Basophil Characteristics as a Marker of the Pathogenesis of Chronic Spontaneous Urticaria in Relation to the Coagulation and Complement Systems.

Chronic spontaneous urticaria (CSU) is a common skin disorder characterized by daily or almost daily recurring skin edema and flare with itch and pruritus anywhere on the body for more than 6 weeks. Although basophil- and mast cell-released inflammatory mediators, such as histamine, play important roles in the pathogenesis of CSU, the detailed underlying mechanism is not clear. Since several auto-antibodies, IgGs which recognize IgE or the high-affinity IgE receptor (FcεRI) and IgEs against other self-antigens, are detected in CSU patients, they are considered to activate both mast cells in the skin and basophils circulating in the blood. In addition, we and other groups demonstrated that the coagulation and complement system also contribute to the development of urticaria. Here, we summarized the behaviors, markers and targets of basophils in relation to the coagulation-complement system, and for the treatment of CSU.

Time Course of Priming Effect of TF Inducers on Synergistic TF Expression and Intra-Cellular Gap Formation of Human Vascular Endothelial Cells via the Extrinsic Coagulation Cascade.

Chronic spontaneous urticaria (CSU) is characterized by daily recurring wheal and flare with itch for more than 6 weeks. The extrinsic coagulation system has been shown to be activated in correlation with CSU severity. We have reported that tissue factor (TF), a trigger of the extrinsic coagulation cascade, is synergistically expressed on vascular endothelial cells by simultaneous stimulation with TF inducers (TFI), followed by activation of the extrinsic coagulation cascade and hyper permeability in vitro. However, vascular endothelial cells are not likely to be simultaneously stimulated by multiple TFIs under physiological conditions. Therefore, in order to know whether sequential, rather than simultaneous, stimuli with interval may induce synergistic activation of TF, we investigated the time course of the priming effects of each TFI for synergistic TF expression in vascular endothelial cells (HUVECs). We stimulated HUVECs with a TFI (first stimulation) and then stimulated cells with another TFI at indicated time points (second stimulation) and detected TF expression and activity. The TF expression induced by simultaneous stimulation diminished in a few hours. However, both synergistic enhancement of TF expression and activation level of the coagulation cascade were detected even when the second stimulation was added 18 or 22 h after the first stimulation. Thus, the priming effect of TFI for synergistic TF expression may persist for a half day or longer.

Real-world efficacy of proactive maintenance treatment with delgocitinib ointment twice weekly in adult patients with atopic dermatitis.

Previous studies have shown the efficacy of delgocitinib (DEL) ointment, a topical Janus kinase inhibitor, against atopic dermatitis (AD). However, there is no available information regarding the efficacy of DEL ointment in maintaining remission. Data of patients with AD who received remission maintenance therapy twice weekly with DEL or topical corticosteroid (TCS) on the affected skin of each upper limb were extracted from the medical records. Efficacy was assessed based on changes in pruritus numerical rating scale (NRS) score, stratum corneum hydration (SCH), erythema index (EI). Of 25 patients, four patients (16%) had eczema flare-ups on the TCS side and eight patients (32%) on the DEL side. The extent of change in each parameter between TCS- and DEL-treated areas of the skin did not differ significantly. The mean changes in the NRS and EI showed a slight improvement on the side treated with TCS and were slightly worse on the side treated with DEL. However, the SCH of the DEL group was maintained, while that of the TCS group worsened. TCS is more likely to be effective than DEL in terms of remission maintenance therapy. However, topical DEL is as effective as topical steroid in the maintenance therapy of AD in dry skin patients.

Clinical and histological characterization of transient dermal pain triggered by sweating stimuli.

BACKGROUND: Tingling dermal pain triggered by sweating impairs the lives of patients with cholinergic urticaria and generalized anhidrosis. However, dermal pain evoked by sweating stimuli has been under investigated. METHODS: To clarify characteristics of tingling dermal pain on sweating, we retrospectively evaluated clinical and histopathological manifestations in 30 patients having the main problem of dermal pain on sweating, and the efficacy of treatments. RESULTS: Dermal pain upon sweating affected mostly young males. It accompanied eruptions upon sweating and/or hypohidrosis in 24 patients, while 6 patients had dermal pain independently of hypohidrosis or eruptions. Dermal pain appeared immediately upon exposure to sweating stimuli, and disappeared within mostly 30 or 10 min. Hypohidrosis was not necessarily generalized but localized or absent. Histological analysis revealed that dermal pain could occur even without morphological changes and inflammation of sweat glands. Hypersensitivity to sweat contents was found only in 26% of patients. Sweat histamine and increase of plasma histamine after thermal induction in patients were significantly higher than those in healthy subjects. Effectiveness of steroid pulse therapy was demonstrated for dermal pain with hypohidrosis. Medications acting on nervous systems and regular sweat-inducing activities for promoting perspiration were also effective. CONCLUSIONS: Short-lasting tingling dermal pain appears immediately upon exposure to sweating stimuli, regardless of developing eruptions and/or presence of hypohidrosis, but possibly in association with sweat and plasma histamine.

A novel detection method for cross-linking of IgE-receptors by autoantibodies in chronic spontaneous urticaria.

BACKGROUND: Autoantibodies (AAbs) against immunoglobulin E (IgE) antibodies (Abs) and their high-affinity receptor alpha subunits (FcεRIα) are key factors in the elicitation of type IIb autoimmune chronic spontaneous urticaria (type IIb aiCSU). In this study, we aimed to develop a new method to detect functional anti-FcεRIα and anti-IgE AAbs, which can crosslink the plural FcεRІα molecules and IgE Abs on the surface of mast cells and basophils, in sera from aiCSU patients using the amplified luminescence proximity homogeneous assay (Alpha). METHODS: Sera were obtained from 14 aiCSU patients, as diagnosed by recurrent chronic spontaneous urticaria episodes and positive results for the autologous serum skin test and/or histamine release test (HRT). The AAbs to FcεRIα and IgE Abs were determined in sera from aiCSU patients using enzyme-linked immunosorbent assay (ELISA) and Alpha by cross-linking (AlphaCL) of IgE Abs and/or FcεRІα. RESULTS: Serum anti-FcεRIα and anti-IgE AAb levels were not significantly different between aiCSU patients and healthy subjects in ELISA. Anti-FcεRIα AAbs were detected in 10 of 14 aiCSU patients who displayed positive (5/5) and negative (5/9) results in the HRT for anti-FcεRIα AAbs by AlphaCL, whereas no signals were observed in healthy subjects. Additionally, anti-IgE AAbs were detected in two of four aiCSU patients who displayed positive results in the HRT for anti-IgE AAbs. CONCLUSIONS: A new assay method using AlphaCL can detect anti-FcεRIα and anti-IgE AAbs with FcεRIα- and IgE-crosslinking abilities in sera from aiCSU patients. This simple and practical assay method may be available as a diagnostic tool for urticaria patients.

A single reaction-diffusion equation for the multifarious eruptions of urticaria.

Urticaria is a common skin disorder characterized by the rapid appearance and disappearance of local skin edema and flares with itching. It is characterized by various macroscopic skin eruptions unique to patients and/or subtypes of urticaria with respect to shape, size, color, and/or duration of eruptions. Nevertheless, the mechanism underlying multifarious eruptions in urticaria is largely unknown. The eruptions are believed to be evoked by histamine release from mast cells in the skin. However, the majority of visible characteristics of urticaria cannot be explained by a simple injection of histamine to the skin. To explain the multifarious eruptions of urticaria, we developed a single reaction-diffusion model suggesting the self-activation and self-inhibition regulation of histamine release from mast cells. Using the model, we found that various geometrical shapes of eruptions typically observed in patients can be explained by the model parameters and randomness or strength of the initial stimuli to mast cells. Furthermore, we verified that the wheal-expanding speed of urticaria, which is shown to be much smaller than that of the intradermal injection experimental system may be explained by our model and a simple diffusion equation. Our study suggests that the simple reaction-diffusion dynamics, including the independent self-activating and -inhibitory regulation of histamine release, may account for the essential mechanism underlying the formation of multifarious eruptions in urticaria.

A validation study of the Japanese version of the Angioedema Activity Score (AAS) and the Angioedema Quality of Life Questionnaire (AE-QoL).

BACKGROUND: Recurrent angioedema (RecAE) has a substantial impact on patients' daily lives. However, there have been no disease-specific patient-reported outcomes (PROs) available in Japan to measure disease activity and health-related QoL impairment in such patients. METHODS: Japanese versions of the Angioedema Activity Score (AAS) and the Angioedema Quality of Life Questionnaire (AE-QoL) were examined for their validity and reliability. By using these questionnaires, the relationship between disease activity and QoL impairment among the Japanese population of RecAE were analyzed in real-world setting. RESULTS: The Japanese AAS and AE-QoL domains showed good internal consistency of 0.967 and > 0.835. For known group validity, AAS28 and AE-QoL total scores were higher in more severe patients than those with milder disease and QoL impairment, respectively. AAS28 showed strong correlation with indexes of disease activity, while the AE-QoL total score correlated with Dermatology Life Quality Index (DLQI). Sufficient reproductivity of the AAS and AE-QoL was shown by their intraclass correlation coefficients of 0.890 and 0.700. The Japanese population is characterized by the total score of AAS28, 34.3 ± 38.8 (mean ± SD); and AE-QoL, 38.7 ± 25.2. Each domain score of AE-QoL was 32.4 ± 29.7 in "Functioning", 35.0 ± 27.8 in "Fatigue/mood", 50.7 ± 30.6 in "Fears/shame", or 24.7 ± 29.8 in "Food". Changes in AAS28 and AE-QoL positively correlated to Patient global assessment of disease activity and DLQI, respectively. CONCLUSIONS: The Japanese AAS and AE-QoL are valid and reliable instruments for Japanese patients with RecAE, and active disease affecting QoL. They help assess disease activity and QoL of RecAE in routine patient care and clinical trials.

Calculation of practical skin donor area for meshed skin grafting in real-world surgery.

Meshed skin grafting is a common technique in operations to minimize surgery on the donor site area. However, the donor site area is empirically determined by surgeons due to the lack of a reliable formula to calculate the donor area required to cover a skin defect. To determine the minimal size for donor skin, the expansion rates of 1.5:1, 3:1, and 6:1 meshed skin graft and the area actually covered by them were investigated in real-world operations. About 51 patients who received 57 operations with meshed skin grafts were enrolled in this study. The average clinical coverage rates of area in cases in which 1.5:1, 3:1, or 6:1 meshed skin grafting was performed were 1.02, 1.29, or 2.18, respectively. Those rates were notably low when recipient sites were concave. The average expansion rates of 1.5:1, 3:1, and 6:1 meshed skin grafts were about 1.16, 1.61, and 2.32, respectively. These results indicate that the size of donor skin should be about 85%, 60%, and 45% size of the recipient site to achieve the target 1.5:1, 3:1, and 6:1 meshed skin graft, respectively. In addition, the donor area should be adjusted in consideration of the shape of the recipient sites.

Roles of omalizumab in various allergic diseases.

IgE and mast cells play a pivotal role in various allergic diseases, including asthma, allergic rhinitis, and urticaria. Treatment with omalizumab, a monoclonal anti-IgE antibody, has significantly improved control of these allergic diseases and introduced a new era for the management of severe allergic conditions. About 10 years of experience with omalizumab treatment for severe allergic asthma confirmed its effectiveness and safety, reducing symptoms, frequency of reliever use, and severe exacerbations in patients with intractable conditions. Omalizumab is particularly useful in childhood asthma, where atopic conditions often determine clinical courses of asthma. Recently, omalizumab is approved for the treatment of chronic spontaneous urticaria (CSU) with the fixed dose of 300 mg. Although the mechanisms underlying the actions of omalizumab in CSU are not fully clarified, nearly 90% of patients with CSU showed a complete or a partial response to omalizumab treatment. Furthermore, omalizumab is just approved for the treatment of severe Japanese cedar pollinosis (JC) based on the successful results of an add-on study of omalizumab for inadequately controlled severe pollinosis despite antihistamines and nasal corticosteroids. For proper use of omalizumab to treat severe JC, co-administration of antihistamines is necessary, while patients should meet the criteria including strong sensitization to Japanese cedar pollen (≥class 3) and poor control under standard treatment. In the management of severe allergic diseases using omalizumab, issues including cost and concerns about relapse after its discontinuation should be overcome. At the same time, possibilities for application to other intractable allergic diseases should be considered.

Type-I-hypersensitivity to 15 kDa, 28 kDa and 54 kDa proteins in vitellogenin specific to Gadus chalcogrammus roe.

BACKGROUND: Fish roe allergy is a common health problem in countries where sea food is a major part of the diet, such as Japan. ß'-component (ß'-c) in fish roe has been identified as a major antigen for patients who show hypersensitivity to various fish roes. However, little is known about causative antigens for patients reactive to fish roe of specific species. METHODS: Serum and basophils were obtained from patients who had reactivity to roes of Gadus chalcogrammus (GC) and/or other fish species. GC roe specific antigens were analyzed by immunoblotting, histamine release assay (HRA) and mass spectrometry. Recombinant-fragments of vitellogenin (Vg) were obtained by the Escherichia coli expression system. RESULTS: Serum IgE of a patient with specific reactions to GC roe bound to 15, 28, 40 and 70 kDa-proteins in GC roe extract. Mass spectrometry analysis revealed that proteins in these bands contained fragments corresponding to Vg. Immunoblotting of Vg immunoprecipitated by rabbit anti-Vg antiserum from the extract revealed 15, 28 and 54 kDa fragments bound by the patient's IgE. These bindings were inhibited by the pretreatment of recombinant phosvitin (rPv) and ß'-c (rß'-c). Fractions obtained by native gel electrophoresis containing 15, 28 and 54 kDa proteins, but not the other fractions, induced significant histamine release from the patient's basophils. Sera of the other patients with GC roe specific-IgE showed IgE binding to rPv and/or rß'-c. CONCLUSIONS: The 15, 28 and 54 kDa-fragments of Vg which include structures of Pv and ß'-c, could be antigens for GC roe specific type-I-hypersensitivity.

Activation of Human Peripheral Basophils in Response to High IgE Antibody Concentrations without Antigens.

Basophils and mast cells have high affinity IgE receptors (FcεRI) on their plasma membrane and play important roles in FcεRI-associated allergic diseases, such as pollen allergy, food allergy, chronic spontaneous urticarial (CSU), and atopic dermatitis (AD). To date, several reports have revealed that high IgE antibody concentrations activate mast cells-which reside in tissue-in the absence of any antigens (allergens). However, IgE antibody-induced activation of basophils-which circulate in blood-has not been reported. Here, we investigated whether IgE antibodies may regulate functions of human peripheral basophils without antigens in vitro. We successfully removed IgE antibodies bound to FcεRI on the surface of human peripheral basophils by treating with 0.1% lactic acid. We also demonstrated that high IgE antibody concentrations (>1 µM) induced histamine release, polarization, and CD203c upregulation of IgE antibody-stripped basophils. Thus, high IgE antibody concentrations directly activate basophils, which express IgE-free FcεRI on the cell surface. This mechanism may contribute to the pathogenesis of patients with AD and CSU who have higher serum IgE concentrations compared to healthy donors.

Chronic spontaneous urticaria and the extrinsic coagulation system.

Chronic spontaneous urticaria (CSU) is a common skin disorder characterized by daily or almost daily recurring skin edema and flare with itch. Recently, the activation of the blood coagulation cascade has been suggested to be involved in CSU, but the trigger of the coagulation cascade remains unclear. In this article, we review recent understanding of the relationship between the pathogenesis of CSU and extrinsic coagulation reactions. In CSU, vascular endothelial cells and eosinophils may play a role as TF-expressing cells for activating the extrinsic coagulation pathway. Moreover, the expression of TF on endothelial cells is synergistically enhanced by the activation of Toll-like receptors and histamine H1 receptors. The activated coagulation factors may induce plasma extravasation followed by degranulation of skin mast cells and edema formation recognized as wheal in CSU. Molecules involved in this cascade could be a target for new and more effective treatments of urticaria.

Sweat allergy.

Sweat allergy is defined as a type I hypersensitivity against the contents of sweat, and is specifically observed in patients with atopic dermatitis (AD) and cholinergic urticaria (CholU). The allergic reaction is clinically revealed by positive reactions in the intradermal skin test and the basophil histamine release assay by sweat. A major histamine-releasing antigen in sweat, MGL_1304, has been identified. MGL_1304 is produced at a size of 29 kDa by Malassezia (M.) globosa and secreted into sweat after being processed and converted into the mature form of 17 kDa. It induces significant histamine release from basophils of patients with AD and/or CholU with MGL_1304-specific IgE, which is detected in their sera. Patients with AD also show cross-reactivity to MGL_1304-homologs in Malassezia restricta and Malassezia sympodialis, but MGL_1304 does not share cross antigenicity with human intrinsic proteins. Malassezia or its components may penetrate the damaged epidermis of AD lesions and interact with the skin immune system, resulting in the sensitization and reaction to the fungal antigen. As well as the improvement of impaired barrier functions by topical interventions, approaches such as anti-microbial treatment, the induction of tolerance and antibody/substance neutralizing the sweat antigen may be beneficial for the patients with intractable AD or CholU due to sweat allergy. The identification of antigens other than MGL_1304 in sweat should be the scope for future studies, which may lead to better understanding of sweat allergy and therapeutic innovations.

Impedance-Based Living Cell Analysis for Clinical Diagnosis of Type I Allergy.

Non-invasive real time evaluation of living cell conditions and functions are increasingly desired in the field of clinical diagnosis. For diagnosis of type I allergy, the identification of antigens that induces activation of mast cells and basophils is crucial to avoid symptoms of allergic diseases. However, conventional tests, such as detection of antigen-specific IgE antibody and skin tests, are either of low reliability or are invasive. To overcome such problems, we hereby applied an impedance sensor for label-free and real-time monitoring of mast cell reactions in response to stimuli. When IgE-sensitized RBL-2H3 cells cultured on the electrodes were stimulated with various concentrations of antigens, dose-dependent cell index (CI) increases were detected. Moreover, we confirmed that the impedance sensor detected morphological changes rather than degranulation as the indicator of cell activation. Furthermore, the CI of human IgE receptor-expressing cells (RBL-48 cells) treated with serum of a sweat allergy-positive patient, but not with serum from a sweat allergy-negative patient, significantly increased in response to purified human sweat antigen. We thus developed a technique to detect the activation of living cells in response to stimuli without any labeling using the impedance sensor. This system may represent a high reliable tool for the diagnosis of type I allergy.