIT was administered using an 8-week cluster protocol followed by 8 weeks of maintenance injections. Primary endpoint was change from pre-treatment baseline in area under the curve (AUC) in total nasal symptom score (TNSS) 0-1 h following nasal allergen challenge (NAC) with timothy grass extract at Week 17. RESULTS: Although 16 weeks of treatment with SCIT+dupilumab did not significantly improve TNSS AUC (0-1 h) following NAC at Week 17 vs SCIT (least squares mean -56.76% vs -52.03%), a higher proportion of SCIT+dupilumab-treated patients (61.5%) achieved SCIT maintenance dose vs SCIT (46.2%). A lower proportion of SCIT+dupilumab-treated patients (7.7%) required epinephrine rescue treatment vs SCIT (19.2%). There were significantly fewer withdrawals in the SCIT+dupilumab group than in the SCIT group (n = 2 [7.7%] vs n = 8 [30.8%]; P = 0.0216); the majority of SCIT group withdrawals were due to SCIT-related intolerability, compared with no discontinuations from the SCIT+dupilumab group. CONCLUSION: In SAR patients, 16 weeks of SCIT+dupilumab may improve SCIT tolerability but did not incrementally reduce post-allergen challenge nasal symptoms compared with SCIT alone. CLINICAL STUDY NUMBER: NCT03558997.

The efficacy of omalizumab treatment in chronic spontaneous urticaria is associated with basophil phenotypes.

BACKGROUND: The mechanisms underlying disease pathogenesis in chronic spontaneous urticaria (CSU) and improvement with omalizumab are incompletely understood. OBJECTIVES: This study sought to examine whether the rate of clinical remission is concordant with baseline basophil features or the rate of change of IgE-dependent functions of basophils and/or plasmacytoid dendritic cells during omalizumab therapy. METHODS: Adults (n = 18) with refractory CSU were treated with omalizumab 300 mg monthly for 90 days. Subjects recorded daily urticaria activity scores, and clinical assessments with blood sampling occurred at baseline and on days 1, 3, 6, 10, 20, 30, 60, and 90 following omalizumab. At baseline, subjects were categorized by basophil functional phenotypes, determined by in vitro histamine release (HR) responses to anti-IgE antibody, as CSU-responder (CSU-R) or CSU-non-responder (CSU-NR), as well as basopenic (B) or nonbasopenic (NB). RESULTS: CSU-R/NB subjects demonstrated the most rapid and complete symptom improvement. By day 6, CSU-R/NB and CSU-NR/NB had increased anti-IgE-mediated basophil HR relative to baseline, and these shifts did not correlate with symptom improvement. In contrast, CSU-NR/B basophil HR did not change during therapy. The kinetics of the decrease in surface IgE/FcεRI was similar in all 3 phenotypic groups and independent of the timing of the clinical response. Likewise, plasmacytoid dendritic cells' surface IgE/FcεRI decline and TLR9-induced IFN-α responses did not reflect clinical change. CONCLUSIONS: Changes in basophil IgE-based HR, surface IgE, or FcεRI bear no relationship to the kinetics in the change in clinical symptoms. Baseline basophil count and basophil functional phenotype, as determined by HR, may be predictive of responsiveness to omalizumab.

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.

Urticaria and Angioedema Across the Ages.

Chronic urticaria (CU) and angioedema can occur at any age. Although most CU with or without angioedema occurs in adults, it can also present in children or the elderly and can complicate pregnancy and breast-feeding. The presentations of CU and angioedema are different in children, middle-aged adults, and older patients as are the differential diagnoses. Therefore, the management of CU and angioedema in these different age groups and special populations needs to take into account the age-specific features of urticaria and angioedema. Here, we describe the evaluation, diagnosis, and treatment of CU and angioedema in children, middle-aged adults, and older patients. This review focuses on CU with or without angioedema and does not discuss acute urticaria or bradykinin-mediated angioedema.

Current and emerging treatments for chronic spontaneous urticaria.

OBJECTIVE: To review the published literature on current and new treatments for chronic spontaneous urticaria (CSU) and to provide guidance on the potential use of these therapeutics. DATA SOURCES: A PubMed search was performed to include English-language articles with the keywords chronic spontaneous urticaria, pathophysiology, quality of life, and treatments, with a preference to those articles written in the last 5 years. ClinicalTrials.gov was reviewed for recent relevant clinical trials related to potential CSU therapeutics. STUDY SELECTIONS: Literature was included if it provided information related to the current understanding of the pathophysiology and management of CSU as well as potential novel therapeutics currently in development. RESULTS: CSU has a significant effect on patients' quality of life. Current therapies include antihistamines, leukotriene receptor antagonists, omalizumab, and immunosuppressants; however, additional treatments are needed. New therapeutics under investigation include IgG1 anti-IgE monoclonal antibodies (ligelizumab), chemoattractant rector-homologous molecule expressed on TH2 cells antagonists (AZD1981), Bruton tyrosine kinase inhibitors (fenebrutinib), anti-siglec-8 monoclonal antibody (AK002), and topical spleen tyrosine kinase inhibitors (GSK2646264). We review the mechanisms of action as well as recently published data from clinical trials regarding the efficacy and safety of these treatments. CONCLUSION: The development of new treatments for CSU will lead to improved options for patients and may assist with improving our understanding of disease pathophysiology.