Do basophil activation tests help elucidate allergic reactions to the ingredients in COVID-19 vaccines?

The worldwide use of COVID-19 vaccines has shown that immediate allergic reactions to the ingredients are rare but should be clarified by means of an allergological work-up. This review aims to highlight the current state of knowledge and possible pathogenesis based on the literature published to date. In addition to recording a detailed history and performing skin tests, cellular tests (basophil activation or basophil histamine release test) by using the vaccines or modified compounds containing polyethylene glycol (PEG), rather than unmodified PEGs, have proven to be particularly helpful. Negative results with vaccines seem to indicate tolerance. Details of the performance of these cellular tests with different vaccines, PEGs of different molecular weights, other ingredients of the vaccines, as well as other PEGylated drugs, and the results in the context of COVID-19 vaccination of various working groups worldwide are summarized.

Clinical utility of the basophil activation test in the diagnosis of sweat allergy.

BACKGROUND: Many patients with atopic dermatitis and cholinergic urticaria display an immediate-type allergy to autologous sweat. Although the histamine release test (HRT) using semi-purified sweat antigen (QR) was available for the detection of immediate sweat allergy, the existence of HRT low responders could not be disregarded. Furthermore, it has not been established whether the results of the HRT are consistent with the autologous sweat skin test (ASwST). We aimed to compare the HRT and basophil activation test (BAT) for the diagnosis of immediate sweat allergy. METHODS: The HRT and BAT were performed on 47 subjects (35 ASwST positive, 12 negative) whose symptoms had worsened on sweating. For the BAT, blood was incubated with QR or crude sweat and CD203c upregulation was assessed. A commercial HRT was performed and histamine release induced by QR was quantified. RESULTS: When excluding non-responders for anti-IgE antibody, the BAT using QR and the HRT had a sensitivity of 100% and 44% and specificity of 75% and 100%, respectively. The BAT and HRT had a positive predictive value of 91.3% and 100% and negative predictive value of 100% and 30%, respectively. The BAT detected 0% non-responders, whereas the HRT identified 22.5%. When using crude sweat for the BAT, the false-positives observed when using QR were not detected. CONCLUSIONS: The BAT using QR displayed a higher sensitivity and negative predictive value and a lower number of non-responders compared with the HRT. Furthermore, the BAT using crude sweat can also be an alternative tool for the ASwST.

Histamine-release test in angioedema patients without urticaria - a retrospective cohort study of 404 patients.

Summary: A subset of patients with angioedema (AE) and urticaria has histamine releasing autoantibodies. The histamine release test (HR-test) has been used as a tool in chronic urticaria to define the autoimmune subgroup and may possibly guide the clinician to a more personalized therapy, like omalizumab and cyclosporine. The prevalence and value of positive histamine releasing autoantibodies in monosymptomatic AE is sparsely described in the literature. The purpose of this study was to report the prevalence of positive histamine releasing autoantibodies in a cohort of patients with recurrent AE and evaluate the usefulness of this test in AE patients. We performed a retrospective cohort study of 612 patients referred due to AE between 1995 and 2013. HR-test results were available in 404 patients. In the sub-group of patients with AE and urticaria, 17.3% had a positive HR-test but only 4.3% of patients with mono-symptomatic AE had a positive HR-test. No statistically significant treatment benefits of antihistamines, corticosteroids or adrenaline were found comparing patients with angioedema +/- urticaria based on the result of the HR-test (negative / positive). Thus, the HR-test result cannot be used as predictor of the efficacy of anti-allergic treatment.

Histamine release positive test associates with disease remission in chronic spontaneous urticaria: a proof-of-concept study.

SUMMARY: Background. Histamine release (HR) test has previously been shown to predict the presence of endogenous histamine-releasing factors in chronic spontaneous urticaria (CSU). Objectives and methods. Twenty CSU patients unresponsive to antihistamine treatment were enrolled in order to evaluate the correlations between HR test results and demographic features, quality of life, disease activity, clinical course, and autologous serum and plasma skin tests (ASST and APST). Results. All patients with positive HR test (9/9, 100%) had a more severe disease activity at onset (urticaria activity score, UAS > 2) when compared to negative HR test patients (5/11; p = 0.04). Quality of life questionnaire's results were not substantially different between HR positive and negative subgroups at baseline (p > 0.05), and results of HR test and ASST/APST did not co-segregate (p > 0.05). After 12 months, patients with a positive HR test had a significant reduction of disease activity (p = 0.003) whereas patients with a negative HR test did not (p > 0.05), leading to disease remission and antihistamine treatment withdrawal in 67% (6/9) of positive HR test patients versus 18% (2/11) of negative HR test patients (p = 0.027). Conclusions. Positive HR test may predict spontaneous CSU remission at 12 months.

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.

Development of hypoallergenic galacto-oligosaccharides on the basis of allergen analysis.

Galacto-oligosaccharides (GOSs) are recognized as prebiotics beneficial to human health through their abilities to modulate gut microbiota. On the other hand, it has been reported that immediate allergic reactions are caused by a GOS product (Bc-GOS) produced by treating lactose with ß-galactosidase derived from Bacillus circulans. The objective of this study was to create a safer GOS product that is less likely to cause GOS-induced allergy (GOS-AL). First, we identified two derivatives of tetrasaccharide sugar chains in Bc-GOS as the factors responsible for GOS-AL by histamine release test (HRT) using blood samples obtained from two GOS-AL patients. Through our search for non-allergic GOS, we developed a new GOS product, SK-GOS, which was produced by catalyzing lactose with ß-galactosidase derived from Sporobolomyces singularis and Kluyveromyces lactis. We regard it as a hypoallergic and safe GOS product that does not cause GOS-AL.

Fungal protein MGL_1304 in sweat is an allergen for atopic dermatitis patients.

BACKGROUND: Sweat is a major aggravating factor of atopic dermatitis (AD) and approximately 80% of patients with AD show type I hypersensitivity against sweat. OBJECTIVE: To identify and characterize an antigen in sweat that induces histamine release from basophils of patients with AD. METHODS: Basophil histamine-releasing activity in sweat was purified by a combination of chromatographies, and proteins were analyzed with mass spectrometry. Recombinant proteins of the sweat antigen were generated, and their biological characteristics were studied by immunoblots, histamine release tests, and neutralization assays. RESULTS: We identified a fungal protein, MGL_1304, derived from Malassezia globosa (M globosa) in the purified sweat antigen. Recombinant MGL_1304 induced histamine release from basophils of most of the patients with AD, in accordance with the semi-purified sweat antigen. Moreover, recombinant MGL_1304 abolished the binding of serum IgE of patients with AD to the semi-purified sweat antigen, or vice versa in immunoblot analysis, and attenuated the sensitization of RBL-48 mast cells expressing human FcɛRI by serum IgE. Studies of truncated mutants of MGL_1304 indicated that IgE of patients with AD recognized the conformational structure of MGL_1304 rather than short peptide sequences. Western blot analysis of the whole lysate, the culture supernatant of M globosa, and the semi-purified sweat antigen showed that MGL_1304 was produced as a minor immunological antigen of M globosa with posttranslational modification, cleaved, and secreted as a 17-kDa major histamine-releasing sweat antigen. CONCLUSION: MGL_1304 is a major allergen in human sweat and could cause type I allergy in patients with AD.

What Basophil Testing Tells Us About CSU Patients - Results of the CORSA Study.

Basophil testing is the most effective single approach for diagnosing type-IIb autoimmune chronic spontaneous urticaria (TIIbaiCSU). A positive basophil test has been linked to long disease duration, higher disease activity, a poor response to antihistamines and omalizumab, and a better response to cyclosporine and fenebrutinib. As of now it is unclear what other features are connected to a positive basophil test in chronic spontaneous urticaria (CSU). We aimed to identify features of basophil test-positive CSU patients. We performed a cross-sectional study of 85 CSU patients. Basophil testing was done with the basophil activation test (BAT) and the basophil histamine release assay (BHRA). Data were analysed using SPSS: Student's t-test, Chi-square test, Odds Ratio, Spearman's correlation test. Of 85 CSU patients, 44% and 28% tested positive with the BAT and BHRA, respectively. These patients showed higher disease activity and impact, lower levels of disease control and total serum IgE, as well as higher rates of having a positive autologous serum skin test (ASST), angioedema, nocturnal symptoms, symptoms for >5 days/week, and thyroid autoantibodies. The ASST, by itself, was not a good predictor of basophil test results, but it predicted a positive basophil test in up to 100% of cases when combined with angioedema, thyroid autoantibodies or low IgE. In conclusion, a positive basophil test is linked to known features of TIIbaiCSU and novel characteristics including nocturnal symptoms. Further studies on basophil test-positive and -negative CSU patients can help to better understand CSU endotypes and to develop better management approaches.

Development and validation of a highly sensitive LC-MS/MS method for in vitro measurement of histamine concentration.

The basophil histamine release test (HRT) is an important in vitro diagnostic assay to evaluate immunoglobin E (IgE)-mediated allergic responses. In this study, a bioanalytical LC-MS/MS method was developed and validated to quantify histamine in the leukocyte suspension from human peripheral blood. The method used pre-column derivatization with phenylisothiocyanate (PITC) and the resulting phenylthiocarbamyl (PTC) histamine was analyzed by positive-ion electrospray ionization using the multiple reaction monitoring mode. Chromatographic separation was achieved using an Imtakt-HT C18 column (2.1 mm × 50 mm, 3.0 µm), with a flow rate of 0.35 mL/min, 2 µL injection, and gradient elution with a mixture of acetonitrile-2 mM ammonium acetate buffer (both containing 0.1% formic acid). The total runtime of the method was 3.0 min including equilibration time. The method had a lower limit of detection of 0.1 ng/mL, and the quantifiable range was 0.1-100 ng/mL in the leukocyte suspension. The intra-day and inter-day precision and accuracy results were within the acceptable limits. It was established that histamine quantification should be performed within 2 h of preparing the leukocyte suspension, and freezing and thawing should be avoided. This method was successfully applied to the diagnosis and evaluation of the pathophysiologic mechanism of respiratory or cutaneous allergic diseases.

Acidic polypeptides A1a, A3 and A4 of Gly m 6 (glycinin) are allergenic for piglets.

Gly m 6 (glycinin) is one of the major antigenic proteins in soybeans responsible for transient hypersensitivity to soybean meal in weaned piglets. The globulin is a hexamer consisting of subunits containing basic and acidic polypeptides. Multiple acidic polypeptides have long been demonstrated to be allergens for humans and play a key role in the overall allergenicity of Gly m 6. To date, knowledge on the allergenicity of the acidic polypeptides for piglets is very limited. The purpose of this study was to identify the acidic polypeptides that were allergenic for piglets and to characterize these acidic polypeptides by ELISA, western blot, skin prick and basophile histamine release test. The IgG and IgE antibody binding capacities of the acidic polypeptides of Gly m 6 were determined using ELISA and western blot analysis with sera from Gly m 6 sensitized piglets. Skin prick test and basophile histamine release test were conducted to measure the effector cell response to the polypeptides. Specific IgG and IgE antibodies against A1a, A3 and A4 of Gly m 6 were identified in the sera of Gly m 6 sensitized piglets. Meanwhile, positive skin prick test and specific histamine release responses were also induced by the acidic polypeptide A1a, A3 and A4 of Gly m 6 from the basophiles of Gly m 6 sensitized piglets. The results demonstrate that the acidic polypeptide A1a, A3 and A4 of Gly m 6 are allergenic for piglets.

Evolution of diagnostic approaches in betalactam hypersensitivity.

INTRODUCTION: Betalactams are the most widely used drugs against infections and the primary cause of antibiotic hypersensitivity reactions. Reaction patterns for different betalactams have been changing in accordance with consumption trends, and vary among countries. As a consequence, in vivo and in vitro tests have had to change with to keep up with new tendencies. Areas covered: This review is focused on advances in betalactam hypersensitivity diagnosis. Changes in in vivo methods have been limited to the inclusion of new haptens. In contrast, major progress has been achieved for in vitro tests since the 1960s, from the first description of immunoassays, the basophil activation test and the lymphocyte transformation test, to the more sophisticated assays developed in last years. Expert commentary: Issues with diagnosis are related to test sensitivity. In vivo tests show higher sensitivity, however they can be risky, especially in severe and life-threatening reactions. Therefore, we believe that in vitro tests should be the preferred method. Current efforts are under way to enhance their sensitivity. Only multidisciplinary approaches involving immunology, proteomics, nanotechnology and chemistry can help us to fully understand conjugate structures and mechanisms involved in hypersensitivity reactions to betalactams, and consequently lead to advances in in vitro methods.

Optimizing diagnostic tests for persulphate-induced respiratory diseases.

BACKGROUND: Persulphates from hair bleaching products are considered the major cause of occupational-rhinitis and asthma in hairdressers. The specific inhalation challenge (SIC) is considered 'reference standard' for diagnosing persulphate-induced asthma and rhinitis; however, the currently validated method of performing SIC with persulphate powder is time consuming with a duration of up to 4 days. The value of skin prick tests (SPTs) and histamine release tests (HRTs) with persulphates is unknown. The aim of this study was to establish a novel rapid SIC with persulphate powder to test for both rhinitis and asthma simultaneously in 1 day. In addition, we assessed the suitability of SPTs and HRTs for detecting persulphate-induced respiratory diseases. METHODS: The study population included 19 hairdressers with a history of work-related rhinitis and/or asthma symptoms, 12 symptomatic controls (10 with concurrent allergic asthma and rhinitis and two with non-allergic asthma), and 40 healthy controls. A previous severe asthmatic reaction and/or anaphylactic reaction to persulphates was considered an exclusion criterion for hairdressers. The 19 hairdressers and 12 symptomatic controls had SIC performed with 3 × 5 min exposures to potassium persulphate powder in a provocation chamber. All participants, including the 40 healthy controls, were subjected also to SPTs and HRTs with three persulphate salts at concentrations of 2-20 % and 0.03-1 %, respectively. RESULTS: None of the symptomatic controls had a nasal or bronchial response to SIC with potassium persulphate. Six hairdressers presented a nasal and two a bronchial response. No severe reactions occurred. No positive SPTs were recorded, neither among hairdressers, symptomatic controls, nor healthy controls. All three groups showed nonspecific non-IgE mediated histamine release to persulphates in HRT. CONCLUSIONS: The proposed method for performing SIC showed a high specificity for detecting persulphate-induced asthma and rhinitis. The rapid SIC was able to produce positive nasal and bronchial responses in symptomatic hairdressers without any severe reactions occurring. SPTs and HRTs cannot predict asthma or rhinitis caused by persulphates.