Applying Surface Plasmon Resonance to Monitor the IgE-Mediated Activation of Human Basophils

ABSTRACTBackgroundThe histamine releasing test which detects histamine released from basophils in vitro is safe, sensitive and widely used for clinical examination in the field of allergy. However, basophils of certain individuals do not release histamine, because of dysfunctions in their intracellular signal transduction (non-responder). To overcome potential shortcomings of the histamine releasing test, we applied surface plasmon resonance (SPR) to detect the activation of basophils.MethodsBasophils of patients with allergy, and those of non-allergic volunteers were isolated from peripheral blood. A batch of basophils obtained from a healthy volunteer was treated with lactic acid and IgE of a patient with atopic dermatitis in order to replace their endogenous IgE. They were fixed on the sensor chip of the SPR apparatus, pretreated with or without various inhibitors for intracellular signal transduction, and exposed to the antigens or anti-IgE antibody.ResultsWhen basophils were sensitized with antigen specific IgE, they immediately caused the increase of resonance angle (AR) in response to either anti-IgE antibody or corresponding antigens, even when they did not release histamine. Moreover, the dose dependent reactions of basophils were reflected by the increase of AR as well as the release of histamine. The increase of AR in response to anti-IgE antibody was reduced by pre-treatment of basophils with inhibitors for intracellular signal transduction, but not more than the level for his- tamine release.ConclusionsSPR biosensors may be superior to the histamine release test for studying functions of human basophils including those not releasing histamine

Sensitization against skin resident fungi is associated with atopy in cholinergic urticaria patients

Background: Cholinergic urticaria (CholU) is a common type of chronic inducible urticaria, characterized by small itchy wheals that appear upon physical exercise or passive warming. Malassezia globosa, a skin resident fungus, has been identified as an antigen that induces mast cell/basophil degranulation and wheal formation through specific IgE, in Japanese patients with atopic dermatitis and CholU. In this study we aimed in assessing the rate of IgE sensitizations against skin resident fungi in European CholU patients. Methods: We assessed serum IgE levels to Malassezia furfur, Candida albicans and Trichophyton mentagrophytes using routine lab testing and Malassezia globosa using a newly established ELISA. We correlated the results to wheal formation and other clinical features. Results: Four patients (of 30 tested) had elevated levels of IgE against Malassezia furfur and Candida albicans and two had elevated levels of IgE against Trichophyton mentagrophytes. Four sera (of 25 tested) had elevated levels of IgE to the Malassezia globosa antigen supMGL_1304. Sensitization to one skin fungus was highly correlated with sensitization to the other tested fungi. We saw highly significant correlations of sensitization to supMGL_1304 with wheal size in the autologous sweat skin test (rs = 0.7, P = 0.002, n = 19), the Erlangen atopy score (rs = 0.5, P = 0.03, n = 19), total IgE serum levels (rs = 0.5, P = 0.04, n = 19) and a positive screen for IgE against common airborne/inhalant allergens s (sx1; rs = 0.54, P = 0.02, n = 19). Conclusions: Sensitization to skin resident fungi including Malassezia globosa is uncommon in European CholU patients, but is associated with atopy and pronounced wheal formation upon dermal contact with their own sweat.Trial registration German Clinical Trials Registry DRKS-ID: DRKS00004277

Elevated Serum IgE against MGL_1304 in Patients with Atopic Dermatitis and Cholinergic Urticaria

ABSTRACTBackground: MGL_1304 secreted by Malassezia globosa is contained in human sweat and induces histamine release from basophils in patients with atopic dermatitis (AD) at a high positive rate. The aims of this study were to establish the enzyme-linked immunosorbent assay (ELISA) measuring specific immunoglobulins against MGL_1304 and to investigate the levels of these immunoglobulins in sera of patients with various allergic diseases.Methods: Purified MGL_1304 from human sweat (QRX) and recombinant MGL_1304 (rMGL_1304) were prepared for ELISA. To quantify the amount of MGL_1304-specific immunoglobulins, the standard serum was created by pooling sera of 20 patients with AD whose basophils released histamine in response to QRX. A monoclonal antibody which exhibited the highest neutralizing ability against QRX was established as Smith-2, and used as a capture antibody for the assay of QRX-specific IgE. A total of 156 subjects [normal controls (n = 23), AD (n = 63), cholinergic urticaria (CU) (n = 24), bronchial asthma (n = 32), and allergic rhinitis (n = 14)] were enrolled in this study.Results: ELISA methods to quantify the specific IgE, IgG and IgG4 against MGL_1304 in sera were successfully established. Levels of QRX-specific IgE in sera of patients with AD and CU were significantly higher than those of normal controls. Moreover, the levels of QRX-specific IgE and rMGL_1304-specific IgE in patients with AD were significantly correlated with their disease severities.Conclusions: These ELISA methods to quantify the specific immunoglobulins against MGL_1304 are easy and useful means to assess allergy to MGL_1304. MGL_1304 contained in sweat is an important antigen for patients with AD and CU

Injury due to extravasation of thiopental and propofol: Risks/effects of local cooling/warming in rats

AbstractInadvertent leakage of medications with vesicant properties can cause severe necrosis in tissue, which can have devastating long-term consequences. The aim of this study was to evaluate the extent of extravasation injury induced by thiopental and propofol, and the effects of cooling or warming of local tissue on extravasation injury at macroscopic and histopathologic levels. Rats were administered intradermally thiopental (2.5mg/100µL) or propofol (1.0mg/100µL). Rats were assigned randomly to three groups: control (no treatment), cooling and warming. Local cooling (18–20°C) or warming (40–42°C) was applied for 3h immediately after agent injection. Lesion sizes (erythema, induration, ulceration, necrosis) were monitored after agent injection. Histopathology was evaluated in skin biopsies taken 24h after agent injection. Thiopental injection induced severe skin injury with necrosis. Peak lesions developed within 24h and healed gradually 18–27 days after extravasation. Propofol induced inflammation but no ulceration, and lesions healed within 1–2 days. Local cooling reduced thiopental- and propofol-induced extravasation injuries but warming strongly exacerbated the skin lesions (e.g., degeneration, necrosis) induced by extravasation of thiopental and propofol. Thiopental can be classified as a “vesicant” that causes tissue necrosis and propofol can be classified as an “irritant”. Local cooling protects (at least in part) against skin disorders induced by thiopental and propofol, whereas warming is harmful

Surface plasmon resonance-biosensor detects the diversity of responses against epidermal growth factor in various carcinoma cell lines

Surface plasmon resonance (SPR) biosensor detects intracellular signaling events as a change of the angle of resonance (AR). We previously reported that the activation of epidermal growth factor receptor (EGFR) on keratinocytes causes a unique triphasic change of AR, whereas the activation of other receptors, such as IgE receptor and adenosine A3 receptor on mast cells, causes a transient monophasic increase of AR. To study the mechanism of AR changes induced by EGFR activation, we introduced wild and mutated EGFR cDNAs into Chinese hamster ovary (CHO) cells and analyzed changes of AR in response to EGF. CHO cells expressing wild-type EGFR showed a triphasic change of AR, whereas cells expressing kinase-dead EGFR (K721 M) showed minimum change of AR. A phosphatidylinositol 3-kinase inhibitor, wortmannin, attenuated the third phase of AR change in CHO cells expressing wild-type EGFR. The pattern of AR change was independent on the concentration of EGF. We also analyzed changes of AR with a nontumorigenic keratinocyte cell line, HaCaT, and several cell lines of carcinoma to explore the feasibility of SPR biosensor as a tool for clinical diagnosis. The activation of HaCaT cells and one out of six carcinoma cell lines showed a full triphasic change of AR. In contrast, five out of the six cell lines showed mono- or bi-phasic change of AR. These results suggest that EGF induces the SPR signals via the phosphorylation of EGFR, and provide a possibility that the SPR biosensor could be applied to the real-time detection and diagnosis of malignant tumors

Evaluation of recombinant MGL_1304 produced by Pichia pastoris for clinical application to sweat allergy

AbstractBackgroundWe previously identified MGL_1304 secreted by Malassezia globosa as a sweat antigen for patients with atopic dermatitis (AD) and cholinergic urticaria (ChU). However, purifying native MGL_1304 from human sweat or culture supernatant of M. globosa (sup-MGL_1304) is costly and time-consuming. Moreover, recombinant MGL_1304 expressed by using Escherichia coli (TF-rMGL_1304) needs a large chaperon protein and lacks the original glycosylation of yeasts. Thus, we generated a recombinant MGL_1304 by Pichia pastoris (P-rMGL_1304) and investigated its characteristic features.MethodsRecombinant MGL_1304 proteins expressed by E. coli and P. pastoris were generated. Properties of these recombinants and native antigens were compared by western blot analysis, histamine release tests (HRT) of patients with AD and ChU, and β-hexosaminidase release tests with RBL-48 cells. P-rMGL_1304-specific IgE in sera of patients with AD were measured by sandwich ELISA.ResultsWestern blot analysis revealed that IgE of patients with AD bound to all MGL_1304 recombinants and native antigens. The histamine releasing ability of P-rMGL_1304 was 100 times higher than that of TF-rMGL_1304, and was comparable to that of sup-MGL_1304. Degranulation rates of RBL-48 cells, sensitized with sera of patients with AD in response to the stimulation of P-rMGL_1304, were comparable to those of sup-MGL_1304, whereas those of TF-rMGL_1304 were relatively weak. The levels of P-rMGL_1304-specific IgE in sera of patients with AD were correlated with their disease severities.ConclusionsP-rMGL_1304 has an antigenicity comparable to the native antigen, and is more useful than TF-rMGL_1304, especially in HRT and degranulation assay of RBL-48 cells

Japanese guidelines for atopic dermatitis 2020.

Atopic dermatitis (AD) is a disease characterized by relapsing eczema with pruritus as a primary lesion, which is frequently encountered in clinical practice. Skin barrier dysfunction leads to enhanced skin irritability to non-specific stimuli and epicutaneous sensitization. In the lesion site, a further inflammation-related reduction in skin barrier function, enhanced irritability and scratching-related stimuli deteriorate eczema, leading to vicious cycle of inflammation. The current strategies to treat AD in Japan from the perspective of evidence-based medicine consist of three primary measures: (i) the use of topical corticosteroids and tacrolimus ointment as the main treatment for the inflammation; (ii) topical application of emollients to treat the cutaneous barrier dysfunction; and (iii) avoidance of apparent exacerbating factors, psychological counseling and advice about daily life. The guidelines present recommendations to review clinical research articles, evaluate the balance between the advantages and disadvantages of medical activities, and optimize medical activity-related patient outcomes with respect to several important points requiring decision-making in clinical practice

Sustained safety and efficacy of ligelizumab in patients with chronic spontaneous urticaria: A one‐year extension study

Background: Ligelizumab, a next-generation, humanized anti-immunoglobulin E (IgE) monoclonal antibody is in development as a treatment for patients with chronic spontaneous urticaria, whose symptoms are inadequately controlled with standard-of-care therapy. Objective: To evaluate the long-term safety and re-treatment efficacy of ligelizumab 240 mg in patients who completed the core study and extension study. Methods: This open-label, single-arm, long-term Phase 2b extension study was designed to assess patients who were previously administered various doses of ligelizumab, omalizumab or placebo in the Phase 2b, dose-finding core study and who presented with active disease after Week 32. In the extension study, patients received ligelizumab 240 mg subcutaneously every 4 weeks, for 52 weeks and were monitored post-treatment for 48 weeks. Results: Overall, ligelizumab was well-tolerated with no newly identified safety signals. A total of 95.4% (226/237) screened patients received ligelizumab 240 mg in the extension study; 84.1% (190/226) of patients experienced at least one treatment-emergent adverse event. Most reported events were mild (41.6%) or moderate (35.8%) and mostly unrelated to the study treatment. At Week 12, 46.5% of patients had a complete response increasing to 53.1% after 52 weeks. Following 52 weeks of extension study treatment, 75.8% (95% confidence interval, 69.9, 81.3) of patients had cumulative complete responses. The median time to relapse in complete responders was 38 weeks. Conclusion: The long-term safety profile of ligelizumab 240 mg in patients with chronic spontaneous urticaria was consistent with the core study and re-treatment efficacy was shown. Trial registration: ClinicalTrials.gov Identifier: NCT02477332 and NCT02649218