Basophil CD63 Research Articles

A Streamlined Strategy for Basophil Activation Testing in a Multicenter Phase III Clinical Trial

BackgroundThe basophil activation test (BAT) has been limited to research settings due to technical issues. Novel approaches using dry, ready-to-use reagents and streamlined protocols offer greater flexibility and may open opportunities for easier implementation in clinical research. ObjectiveUsing a streamlined BAT (sBAT) strategy and the settings of the baseline study of the EPITOPE trial of EPicutaneous ImmunoTherapy (EPIT™) for peanut allergy, we aimed to assess the feasibility of implementing BAT in a multicenter trial and to evaluate its utility in predicting the outcomes of peanut double-blind placebo-controlled food challenge (DBPCFC). MethodsWhole blood samples were collected from subjects aged 1-3 years (n=241) undergoing baseline eligibility DBPCFC in the EPITOPE study across 15 clinical sites in North America. After preparation with sBAT reagents, processed samples were analyzed in a single central laboratory within 5 days of collection and preparation. The eliciting dose (ED) at DBPCFC was determined using PRACTALL criteria. Using a machine learning (ML) approach which incorporated BAT-derived features, clinical characteristics, and peanut-specific IgE, the ability to predict outcomes of interest (ED [<300 mg or >300 mg] and use of epinephrine) was assessed using data randomly split into training (n=182) and validation (n=59) subsets. ResultsThe expression of basophil activation markers CD203c and CD63 correlated with ED and severity outcomes of DBPCFC. Most informative concentrations of peanut extract in the sBAT assay for these associations were 1 and 10 ng/ml. Using ML to assess the ability to predict the outcomes of DBPCFC, the best models using only the BAT-derived features provided relatively high sensitivities of 0.86 and 0.85 for predicting eliciting dose and epinephrine use, respectively, while specificities were lower, ranging from 0.60 to 0.80. While including specific IgE and SPT data in addition to those from sBAT did not improve the ability to identify individuals most at risk for severe reactions, it did improve the ability to identify patients with an eliciting dose above 300 mg. ConclusionIn addition to facilitating implementation in multicenter trials, sBAT retains the potential of BAT to characterize allergic patients and confirms its potential to contribute to predicting the outcome of oral food challenges.

Sequential engagement of adhesion molecules and cytokine receptors impacts both piecemeal and anaphylactic degranulation of human basophils.

Basophils are rare granulocytes in circulation which home to tissues in a process depending on rolling, adhesion and cytokine exposure. However, it is still unclear how these steps affect basophil degranulation. Our aim was to imitate these processes associated with homing by sequential crosslinking of adhesion molecules and cytokine exposure and evaluate the effect on basophil piecemeal (PMD) and anaphylactic degranulation (AND). Blood donors with or without allergic asthma were recruited from an ongoing cohort study. Basophils were subjected to CD62L-, CD49d- or CD11b crosslinking and IL-3 or IL-33 stimulation in different orders followed by anti-IgE and fMLP stimulation. Basophil CD203c and CD63 expression were analysed by flow cytometry to determine PMD and AND, respectively. IL-3 induced PMD in basophils and combined with CD62L- or CD11b crosslinking, IL-3 potentiated the degranulation regardless of sequential order. IL-3 priming followed by adhesion molecule crosslinking induced AND and potentiated the effect of anti-IgE. CD62L- and CD11b crosslinking did not further potentiate this effect. CD49d crosslinking followed by IL-3 increased CD63 expression following anti-IgE. IL-3 potentiated the effect of fMLP on AND while adhesion molecule crosslinking did not. IL-33 had impact on PMD only when followed by adhesion molecule crosslinking but did not potentiate neither IgE-dependent nor IgE-independent degranulation. Our data indicate that sequential interactions between basophils, cytokines and adhesion molecule ligands have a decisive effect on basophil degranulation and that these interactions are operational for fine-tuning the activity of tissue dwelling basophils. These data should be considered when the effect of different pharmaceutical on basophil function is studied.

Higher House Dust Mite-Specific IgE Levels among Chronic Spontaneous Urticaria Patients May Implicate Higher Basophil Reactivity

Introduction: Allergen-specific IgE (sIgE) sensitization exists in a considerable fraction of chronic spontaneous urticaria (CSU) patients. Basophils have been implicated in the pathogenesis of CSU. This paper aimed to explore the relationship between allergic sensitization and basophil reactivity in CSU and the possible underlying mechanism. Methods: Basophil-enriched leukocytes were isolated from the peripheral blood of 76 CSU patients and 9 healthy controls. Basophil CD63 and FcεRIα (the alpha subunit of the high-affinity IgE receptor) expression in the blood samples with various house dust mite (HDM)-sIgE levels were determined by flow cytometry. Basophil reactivity and SHIP-1 (a molecule related to the IgE/FcεRI signaling pathway) expression were analyzed after stimulation with an HDM allergen or other stimuli. Results: HDM-sIgEstrong positive (≥3.5 kU/L) CSU patients had a significantly higher mean percentage of basophil CD63 and higher baseline levels of FcεRIα expressed by basophils than HDM-sIgEnormal (<0.35 kU/L) CSU patients and healthy controls; the same went for total serum IgE. After stimulation with Dermatophagoides pteronyssinus peptidase 1 (Derp1) alone or together with Derp1-sIgE, the stimulation index of CD63 and levels of FcεRIα expressed by basophils in HDM-sIgEstrong positive CSU patients were significantly higher than those in HDM-sIgEnormal CSU patients and healthy controls. Significantly more SHIP-1 mRNA expression in HDM-sIgEstrong positive CSU patients was induced after the combined stimulation in comparison to other subjects. Conclusion: CSU patients with higher HDM-sIgE levels (≥3.5 kU/L) may have higher CD63 and FcεRIα expression on peripheral blood basophils. Peripheral blood basophils in these CSU patients are more responsive to HDM allergen stimulation. Higher HDM-sIgE levels among CSU patients may implicate higher basophil reactivity.

Changes of basophil activation before and after treatment in children with allergic rhinitis and its clinical significance

ObjectiveTo investigate the changes of basophil activation before and after treatment of children with allergic rhinitis and its clinical significance. MethodsA total of 18 children with moderate to severe persistent allergic rhinitis in the acute phase were included as the subjects of this study. Based on the conventional therapy for allergic rhinitis, 2mL of anticoagulated peripheral blood was taken before the treatment (acute phase) and after the remission of clinical symptoms and signs (remission period), respectively. Inhalant allergen stimulation was performed in vitro and basophil activation status (expressions of CD63 and CD203c) was detected by flow cytometry so as to analyze the changes of basophil activation before and after treatment. Results1. The mean value of VAS score in children with allergic rhinitis before treatment was 8 (6, 9), while that in the post-treatment remission period was 2 (0, 3.2). The symptoms were greatly improved after treatment and the VAS score was decreased significantly. The differences were statistically significant (P<0.0001). 2. The mean expression rate of basophil CD63 (% CCR3+ CD63+) and CD203c (% CCR3+ CD203c+) was 74.35% (52.0%, 81.8%) and 69.2% (43.7%, 81.3%), respectively in pre-treatment acute phase, while that of CD63 (% CCR3+ CD63+) and CD203c (% CCR3+ CD203c+) was 41.5% (24.5%, 80.4%) and 42.1% (15.2%, 81.0%), respectively in post-treatment remission period. The differences were statistically significant (P<0.05). ConclusionAccording to the published basic and clinical researches, basophils may be important immune cells involved in allergic rhinitis. Basophil activation test can be used as an effective tool for allergen detection. The dynamic observation of basophil activation can provide an immunological basis for the clinical control of allergic rhinitis.

Activated steady status and distinctive FcεRI-mediated responsiveness in basophils of atopic dermatitis

BackgroundAlthough basophils are considered to play an important role for maintenance of type 2 inflammation in atopic dermatitis (AD), studies on basophils in AD patients are limited. Some studies have reported the activation status, including CD203c and CD63, of peripheral blood basophils in AD patients. MethodsWe examined the features of circulating basophils in AD patients, assessed cell surface marker expressions and total serum IgE, and compared basophil responsiveness to stimulation between AD patients and healthy controls (HCs). In addition, the correlations among AD severity, laboratory factors, and features of basophils were examined. Blood samples from 38 AD patients and 21 HCs were analyzed. Basophil response markers CD203c and CD63, and expression of surface-bound IgE and FcεRI on basophils were measured. CD203c and CD63 expressions induced by stimulation with anti-IgE and anti-FcεRI antibodies were measured. Clinical/laboratory factors including total serum IgE were examined for correlations with these basophil parameters. ResultsBaseline CD203c and CD63 expression on basophils were significantly higher in AD patients compared with HCs. The CD203c/CD63 response ratio to anti-FcεRI stimulation was higher than that to anti-IgE stimulation in AD patients, but not HCs. FcεRI expression on basophils was higher in AD patients than in HCs, although surface-bound IgE on basophils was equivalent. Total serum IgE had negative correlations with surface-bound IgE and CD63 responsiveness to anti-IgE stimulation. ConclusionsBasophils were spontaneously activated under steady-state conditions in AD patients and responsiveness to anti-IgE stimulation was lower than in HCs. Despite high serum IgE and high basophil FcεRI expression, surface-bound IgE on basophils remained relatively low. Basophils might be suppressed or exhausted regarding FcεRI signaling via IgE in severe AD.

Basophil Activation Marker Selection, CD63 or CD203c, Improves Sensitivity of Basophil Activation Test Depending on the Clinical Entity in Immediate Allergic Reactions to Betalactams

Basophil activation test (BAT) is a reliable in vitro tool to evaluate immediate allergic reactions to betalactams (BL). The optimal activation marker for BAT analysis could depend on the mechanism involved. The aim of the study was to evaluate the role of CD63 and CD203c in basophil activation from amoxicillin (AX) and clavulanic acid (CLV) allergic patients with different clinical entities: urticaria (URT), anaphylaxis (ANA) and anaphylactic shock (AS).

A Prospective Validation of the NUT CRACKER Diagnostic Algorithm for Walnut and Pecan Allergy with Prediction of Severity

We previously devised an algorithm using skin prick tests (SPT), basophil activation tests (BAT), and co-allergy status to reduce the need for oral food challenges (OFCs) in 63 patients with suspected walnut/pecan allergies. To validate prospectively the NUT CRACKER (Nut Co-Reactivity-Acquiring Knowledge for Elimination Recommendations) diagnostic algorithm in a new cohort of patients (n= 120) and to study the utility of SPT and BAT in predicting walnut-pecan allergy severity in both groups (n=183). Patients (n= 183) aged 8 (6-11) years, median (interquartile range), with suspected tree nut allergy were studied. SPT used ground nut extract (10 mg/mL), and BAT assessed allergen-induced basophil CD63 expression. Allergy was determined based on a recent reaction or a positive OFC, and tolerance was defined by regular consumption or a negative OFC. Walnut BAT was significantly higher in walnut/pecan dual compared with single walnut allergy (P= .003) and predicted the need for epinephrine during positive walnut OFCs (P= .009). Results of walnut and pecan BAT correlated with the corresponding nut eliciting dose (P= .014 and P<.001, respectively). Receiver operating curves for walnut and pecan allergy in the prospective cohort yielded area under the curves ranging from 0.87 to 0.93 for SPT and BAT. Concordant with the original study, pecan-allergic patients were all co-allergic for walnut. The algorithm decreased the need for OFCs by 78.8 % with 6 of 240 (2.5%) falsely positives and no false negatives. The algorithm was validated prospectively and awaits broader testing across other populations. The use of BAT further associates with severity in walnut/pecan allergy.

Establishment of a basophil activation test in BN rats

Allergies induced by low molecular weight compounds (LMWCs) have become a major problem in clinical medication. Effective preclinical prediction of sensitization can solve this problem; however, there are currently no reliable methods to predict sensitization, and it is necessary to establish a more effective model. The basophil activation test (BAT) has been widely used clinically to diagnose and research allergic diseases with high sensitivity. The purpose of this study was to detect the expression of CD63 in basophils in OVA-sensitized brown Norway (BN) rats, establishing a model for the BAT to assess the sensitization of the low molecular weight compound PG. The number of basophils in rats was detected by flow cytometry and blood smear analysis. The peripheral blood of OVA-sensitized rats was incubated with OVA, and the increase in CD63 on basophils was greater than that with PBS in vitro. After penicillin G-conjugated OVA (PG/OVA) was incubated with the peripheral blood of penicillin G-conjugated BSA (PG/BSA)-sensitized rats, the expression of CD63 on basophils was significantly higher than that with PBS. The basophils in the sensitized rats were again exposed to the same antigen in vitro, and flow cytometry detected a significant increase in CD63, demonstrating that the rat BAT model was successfully built, and it can be used to evaluate the potential sensitization of low molecular weight compounds.

The CD63 basophil activation test as a diagnostic tool for assessing autoimmunity in patients with chronic spontaneous urticaria

Over the past years, it has become widely recognized that a proportion of chronic spontaneous urticaria (CSU) cases is of autoimmune origin, however, the search for reliable diagnostic tools to confirm underlying autoimmune pathophysiology is ongoing. The CD63 basophil activation test (CD63 BAT) has recently become useful for diagnosing autoimmune CSU. To analyse the correlation between positive CD63 BAT results, total IgE antibody levels, and the presence of autoimmune thyroiditis as a comorbidity in patients diagnosed with CSU. We performed a retrospective analysis of CD63 BAT results obtained from 87 CSU and 20 non-CSU patients. The information extracted from the patients' records included age, gender, total IgE levels, clinical history of autoimmune thyroiditis (AT), and the presence of anti-thyroid autoantibodies. Positive CD63 BAT results were significantly more frequent in CSU patients compared with non-CSU subjects (p=0.045). Furthermore, we found a strong significant negative correlation between the stimulation index (SI) value for CD63 BAT and total IgE levels in CD63 BAT-positive CSU patients (p=0.004; Spearman's rank correlation coefficient ρ=-0.322), meaning that higher SI values corresponded to lower total IgE values, and vice versa. The current standard set of diagnostic tools cannot be reliably used to determine when CSU is caused by autoimmune mechanisms. There is evidence that CD63 BAT represents a helpful diagnostic tool for detecting underlying autoimmunity. We show that high SI values in CD63 BAT-positive CSU patients correlate negatively with their total IgE levels. The clinical relevance of this effect needs to be investigated further.

IgE-binding epitope mapping of tropomyosin allergen (Exo m 1) from Exopalaemon modestus, the freshwater Siberian prawn

Exopalaemon modestus (EM) is a shrimp delicacy that could cause food allergy, the major allergen of EM is Exo m 1. The amino acid (AA) sequence, IgE-binding epitopes and allergenic peptides in gastrointestinal (GI) digests of Exo m 1, and their effects on basophil function were investigated. Exo m 1 has an AA-sequence of high similarity with other shrimp tropomyosins, while not 100% matching. The IgE-binding epitopes of Exo m 1 are epitope 1 (43–59, VHNLQKRMQQLENDLDS), epitope 2 (85–105, VAALNRRIQLLEEDLERSEER), epitope 3 (131–164, ENRSLSDEERMDALENQLKEARFLAEEADRKYDE), epitope 4 (187–201, ESKIVELEEELRVVG) and epitope 5 (243–280, ERSVQKLQKEVDRLEDELVNEKEKYKSITDELDQTFSE). Among the thirty-three peptides of Exo m 1 identified in GI digests, two were highly recognized by IgE, twenty-four moderately or weakly bound IgE, and seven had no IgE-reactivities. These IgE-binding epitopes and GI digestion induced-allergenic peptides could activate basophil degranulation, and CD63 and CD203c expression, they could be potential peptide-based immunotherapy for shrimp allergic individuals.

Clinical and immunological differences between asymptomatic HDM-sensitized and HDM-allergic rhinitis patients.

Confirmation of the clinical relevance of sensitisation is important for the diagnosis of allergic rhinitis. To investigate the usefulness of an in vitro basophil activation test and component-resolved diagnosis in distinguishing between symptomatic allergic rhinitis patients and asymptomatic sensitization to house dust mites (HDMs). Thirty-six subjects with a positive skin prick test (SPT) for HDM were divided into a symptomatic (n=17) and an asymptomatic (n=19) group on the basis of their clinical history and a nasal provocation test. A basophil CD63 response to in vitro stimulation with Dermatophagoidespteronyssinus whole allergen extract and the IgE reactivity profiles for Der p 1, 2, 4, 5, 7, 10, 11, 14, 15, 18, 21, 23 were evaluated. Serum IgE and IgG specific to Dpteronyssinus whole allergen extract and total IgE were measured. There were no statistically significant differences in the levels of IgE (IgE levels were higher in symptomatic patients with P=0.055) and IgG specific to Dpteronyssinus and total IgE. Symptomatic patients showed a lower threshold for in vitro basophil activation (3.33ng/mL vs 33.3ng/mL), a higher area under the curve (AUC) of basophil activation (171 vs 127) (P=0.017), a higher response to positive control with anti-FcεRI stimulation (97% vs 79%) (P<0.001), a recognition of more HDM allergens (4 vs 2) and more frequent sensitization to rDer p 7 (P=0.016) and rDer p 23 compared to asymptomatic subjects (P=0.018). There was a positive correlation (r=0.63; P<0.001) between the number of recognized allergens and the AUC of basophil activation. In the subjects studied, the differences in the basophil response to Dpteronyssinus allergen extract, number of recognized HDM allergens and reactivity to rDer p 7 and rDer p 23 distinguish symptomatic from asymptomatic HDM sensitisation better than SPT or allergen extract-specific IgE. Information regarding the clinical relevance of sensitization is important for the prescription of allergen-specific immunotherapy.

Clinical utility of basophil activation test in diagnosis and predicting severity of mugwort pollen-related peach allergy

BackgroundCross-reactivity between pollen and plant foods results in low specificity of food-IgE and skin prick testing, which may cause over-diagnosis. A test that can accurately diagnose pollen-related food allergy and identify patients at risk of developing severe reactions is needed. This study evaluates basophil CD63 expression as a biomarker for diagnosis and predicting severity of mugwort pollen-related peach allergy. MethodsBased on their allergic reactions to peach, an oral allergy symptom group (OAS, n ​= ​15), a systemic reaction group (SR, n ​= ​23), a peach-sensitized but tolerant group (PST, n ​= ​21) and a non-peach-sensitized nonallergic group (NSE, n ​= ​10) were identified among mugwort pollen allergic patients. Measurements of specific IgE to peach and its components, and basophil activation test (BAT) were performed. ResultsUpon stimulation with peach extract, BAT in peach-allergic patients (OAS and SR groups) showed a significant dose-dependent upregulation of CD63 compared with PST patients, but showed no difference between SR and OAS groups. BAT to Pru p 3 could discriminate not only between sensitization and clinical allergy, but also between OAS and systemic reactions. BAT to Pru p 3 revealed 92% sensitivity, 95% specificity, 92% positive predictive value, and 92% negative predictive value. Receiver operating characteristic curves showed that BAT to Pru p 3 had the largest area under the curve. ConclusionsIn the diagnosis of mugwort pollen-related peach allergy, BAT to Pru p 3 is superior to testing for IgE specific for peach and its components. Additionally, basophil activation can predict clinical severity.

Influence of polyphenolic content on the in vitro allergenicity of old and new apple cultivars: A pilot study.

More than 70% of birch pollen-allergic individuals are affected by a cross-allergy from apples. The aim of this study was to determine if an increased polyphenolic content of apples is inversely related to clinical allergic reactions in sufferers. The polyphenolic content of two old and two new apple cultivars was analyzed using high performance liquid chromatography. The in vitro concentration of sulfidoleukotrienes and the CD63 basophil activation of 27 birch pollen sufferers with cross-reactivity to apples were determined with cellular antigen stimulation and basophil activation tests after incubation with different apple cultivars. The flesh of old cultivars was characterized by significantly higher total polyphenolic content (86.1 ± 5.5 µg/g) than that of new cultivars (24.7 ± 7.2 µg/g). The concentration of sulfidoleukotrienes and the CD63 basophil activation of old apple cultivars was up to 62% lower than new ones and decreased as the degree of enzymatic browning increased. Old apples cultivars are better tolerated than new ones by birch pollen-allergic individuals. The in vitro allergenicity (activation of effector cells) of apples depends on the total polyphenolic content and the degree of enzymatic browning.

Comparison of Basophil Activation Test and Skin Testing Performances in NMBA Allergy

Neuromuscular blocking agents (NMBAs) are the main agents involved during perioperative immediate hypersensitivity. The etiological diagnosis (IgE-mediated allergy vs nonallergy) is linked to the clinical presentation together with tryptase and histamine levels and skin test results. The role of basophil activation test (BAT) needs to be better defined in this setting. To assess the role of BAT compared with the results of skin testing in 31 patients experiencing immediate NMBA hypersensitivity and compare skin test results and BAT performances in the identification of alternative NMBAs. Histamine and tryptase levels were quantified. Anesthetic drugs, including NMBAs, were skin-tested. Basophil CD63 and CD203c expressions were measured in response to serial dilutions of the different NMBAs. Allergy and Nonallergy groups involved 19 and 12 patients, respectively. Circulating histamine and tryptase levels were significantly increased in allergic patients. In the Allergy group, while skin test results were positive in 100% (19 of 19) of the cases, BAT positivity to the culprit NMBA reached 78.9% (15 of 19) when combining CD63 and CD203c. NMBAs cross-reactivity was identified through skin testing and BAT in 36.8% (7 of 19) and 26.3% (5 of 19) of the cases, respectively. The concordance (culprit and cross-reactive NMBAs) between skin tests and BATs was between 73.6% (14 of 19) and 100% (19 of 19) for each NMBA. Negative skin-tested NMBAs were uneventfully used in 7 NMBA-allergic patients. In the Nonallergy group, skin test results were negative in 100% of the cases while BAT result was positive once (CD63 upregulation). In our technical conditions, BAT does not replace skin testing in the assessment of NMBA allergy.

Blocking Allergic Reaction through Targeting Surface-Bound IgE with Low-Affinity Anti-IgE Antibodies.

Allergic disorders have now become a major worldwide public health issue, but the effective treatment options remain limited. We report a novel approach to block allergic reactivity by targeting the surface-bound IgE of the allergic effector cells via low-affinity anti-human IgE Abs with dissociation constants in the 10-6 to 10-8 M range. We demonstrated that these low-affinity anti-IgE mAbs bind to the cell surface-bound IgE without triggering anaphylactic degranulation even at high concentration, albeit they would weakly upregulate CD203c expression on basophils. This is in contrast to the high-affinity anti-IgE mAbs that trigger anaphylactic degranulation at low concentration. Instead, the low-affinity anti-IgE mAbs profoundly block human peanut- and cat-allergic IgE-mediated basophil CD63 induction indicative of anaphylactic degranulation; suppress peanut-, cat-, and dansyl-specific IgE-mediated passive cutaneous anaphylaxis; and attenuate dansyl IgE-mediated systemic anaphylaxis in human FcεRIα transgenic mouse model. Mechanistic studies reveal that the ability of allergic reaction blockade by the low-affinity anti-IgE mAbs was correlated with their capacity to downregulate the surface IgE and FcεRI level on human basophils and the human FcεRIα transgenic mouse bone marrow-derived mast cells via driving internalization of the IgE/FcεRI complex. Our studies demonstrate that targeting surface-bound IgE with low-affinity anti-IgE Abs is capable of suppressing allergic reactivity while displaying an excellent safety profile, indicating that use of low-affinity anti-IgE mAbs holds promise as a novel therapeutic approach for IgE-mediated allergic diseases.

Mechanistic correlates of clinical responses to omalizumab in the setting of oral immunotherapy for milk allergy

In our recent clinical trial, the addition of omalizumab to oral immunotherapy (OIT) for milk allergy improved safety, but no significant clinical benefit was detected. We sought to investigate mechanisms by which omalizumab modulates immunity in the context of OIT and to identify baseline biomarkers that predict subgroups of patients most likely to benefit from omalizumab. Blood was obtained at baseline and multiple time points during a placebo-controlled trial of OIT for milk allergy in which subjects were randomized to receive omalizumab or placebo. Immunologic outcomes included measurement of basophil CD63 expression and histamine release and casein-specific CD4+ regulatory T-cell proliferation. Biomarkers were analyzed in relationship to measurements of safety and efficacy. Milk-induced basophil CD63 expression was transiently reduced in whole blood samples from both omalizumab- and placebo-treated subjects. However, IgE-dependent histamine release increased in washed cell preparations from omalizumab- but not placebo-treated subjects. No increase in regulatory T-cell frequency was evident in either group. Subjects with lower rates of adverse reactions, regardless of arm, experienced better clinical outcomes. Pre-OIT basophil reactivity positively associated with occurrence of symptoms during OIT, whereas the baseline milk IgE/total IgE ratio correlated with the likelihood of achieving sustained unresponsiveness. Acombination of baseline basophil and serologic biomarkers defined a subset of patients in which adjunctive therapy with omalizumab was associated with attainment of sustained unresponsiveness and a reduction in adverse reactions. Combining omalizumab therapy with milk OIT led to distinct alterations in basophil reactivity but not T-cell responses. Baseline biomarkers can identify subjects most likely to benefit from adjunctive therapy with omalizumab.

Altered basophil function in patients with chronic kidney disease on hemodialysis .

Chronic kidney disease (CKD) leads to impairment of immune cell function. Given the potential role of basophils in the pathogenesis of CKD, we aimed to study the basophil responsiveness towards microbial antigen exposure, judged as adhesion molecule expression and degranulation, in CKD patients on hemodialysis. We selected markers linked to two crucial biological phases: the transmigration and degranulation processes, respectively. For the transmigration process, we selected the adhesion molecules CD11b, active CD11b epitope, and CD62L and for the degranulation process CD203c (piecemeal degranulation marker), CD63 (degranulation marker), and CD300a (inhibitory marker of degranulation). We measured basophil responsiveness after stimulation of different activation pathways in basophils using lipopolysaccharide (LPS), peptidoglycan (PGN), formyl-methyinoyl-leucyl-phenylalanine (fMLP), and anti-FcεRI-ab. The expression of CD63 in basophils following activation by fMLP was significantly higher in the patient group compared to matched healthy controls, but no differences were observed after activation by anti-FcɛI. CD300a expression was significantly higher in patients following activation by fMLP and anti-FcɛI, and the active epitope CD11b expression was significantly higher in patients after LPS activation. In addition, we found that CD62L was not shed from the cell surface after activation with LPS and fMLP. A slight downregulation was noted after activation with anti-FcɛI in healthy controls. Together, these data demonstrate that basophil functions related to adhesion and degranulation are altered in CKD patients on hemodialysis, which indicates a potential role for the basophil in the pathogenesis of complications related to infections.

Basophil Activation Test is a Relevant Biomarker of the Outcome of Rapid Desensitization in Platinum Compounds-Allergy

Rapid drug desensitization (RDD) has become a cornerstone in the management of immediate drug hypersensitivity reactions (DHRs) to chemotherapeutic agents. Because of the inherent risk of anaphylaxis during RDD, biomarkers to predict patients at risk of developing such severe reactions are needed. The basophil activation test (BAT) has been used in DHRs as a diagnostic tool. We evaluated basophil CD63 and CD203c expression (BAT) as a biomarker to assess the safety and effectiveness of RDD in platinum compounds-allergic patients. Patients allergic to platinum compounds (n= 15) undergoing RDD were assessed through clinical history, skin testing, serum tryptase levels, and BAT. BAT was performed immediately before RDD, assessing CD203c and CD63 expression on basophils. BAT was also performed in 6 patients tolerant to platinum compounds and in 6 healthy volunteers. BAT was positive to CD203c or CD63 in 11 out of 15 patients allergic to platinum compounds (73%), with increased expression of CD203c and CD63 in 11 (73%) and 6 (40%) patients, respectively. Increased CD63 expression tended to be associated with more severe initial reactions. All controls had negative test results. Reactions during RDD were associated with BAT positivity and increased tryptase levels. Only 1 of 4 patients with negative BAT had a mild reaction during RDD. BAT remained positive in multiple sequential RDD. BAT identified patients allergic to platinum compounds with an increased risk of reactions during desensitization and higher CD63 expression was observed in severe reactions. Multiple RDDs to platinum compounds did not induce persistent hyporesponsiveness on basophils. BAT is a potential biomarker for RDD.

Exploratory analysis of CD63 and CD203c expression in basophils from hazelnut sensitized and allergic individuals.

BackgroundSensitization to hazelnut (HN) is frequent and requires clarification to determine whether this sensitization is clinically relevant. The aim of this study was to investigate basophil activation profiles in HN-sensitized and allergic subjects.MethodsBasophil activation was determined by flow cytometric analyses of CD63 and CD203c expression using several HN allergen concentrations. Depending on their clinical reaction pattern, an oral allergy symptom group (OAS, n = 20), a systemic reaction group (n = 12) and a sensitized group without clinical symptoms (n = 20) were identified. Additionally, 10 non-allergic and non-sensitized individuals served as controls.ResultsCD63 and CD203c expression differed between allergic (OAS and systemic group) and sensitized subjects. The HN concentration required to activate 30% of CD203c+ basophils [effective concentration (EC)30] was significantly higher in sensitized versus the allergic group (p = 0.0089). This was more pronounced when the basophil allergen threshold sensitivity (CD-sens) was calculated (CD63: p = 0.018; CD203c: p = 0.009).ConclusionOur data indicate that the basophil activation test may provide information to better distinguish between sensitized and allergic subjects if several allergen concentrations are considered. CD203c expression displayed a better discrimination compared to CD63; therefore, its diagnostic value might be superior compared with CD63.Electronic supplementary materialThe online version of this article (doi:10.1186/s13601-016-0134-7) contains supplementary material, which is available to authorized users.

Positive CD63 Basophil Activation Tests Are Common in Children with Chronic Spontaneous Urticaria and Linked to High Disease Activity

Background: The basophil activation test (BAT) using CD63 expression is a sensitive and specific tool for the diagnostic workup of autoimmune chronic spontaneous urticaria (CSU). The definition of a positive BAT is directly dependent on the reference range and the cutoff values established in control populations. As of now, the pediatric reference range and cutoff values of the CD63 BAT remain to be established. Methods: In this study, we analyzed CD63 expression in 80 children (1-17 years old) without chronic urticaria (i.e., controls) and compared the values to those of a pediatric cohort of 105 CSU patients and 23 physical urticaria (PU) patients. Results: Based on the log-normal distribution of CD63 values in control subjects, the reference range and the cutoff for positive CD63 BAT values was established to be 1.2-1.8% (95% CI) and 1.8%, respectively. Children with CSU showed significantly elevated and significantly increased BAT values compared to healthy controls (Wilcoxon rank test p value <0.001). In contrast, no difference was found between BAT results in controls and PU patients. In pediatric CSU patients, a higher disease activity was associated with higher BAT values. Conclusions: Our study provides, for the first time, reference and cutoff values for the CD63 BAT in children. Our findings show that positive CD63 BAT are common in children with CSU and linked to a high disease activity.