Secretion of cytokines, histamine and leukotrienes in chronic urticaria

Leukotriene receptor antagonists as adjuvant therapy of antihistamines in chronic urticaria: a systematic review and meta-analysis

Certain guidelines recommend a second-generation H1-antihistamine (AH) as first-line treatment for patients with chronic urticaria (CU). However, some patients show insufficient response to a standard dose of this therapy and might benefit from adding leukotriene receptor antagonists (LTA). Therefore, we aimed to perform a systematic review and meta-analysis comparing LTA plus antihistamines with antihistamines alone. We performed a systematic review and meta-analysis, searching PubMed, EMBASE, and Cochrane Central for randomized clinical trial (RCT) data comparing LTA plus AH treatment to AH alone in patients with CU. Statistical analysis was performed using R Studio 4.3.2. Heterogeneity was assessed with I2 statistics. Three studies comprising 234 patients with urticaria were included. The mean age was 37.23 years in the leukotriene antagonist + antihistamines (LTA + AH) group and 39.14 years in the antihistamines (AH) group. Follow-up ranged from 2 to 18 months between studies. There was no statistically significant difference between groups in terms of TSS level (SMD: -74.82; 95% CI: -222.66 to 73.02; P = 0.32; I2 = 98%), neither in terms of pruritus (MD: -0.07; 95% CI: -0.42 to 0.28; P = 0.70; I2 = 74%). After sensitivity analysis, with the systematic exclusion of each study from the grouped estimates, the result for TSS level did not change. These findings suggest that leukotriene receptor antagonists with antihistamines do not have better outcomes than antihistamines alone regarding TSS and pruritus in patients with CU.

Atopy in chronic urticaria: an important yet overlooked issue

Chronic urticaria (CU) is one of the most common dermatological diseases and has a significant impact on the quality of life of patients. However, the pathogenesis of this disease remains unclear. Autoimmunity in chronic spontaneous urticaria (CSU) has received considerable attention and has been studied previously. Atopy is an important characteristic of CU; however, it has not been fully recognized. Atopy predisposes individuals to immune responses to allergens, leading to type 2 inflammation and immunoglobulin E (IgE) overproduction. Compared with healthy individuals, patients with CU have a higher proportion of atopy, and an atopic background is correlated with the clinical characteristics of CU. The total IgE levels in patients with CU is significantly higher than those in healthy individuals. Although its level is not higher than that in classic allergic diseases, it is closely related to CU. Exogenous allergens, auto-allergens, and specific IgEs, which are closely related to atopy, have been reported, and their roles in CU pathogenesis are also being studied. Local and systemic atopic inflammation is present in patients with CU. This review summarizes the current knowledge regarding atopy and CU, speculating that there are CU subtypes, such as atopic CSU or atopic chronic inducible urticaria (CIndU) and that atopy may be involved in the pathogenesis of CU. These findings provide a new perspective for a comprehensive understanding of the clinical features of CU and further research regarding its pathogenesis.

Embryonic-stem-cell-derived mesenchymal stem cells relieve experimental contact urticaria by regulating the functions of mast cells and T cells

Contact urticaria (CU) is an inflammatory skin disorder triggered by specific substances upon skin contact, leading to immediate acute or chronic manifestations characterized by swelling and redness. While mesenchymal stem cells (MSCs) are increasingly recognized for their therapeutic potential in immune diseases, research on the efficacy and mechanisms of stem cell therapy for urticaria remains scarce. This study investigates the regulatory role of embryonic-stem-cell-derived multipotent MSCs (M-MSCs) administered in a CU mouse model. Therapeutic effects of M-MSC administration were assessed in a Trimellitic anhydride-induced contact urticaria model, revealing significant inhibition of urticarial reactions, including ear swelling, itchiness, and skin lesion. Moreover, M-MSC administration exerted control over effector T cell activities in major lymphoid and peripheral tissues, while also suppressing mast cell degranulation in peripheral tissues. Notably, the inhibitory effects mediated by M-MSCs were found to be TGF-β-dependent. Our study demonstrates the capacity of M-MSCs to regulate contact urticaria in a murine model, harmonizing the activation of inflammatory T cells and mast cells. Additionally, we suggest that TGF-β derived from M-MSCs could play a pivotal role as an inhibitory mechanism in contact urticaria.

Expression of CCR8 and CCX-CKR on Basophils in Chronic Urticaria Is Amplified by IgE-Mediated Activation

Recruitment to the local tissue and alerted phenotype are the hallmarks of basophils in chronic urticaria (CU). Chemokine receptors such as chemokine (C-C motif) receptor 4 (CCR4) or CCR8 have been studied in skin diseases, e.g., atopic dermatitis, but not in CU. In this study, we aimed to define CU's basophil homing potential and receptor profile and the effect of Omalizumab treatment on these. Unstimulated and activated (anti-IgE, fMLP, C5a, and Substance P) whole blood basophils from 11 Omalizumab-treated CU patients and 10 healthy subjects were investigated with flow cytometry. Unstimulated basophils in CU showed higher expression of the skin-associated (CCR8) and scavenger (CCX-CKR) receptors and lower expression of the lung-associated (CCR3) receptor in contrast to healthy ones. IgE-mediated activation increased the percentage of CCR8 and CCX-CKR in CU compared to healthy group and elevated the expression of the lung-associated chemokine receptor, XCR1, in all groups. A trend of augmented expression of the coagulation cascade (CD87) and fMLP (FPR1) receptors was seen on basophils in CU, while a tendency of reduced expression was seen for itch (IL-31RA) and immunotolerance (CD109) receptors. fMLP and C5a increased the expression of CCR4, CCR8, CCX-CKR, and CD87 and decreased CCR2 and CCR3, though no changes between the groups were found. In conclusion, CU basophils exhibit skin-homing potential amplified by IgE-mediated stimulation.

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.

Exhaled Nitric Oxide Level in Pharynx Angioedema

Airway inflammation is related to increased nitric oxide production. It can be assessed noninvasively with exhaled nitric oxide measurement. As airway inflammation was supposed to be present in chronic urticaria and angioedema patients we hypothesized increased exhaled nitric oxide in this group. Twenty-six symptomatic chronic urticaria patients with an acute episode of pharynx angioedema (17 women and 9 men, median age 35) were included in the study group. None of the patients reported a history of asthma, allergic rhinitis or cigarette smoking. The control group consisted of 29 non-smoking healthy subjects (19 women and 10 men, median age 22) without any history of atopy. Exhaled nitric oxide measurement was performed in all subjects. Exhaled nitric oxide levels in the angioedema group did not differ statistically significantly from those detected in healthy subjects (15.5 ppb and 17.0 ppb respectively). Our results indicate the lack of airway inflammation in chronic urticaria patients with pharynx angioedema.

Targeted Therapy for Chronıc Spontaneous Urtıcarıa: Ratıonale and Recent Progress

Chronic spontaneous urticaria (CSU) is characterized by the presence of wheals, angioedema, or both for at least 6 weeks. It may persist for a long time-up to 50% of the patients have been reported to be symptomatic 5 years after the onset. Some patients can suffer more than one episode of CSU during their lifetime. Considering the recurrences, disabling symptoms, and significant impact on quality of life, proper and effective treatment of CSU is critical. The use of antihistamines (AHs) is still the mainstay of treatment. However, given the low rates of response to AHs (38.6% and 63.2% to standard doses and higher doses, respectively), the complete control of symptoms seems difficult to attain. The use of omalizumab for CSU has been a major breakthrough in the care of patients with CSU. However, the partial response and lack of response to omalizumab in a subgroup of patients, as high as 70% in some studies, make the development of alternative treatments desirable. Ever-increasing knowledge on the pathogenesis is making new target molecules available and enabling drug development for CSU. In addition to drug repurposing as in anti-IL-4/13, IL-5, and IL-17 antibodies, novel targeted therapy options such as ligelizumab and Bruton's tyrosine kinase inhibitors are currently undergoing clinical trials and will be available in the near future. This article reviews the current challenges in the treatment of CSU, the pathogenesis and potential target molecules, and the rationale for novel treatments and their rapidly developing status.

The pruritogenic role of the type 2 immune response in diseases associated with chronic itch

While there is a vast array of aetiologies that may lead to chronic pruritus, recent data suggests that many of these conditions share similar interactions between keratinocytes, nerves, and the immune system. Specifically, the type 2 immune response, including Th2 T Cells and their related cytokines, has been noted to play a major role in the development of pruritus in a variety of itchy conditions. To date, atopic dermatitis is the most striking example of this pathogenesis. However, the body of literature supporting its role in many other itchy conditions, including other inflammatory, bullous, as well as systemic diseases, continues to grow. In addition, new treatments targeting this type 2 immune system continue to be developed and investigated. In the current review, we present the current body of literature supporting the role of the type 2 immune response in itchy conditions beyond atopic dermatitis as well as potential therapeutic options that target this pathway for chronic itch.

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.

Role of Helicobacter pylori Eradication in Chronic Spontaneous Urticaria: A Propensity Score Matching Analysis

Objective

To investigate the role of Helicobacter pylori (HP) eradication in chronic spontaneous urticaria (CSU) treatment.

Methods

Retrospective analysis was performed on the clinical data of 522 patients with CSU who underwent a HP breath test in Hangzhou Third People’s Hospital between January 2018 and December 2019. The CSU-HP(+) group consisted of patients with CSU and HP infection, who were treated with antihistamines combined with HP eradication therapy. The CSU-HP(-) group consisted of patients with CSU alone, who were treated with antihistamines. Propensity score matching (PSM) analysis, using the nearest neighbor matching method on a 1:1 basis, was performed to ensure the characteristics of the CSU-HP(+) and CSU-HP(-) groups were similar. Factors, including age, gender, white blood cells, red blood cells, platelets, alanine transaminase, creatinine, immunoglobulin E, and pre-treatment urticaria activity score (UAS), were matched to obtain a balanced cohort of patients in each group. Therapeutic effects were compared after matching. t-tests, Χ² test, and McNemar’s test were used for comparison between the two groups before and after matching.

Results

Patients in the CSU-HP(+) group reported significantly more gastrointestinal symptoms than those in the CSU-HP(-) group. UAS scores in the second week of treatment were significantly different between the two groups. After 3 months, the recurrence rate in the CSU-HP(+) group was lower than in the CSU-HP(-) group.

Conclusion

Eradication of HP infection in patients with CSU helps relieve gastrointestinal symptoms, improves the therapeutic effect of CSU within 2 weeks, and reduces the recurrence rate 3 months after treatment.

The KAAACI/KDA Evidence-Based Practice Guidelines for Chronic Spontaneous Urticaria in Korean Adults and Children: Part 2. Management of H1-Antihistamine-Refractory Chronic Urticaria

Quite a few patients with chronic spontaneous urticaria (CSU) are refractory to H₁-antihistamines, even though the dose of H₁-antihistamines is increased up to 4-fold. CSU that is not controlled with H₁-antihistamines results in increased disease burden. Several immunomodulators have been used to manage these patients. The guidelines reported herein are connected to Part 1 of the KAAACI/KDA Evidence-Based Practice Guidelines for Chronic Spontaneous Urticaria in Korean Adults and Children, and aimed to provide evidence-based recommendations for the management of H₁-antihistamine-refractory CSU. Part 2 focuses on the more commonly used additional treatment options for refractory CSU, including omalizumab, cyclosporine, leukotriene receptor antagonist, dapsone, methotrexate, and phototherapy. The evidence to support their efficacy, dosing, safety, and selection of these agents is systematically reviewed. To date, for patients with refractory CSU, the methodologically sound data to evaluate the use of omalizumab has been growing; however, the evidence of other immunomodulators and phototherapy is still insufficient. Therefore, an individualized stepwise approach with a goal of achieving complete symptom control and minimizing side effects can be recommended. Larger controlled studies are needed to elevate the level of evidence to select a rational therapeutic agent for patients with refractory CSU.

Evaluation of carotid intima media thickness and hematologic inflammatory markers in patients with chronic spontaneous urticaria

Introduction

Low grade inflammation is associated with chronic spontaneous urticaria (CSU) and atherosclerosis. There are little data on the relationship between urticarial inflammation and atherosclerosis. The neutrophil lymphocyte ratio (NLR), platelet lymphocyte ratio (PLR) and mean platelet volume (MPV) have recently been studied in many diseases as a biomarker of inflammation.

Aim

To evaluate hematologic inflammatory parameters and subclinical atherosclerosis in CSU patients.

Material and methods

C-reactive protein (CRP), NLR, PLR, MPV and carotid intima media thickness (CIMT) in CSU patients were compared with healthy controls. Thirty CSU patients and 30 healthy controls participated in the study.

Results

Thirty CSU patients and 30 healthy controls participated in the study. 53.3% of the patient group were females, 46.7% were males and the mean age was 37.7 ±7.7. 53.3% of the healthy control group were females, 46.7% were males and the mean age was 37.1 ±7.2. Body mass index was 24.63 ±2.7 kg/m² in the patient group and 24.83 ±2.5 kg/m² in the control group. Left and right CIMT and CRP values were higher in CSU patients and high-density lipoproteins (HDL) values were lower in the CSU patients. There was a positive correlation between the right and left CIMT and urticaria activity severity 4 (UAS4), disease severity, and triglycerides in the patient group, also a negative correlation was found between the right and left CIMT and the HDL values. C-reactive protein was also correlated with UAS4 and disease severity.

Conclusions

This is the first study to evaluate subclinical atherosclerosis in CSU patients. Chronic spontaneous urticaria may be associated with an increased atherosclerotic risk. Serum CRP concentration can also be used as an objective parameter to evaluate disease severity.

Treatment of chronic spontaneous urticaria: Immunomodulatory approaches

This paper summarizes and reviews the mechanisms of action and data concerning efficacy of recommended treatments as well as other treatments that have been tested, independently of the outcomes, in the management of chronic spontaneous urticaria. Due to the central role of mast cells, basophils and histamine in the pathophysiology of this disease, H₁-antihistamines remain the first-line treatment. However, current knowledge about this complex disease, also recognizes an important role for T lymphocytes, B lymphocytes, and autoantibodies. Implications of these others mediators thus provide further targets for treatment. Indeed, agents previously used to treat other autoimmune and inflammatory diseases, have demonstrated efficacy in chronic spontaneous urticaria and are therefore potential therapeutic alternatives for antihistamine unresponsive patients.

Association of TG2 from mast cells and chronic spontaneous urticaria pathogenesis

BACKGROUND

Mast cells and their mediators play important roles in chronic spontaneous urticaria (CSU) pathogenesis. Transglutaminase 2 (TG2) is expressed in activated mast cells and contributes to airway inflammation in allergic asthma.

OBJECTIVE

To investigate the role of TG2 in CSU.

METHODS

Patients with CSU (n = 72) and healthy controls (n = 51) were evaluated. Skin biopsy specimens were obtained from 5 patients with CSU and 2 healthy controls. Cord blood-derived human mast cells and peripheral blood-derived human mast cells were activated with IgE. TG2 activity and inflammatory mediators, such as histamine, leukotriene C4, and cytokines, were measured in serum or supernatant from cultured mast cells by enzyme-linked immunosorbent assay. Colocalization of mast cells and TG2 was determined in skin tissues by immunofluorescence.

RESULTS

TG2 activity was significantly higher in serum samples from patients with CSU than in serum samples from healthy controls (P < .001). Colocalization of mast cell surface marker c-kit and TG2 was significantly increased in the lesional skin of patients with CSU compared with that in healthy controls. The levels of histamine, leukotriene C4, tumor necrosis factor α, transforming growth factor β, and interleukins 4, 5, and 6 were significantly higher in patients with CSU than in healthy controls (P < .001). Serum TG2 levels had positive correlations with each inflammatory mediator (P < .001). TG2 activity was increased in cord blood-derived human mast cells (CBMCs) and peripheral blood-derived human mast cells activated with IgE compared with those without activation (P < .05).

CONCLUSION

Our findings suggest that TG2 expressed in and released from mast cells plays an important role in CSU pathogenesis.

Activation of Human Basophils by A549 Lung Epithelial Cells Reveals a Novel IgE-Dependent Response Independent of Allergen

Evidence for epithelial cell (EC)-derived cytokines (e.g., thymic stromal lymphopoietin [TSLP]) activating human basophils remains controversial. We therefore hypothesize that ECs can directly activate basophils via cell-to-cell interaction. Basophils in medium alone or with IL-3 ± anti-IgE were coincubated with TSLP, IL-33, or IL-25. Analogous experiments cocultured basophils (1-72 h) directly with EC lines. Supernatants were tested for mediators and cytokines. Abs targeting receptors were tested for neutralizing effects. Lactic acid (pH 3.9) treatment combined with passive sensitization tested the role of IgE. Overall, IL-33 augmented IL-13 secretion from basophils cotreated with IL-3, with minimal effects on histamine and IL-4. Conversely, basophils (but not mast cells) released histamine and marked levels of IL-4/IL-13 (10-fold) when cocultured with A549 EC and IL-3, without exogenous allergen or IgE cross-linking stimuli. The inability to detect IL-33 or TSLP, or to neutralize their activity, suggested a unique mode of basophil activation by A549 EC. Half-maximal rates for histamine (4 h) and IL-4 (5 h) secretion were slower than observed with standard IgE-dependent activation. Ig stripping combined with passive sensitization ± omalizumab showed a dependency for basophil-bound IgE, substantiated by a requirement for cell-to-cell contact, aggregation, and FcεRI-dependent signaling. A yet unidentified IgE-binding lectin associated with A549 EC is implicated after discovering that LacNAc suppressed basophil activation in cocultures. These findings point to a lectin-dependent activation of basophil requiring IgE but independent of allergen or secreted cytokine. Pending further investigation, we predict this unique mode of activation is linked to inflammatory conditions whereby IgE-dependent activation of basophils occurs despite the absence of any known allergen.

Basophil markers for identification and activation in the indirect basophil activation test by flow cytometry for diagnosis of autoimmune urticaria

Background

The indirect basophil activation test using flow cytometry is a promising tool for autoimmune urticaria diagnosis. We aimed to identify better donor basophils (from atopic vs. non-atopic donors and interleukin-3 primed vs. unprimed basophils) and improve basophil identification and activation markers (eotaxin CC chemokine receptor-3 [CCR3] vs. CD123 and CD63 vs. CD203c).

Methods

Donor basophils were obtained from non-atopic and atopic group O donors. Positive control sera were artificially prepared to simulate autoimmune urticaria patients' sera. Patient sera were obtained from nine children with chronic urticaria. Assay sensitivity was compared among each variation by using positive control sera (n=21), applying cutoff values defined from negative control sera (n=20).

Results

For basophil identification, a combination of CCR3 and CD123 markers revealed a higher correlation with automated complete blood count (r=0.530) compared with that observed using CD123 (r=0.498) or CCR3 alone (r=0.195). Three activation markers on the atopic donor basophils attained 100% assay sensitivity: CD203c on unprimed basophils, CD63+CD203+ or CD63 alone on primed basophils; however, these markers on the non-atopic donor basophils attained lower assay sensitivity.

Conclusions

For basophil identification markers, a combination of CD123 and CCR3 is recommended, while CD123 alone may be used as an alternative. Donor basophils should be obtained from an atopic donor. For basophil activation markers, either CD203c alone on unprimed basophils or CD203c and CD63 on primed basophils are recommended, while CD63 alone on primed basophils may be used as an alternative.

Human basophils are a source of - and are differentially activated by - IL-31

BACKGROUND

Basophils are important effector cells involved in the pathogenesis of inflammatory skin diseases including chronic urticaria which is associated by increased IL-31 serum levels. So far the effects of IL-31 on human basophils are unknown.

OBJECTIVE

To analyse the functional role of IL-31 in basophil biology.

METHODS

IL-31 expression was evaluated in skin samples derived from chronic spontaneous urticaria patients. Oncostatin M receptor (OSMR), IL-31 receptor A (RA) and IL-31 protein expressions were analysed on human basophils from healthy donors. Basophil responses to IL-31 were assessed for chemotaxis, externalization of CD63 and CD203c as well as the release of histamine, IL-4 and IL-13.

RESULTS

IL-31RA and OSMR were expressed on human basophils. IL-31 was strongly expressed in the skin of patients with chronic spontaneous urticaria and was released from isolated basophils following either anti-IgE, IL-3 or fMLP stimulation. IL-31 induced chemotaxis and the release of IL-4 and IL-13 which was specifically inhibited by anti-IL-31RA and anti-OSMR. Conversely, IL-31 had no effect on CD63 and CD203c externalization or histamine release.

CONCLUSIONS AND CLINICAL RELEVANCE

Human basophils are a source of -and are activated by - IL-31 with the release of pro-inflammatory cytokines and the induction of chemotaxis indicating an important novel function of IL-31 in basophil biology.

Periostin and Interleukin-13 Are Independently Related to Chronic Spontaneous Urticaria

Chronic spontaneous urticaria (CSU) is a complex idiopathic disease of the skin with various cellular infiltrations. Although mast cells are key effector cells in the pathogenesis of CSU, CD4+ T helper 2 cells also have particular roles in the development and maintenance of CSU. Periostin is known as a downstream molecule of interleukin (IL)-4 and IL-13, key cytokines of type 2 immune responses. In this study, we examined periostin and IL-13 levels in the sera of patients with CSU (n=84) and healthy normal controls (NCs, n=43). Periostin levels were significantly lower in the CSU group than in NCs (71.4±21.8 vs 85.1±22.4 ng/mL, P=0.04). Periostin levels were also lower in the severe CSU group than those in mild CSU (59.7±18.0 vs 73.4±22.0 ng/mL, P=0.04). However, IL-13 levels were significantly higher in patients with CSU than in NCs (508.5±51.2 vs 200.7±13.3 pg/mL, P=0.001). In conclusion, periostin and IL-13 may be independently related to the pathogenesis of CSU.

Chronic spontaneous urticaria and internal parasites--a systematic review

Chronic spontaneous urticaria (CSU) is defined as persistent wheals, angioedema, or both lasting for >6 weeks due to known or unknown causes. Some epidemiological studies and case reports suggest that internal parasite infections (PI) can cause CSU. Here, we provide a systematic overview of published findings on the prevalence and relevance of PI in CSU and we discuss possible pathomechanisms. The prevalence of PI in CSU was investigated by 39 independent studies and comorbidity reportedly ranged from 0 to 75.4% (two-thirds of these studies reported infection rates of 10% or less). The prevalence of PI in adult and pediatric CSU patients ranged from 0% to 75.4% and from 0% to 37.8%, respectively. CSU patients were more often diagnosed with protozoa and had a significantly higher risk of toxocariasis seropositivity and Anisakis simplex sensitization when compared to healthy controls. Patients with chronic urticaria more frequently had seropositivity of fasciolosis, Anisakis simplex sensitization, and the presence of Blastocystis hominis allele 34 (ST3) as compared with control subjects. In 21 studies, efficacy of treatment with antiparasitic drugs ranged from 0 to 100% (35.7% of 269 CSU patients benefitted). In 9 (42.8%) of 21 studies, more than 50% of efficacy was observed. The reported rate of urticaria comorbidity in PI patients in 18 independent studies is 1-66.7%. Urticaria including CSU might be a quite common symptom of strongyloidiasis and blastocystosis. Pathogenic mechanisms in CSU due to PI may include specific IgE, Th2 cytokine skewing, eosinophils, activation of the complement, and the coagulation systems.

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.

Update and insights into treatment options for chronic spontaneous urticaria

Chronic spontaneous urticaria (CSU) is defined as itchy weals, angio-oedema, or both, arising spontaneously without external physical stimuli. Symptoms of the disease continue to develop for more than 6 weeks. It carries a high socioeconomic burden with considerable health care costs. Second generation H1-antihistamines are the mainstay of urticaria treatment and are the only licensed option. However, many patients are resistant to H1-antihistamine therapy. Omalizumab has proven to be an effective therapeutic option in patients with recalcitrant chronic urticaria. Ciclosporin appears to be more beneficial in patients with functional histamine releasing autoantibodies as a cause of their disease. This review article will highlight the major therapeutic options available today for the management of CSU knowing that good quality evidence for efficacy of many agents is scarce except for H1-antihistamines and omalizumab.

Positive associations between infections of Toxoplasma gondii and seropositivity with Anisakis simplex in human patients suffering from chronic urticaria

Toxoplasma gondii is a food-borne and orofecal microorganism which produces chronic infection, and attempts have been made to prove its negative association with atopy in the context of the hygiene hypothesis. Anisakis simplex is a fish parasite associated with chronic urticaria (CU) in endemic regions. We analysed the relationship between both infectious agents in CU. We included 42 patients with chronic urticaria (18 patients with CU associated with A. simplex sensitization and 24 not sensitized CU patients). Patients were assessed for atopy by a skin prick test (SPT) against common aeroallergens and for respiratory symptoms. Anisakis simplex sensitization was assessed by SPT and specific IgE by CAP fluoro-enzyme immunoassay (CAP-FEIA). Anti-T. gondii IgG levels were measured by enzyme-linked immunosorbent assay (ELISA). CU patients were analysed with respect to T. gondii seropositivity, A. simplex sensitization, atopy and immigrant status. The seroprevalence of T. gondii was 40.5% in CU patients and 42.1% in the control group. Immigrants were more frequently infected by T. gondii (41.2% versus 12%; P =0.036). Anti-T. gondii IgG antibodies were associated with past A. simplex parasitism (odds ratio 6.73; P =0.03) and independently with atopic sensitization (odds ratio 5.85; P =0.04). In CU patients, T. gondii has no protective effect on atopic sensitization or A. simplex sensitization.

Assessment of Interleukins IL-4, IL-6, IL-8, IL-10 in Acute Urticaria

Background

Urticaria is a skin disease that affects approximately 5% of the general population and manifests itself, not only as an acute but also as a chronic disease. The etiology of the disease varies as well as its clinical manifestations which extend from the presence of urticarial hives to the potentially mortal angioedema. There is a great interest to the disease not only due to its special clinical manifestation but also due to its pathogenetic mechanism. New data in the medical bibliography support the participation of interleukins (ILs) in the pathophysiology of urticaria. The aim of the study is to contribute in the comprehension of possible participation of certain ILs in the pathogenesis of acute urticaria.

Methods

Our study concerns four ILs, IL-4, IL-6, IL-8 and IL-10, simultaneously and their quantitative changes during the acute phase of urticaria as well as 2 weeks after drug administration. Moreover, ILs levels of patients were compared with those of matched healthy controls. All measurements have been done by the ELISA method. The statistical analysis was done by SPSS.

Results

The results present increased levels (in 51 patients vs. 22 matched healthy controls) of all four ILs during the acute phase. Especially for IL-4 this increase was statistically very significant (P < 0.001). Statistically marginally significant decrease was also observed for IL-10 concentrations (P < 0.059), for the two blood samples (acute phase and 2 weeks later).

Conclusion

It is suggested by the present study that certain ILs might play an important role in the pathogenetic mechanism of urticaria. IL-4 and IL-10 participation seems to be relatively more significant. Possibly, ILs, liberated by mast cells, induce an influx of leukocytes in the dermis, therefore participating in the development of acute urticaria inflammation.

Hypersensitivity linked to exposure of broad bean protein(s) in allergic patients and BALB/c mice

OBJECTIVE

Broad bean (Vicia faba L.), a common vegetable, belongs to the family Fabaceae and is consumed worldwide. Limited studies have been done on allergenicity of broad beans. The aim of this study was to determine if broad bean proteins have the ability to elicit allergic responses due to the presence of clinically relevant allergenic proteins.

METHODS

Simulated gastric fluid (SGF) assay and immunoglobulin E (IgE) immunoblotting were carried out to identify pepsin-resistant and IgE-binding proteins. The allergenicity of broad beans was assessed in allergic patients, BALB/c mice, splenocytes, and RBL-2H3 cells.

RESULTS

Eight broad bean proteins of approximate molecular weight 70, 60, 48, 32, 23, 19, 15, and 10 kDa that remained undigested in SGF, showed IgE-binding capacity as well. Of 127 allergic patients studied, broad bean allergy was evident in 16 (12%). Mice sensitized with broad bean showed increased levels of histamine, total and specific IgE, and severe signs of systemic anaphylaxis compared with controls. Enhanced levels of histamine, prostaglandin D2, cysteinyl leukotriene, and β-hexosaminidase release were observed in the primed RBL-2H3 cells following broad bean exposure. The levels of interleukin IL-4, IL-5, IL-13 and regulated on activation, normal T-cell expressed and secreted were found enhanced in broad bean-treated splenocytes culture supernatant compared with controls.

CONCLUSION

This study inferred that broad bean proteins have the ability to elicit allergic responses due to the presence of clinically relevant allergenic proteins.

Molecular genetic mechanisms of chronic urticaria

Chronic urticaria (CU) is a common allergic skin disease that requires long-term pharmacological treatment. Some patients with severe CU suffer a poor quality of life. Although the pathogenic mechanisms of CU are not clearly understood, several groups have suggested that genetic mechanisms are involved in various CU cohorts. To further understand the molecular genetic mechanisms of CU, we summarize recent genetic data in this review. Although a few HLA alleles were suggested to be candidate markers in different ethnic groups, further replication studies that apply the recent classification are needed. Genetic polymorphisms in histamine-related genes, including FcεRI and HNMT, were suggested to be involved in mast cell activation and histamine metabolism. Several genetic polymorphisms of leukotriene-related genes, such as ALOX5, LTC4S, and the PGE2 receptor gene PTGER4, were suggested to be involved in leukotriene overproduction, a pathogenic mechanism. Further investigations using candidate gene approaches and genome-wide association studies (GWAS) will provide new insights into the molecular genetic mechanisms of CU, which will provide new marker genes for differentiation of CU phenotypes and identification of potential therapeutic targets.

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.

Angioedema

Angioedema can be caused by either mast cell degranulation or activation of the kallikrein-kinin cascade. In the former case, angioedema can be caused by allergic reactions caused by immunoglobulin E (IgE)-mediated hypersensitivity to foods or drugs that can also result in acute urticaria or a more generalized anaphylactic reaction. Nonsteroidal anti-inflammatory drugs (cyclooxygenase 1 inhibitors, in particular) may cause angioedema with or without urticaria, and leukotrienes may have a particular role as a mediator of the swelling. Reactions to contrast agents resemble allergy with basophil and mast cell degranulation in the absence of specific IgE antibody and can be generalized, that is, anaphylactoid. Angioedema accompanies chronic urticaria in 40% of patients, and approximately half have an autoimmune mechanism in which there is IgG antibody directed to the subunit of the IgE receptor (40%) or to IgE itself (5%-10%). Bradykinin is the mediator of angioedema in hereditary angioedema types I and II (C1 inhibitor [INH] deficiency) and the newly described type III disorder some of which are caused bya mutation involving factor XII. Acquired C1 INH deficiency presents in a similar fashion to the hereditary disorder and is due either toC1 INH depletion by circulating immune complexes or to an IgG antibody directed to C1 INH. Although each of these causes excessive bradykinin formation because of activation of the plasma bradykinin-forming pathway, the angioedema due to angiotensin-converting enzyme inhibitors is caused by excessive bradykinin levels due to inhibition of bradykinin degradation. Idiopathic angioedema (ie, pathogenesis unknown) may be histaminergic, that is, caused by mast cell degranulation with histamine release, or nonhistaminergic. The mediator pathways in the latter case are yet to be defined. A minority may be associated with the same autoantibodies associated with chronic urticaria. Angioedema that is likely to be life threatening (laryngeal edema or tongue/pharyngeal edema that obstructs the airway) is seen in anaphylactic/anaphylactoid reactions and the disorders mediated by bradykinin.

Diagnosis and treatment of urticaria and angioedema: a worldwide perspective

: Urticaria and angioedema are common clinical conditions representing a major concern for physicians and patients alike. The World Allergy Organization (WAO), recognizing the importance of these diseases, has contributed to previous guidelines for the diagnosis and management of urticaria. The Scientific and Clinical Issues Council of WAO proposed the development of this global Position Paper to further enhance the clinical management of these disorders through the participation of renowned experts from all WAO regions of the world. Sections on definition and classification, prevalence, etiology and pathogenesis, diagnosis, treatment, and prognosis are based on the best scientific evidence presently available. Additional sections devoted to urticaria and angioedema in children and pregnant women, quality of life and patient-reported outcomes, and physical urticarias have been incorporated into this document. It is expected that this article will supplement recent international guidelines with the contribution of an expert panel designated by the WAO, increasing awareness of the importance of urticaria and angioedema in medical practice and will become a useful source of information for optimum patient management worldwide.

Add-on montelukast in antihistamine-resistant chronic idiopathic urticaria

BACKGROUND

Antihistamines (AH) alleviate pruritus and decrease the incidence of hives in patients with chronic idiopathic urticaria (CU). However, some patients do not respond completely to this therapy. We hypothesized that some of them might benefit from the addition of leukotriene receptor antagonists (LA).

METHODS

We screened patients diagnosed and treated for CU and selected those that had symptoms despite antihistamine treatment. In a double-blind crossover study, patients took the leukotriene antagonist montelukast (10 mg per day) or placebo. Efficacy was assessed by a symptom score.

RESULTS

In a group of 22 patients, the symptom score was not significantly different between periods using montelukast (48.8; 0-214) or placebo (68.5; 0-230). However in the subgroup of five patients with the most severe urticaria, defined as patients with symptom scores in the upper quartile at inclusion in the study, montelukast (41; 11 214) was superior to placebo (95.5; 48 230; p < 0.05), but only when using an in-house symptom score questionnaire and not when using a validated urticaria activity score questionnaire.

CONCLUSIONS

We showed that in patients with antihistamine-resistant CU the addition of montelukast significantly diminished symptoms in only a small minority of patients. However, response to add-on montelukast was seen in the subgroup of patients with particularly severe disease. To confirm this observation, a study with a larger group of patients is warranted.

Acute-phase response in chronic urticaria

The patterns of acute-phase response (APR) biomarkers differ upon various inflammatory conditions. Little information is available on the systemic inflammatory response in urticaria/angio-oedema. It has been shown that concentrations of circulating APR biomarkers, IL-6 and C-reactive protein (CRP), are elevated more in severe chronic urticaria (CU) than in patients showing milder urticarial symptoms. It is not clear whether the increase of IL-6 and CRP is merely an epiphenomenon or may contribute to the pathogenesis of CU. It is tempting to speculate that mediators of APR may enhance urticarial inflammation. In addition, there is some association between APR and activation of coagulation/fibrinolysis in CU. It is well known that even slight elevation in CRP baseline concentration is enough to produce significant increase in cardiovascular risk. In this light, one should ask whether CU patients, in particular those showing stronger systemic inflammatory response and long-lasting course are more vulnerable to the cardiovascular events. Apart from highly troublesome symptoms and low quality of life, CU may then involve some remote, serious systemic consequences. Taken together, CU can be identified as a mast cell- and basophil-dependent inflammatory disorder of the skin, which is accompanied by APR. Characterization of APR in CU may appear essential for an insight into the activity of this disease and for assessment of the inflammation degree. Moreover, measurement of these biomarkers might be particularly relevant while assessing CU patients demanding an anti-inflammatory or immunosuppressive therapy. This review summarizes information regarding APR in the course of urticaria/angio-oedema.

Different serum cytokine levels in chronic vs. acute Anisakis simplex sensitization-associated urticaria

The knowledge on immune mechanisms of chronic urticaria (CU) at the cytokine level is widely scarce. We compared pro- and anti-inflammatory as well as Th1- and Th2-associated serum cytokine levels in two phenotypes of CU: associated with (CU+) and without (CU⁻) sensitization against Anisakis simplex, a ubiquitous fish parasite, that has been associated with acute urticaria in gastro-allergic anisakiasis (GAA) and with CU+. Thirteen CU+ and 19 CU⁻ patients were compared with 13 GAA patients and 15 control subjects for cytokines, measured by cytometric bead array. Urticaria activity score was positively correlated with IL-6 in CU⁻. Serum levels of IL-10 were lower in CU+ and CU⁻ with respect to the control group. Median IFN-γ was lower in all urticaria groups. Patients with previous parasitism by A. simplex displayed higher TGF-β levels than subjects without previous parasitism. The main finding was lower levels of IL-17 in CU+ with respect to GAA or controls, with a further tendency to even lower levels in CU⁻. Different urticaria phenotypes are associated with distinct serum cytokine levels.

Are chronic urticaria, analgesic intolerance and seasonal rhinitis markers of different severities and phenotypes of the asthma they accompany?

BACKGROUND

Asthma is a heterogeneous disease that presents with different clinical phenotypes. We aimed to compare the patients with asthma diagnosis alone with the patients, who, in addition to their asthma had accompanying analgesic intolerance (AI), chronic urticaria (CU) or seasonal rhinitis (SR) if there are any distinctions and specific characteristics of these defined patient groups.

METHODS

Eighty-four asthma patients diagnosed with SR, 46 with CU, 75 with AI and 71 patients with asthma alone were enrolled to the study retrospectively. The reference group for the comparisons was the group with asthma diagnosis alone.

RESULTS

The mean age of all patients was 37.2±13 (15-80) and 70.7% of them were females. Asthma patients with SR had a significantly earlier onset of asthma (age: 27.4±10.8 and 34.5±15.9; respectively, p<0.01), significantly better pulmonary function tests and were significantly more atopic (92.9% and 28.8%; p<0.001). Moderate-to-severe asthma significantly correlated with older age at the time of diagnosis, older age of asthma onset, higher body mass index, less atopy and fewer pollen sensitivity. Asthma severity of patients with SR was significantly milder than the reference group (OR: 0.6, 95% CI 0.5-0.8). Asthma with AI tended to be more severe although the relation was insignificant (OR:1.6 95% CI:0.8-3.5).

CONCLUSIONS

Asthma patients with SR have significantly milder and earlier onset of asthma, better pulmonary function tests and are significantly more atopic while asthma with AI tends to be more severe. Asthma with CU does not show a specific phenotypic characteristic.

Chronic urticaria: assessment of current treatment

Chronic urticaria is heterogenous, long-persisting and has a severe impact on quality of life and daily work. Effective treatment is essential but remains a confounding problem. This review summarizes available treatment strategies for chronic urticaria and their strength of evidence. Besides treatment of identified triggering factors such as chronic persistent bacterial infections (e.g., with Helicobacter pylori, streptococci, staphylococci or yersinia), standard treatment consists of nonsedating H1-antihistamines. Most patients require increasing (off-label) dosages that should be taken daily and regularly, however, this still fails in a third of cases. Reliable alternatives in the world literature are rare and the level of evidence is low. Certain subgroups may display benefit from additional treatment with cyclosporine A, cysteinyl leukotriene receptor antagonists, chloroquine, dapsone or other alternatives. A practicable step-wise treatment approach is given to optimize and individualize the treatment of patients with chronic urticaria.

Treatment of Chronic Idiopathic Urticaria with Levamisole: A Multicentre, Randomized, Double-Blind, Controlled Trial

The objective of this study was to evaluate the efficacy of treating chronic idiopathic urticaria (CIU) with levamisole in combination with levocetirizine. This was a multicentre, randomized, double-blind, controlled trial that included 132 patients with active CIU who were treated for 6 weeks with either levocetirizine alone (control group; n = 65) or levamisole plus levocetirizine (treatment group; n = 67). Response to therapy was evaluated by measuring the efficacy rate. After 2 weeks of treatment, there was no significant difference in the efficacy rate between the treatment and control groups (54.84% and 42.37%, respectively). After 6 weeks of treatment, a statistically significant difference in the efficacy rate was observed between the groups (76.27% and 54.39% for the treatment and control groups, respectively). This study demonstrated that a combination of levamisole plus levocetirizine is more effective than levocetirizine alone and potentially provides a new, promising approach to the treatment of CIU.

Pathogenesis of chronic urticaria

Chronic urticaria is defined as the presence of urticaria (hives) for at least 6 weeks with the assumption that it occurs daily or close to it. If we eliminate physical urticarias and urticarial vasculitis from consideration, the remainder can be divided into autoimmune chronic urticaria (45%) and idiopathic chronic urticaria (55%). The autoimmune subgroup is associated with the IgG anti-IgE receptor alpha subunit in 35-40% of patients and IgG anti-IgE in an additional 5-10%. These autoantibodies have been shown to activate blood basophils and cutaneous mast cells in vitro with augmentation of basophil activation by complement and release of C5a, in particular. Binding methods (immunoblot and ELISA) yield positives in many autoimmune diseases as well as occasional normal subjects or patients with other forms of urticaria but most such sera are non-functional. Activation of basophils or mast cells causing histamine release is quite specific for chronic urticaria and defines the autoimmune subgroup. Although pathogenicity is not formally proven, the antibodies cause wealing upon intradermal injection, and removal of the autoantibody leads to remission. A cellular infiltrate is seen to be characterized by mast cell degranulation and infiltration of CD4+ T lymphocytes, monocytes, neutrophils, eosinophils, and basophils. The intensity of the infiltrate and clinical severity of the disease (including accompanying angio-oedema) is more severe in the autoimmune subpopulation. This latter group also has a higher evidence of human leucocyte antigen DR alleles associated with autoimmunity and a 25% incidence of antithyroid antibodies with diagnosed hypothyroidism in some. Hypo-responsiveness of patients' basophils to anti-IgE and hyperresponsiveness to serum defines another subpopulation (at least 50%) that overlaps the idiopathic and autoimmune subgroups. Hypo-responsiveness to anti-IgE has been shown to be associated with elevated levels of cytoplasmic phosphatases that inhibit degranulation. Reversal of the abnormality is seen with disease remission. Further work will be needed to distinguish whether this is a cause or a consequence of persistent urticaria and to further assess the relationship (or lack thereof) of altered responsiveness (decreased or increased) with the presence or absence of activating autoantibodies.

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.

Increased circulating pro-inflammatory cytokines and imbalanced regulatory T-cell cytokines production in chronic idiopathic urticaria

The immunologic characterization of chronic idiopathic urticaria (CIU), mainly regarding cytokine profile needs more investigation. We examined circulating inflammatory cytokine levels, T-cell induced secretion, and cytokine mRNA expression in patients with CIU subjected to the intradermal autologous serum skin test (ASST). Increased levels of circulating pro-inflammatory cytokines, such as TNF-alpha, IL-1beta, IL-12p70, and IL-6 have been observed in most of patients with CIU, together with an enhancement of IL-2 secretion following T-cell stimulation. Highlighting the inflammatory profile in CIU found in ASST positive, is the enhanced B-cell proliferative responsiveness and increased IL-17 secretion levels. ASST-positive patients also exhibited impaired IL-4 secretion associated with increased IL-10 production. Altered cytokine expression in patients with ASST-negative, was the down-modulation of spontaneous IL-10 mRNA expression levels in peripheral blood mononuclear cells. Our findings support the concept of immunologic dysregulation in CIU, revealing a systemic inflammatory profile associated with disturbed cytokine production by T cells, mainly related to IL-17 and IL-10 production.

Progress and challenges in the understanding of chronic urticaria

: Chronic urticaria is a skin disorder characterized by transient pruritic weals that recur from day to day for 6 weeks or more. It has a great impact on patients' quality of life. In spite of this prevalence and morbidity, we are only beginning to understand its physiopathology and we do not have a curative treatment. Moreover, a patient with chronic urticaria may undergo extensive laboratory evaluations seeking a cause only to be frustrated when none is found. In recent years there have been significant advances in our understanding of some of the molecular mechanisms responsible for hive formation. The presence and probable role of IgG autoantibodies directed against epitopes expressed on the alpha-chain of the IgE receptor and to lesser extent, to IgE in a subset of patients is generally acknowledged. These autoantibodies activate complement to release C5a, which augments histamine release, and IL4 and leukotriene C4 are released as well. A perivascular cellular infiltrate results without predominance of either Th1 or Th2 lymphocyte subpopulations. Basophils of all chronic urticaria patients (autoimmune or idiopathic) are hyperresponsive to serum, regardless of source, but poorly responsive to anti IgE. In this review we will summarize the recent contributions to this field and try to provide insights to possible future directions for research on this disease.

Chronic urticaria: what is new, where are we headed

Chronic urticaria can be defined as the occurrence of widespread daily or nearly daily wheals for at least 6 weeks, which may be accompanied by angioedema. It is a disease with a considerable impact on patients' quality of life. Furthermore, these patients may undergo extensive laboratory evaluations seeking a cause only to be frustrated when none is found. There is no curative treatment for this disorder and we do not understand the mechanisms that lead to the onset of disease. However, in recent years there have been significant advances in the understanding of some of the molecular mechanisms that cause cutaneous inflammation that is manifest as urticaria and angioedema. In this review we will summarize our recent contributions to this field and try to offer insights regarding future directions for research.

Evidence of in vivo basophil activation in chronic idiopathic urticaria

BACKGROUND

Approximately 40% of chronic idiopathic urticaria (CIU) subjects have autoantibodies to either FcepsilonRIalpha or IgE. The effect of such autoantibodies on circulating basophil activation status is unknown.

OBJECTIVE

The expression of cell surface activation markers on basophils from CIU, non-allergic, and allergic subjects were compared. Further, the relationship between marker expression and serum factors reported in CIU, such as histamine-releasing activity (HRA) and immunoreactivity to FcepsilonRIalpha were examined.

METHODS

Peripheral blood was obtained from CIU, allergic, and non-allergic donors and fractionated by density gradients. Enriched basophils (1-12%) were analysed by flow cytometry for expression of activation markers including CD63, CD69, and CD203c. Dilutions of serum (5-50%) were analysed for HRA on basophils from a normal donor. Serum was tested for immunoreactivity by western blotting to a standard cell lysate prepared from an RBL-SX38 cell line transfected with human FcepsilonRIalpha.

RESULTS

CIU subjects (n=9) and allergic subjects (n=8) exhibited enhanced expression of CD63 and CD69, as compared with non-allergic subjects (n=7); however, no difference was seen among groups for CD203c expression. Five CIU and two non-allergic subjects had evidence of significant serum HRA (>20%), whereas two CIU, two allergic, and three non-allergic subjects had evidence of serum immunoreactivity to FcepsilonRIalpha. Serum HRA and serum immunoreactivity to FcepsilonRIalpha were not associated with enhanced surface marker expression.

CONCLUSION

Basophil activation marker expression is increased in CIU subjects and is not associated with serum factors. In addition, serum HRA and FcepsilonRIalpha immunoreactivity are not unique to CIU, or related to enhanced circulating basophil marker expression.

Urticaria: selected highlights and recent advances

Urticaria has been called a vexing problem and remains so today. The most important part of the diagnostic evaluation remains a comprehensive and detailed history and physical examination, supplemented with limited laboratory testing. Although acute urticaria has been relatively well understood for some time, significant and important recent advances in under-standing the pathogenesis of chronic urticaria are beginning to provide insight in this challenging field, notably the identification of many of these patients with an autoimmune etiology. Antihistamines of various types continue to represent the keystone of symptomatic treatment, with adjunctive support from medications of other classes, such as antileukotrienes, adrenergics, and immunosuppressive and anti-inflammatory agents (including steroids and cyclosporine). Although some progress has been made at improving symptomatic control of urticaria, further research and discovery are necessary before there can yet be an effective impact on the underlying course and natural history of this condition.

A possible role for cysteinyl-leukotrienes in non-ionic contrast media induced adverse reactions

PURPOSE

To test whether mono- or dimeric X-ray contrast media (CM) may induce the de novo production of cysteinyl-leukotriens (cys-LT), that could contribute to allergic/allergy-like side effects.

MATERIALS AND METHODS

Leukocytes from 39 patients receiving iopromide or iotrolan for routine CT-examination were analyzed for the production of cys-LT. Histamine levels were analyzed in plasma specimens. One patient with a positive history of a previous CM-reaction did not receive CM-injection.

RESULTS

Three patients of the iopromide and five of the iotrolan group showed adverse reactions. Reactors had increased cys-LT values in samples obtained before CM-injection induced by the positive control (anti-FcepsilonRI antibodies) (6763.7 pg/ml+/-1367.3 versus 2299.8 pg/ml+/-399.2; p<0.007). Patients with versus without CM-reaction did not differ significantly with respect to their histamine values before CM-administration. In vitro iopromide (p<0.0002) and iotrolan (p<0.0008) induced significant cys-LT production as compared to IL-3 stimulation. In vivo both CM induced a significant increase 6h after CM administration (p<0.05).

CONCLUSION

Our findings suggest that both CM seem to induce cys-LT production. As to whether the observed increased values in pre-dose samples of patients with as compared to those without reactions could contribute to identify high risk patients should be investigated in larger patient groups in future.

Serum cytokine changes in Turkish children infected with Giardia lamblia with and without allergy: Effect of metronidazole treatment

The present report is a case control study aimed to determine the levels of cytokines and other parameters in the sera of allergy-complicated and uncomplicated giardiasic children before and after metronidazole treatment. The study included a total of 126 subjects; 52 giardiasic children, 34 allergy-complicated giardiasis (36.9%) and 34 healthy controls, as well as six cases of giardiasis simultaneously infected with other parasites or bacterial pathogens. Serum levels of tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1beta, soluble IL-2 receptor (sIL-2R), IL-6, IL-8, nitric oxide (NO), and C-reactive protein (CRP) were determined. TNF-alpha and sIL-2R levels significantly increased in giardiasic cases. IL-1beta, IL-6, IL-8, CRP, and NO levels increased only in the cases associated with allergy. All increased variables significantly decreased following metronidazole treatment and returned to normal levels. Metronidazole-treated patients became 100% parasite free. In conclusion, increased TNF-alpha and sIL-2R may be involved in pathogenesis of non-allergic giardiasis and probably Th1 type immune response seems to be predominant and this response may be protective rather than causative of the disease. Activation of the immune system takes place in giardiasis. It is broader and more intense in allergy-complicated giardiasis than that of uncomplicated cases, most probably due to non-invasive character of G. lamblia. Enhanced IgE production pointed to Th2-type immune response and confirms its association with allergy.