Infiltrating cells and related cytokines in lesional skin of patients with chronic idiopathic urticaria and positive autologous serum skin test

Immunopathogenesis of urticaria: a clinical perspective on histamine and cytokine involvement

BACKGROUND

Urticaria is a clinical condition characterized by the appearance of wheals (hives), angioedema, or both. Over the last several decades, a better understanding of the mechanisms at play in the immunopathogenesis of urticaria has underscored the existence of numerous urticaria subtypes. Separating the different kinds of urticaria explicitly helps find the best detection method for the management of this skin disorder. Subtypes of urticaria also include both spontaneous and physical types. The conventional ones include spontaneous urticaria, constituting both acute and chronic urticaria. Therefore, a broad and effective therapy is essential for the diagnosis and treatment of urticaria.

METHODS

To understand the immunopathogenesis of urticaria, various databases, including PubMed, Scopus, and Web of Science, were used to retrieve original articles and reviews related to urticaria. While information on several clinical trials were obtained from clinicaltrials.gov database.

RESULTS

This article highlights the immunopathogenesis involved in the intricate interaction between cellular infiltration, immune reactions, coagulation cascades, and autoantibodies that underlie urticaria's pathophysiology.

CONCLUSION

The recent progress in understanding urticaria can help to understand the intricate characteristics in the immunopathogenesis of urticaria and could play a beneficial role in the management of urticaria.

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.

Beyond Allergies-Updates on The Role of Mas-Related G-Protein-Coupled Receptor X2 in Chronic Urticaria and Atopic Dermatitis

Mast cells (MCs) are an important part of the immune system, responding both to pathogens and toxins, but they also play an important role in allergic diseases, where recent data show that non-IgE-mediated activation is also of relevance, especially in chronic urticaria (CU) and atopic dermatitis (AD). Skin MCs express Mas-related G-protein-coupled receptor X2 (MRGPRX2), a key protein in non-IgE-dependent MC degranulation, and its overactivity is one of the triggering factors for the above-mentioned diseases, making MRGPRX2 a potential therapeutic target. Reviewing the latest literature revealed our need to focus on the discovery of MRGPRX2 activators as well as the ongoing vast research towards finding specific MRGPRX2 inhibitors for potential therapeutic approaches. Most of these studies are in their preliminary stages, with one drug currently being investigated in a clinical trial. Future studies and improved model systems are needed to verify whether any of these inhibitors may have the potential to be the next therapeutic treatment for CU, AD, and other pseudo-allergic reactions.

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

Background

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

Objectives

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

Methods

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

Results

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

Conclusion

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

Chronic 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.

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.

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

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

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

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

Presence of IgE Autoantibodies Against Eosinophil Peroxidase and Eosinophil Cationic Protein in Severe Chronic Spontaneous Urticaria and Atopic Dermatitis

Purpose

Eosinophils are frequently found in atopic dermatitis (AD) and chronic spontaneous urticaria (CSU) that release eosinophil peroxidase (EPX) and eosinophil cationic protein (ECP). Continuous exposure to these proteins could trigger an autoimmune response which may contribute to the pathogenesis and severity of skin inflammation. In this study, we investigate the immunoglobulin E (IgE) response against eosinophil proteins in CSU and AD.

Methods

We recruited patients with severe AD, severe CSU and healthy subjects to explore the presence of IgE autoantibodies and cross-reactivity against EPX, ECP and thyroid peroxidase (TPO). The potential cross-reactive epitopes among the peroxidase family were determined using in silico tools.

Results

The frequencies of anti-EPX IgE (28.8%) and anti-ECP IgE (26.6%) were higher in the AD group, and anti-TPO IgE was higher in the CSU group (27.2%). In the CSU group, there was a correlation between the anti-EPX IgE and anti-TPO IgE levels (r = 0.542, P < 0.001); TPO inhibited 42% of IgE binding to EPX, while EPX inhibited 59% of IgE binding to TPO, suggesting a cross-reactivity with EPX as a primary sensitizer. There was greater inhibition when we used a pool of sera CSU and AD, TPO inhibited 52% of IgE binding to EPX, while EPX inhibited 78% of IgE binding to TPO. In silico analysis showed a possible shared epitope in the peroxidase protein family.

Conclusions

IgE against eosinophil proteins may contribute to chronic inflammation in patients with AD and CSU. Cross-reactivity between EPX and TPO could explain thyroid problems in CSU patients.

A novel histopathological scoring system to distinguish urticarial vasculitis from chronic spontaneous urticaria

Background

Urticarial vasculitis (UV) is defined by long‐lasting urticarial lesions combined with the histopathologic findings of leukocytoclastic vasculitis. As one of the major unmet needs in UV, diagnostic criteria are rather vague and not standardized. Moreover, there seems to be considerable overlap with chronic spontaneous urticaria (CSU), particularly for the normocomplementemic variant of UV. Therefore, this study aimed to develop a diagnostic scoring system that improves the histopathologic discrimination between UV and CSU.

Methods

Lesional skin sections of patients with clinical and histopathologic diagnosis of UV (n = 46) and CSU (n = 51) were analyzed (blinded to the diagnosis) for the following pre‐defined criteria: presence of leukocytoclasia, erythrocyte extravasation, fibrin deposits, endothelial cell swelling, ectatic vessels, blurred vessel borders, dermal edema, intravascular neutrophil, and eosinophil numbers and numbers of dermal neutrophils, macrophages and mast cells.

Results

The greatest differences between UV and CSU samples were observed for leukocytoclasia (present in 76% of UV vs. 3.9% of CSU samples; p < 0.0001), erythrocyte extravasation (present in 41.3% of UV vs. 2.0% of CSU samples; p < 0.0001), and fibrin deposits (present in 27.9% of UV vessels vs. 9.7% of CSU vessels; p < 0.0001). Based on these findings, we developed a diagnostic score, the urticarial vasculitis score (UVS), which correctly assigned 37 of 46 cases of UV and 49 of 51 cases of CSU to the previously established diagnosis.

Conclusion

Our results suggest that the UVS, a combined quantitative assessment of the three criteria leukocytoclasia, fibrin deposits and extravasated erythrocytes, distinguishes UV from CSU in skin histopathology. The UVS, if validated in larger patient samples, may help to improve the diagnostic approach to UV.

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

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

Mediators of Inflammation and Angiogenesis in Chronic Spontaneous Urticaria: Are They Potential Biomarkers of the Disease?

In chronic spontaneous urticaria (CSU), different pathophysiological mechanisms, potentially responsible for the development of the disease, have been recently described. It is likely that the activation of skin mast cells with consequent release of histamine and other proinflammatory mediators is responsible for vasodilation in the lesional skin of CSU. However, the underlying causes of mast cell activation in the disease are largely unknown and remain to be identified. Thus, in this review, we discuss new insights in the pathogenesis of CSU, focusing on inflammation and angiogenesis. The understanding of these mechanisms will enable the identification of biomarkers useful for the diagnosis, follow-up, and management of CSU and will allow the development of novel, more specific, and patient-tailored therapies.

Analysis of the changes in Th9 cells and related cytokines in the peripheral blood of spontaneous urticaria patients

Spontaneous urticaria (SU) is characterized by immune deregulation of mast cells and T helper (Th) cells. Th9 cells, a subset of Th cells, serve a key role in initiating mast cell accumulation and activation. To understand the role of Th9 cells in the pathogenesis of SU, the authors conducted a control study of 28 patients with acute SU (ASU) and chronic SU (CSU) and 28 healthy controls. The percentage of Th9 cells in peripheral blood was assessed using flow cytometry and levels of Th9 related serum cytokines including interleukin (IL)-4, IL-9, IL-17A, IL-33, IL-1β and transforming growth factor-β1 (TGF-β1) using Luminex 200. ASU patients exhibited higher percentages of Th9 cells and increased serum levels of cytokines IL-9, IL-4 and TGF-β1 compared to healthy controls. In addition, high mRNA expression of the PU.1 transcription factor was observed in ASU patients. However, the percentage of Th9 cells was similar between patients with CSU and healthy controls. Furthermore, the percentage of Th9 cells demonstrated a positive correlation with IL-4 and IL-9 levels in the peripheral blood of ASU patients, but not with disease severity. The current findings suggested that the numbers of Th9 cells increased in ASU patients and indicated its novel role in the pathogenesis of ASU.

Cellular Infiltrate and Related Cytokines, Chemokines, Chemokine Receptors and Adhesion Molecules in Chronic Autoimmune Urticaria: Comparison between Spontaneous and Autologous Serum Skin Test Induced Wheal

In recent years, the demonstration of circulating functional autoantibodies against the high affinity IgE receptor or against IgE themselves in about one-third of patients with chronic idiopathic urticaria has suggested that an autoimmune mechanism might be involved in the pathogenesis of the disease [the so-called chronic autoimmune urticaria (CAIU)]. In this study we compare findings from serum-induced and spontaneous wheals with regard to immunohistochemical markers of disease activity and discuss whether autologous serum skin test (ASST) may be regarded as an in vivo experimental model of the physiological stimulus causing urticaria skin condition, or if it does not reproduce the whole of the mechanisms operating in the development of spontaneous wheals. By means of immunohistochemical technique, we analyzed specimens from just-developed spontaneous wheals and from serum-evoked wheals of six CAIU patients, to glean information on cellular infiltrate and related cytokines, chemokines, chemokine receptors and adhesion molecules. According to the results of our study, spontaneous urticaria lesions seem to be sustained by a characteristic inflammation pattern where neutrophils, adhesion molecules, IL-8 and chemokine receptors play a main role in flogosis triggering and, consequently, disease development. On the contrary, ASST-induced wheals seem to imply different activities mainly represented by basophil granulocytes and related molecules, i.e. IL-4. Although it represents an efficacious diagnostic instrument to screen CAIU patients, ASST is not an exhaustive model of the many immunopathogenic pathways operating in the development of urticaria lesions, especially with regard to systemic activation networks.

Identification of a Th2- and Th17-skewed immune phenotype in chronic urticaria with Th22 reduction dependent on autoimmunity and thyroid disease markers

BACKGROUND

Chronic urticaria is a condition with many inciting factors and often presents a therapeutic challenge to clinicians. In addition to a central role for mast cells, an immune dysregulated state related to cytokine/chemokine alterations is increasingly being recognized.

METHODS

Biopsies of chronic urticaria (n = 11) and normal skin (n = 5) were evaluated with immunostains for CD117, CD3 and dual stains for CD4/T-bet, GATA-3, STAT-3 or BNC-2 (transcription factors specific and mutually exclusive for Th1, Th2, Th17 and Th22 cells, respectively). Clinical data, including autoantibodies and thyroid function tests, and the number of CD117+ mast cells and percent of Th1, Th2, Th17 and Th22 of CD3+ T-cells were compared.

RESULTS

Th2 cells and Th17 cells were significantly more frequent in chronic urticaria than controls. In contrast, there was no significant difference in mast cells, Th1 cells or Th22 cells. Three of nine chronic urticaria patients had evidence of autoimmune disease; biopsies from these patients trended toward a greater number of mast cells and decreased percent of Th-cell subtypes as compared with those without autoimmunity markers, with significantly less Th22 cells.

CONCLUSIONS

These findings provide novel insight into the role of Th2 and Th17 in chronic urticaria pathophysiology and may impact therapy.

Immunological events in chronic spontaneous urticaria

Chronic spontaneous urticaria (CSU) is a highly debilitating skin disease associated with systemic features. We have made significant progress in several aspects relating to this condition. However, the exact physiopathology remains unknown. There is mounting evidence for an autoimmune basis, demonstrated by the CSU serum ability to activate healthy donors skin mast cells and blood basophils. However, it is only seen among 35–40% of patients. Mast cells and basophils play an important role in this skin condition. Both cells in CSU patients have unique features that differentiate them from basophils and mast cells from healthy donors. In the case of basophils, basopenia is typically found in CSU patients. Basophils from CSU patients also tend to be hyporesponsive to stimuli that act through the IgE receptor, responsive to other stimuli as MCP-1 or C5a, and hyperesponsive when incubated with sera. Eosinophils are also present in CSU skin biopsies, yet their exact role has not yet been defined. Likewise, endothelial cells also play a function, as indirectly demonstrated by an increase of vasoactive peptides in skin and plasma of CSU patients’ samples. All these facts orchestrate a systemic inflammation response producing a significant increase of several inflammatory markers. Unfortunately, we lack a unitary model that could explain the exact role of each of these players. In this review, we will describe the history and discover the pathway to the present knowledge on the immunological facts of this disease.

Chronic idiopathic angioedema: a single center experience

OBJECTIVE

Chronic idiopathic angioedema (CIA) is defined as three or more episodes of angioedema in a period of > 6 months without a clear etiology. In the study, we tried to explore clinical and laboratory characteristics of patients with CIA unaccompanied by urticaria.

METHODS

We retrospectively reviewed clinical and laboratory characteristics of 1238 patients with chronic urticaria and/or angioedema referred to our allergy clinic.

RESULTS

Eight hundred and forty-one (67.9%) subjects had chronic urticaria without angioedema (CU Group), 323 (26.1%) had both urticaria and angioedema (CU + CA group), and 74 (5.9%) had chronic angioedema without urticaria (CA). In 29 (39.2%) cases of CA, no etiologic factor of angioedema was discovered, thus the patients were defined as having chronic idiopathic angioedema (CIA Group). Twenty-two (75.8%) subjects had antihistamine-responsive CIA and seven (24.1%) had antihistamine-unresponsive CIA. There were no statistically significant differences in clinical (except of urticarial eruptions) and laboratory characteristics between CU, CA + CU, and CIA groups. Antihistamine responsive and antihistamine-unresponsive CIA groups had no distinguishable clinical or laboratory features.

CONCLUSIONS

We suppose that CIA, at least its antihistamine-responsive form, represents a rare form of chronic spontaneous urticaria. The reasons why in CIA there are no other clinical signs of mast cell/basophil activation, such as pruritus, urticarial, and dermatographism, are largely unknown and have to be elucidated in future studies.

Chronic spontaneous urticaria: etiology and pathogenesis

Urticaria affects individuals of all ages and is commonplace. Nearly 1 in 5 individuals will experience an episode of urticaria in their lifetime, while the chronic form of disease has an estimated annual prevalence of approximately 1% of the population. Given the similarity of chronic urticaria symptoms to those seen in patients suffering an allergic reaction, the condition often leads to a search for an external cause. In most cases, no external trigger factor is identified. At present several theories of pathogenesis exist, none of which is firmly established.

CCL5/RANTES, sVCAM-1, and sICAM-1 in chronic spontaneous urticaria

BACKGROUND

Chronic urticaria (CU) is a common disease characterized by recurrent itchy wheals and/or angioedema for more than 6 weeks. We aimed to investigate the potential involvement of chemotactic mediators and soluble adhesion molecules as markers of endothelial dysfunction in the pathogenesis of chronic spontaneous urticaria (CSU). The potential relevance of these soluble mediators in the evaluation of disease activity was also investigated.

METHODS

We measured the levels of CCL5/RANTES, CXCL8/IL-8, sVCAM-1, and sICAM-1 in the sera of 87 patients with CSU and 61 normal healthy subjects (NHS) using ELISA assays. According to the results of autologous serum skin tests (ASST), CSU patients were classified into ASST-positive and ASST-negative subgroups. Furthermore, we investigated in 4 patients whether H₁-antihistamine therapy decreases sVCAM-1 and sICAM-1 levels.

RESULTS

We detected a significantly higher concentration of CCL5/RANTES (p < 0.0001) but not of CXCL8/IL-8 in CSU patients compared to NHS. The serum levels of sICAM-1 and sVCAM-1 were significantly increased in CSU patients compared to NHS (p = 0.0121 and p = 0.0043, respectively). No difference in chemokine or soluble adhesion molecule levels was detected between the ASST-positive and ASST-negative subgroups. A positive correlation was found between sICAM-1 and sVCAM-1 (p = 0.0022) but not between these and CCL5/RANTES. After H₁-antihistamine therapy, sVCAM-1 and sICAM-1 levels did not decrease in the 4 CSU patients tested.

CONCLUSIONS

Our study suggests that CCL5/RANTES, sICAM-1, and sVCAM-1 play a potential role in the pathogenesis of CSU but they do not parallel disease activity and are not predictive of the response to H₁-antihistamine therapy.

mRNA profiles of cytokine receptors in unstimulated peripheral blood mononuclear cells from patients with chronic idiopathic urticaria

This present study was aimed to investigate the roles of the receptors of Th1/Th2 cytokines and chemokines in the pathogenesis of chronic idiopathic urticaria (CIU). Thirty patients with CIU, 30 patients with dermographism and 30 healthy controls were randomly enrolled. Reverse transcription-PCR (RT-PCR) was used to analyze the mRNA of cytokine receptors in peripheral blood mononuclear cells (PBMCs). The mRNA levels of tumor necrosis factor receptor (TNFR), interferon-γ receptor (IFN-γR), and interleukin-10 receptor (IL-10R) were statistically increased in the CIU group (P < 0.05), while IL-2R, IL-4R, IL-6R, and IL-13R showed no significant differences between the CIU and other groups. The mRNA levels of CCR3 and CCR6 were statistically increased in the CIU group (P < 0.05). The toll-like receptor 2 (TLR2) mRNA level was significantly lower in the CIU group than the healthy control group (P < 0.05). These findings indicate that the regulation of mRNA of TNFR, IFN-γR, IL-10R, CCR3, CCR6 and TLR2 may be involved in the pathogenesis of CIU.

Serum concentration of IL-17, IL-23 and TNF-α among patients with chronic spontaneous urticaria: association with disease activity and autologous serum skin test

BACKGROUND

Chronic spontaneous urticaria (CSU) is a common skin disorder, which is considered in a subset of patients to be an autoimmune disorder. T helper 17 (Th17) cells are crucially involved in the pathogenesis of some autoimmune diseases.

OBJECTIVES

Our aim was to test the association of Th17 with CSU. We examined interleukin (IL)-17, IL-23 and tumor necrosis factor-alpha (TNF-α) serum levels in CSU patients and studied their association with urticaria activity and autologous serum skin test (ASST).

SUBJECTS AND METHODS

Serum concentration of IL-17, IL-23 and TNF-α were measured in 75 patients with CSU and 30 healthy control subjects. Disease activity was assessed by using urticaria activity score (UAS) as recommended by EAACI/GA(2)LEN/EDF/WAO Guidelines.

RESULTS

Serum concentration of IL-17, IL-23 and TNF-α were significantly higher in CSU patients as compared with the healthy control subjects (mean: 35.51 ± 31.14 vs. 4.60 ± 1.38 pg/mL; P < 0.001, 38.95 ± 27.82 vs. 9.87 ± 4.62 pg/mL; P > 0.001 and 17.93 ± 6.05 vs. 6.87 ± 3.73 pg/mL; P = 0.004, respectively). There were significant positive correlation between serum IL-17, IL-23, TNF-α and disease activity assessed by cumulative UAS for 7 days before blood sampling. The Serum concentration of IL-17, IL-23 and TNF-α were also significantly higher in ASST positive patients than in ASST negative patients.

CONCLUSION

Our results showed high serum levels of IL-17, IL-23 and TNF-α among CSU patients which may highlight a functional role of these cytokines in the pathogenesis of this important and common skin disease. It also may provide the rationale for new treatment strategies in chronic urticaria.

Narrowband ultraviolet B (311 nm, TL01) phototherapy in chronic ordinary urticaria

BACKGROUND

Chronic ordinary urticaria (COU) can severely reduce quality of life and be difficult to control. Ultraviolet (UV) A and UVB phototherapy has been reported to decrease the release of histamine from either mast cells and/or basophils. Previous small studies have suggested that UVB phototherapy is a good alternative treatment for COU.

OBJECTIVES

The purpose of this study was to assess the efficacy of narrow-band UVB (NB-UVB) phototherapy for COU.

MATERIALS AND METHODS

Twenty-two patients (three male, 19 female) received NB-UVB phototherapy. These patients had not responded to at least two H1 antihistamines, and most had been treated with a variety of antihistamine combinations. Clinical responses were assessed according to an outcome scoring scale. During both visits, patients were administered the following: the visual analogue scale (VAS) on present pruritus and/or whealing; chronic urticaria impact on patients' quality of life according to the interference with daily activities, quality of sleep, and flare-up rates.

RESULTS

The median number of treatments was 31.4 (9-44), and the mean top dose was 9.46 J/cm(2) (1.1-16.4 J/cm(2)). NB-UVB treatment led to clearance in 10 patients (45%), marked improvement in five (22%), and moderate improvement in seven (31%) patients according to an outcome scoring scale. Mild side effects were observed in two patients. Six patients who cleared or observed marked improvement remained clear at follow-up for a period of six months to one year, and other patients had a few recurrent lesions that did not need retreatment. For VAS scores and total chronic urticaria impact on patients' quality of life scores, the differences between baseline and after treatment scores were significantly lower (P < 0.001, P < 0.001, respectively).

CONCLUSION

Narrow-band UVB (NB-UVB) therapy is an effective, well-tolerated treatment option in second-line therapy for COU. This therapy can lead to subjective relief of pruritus and whealing and objective reduction of whealing. Further larger studies with longer follow-up periods are necessary to determine the proper clinical response and long-term complications of this therapy in COU.

Increased mean platelet volume and C-reactive protein levels in patients with chronic urticaria with a positive autologous serum skin test

INTRODUCTION

Activation of the coagulation cascade resulting in thrombin production is a prominent feature of exacerbations in chronic spontaneous urticaria (CU). Autologous serum skin test (ASST) causes wheal-and-flare reactions in 30% to 50% of CU cases.

OBJECTIVE

The aim of this study was to evaluate the clinical and laboratory data in patients with CU with positive and negative ASST. To understand the role of platelets in CU, we investigated the relation between CU clinical severity, platelet count and their mean platelet volume (MPV).

METHODS

Clinical and laboratory data were prospectively collected from 373 patients with CU who attended our Allergy and Clinical immunology Clinic during the period 2003 to 2007. The laboratory data were compared with 46 healthy subjects.

RESULTS

There were no significant differences in platelet counts between the groups, nevertheless the platelets in ASST-positive CU patients were characterized by a higher MPV (9.12 +/- 1.25 fl), than that in ASST-negative patients (7.95 +/- 1.08 fl; P = 0.039) and control group (7.72 +/- 1.04 fl; P = 0.007). There was a significant positive correlation between CU severity score and MPV in ASST-positive patients (r = 0.44; P < 0.001) but not in ASST-negative patients. Higher levels of C-reactive protein (5.31 +/- 2.74 mg/L) were measured in the ASST-positive CU group compared with the ASST-negative CU group (2.53 +/- 1.27; P = 0.029) and the control group (2.34 +/- 1.38; P = 0.003).

CONCLUSION

CU with positive ASST is characterized with higher clinical severity, increased MPV and C-reactive protein.

Clinical evaluation and treatment of chronic urticaria

Chronic urticaria is a common disease characterized by recurrent pruritic wheals with surrounding erythema for >6 weeks. It is associated with a significant health care burden and affects patient quality of life. The etiology of chronic urticaria is often difficult to elucidate; however, known etiologies include autoimmune urticaria, physical urticarias (eg, cold, cholinergic, and delayed pressure urticaria), and idiopathic urticaria. The etiology is unknown in many patients, leading to a diagnosis of chronic idiopathic urticaria. The diagnosis of chronic idiopathic urticaria can be challenging for the primary care physician because of the disease's chronic symptoms. Diagnosis requires a detailed patient history and comprehensive physical examination, with additional testing tailored to the patient's history. Effective treatments include antihistamines, leukotriene receptor antagonists in combination with antihistamines, and oral immunomodulatory drugs, including corticosteroids, cyclosporine, dapsone, hydroxychloroquine, and sulfasalazine. Newer experimental therapies include intravenous immunoglobulin and omalizumab. This article reviews the pathophysiology, diagnosis, and treatment of chronic urticaria.

Basophil responsiveness in chronic urticaria

Chronic urticaria is a common skin disease without an etiology in the majority of cases. The similarity of symptoms and pathology to allergen-induced skin reactions supports the idea that skin mast cell and blood basophil IgE receptor activation is involved; however, no exogenous allergen trigger has been identified. Recent evidence supports a role for blood basophils in disease expression. Specifically, blood basopenia is noted in active disease with the recruitment of blood basophils to skin lesional sites. In addition, blood basophils display altered IgE receptor-mediated degranulation that reverts in disease remission. In active chronic idiopathic urticaria (CIU) subjects, changes in IgE receptor-signaling molecule expression levels accompany the altered degranulation function in blood basophils. The arrival of therapies targeting IgE has further shown that altered blood basophil degranulation behavior has potential use as a disease biomarker in CIU.

New concepts in chronic urticaria

Chronic urticaria is a common skin disease without a clear etiology in the vast majority of cases. The similarity of symptoms and lesion pathology to allergen-induced skin reactions supports the idea that skin mast cell and blood basophil IgE receptor activation is involved; however, no exogenous allergen trigger has been identified. The presence of serum IgG autoantibodies targeting IgE or the IgE receptor in approximately 40% of CIU cases supports the theory of an autoimmune basis for the disease. However, issues remain with the assays to detect autoantibodies among other serum factors, the relationship of autoantibodies to CIU disease activity, and the occurrence of autoantibodies in healthy subjects. Other studies have identified altered IgE receptor degranulation that reverts in disease remission and is accompanied by changes in signaling molecule expression and function in mast cells and basophils in active CIU subjects. The arrival of therapies targeting IgE and the IgE receptor pathway elements has potential use in CIU.

Stress-induced neurogenic inflammation in murine skin skews dendritic cells towards maturation and migration: key role of intercellular adhesion molecule-1/leukocyte function-associated antigen interactions

The skin continuously serves as a biosensor of multiple exogenous stressors and integrates the resulting responses with an individual's central and peripheral endogenous response systems to perceived stress; it also acts to protect against external challenges such as wounding and infection. We have previously shown in mice that stress induces nerve growth factor- and substance P-dependent neurogenic inflammation, which includes the prominent clustering of MHC class II(+) cells. Because the contribution of dendritic cells (DCs) in response to stress is not well understood, we examined the role of DCs in neurogenic inflammation in murine skin using a well-established murine stress model. We show that sound stress increases the number of intradermal langerin(+) and CD11c(+) DCs and induces DC maturation, as indicated by the up-regulated expression of CD11c, MHC class II, and intercellular adhesion molecule-1 (ICAM-1). Blocking of ICAM-1/leukocyte function-associated antigen-1 interactions significantly abrogated the stress-induced numeric increase, maturation, and migration of dermal DCs in vivo and also reduced stress-induced keratinocyte apoptosis and endothelial cell expression of ICAM-1. In conclusion, stress exposure causes a state of immune alertness in the skin. Such adaptation processes may ensure protection from possible infections on wounding by stressors, such as attack by predators. However, present-day stressors have changed and such adaptations appear redundant and may overrun skin homeostasis by inducing immune dermatoses.

Defective functions of circulating CD4+CD25+ and CD4+CD25- T cells in patients with chronic ordinary urticaria

BACKGROUND

Patients with chronic ordinary urticaria (CU) are divided into two groups: 30-50% have chronic autoimmune urticaria, and the remainder have chronic idiopathic urticaria. CD4(+)CD25(+) regulatory T (Treg) cells play critical roles in maintaining peripheral tolerance and preventing autoimmunity, but the characteristics of Treg cells have not yet been defined in CU.

OBJECTIVE

To identify whether CD4(+) T cells play an important immunoregulatory role in the etiology of CU, we determined the frequencies and functions of circulating CD4(+)CD25(+) and CD4(+)CD25(-) T cells in CU patients and healthy control subjects, with special focus on the characteristics of CD4(+)CD25(+) T cells.

METHODS

Peripheral blood mononuclear cells (PBMCs) were obtained from CU and healthy controls in this study. The frequency of CD4(+)CD25(+) T cells in PBMCs was detected by flow cytometry. The expression levels of forkhead box P3 (FOXP3) and transforming growth factor-beta (TGF-beta) in CD4(+)CD25(+) T cells were detected by real-time PCR. Furthermore, the suppressive function of CD4(+)CD25(+) T cells was analyzed. Additionally, the Th1/Th2 cytokine secretory profile in mitogen-stimulated CD4(+)CD25(-) T cells was measured by ELISA.

RESULTS

An increased frequency of CD4(+)CD25(+) T cells was observed in CU patients (n=19) compared to control subjects (n=7). No significant difference was detected in the expression levels of FOXP3 or TGF-beta between CU patients (n=14) and control subjects (n=7). Strikingly, the suppressive capacity of CD4(+)CD25(+) Treg cells from 2 of 5 CU patients was partially defective. We also found that cytokine production from CD4(+)CD25(-) T cells was significantly reduced in CU patients (n=9) compared to healthy donors (n=11).

CONCLUSIONS

Our data demonstrate that CD4(+)CD25(+) and CD4(+)CD25(-) T cells in PBMCs exhibit defective functions in CU patients.

Prospective randomized non-blinded clinical trial on the use of dapsone plus antihistamine vs. antihistamine in patients with chronic idiopathic urticaria

BACKGROUND

Treatment of chronic idiopathic urticaria (CIU) is difficult.

OBJECTIVE

The purpose of this study was to evaluate the efficacy and safety of dapsone in CIU.

METHODS

The response to dapsone was evaluated in 65 CIU patients with a randomized, two armed study: 3-month dapsone + desloratadin and 3-month desloratadin. All were followed for up to 3 months and 3 months after; all took desloratadine 10 mg daily throughout the study. The primary measure of efficacy was a daily urticaria activity score (UAS) of weal numbers and itch (maximum score, 42 per week).

RESULTS

Sixty-five patients completed the randomized 3-month trial medication. Mean reduction in UAS from baseline at 3 months was 7 [95% confidence interval (95% CI), 6.92-7.08] for active group and 5.77 (95% CI, 5.47-6.08) for control subjects (P < 0.001). The reduction in visual analogue score (VAS) at 3 months for active group (mean, 2.58; 95% CI, 2.33-2.83) and control subjects (mean, 2.55; 95% CI, 2.38-2.73) was also significant (P < 0.001). The reduction of UAS and VAS at 3 months compared between active group and control subjects showed no significant difference. Mean reduction in UAS from the end of the study at 3 months after was 1.16 and -4.8 for active and control subjects, respectively. These results were compared with each other, and it was statistically significant (P <or= 0.05).

LIMITATIONS

No placebo was used. The study was not blinded. Lack of blinding may have led to bias. The follow-up period was short.

CONCLUSION

This study shows that dapsone leads to a persistent decrease in VAS and UAS and is associated with complete remission in some patients.

Cellular adhesion molecules in chronic urticaria: modulation of serum levels occurs during levocetirizine treatment

BACKGROUND

Some antihistamines are capable of reducing levels of adhesion molecules in wealing tissues of patients with chronic urticaria (CU).

OBJECTIVES

To determine if 6 weeks of therapy with levocetirizine 5 mg once daily would also induce any decrease in serum levels of intercellular adhesion molecule-1, vascular cell adhesion molecule-1, endothelial leucocyte adhesion molecule-1 (ELAM-1) or P-selectin in subjects with CU and chronic autoimmune urticaria.

METHODS

Thirty-six patients with CU (18 with positive and 18 with negative autologous serum skin test) were studied, together with 10 control healthy subjects. All patients received levocetirizine 5 mg daily. Serum soluble cellular adhesion molecule (CAM) levels were determined by immunoenzymatic assay before and after the end of the study period. Disease activity was recorded according to the EAACI/GA(2)LEN/EDF scoring system.

RESULTS

After levocetirizine therapy CAM levels decreased in patients with CU, significantly in the cases of ELAM-1 and P-selectin. Patients' clinical scores improved during regular antihistamine therapy.

CONCLUSIONS

Levocetirizine 5 mg daily demonstrated a broad anti-inflammatory effect in patients with CU. The significant decrease in serum levels of ELAM-1 and P-selectin might reflect the inhibitory activity on neutrophil rolling and extravasation towards inflamed skin.

The comparative effects of tacrolimus and hydrocortisone in adult atopic dermatitis: an immunohistochemical study

BACKGROUND

While many studies have demonstrated the efficacy and safety of tacrolimus ointment in the treatment of atopic dermatitis (AD), only a few have investigated the effects of tacrolimus on inflammatory cells and their cytokine gene expression in patients with AD.

OBJECTIVES

To characterize further the immunophenotype of infiltrating cells and the production of certain cytokines before and after treatment with topical tacrolimus and hydrocortisone butyrate.

METHODS

Nine adult patients with moderate to severe AD were treated with tacrolimus ointment, while seven control patients were treated with hydrocortisone butyrate ointment. We performed lesional skin biopsies before and after treatment. These were stained immunohistochemically with a panel of monoclonal antibodies including those to CD1a, CD3, CD4, CD8, myeloperoxidase, EG1, EG2, tryptase, interferon-gamma, interleukin (IL)-4, IL-5, IL-12, IL-13, receptors for CXC chemokines (CXCR) 3 and 4, and receptor 3 for CC chemokines.

RESULTS

CD3+, CD4+ and CD8+ lymphocytes, and eosinophil and neutrophil granulocytes were significantly reduced in post-treatment tacrolimus specimens, while CD1a+ cells and mast cells were not. The expression of cytokines and chemokine receptors tested, except for CXCR3, was diminished by tacrolimus treatment. Moreover, tacrolimus produced a greater reduction of lymphocytes, eosinophils and most cytokines than that induced by hydrocortisone butyrate.

CONCLUSIONS

Tacrolimus not only inhibits T-lymphocyte proliferation and cytokine production, but also plays an important role in the IL-12-induced shift from a T-helper (Th) 2 to a Th1 cytokine profile that characterizes the development of chronic AD. Tacrolimus also demonstrates wider pharmacodynamic effects than hydrocortisone.

The CD40/CD40 ligand system is expressed in the cutaneous lesions of erythema multiforme and Stevens-Johnson syndrome/toxic epidermal necrolysis spectrum

BACKGROUND

Erythema multiforme (EM) and Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN) are determined by a dysregulation of cellular immunity.

OBJECTIVES

To evaluate the effector role of cellular immunity and the involvement of the CD40/CD40 ligand (CD40L) system in the pathogenesis of EM and SJS/TEN.

METHODS

Biopsy specimens from eight patients with EM and six with SJS/TEN were stained for immunohistochemical examination using the alkaline phosphatase/antialkaline phosphatase method. The monoclonal antibodies used included those to CD1a, CD4, CD8, CD40, CD40L, CD68, Fas, Fas ligand (FasL) and myeloperoxidase.

RESULTS

The cellular infiltrate in both EM and SJS/TEN lesions was composed mainly of T lymphocytes and CD68+ macrophages. We also detected large amounts of neutrophils. Fas and FasL were very highly expressed in SJS and TEN, but weakly in EM. CD40 staining was strong in all tissue sections; there were numerous CD40L+ cells in SJS/TEN but much fewer in EM.

CONCLUSIONS

Activated T lymphocytes and macrophages, but also neutrophils, are presumably the main triggers of mucocutaneous damage in the SJS/TEN disease spectrum. The Fas/FasL system is significantly expressed in SJS/TEN lesions, but not in EM, where this apoptotic pathway presumably does not play a pivotal role in the epidermal damage. We suggest that the CD40/CD40L system may represent an important pathway of induction of SJS/TEN lesions, while in EM it would contribute to the immunoinflammation only as a second-line mechanism.

Chronic urticaria is associated with mast cell infiltration in the gastroduodenal mucosa

Chronic urticaria (CU) is characterized by recurrent itching skin eruptions caused by mast cell degranulation. Relapses can be provoked by food intake. The aim of this study was to investigate if the mast cell number in the gastroduodenal mucosa is increased in CU patients, and whether mast cell counting by pathologists is clinically useful. We defined two study groups: 50 disease controls (16 Belgians and 34 Italians) and 43 Belgian CU patients. Mast cells were detected using immunohistochemistry for tryptase and CD117. The mast cell number in the disease controls was 20.2/high-power filed (HPF; 133.3/mm2) in the stomach and 32.5/HPF (209.2/mm2) in the duodenum. There was no difference between Belgian and Italian controls, indicating that dietary habits have no influence on the normal gastroduodenal mast cell number. In CU patients, mast cell numbers were significantly higher: 32.4/HPF (186.0/mm2) in the stomach (P<0.0001) and 44.8/HPF (246.0/mm2) in the duodenum (P=0.0002). CU is thus associated with mast cell infiltration in the gastroduodenal mucosa, even if patients do not have gastrointestinal symptoms. Mast cell counting in gastroduodenal biopsies of CU patients can be useful in selecting patients who may respond to a therapy with intestinal mast-cell-stabilizing agents.

Basophils and mast cells in chronic idiopathic urticaria

Chronic idiopathic urticaria (CIU) is diagnosed in patients when urticarial eruptions recur for more than 6 weeks, and no specific cause is determined. Given that urticaria resembles the lesions induced by injection of histamine or allergen into the skin, a role for mast cells or basophils has been proposed in the generation of localized urticarial lesions. However, currently, the exact mechanisms governing regional mast cell or basophil activation are unknown. In the past decade, there has been mounting interest in viewing CIU as an autoimmune disease, given the presence of circulating autoantibodies to IgE or the alpha subunit of the high-affinity IgE receptor (FceRI) in a subset of patients. In this review, we propose that in addition to autoantibodies, specific differences in the expression of FceRI-signaling molecules in the basophils or mast cells of CIU patients may contribute to the generation of urticarial eruptions.

Chronic idiopathic urticaria: infiltrating cells and related cytokines in autologous serum-induced wheals

The term chronic autoimmune urticaria (CAIU) is used for chronic urticaria in subjects who present a whealing response to the intradermal injection of autologous serum, suggesting the presence of pathogenic antibody activities. In this study, we examined 28 chronic urticaria subjects with positive autologous serum skin test (ASST), all of whom presented autologous serum-induced lesions at different evolutive stages. Punch biopsies were taken from lesional skin of six subjects at 10', eight subjects at 30', six subjects at 60', and four subjects each at 24 and 48 h. Immunological studies focussed on infiltrating cell immunophenotype and related cytokines, chemokines and chemokine receptors, adhesion molecules. Immunohistochemical staining was performed to measure expression of CD3, CD4, CD8, tryptase, eosinophil cationic protein, myeloperoxidase, basophil granular protein, IL-4, IL-5, IL-8, CCR3 and CXCR3, ICAM-1, VCAM and ELAM. Control staining was done on unaffected skin from the patients and normal skin from four healthy donors. The main infiltrating population was represented by neutrophils, seen focally in both unaffected skin (P = 0.001) and healthy controls (P = 0.003). IFN-gamma and IL-5 were expressed focally in autologous wheals. Significant staining for IL-4 was seen at 30'. CCR3 and CXCR3 were expressed less in autologous wheals than in uninvolved skin (P < 0.0001; P = 0.002). Cellular adhesion molecules (CAMs) reached their highest expression at 30' and 60' in induced lesions, and they showed strong expression also in unaffected skin (ICAM-1: P < 0.0001). Our data show that the immunoinflammatory features of ASST-induced wheals involve a prevalent role of lymphocytes (with a mixed Th1/Th2 response), with strong neutrophil infiltration and activity and involvement of the chemokine pathway. We interpreted the finding of inflammatory cells and mediator up-regulation in uninvolved CIU skin as a sign of prolonged and widespread "urticarial status".