Biomarkers In Chronic Spontaneous Urticaria: Current Targets And Clinical Implications

Mast cell signaling and its role in urticaria

Chronic urticaria is a mast cell (MC)-driven disease characterized by the development of itching wheals and/or angioedema. In the last decades, outstanding progress has been made in defining the mechanisms involved in MC activation, and novel activating and inhibitory receptors expressed in MC surface were identified and characterized. Besides an IgE-mediated activation through high-affinity IgE receptor cross-linking, other activating receptors, including Mas-related G-protein-coupled receptor-X2, C5a receptor, and protease-activated receptors 1 and 2 are responsible for MC activation. This would partly explain the reason some subgroups of chronic spontaneous urticaria (CSU), the most frequent form of urticaria in the general population, do not respond to IgE target therapies, requiring other therapeutic approaches for improving the management of the disease. In this review, we shed some light on the current knowledge of the immunologic and nonimmunologic mechanisms regulating MC activation in CSU, considering the complex inflammatory scenario underlying CSU pathogenesis, and novel potential MC-targeted therapies, including surface receptors and cytoplasmic signaling proteins.

Blood Adhesion Molecules as Biomarkers in Children with Chronic Urticaria

BACKGROUND

The prevailing etiological model of both acute and chronic urticaria implicates specific allergen exposure that triggers the local release of vasoactive factors and inflammatory adhesion molecules, including vascular cell adhesion molecule 1 (VCAM-1), intercellular adhesion molecule 1 (ICAM-1), endothelial leukocyte adhesion molecule 1 (ELAM-1), P-selectin and E-selectin in the superficial dermis. This study focused on the possible role of VCAM-1 and ICAM-1 as biomarkers in children with acute and chronic urticaria.

METHODS

This study involved 184 children, 40 with acute urticaria, 71 with chronic urticaria, and 73 matched comparison subjects. The serum levels of ICAM-1 and VCAM-1 were determined in venous blood in all the participants on enrollment. Antihistamine treatment was administered to all the patients. In the children with chronic urticaria, the Urticaria Activity Score Questionnaire (UAS7) was completed daily by the parents. In 16 of the patients with acute urticaria and 43 with chronic urticaria, the serum levels of ICAM-1 and VCAM-1 were determined at follow-up after 6-8 weeks of treatment.

RESULTS

The mean serum levels of both VCAM-1 and ICAM-1 were higher in both groups of children with urticaria than in the comparison subjects at the start of the study. In the chronic urticaria group, the levels decreased significantly (p = 0.03 and p = 0.01, respectively) following treatment. Similarly, the acute urticaria group exhibited significant reduction in the mean levels of VCAM and ICAM (p < 0.001). In both groups, the mean level of ICAM after treatment was comparable with that of the comparison group.

CONCLUSIONS

VCAM-1 and ICAM-1 are suggested as promising biomarkers for monitoring both acute and chronic urticaria in children. Future research should explore their utility in larger cohorts and investigate their role in personalized treatment strategies.

Identification of key genes and molecular mechanisms of chronic urticaria based on bioinformatics

Chronic urticaria (CU) is characterized by persistent skin hives, redness, and itching, enhanced by immune dysregulation and inflammation. Our main objective is identifying key genes and molecular mechanisms of chronic urticaria based on bioinformatics. We used the Gene Expression Omnibus (GEO) database and retrieved two GEO datasets, GSE57178 and GSE72540. The raw data were extracted, pre-processed, and analyzed using the GEO2R tool to identify the differentially expressed genes (DEGs). The samples were divided into two groups: healthy samples and CU samples. We defined cut-off values of log2 fold change ≥1 and p < .05. Analyses were performed in the Kyoto Encyclopaedia of Genes and Genomes (KEGG), the Database for Annotation, Visualization and Integrated Discovery (DAVID), Metascape, Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) and CIBERSOFT databases. We obtained 1613 differentially expressed genes. There were 114 overlapping genes in both datasets, out of which 102 genes were up-regulated while 12 were down-regulated. The biological processes included activation of myeloid leukocytes, response to inflammations, and response to organic substances. Moreover, the KEGG pathways of CU were enriched in the Nuclear Factor-Kappa B (NF-kB) signaling pathway, Tumor Necrosis Factor (TNF) signaling pathway, and Janus kinase/signal transducers and activators of transcription (JAK-STAT) signaling pathway. We identified 27 hub genes that were implicated in the pathogenesis of CU, such as interleukin-6 (IL-6), Prostaglandin-endoperoxide synthase 2 (PTGS2), and intercellular adhesion molecule-1 (ICAM1). The complex interplay between immune responses, inflammatory pathways, cytokine networks, and specific genes enhances CU. Understanding these mechanisms paves the way for potential interventions to mitigate symptoms and improve the quality of life of CU patients.

Serum Amyloid A as a Potential Biomarker for Disease Activity in Chronic Spontaneous Urticaria

BACKGROUND

Chronic spontaneous urticaria (CSU) is an inflammatory skin disease with a complex physiopathology. Serum amyloid A (SAA), an acute-phase reactant, has been proposed as a potential biomarker in urticaria but has yet to be studied in a population with CSU or correlated with disease activity as indicated by the Urticaria Activity Score summed over 7 days (UAS7).

OBJECTIVE

We sought to determine SAA-1 levels in patients with CSU and correlate them with its activity and control, as well as with clinical features of CSU and other potential blood biomarkers.

METHODS

We conducted a retrospective multicenter study of 67 patients with CSU, from whom we obtained demographic and clinical data, UAS7 as an indicator of CSU activity, and blood and serum markers.

RESULTS

SAA-1 levels positively correlated with UAS7 (rs = 0.47, P < .001). SAA-1 levels were higher in patients with noncontrolled (UAS7 > 6) CSU than in those with controlled (UAS ≤ 6) CSU (P < .001) and were also higher in patients with concomitant angioedema (P = .003) or delayed pressure urticaria (P = .003).

CONCLUSION

We propose SAA-1 as a potential biomarker for activity in CSU. Further studies are required to evaluate its potential role as a biomarker for other CSU outcomes, such as response to treatment.

Effect of Allergen-Specific Immunotherapy on Transcriptomic Changes in Canine Atopic Dermatitis

Canine atopic dermatitis (cAD) is a genetic, chronic, and recurrent inflammatory and pruritic skin disorder. Allergen-specific immunotherapy (ASIT) is presently recognized as the only clinically effective disease-modifying treatment for allergies. The aim of our study was to analyze the changes in gene expression observed in the peripheral blood nuclear cells of cAD patients subjected to ASIT. Blood samples designated for transcriptomic analyses were collected from AD dogs twice, before and six months after ASIT, and also from healthy dogs. Statistical analysis revealed 521 differentially expressed transcripts, among which 241 transcripts represented genes with well-described functions. Based on the available literature, we chose nine differentially expressed genes (RARRES2, DPP10, SLPI, PLSCR4, MMP9, NTSR1, CBD103, DEFB122, and IL36G) which may be important in the context of the dysregulated immune response observed in cAD patients. The expressions of five out of the nine described genes (DPP10, PLSCR4, NTSR1, DEFB122, and IL36G) changed after the application of ASIT. The expressions of three of these genes returned to the level observed in the healthy control group. The genes listed above need further investigation to determine details of their role in the molecular mechanism of immune tolerance induction in response to allergen-specific immunotherapy.

Circulating Pentraxin-3 and its association with C-reactive protein levels and disease activity in patients with chronic spontaneous urticaria

INTRODUCTION

Pentraxin-3 (PTX3) is a soluble long pentraxin molecule that regulates inflammatory responses. This study aimed to determine the plasma levels of plasma PTX-3 as an inflammation marker in chronic spontaneous urticaria (CSU) and whether the PTX3 levels correlate with disease activity and other clinical parameters, including acute phase reactants and biomarkers.

METHODS

The study included 70 CSU patients and 30 healthy controls. Plasma PTX3 levels were measured by ELISA. CSU disease activity was evaluated with the urticaria activity score summed over 7 days. Complete blood count, C-reactive protein (CRP), transaminases, total IgE, antinuclear antibody, anti-thyroid peroxidase, anti-thyroglobulin, and D-dimer levels were recorded.

RESULTS

Of the 70 patients, 52 (74.3%) were female, with a mean age of 37.51 ± 11.80 years. Disease activity was severe in 43, moderate in 15, and mild in 12 patients. Mean PTX3 levels were elevated in CSU patients compared to healthy controls (0.81 vs. 0.55 ng/mL, p = 0.031). The mean CRP levels were higher in patients than in the controls (4.26 vs. 1.57 mg/L, p = 0.023). Patients also had higher D-dimer levels than the controls (5.96 vs. 0.59 mg/L, p < 0.001). A significant positive correlation was found between PTX3 and CRP levels (r = 0.508, p < 0.001) and between D-dimer levels and UAS7 (r = 0.338, p = 0.004) and CRP (r = 0.213, p = 0.034) levels. A multivariable stepwise regression analysis showed that the one-unit increase in the CRP level increased to 38.19 units in the PTX3 level (95% confidence interval [17.40-58.98], p < 0.001).

CONCLUSION

Circulating levels of CRP and PTX3, two members of the pentraxin family, are significantly correlated and elevated in CSU patients with increasing disease activity, indicating their utility as inflammatory markers in CSU.

Efficacy and safety of omalizumab therapy in urticaria vasculitis

Urticarial vasculitis (UV) is a small-vessel leukocytoclastic vasculitis characterized by different clinical manifestations ranging from long-lasting urticarial lesions to severe and potentially life-threatening multi-organ involvement. Omalizumab (OMA), anti-IgE recombinant humanized IgG1 monoclonal antibody, has been successfully used to treat few cases of severe and/or refractory UV. In this study we report our experience on 6 patients with refractory normocomplementemic UV successfully treated with anti-IgE therapy (OMA), suggesting that this biological therapy may be a safe and effective therapeutic option in UV.

Omalizumab versus cyclosporin-A for the treatment of chronic spontaneous urticaria: can we define better-responding endotypes?

Background

Chronic Spontaneous Urticaria (CSU) is characterized by recurrent wheals and/or angioedema for longer than 6-weeks. Guidelines recommend Omalizumab (Oma) as first-line and Cyclosporine-A (Cs-A) as second-line treatment in antihistamine resistant CSU. This step-wise algorithm might be time-consuming and costly.

Objective

To determine indicators of response to Oma or Cs-A in CSU patients.

Methods

We retrospectively analyzed data from seven centers in Turkey; the inclusion criteria for patients were to receive both Oma and Cs-A treatment (not concurrently) at some point in time during their follow-up. Clinical and laboratory features were compared between groups.

Results

Among 110 CSU patients; 47 (42.7%) were Oma-responders, 15 (13.6%) were Cs-A-responders, and 24 (21.8%) were both Oma and Cs-A responders and 24 (21.8%) were non-responders to either drug. High CRP levels were more frequent in Cs-A-responders (72.7% vs. 40.3%; p = 0.055). Oma-responders had higher baseline UCT (Urticaria Control Test) scores (6 vs. 4.5; p = 0.045). Responders to both drugs had less angioedema and higher baseline UCT scores compared to other groups (33.3% vs. 62.8%; p = 0.01 and 8 vs. 5; p = 0.017). Non-responders to both drugs had an increased frequency in the female gender and lower baseline UCT scores compared to other groups (87.5% vs. 61.6%; p = 0.017 and 5 vs. 7; p = 0.06).

Study Limitations

Retrospective nature, limited number of patients, no control group, the lack of the basophil activation (BAT) or BHRA (basophil histamine release assay) tests.

Conclusions

Baseline disease activity assessment, which considers the presence of angioedema and disease activity scores, gender, and CRP levels might be helpful to predict treatment outcomes in CSU patients and to choose the right treatment for each patient. Categorizing patients into particular endotypes could provide treatment optimization and increase treatment success.

Exploring Long Non-Coding RNAs Associated with IP3/DAG Signaling Pathway as Potential Biomarkers Involved in Mast Cell Degranulation in Chronic Spontaneous Urticaria with 2-Year Follow-Up

Purpose

Chronic spontaneous urticaria (CSU) pathogenesis involves mast cell degranulation induced by the inositol 1,4,5-trisphosphate/diacylglycerol (IP3/DAG) pathway, but the condition lacks specific biomarkers. This study was performed to investigate long non-coding RNA (lncRNA) expression profiles, identify those associated with IP3/DAG pathway, and assess their diagnostic and prognostic value for CSU.

Methods

Ten samples were selected from CSU and control groups, and microarray was performed to screen differentially expressed (DE) lncRNAs and mRNAs. Bioinformatic and co-expression network analyses were used to identify lncRNAs associated with IP3/DAG pathway. Quantitative real-time polymerase chain reaction was used to validate lncRNA expression levels. Combined with disease characteristics and serum indices detected with enzyme-linked immunosorbent assays, Spearman analysis and logistic regression were applied to analyze lncRNA-associated disease risk. Receiver operating characteristic (ROC) curves and 2-year follow-up data were applied to evaluate lncRNA diagnostic and prognostic value.

Results

A total of 678 up- and 573 downregulated DE lncRNAs and 609 up- and 176 downregulated DE mRNAs were identified. Seven lncRNAs (upregulated T264761, T280622, ENST00000587970, T224062, ENST00000562459, and his-1_RNA_dna; downregulated ENST00000417930) were associated with the IP3/DAG pathway. D-dimer and histamine levels were significantly different between the two groups. Correlation analysis showed that his-1_RNA_dna positively correlated with the frequency of symptom appearance, while his-1_RNA_dna, ENST00000417930, T264761, and T280622 negatively correlated with the maximum wheal diameter. Regression analysis showed T264761 was associated with CSU risk. ROC analysis showed that the specificity of T264761 was 90%, with an area under the curve of 0.666. In follow-up, the rate of well-controlled disease in the low T264761 expression group was 82.61%.

Conclusion

This study established lncRNA and mRNA expression profiles in CSU and identified lncRNAs associated with IP3/DAG pathway, which is mechanistically involved in this disease. T264761 may be a novel biomarker for CSU, but further study is needed to confirm its specific mechanism.

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.

Advances and novel developments in molecular allergology

The continuous search for new allergens and the design of allergen derivatives improves the understanding of their allergenicity and aids the design of novel diagnostic and immunotherapy approaches. This article discusses the recent developments in allergen and epitope discovery, allergy diagnostics and immunotherapy. Structural information is crucial for the elucidation of cross-reactivity of marker allergens such as the walnut Jug r 6 or that of nonhomologous allergens, as shown for the peanut allergens Ara h 1 and 2. High-throughput sequencing, liposomal nanoallergen display, bead-based assays, and protein chimeras have been used in epitope discovery. The binding of natural ligands by the birch pollen allergen Bet v 1 or the mold allergen Alt a 1 increased the stability of these allergens, which is directly linked to their allergenicity. We also report recent findings on the use of component-resolved approaches, basophil activation test, and novel technologies for improvement of diagnostics. New strategies in allergen-specific immunotherapy have also emerged, such as the use of virus-like particles, biologics or novel adjuvants. The identification of dectin-1 as a key player in allergy to tropomyosins and the formyl peptide receptor 3 in allergy to lipocalins are outstanding examples of research into the mechanism of allergic sensitization.

Potential clinical and serological predictors of chronic spontaneous urticaria relapse in patients under omalizumab treatment

Background: Omalizumab is not considered a disease-modifying drug and, accordingly, a large proportion of patients experience a relapse following withdrawal from treatment. Patients & methods: A total of 42 patients who underwent at least one cycle of treatment with omalizumab were enrolled. Two groups of relapsed and not-relapsed subjects were compared. Then, patients were divided into subgroups. Results: Female patients relapse more frequently than male subjects. Patients who relapsed complained a long duration of disease, while patients who did not relapse had short a history of disease. Very early responders are thought to have a high recurrence rate. Basal IgE levels were increased in early responders and cholesterol levels were high in very early responders, who relapse following withdrawal from omalizumab. High D-dimer levels were observed in late responders. Conclusion: The identification of clinical and serological predictors will play a pivotal role in the future management of patients treated with omalizumab.

Improving of psychological status and inflammatory biomarkers during omalizumab for chronic spontaneous urticaria

Background:

Depression and anxiety are the most common psychiatric comorbidities in chronic spontaneous urticaria (CSU). Omalizumab is a monoclonal antibody approved for CSU treatment. We evaluated the prevalence of anxiety and depression in CSU patients before and after treatment with omalizumab.

Materials & methods:

A total of 30 patients were enrolled in the study: 15 patients affected by CSU and treated with omalizumab and the other 15 healthy subjects did not receive any systemic therapy. All patients were evaluated using Hospital Anxiety and Depression Scale, CRP and erythrocyte sedimentation rate, at baseline and after 6 months.

Results:

The omalizumab group after 6 months of therapy had a decrease of all the scores and biomarkers.

Conclusion:

Omalizumab allowed an improvement of urticaria and mental comorbidities.

Depression and anxiety are the most common psychiatric comorbidities in chronic spontaneous urticaria (CSU). We evaluated the prevalence of anxiety and depression in CSU cases and serum levels of inflammatory biomarkers in CSU patients affected also by psychiatric disorders before and after treatment with omalizumab. Omalizumab induced an improvement of urticaria and concurrent mental comorbidities.