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Our previous work demonstrated that basophils regulate a suite of malaria phenotypes, including intestinal mastocytosis and permeability, the immune response to infection, gametocytemia, and parasite transmission to the malaria mosquito Anopheles stephensi. Given that activated basophils are primary sources of the regulatory cytokines IL-4 and IL-13, we sought to examine the contributions of these mediators to basophil-dependent phenotypes in malaria. We generated mice with basophils depleted for IL-4 and IL-13 (baso IL-4/IL-13 (-)) and genotype controls (baso IL-4/IL-13 (+)) by crossing mcpt8-Cre and Il4/Il13fl/fl mice and infected them with Plasmodium yoelii yoelii 17XNL. Conditional deletion was associated with ileal mastocytosis and mast cell (MC) activation, increased intestinal permeability, and increased bacterial 16S levels in blood, but it had no effect on neutrophil activation, parasitemia, or transmission to A. stephensi. Increased intestinal permeability in baso IL-4/IL-13 (-) mice was correlated with elevated plasma eotaxin (CCL11), a potent eosinophil chemoattractant, and increased ileal MCs, proinflammatory IL-17A, and the chemokines MIP-1α (CCL3) and MIP-1β (CCL4). Blood bacterial 16S copies were positively but weakly correlated with plasma proinflammatory cytokines IFN-γ and IL-12p40, suggesting that baso IL-4/IL-13 (-) mice failed to control bacterial translocation into the blood during malaria infection. These observations suggest that basophil-derived IL-4 and IL-13 do not contribute to basophil-dependent regulation of parasite transmission, but these cytokines do orchestrate protection of intestinal barrier integrity after P. yoelii infection. Specifically, basophil-dependent IL-4/IL-13 control MC activation and prevent infection-induced intestinal barrier damage and bacteremia, perhaps via regulation of eosinophils, macrophages, and Th17-mediated inflammation.

In defying conventional views that dismissed itch as trivial, I persisted in studying basophils and ILC2s in human skin and atopic dermatitis. My research on JAK inhibitors for itch ultimately led to FDA-approved drugs. This is my story of disregarding categories and definitions—a story about an unconventional path in science that emphasizes innovation over conformity. [ABSTRACT FROM AUTHOR]

(1) Background: The basophil activation test (BAT) is a functional whole blood-based ex vivo assay to quantify basophil activation after allergen exposure by flow cytometry. One of the most important prerequisites for the use of the BAT in the routine clinical diagnosis of allergies is a reliable, standardized and reproducible data analysis workflow. (2) Methods: We re-analyzed a public mass cytometry dataset from peanut (PN) allergic patients (n = 6) and healthy controls (n = 3) with our binning approach "pattern recognition of immune cells" (PRI). Our approach enabled a comprehensive analysis of the dataset, evaluating 30 markers to achieve optimal basophil identification and activation through multi-parametric analysis and visualization. (3) Results: We found FcεRIα/CD32 (FcγRII) as a new marker couple to identify basophils and kept CD63 as an activation marker to establish a modified BAT in combination with our PRI analysis approach. Based on this, we developed an algorithm for automated raw data processing, which enables direct data analysis and the intuitive visualization of the test results including controls and allergen stimulations. Furthermore, we discovered that the expression pattern of CD32 correlated with FcεRIα, anticorrelated with CD63 and was detectable in both the re-analyzed public dataset and our own flow cytometric results. (4) Conclusions: Our improved BAT, combined with our PRI procedure (bin-BAT), provides a reliable test with a fully reproducible analysis. The advanced bin-BAT enabled the development of an automated workflow with an intuitive visualization to discriminate allergic patients from non-allergic individuals. [ABSTRACT FROM AUTHOR]

Background: Galectin‐9 (Gal‐9) has been implicated in allergic and autoimmune diseases, but its role and relevance in chronic spontaneous urticaria (CSU) are unclear. Objectives: To characterize the role and relevance of Gal‐9 in the pathogenesis of CSU. Methods: We assessed 60 CSU patients for their expression of Gal‐9 on circulating eosinophils and basophils as well as T cell expression of the Gal‐9 receptor TIM‐3, compared them with 26 healthy controls (HCs), and explored possible links with disease features including disease activity (urticaria activity score, UAS), total IgE, basophil activation test (BAT), and response to omalizumab treatment. We also investigated potential drivers of Gal‐9 expression by eosinophils and basophils. Results: Our CSU patients had markedly increased rates of circulating Gal‐9+ eosinophils and basophils and high numbers of lesional Gal‐9+ cells. High rates of blood Gal‐9+ eosinophils/basophils were linked to high disease activity, IgE levels, and BAT negativity. Serum levels of TNF‐α were positively correlated with circulating Gal‐9+ eosinophils/basophils, and TNF‐α markedly upregulated Gal‐9 on eosinophils. CSU patients who responded to omalizumab treatment had more Gal‐9+ eosinophils/basophils than non‐responders, and omalizumab reduced blood levels of Gal‐9+ eosinophils/basophils in responders. Gal‐9+ eosinophils/basophils were negatively correlated with TIM‐3+TH17 cells. Conclusion: Our findings demonstrate a previously unrecognized involvement of the Gal‐9/TIM‐3 pathway in the pathogenesis CSU and call for studies that explore its relevance. [ABSTRACT FROM AUTHOR]

Derived from the myeloid lineage, granulocytes, including basophils, eosinophils, and neutrophils, along with mast cells, play important, often disparate, roles across the allergic disease spectrum. While these cells and their mediators are commonly associated with allergic inflammation, they also exhibit several functions either promoting or restricting tumor growth. In this Position Paper we discuss common granulocyte and mast cell features relating to immunomodulatory functions in allergy and in cancer. We highlight key mechanisms which may inform cancer treatment and propose pertinent areas for future research. We suggest areas where understanding the communication between granulocytes, mast cells, and the tumor microenvironment, will be crucial for identifying immune mechanisms that may be harnessed to counteract tumor development. For example, a comprehensive understanding of allergic and immune factors driving distinct neutrophil states and those mechanisms that link mast cells with immunotherapy resistance, might enable targeted manipulation of specific subpopulations, leading to precision immunotherapy in cancer. We recommend specific areas of investigation in AllergoOncology and knowledge exchange across disease contexts to uncover pertinent reciprocal functions in allergy and cancer and allow therapeutic manipulation of these powerful cell populations. These will help address the unmet needs in stratifying and managing patients with allergic diseases and cancer. [ABSTRACT FROM AUTHOR]

The current study was conducted on aborted and pregnant women suspected of being infected with cytomegalovirus in The-Qar Governorate. (90) Serum samples of pregnant and aborted women were examined using the Enzyme-linked Immunosorbent assay(ELISA). through the examination, (50) sample of women infected with CMV virus were found, with rate of 55.55%, where it was found that (43) sample of them carried the IgG antibody, with a rate of 48.88%, and(5) sample with the IgM immunoglobulin antibody, with a rate of (5.5%), and (2) sample of Igm+IgG, with a rate of (2.2% .) Through the study of blood parameters that was conducted on (40) blood samples of women infected with the virus, compared to (10) blood samples of uninfected women there was a decrease in the blood hemoglobin rate (Hb)(11.54%) and compressed blood volume by (0.35) compared to the control group, three were no significant difference(p>0.05) for the total number of white blood cells. When conducting a differential of white blood cells for infected women it was found that there was an increase in the percentage of lymphocytes by (40.50), While no significant differences were observed (p>0.05) in the percentage of monocytes,neutrophils eosinophils, and basophils. As for the phagocytosis factor, an increase in the phagocytosis factor was recorded for infected women compared to the control group, as the phagocytosis factor for infected women reached 12-60% and for the control group 47.10%. [ABSTRACT FROM AUTHOR]

Background Methods Results Conclusions Delabelling pathways offer confirmatory diagnosis and can prevent unnecessary second‐line therapies or drug desensitization procedures after chemotherapeutic hypersensitivity reactions (CHT‐HSRs). However, these pathways rely on risky in vivo tests. Data on whether in vitro tests could be helpful are scarce. We assessed the role of basophil activation test (BAT) in the diagnosis of HSRs to platin salts (PSs) and taxanes (TXs) in a well‐defined population featuring varied endophenotypes and severities of HSRs.We conducted a 3‐year‐long multicentric, prospective study with 121 suspected‐immediate CHT‐HSR patients. The allergy workup included clinical history (initial reaction based on Type I, cytokine release syndrome, and mixed phenotype's symptoms and if unable to fit in any of these, as “indeterminate”), skin testing (ST), and drug provocation testing (DPT), provided risk assessment was favorable. Final diagnosis classified patients as “hypersensitive,” “non‐hypersensitive,” or “inconclusive.” We performed BAT using CD63 and CD203c as activation markers in patients and controls. Patients underwent DPT regardless of BAT results to prevent bias.ST positivity significantly correlated with skin involvement, Type I phenotype, cancer recurrence, and lifetime exposures before reactions. DPTs were negative in all indeterminate phenotype patients (p = .02) and those considered low‐risk, whereas they were negative in 62% moderate‐risk patients. 55% were confirmed as hypersensitive (mainly Type I reactions, p < .0001), 24% as non‐hypersensitive (mainly TXs and indeterminate phenotypes), and 21% as inconclusive. BAT showed 79% sensitivity in Type I IgE‐mediated reactions to PSs with a high correlation to ST.BAT is a promising tool for delabelling and endotyping CHT‐HSRs, especially Type I reactions to PSs, possibly identifying patients at risk of positive DPT. ST seems useful in confirming CHT‐HSRs, especially PS‐induced reactions, and DPT remains the gold standard, being essential even in moderate‐risk patients. [ABSTRACT FROM AUTHOR]

Introduction: The Janus kinase (JAK) family includes four cytoplasmic tyrosine kinases (JAK1, JAK2, JAK3, and TYK2) constitutively bound to several cytokine receptors. JAKs phosphorylate downstream signal transducers and activators of transcription (STAT). JAK-STAT5 pathways play a critical role in basophil and mast cell activation. Previous studies have demonstrated that inhibitors of JAK-STAT pathway blocked the activation of mast cells and basophils. Methods: In this study, we investigated the in vitro effects of ruxolitinib, a JAK1/2 inhibitor, on IgE- and IL-3-mediated release of mediators from human basophils, as well as substance P-induced mediator release from skin mast cells (HSMCs). Results: Ruxolitinib concentration-dependently inhibited IgE-mediated release of preformed (histamine) and de novo synthesized mediators (leukotriene C4) from human basophils. Ruxolitinib also inhibited anti-IgE- and IL-3-mediated cytokine (IL-4 and IL-13) release from basophils, as well as the secretion of preformed mediators (histamine, tryptase, and chymase) from substance Pactivated HSMCs. Discussion: These results indicate that ruxolitinib, inhibiting the release of several mediators from human basophils and mast cells, is a potential candidate for the treatment of inflammatory disorders. [ABSTRACT FROM AUTHOR]

Haematological investigation is an important component of stress and immune response assessment and holds great potential for evaluating amphibian welfare. The olm (Proteus anguinus) is a neotenic, cave-dwelling salamander endemic to the Dinaric Karst and classified as a vulnerable species by the IUCN. The aim of the present study was to gain basic knowledge about the haematology of this endangered species and to establish reference values of leucocyte differential counts. Blood smears were obtained from recently captured animals and compared to smears from the same animals in long-term captivity (up to five years). The elongated erythrocytes are nucleated and are among the largest in vertebrates, which is also reflected in their lower concentration per millilitre of blood. The circulating blood can contain mitotically active, immature erythrocytes (erythroblasts), indicating that erythrocytes of the olm can undergo proliferation and maturation in circulating blood. Olms show a typical urodele leucocyte profile, with lymphocytes predominating, followed by neutrophils, although the proportion of lymphocytes is higher than in other urodeles. Eosinophil and monocyte counts were relatively low, while basophils were nearly absent. We found no statistically significant differences in leucocyte counts or in neutrophil to lymphocyte ratio neither between recently captured olms and same animals during captivity nor between the sexes, except for lower neutrophil count in captive females. Thus, no differences in stress levels between recently captured olms and captive olms were detected via haematological investigations. The significance of these results is discussed in the context of detecting stress and immune responses in olms. [ABSTRACT FROM AUTHOR]

Non-coding RNA expression has shown to have cell type-specificity. The regulatory characteristics of these molecules are impacted by changes in their expression levels. We performed next-generation sequencing and examined small RNA-seq data obtained from 6 different types of blood cells separated by fluorescence-activated cell sorting of severe COVID−19 patients and healthy control donors. In addition to examining the behavior of piRNA in the blood cells of severe SARS-CoV−2 infected patients, our aim was to present a distinct piRNA differential expression portrait for each separate cell type. We observed that depending on the type of cell, different sorted control cells (erythrocytes, monocytes, lymphocytes, eosinophils, basophils, and neutrophils) have altering piRNA expression patterns. After analyzing the expression of piRNAs in each set of sorted cells from patients with severe COVID−19, we observed 3 significantly elevated piRNAs - piR−33,123, piR−34,765, piR−43,768 and 9 downregulated piRNAs in erythrocytes. In lymphocytes, all 19 piRNAs were upregulated. Monocytes were presented with a larger amount of statistically significant piRNA, 5 upregulated (piR−49039 piR−31623, piR−37213, piR−44721, piR−44720) and 35 downregulated. It has been previously shown that piR−31,623 has been associated with respiratory syncytial virus infection, and taking in account the major role of piRNA in transposon silencing, we presume that the differential expression patterns which we observed could be a signal of indirect antiviral activity or a specific antiviral cell state. Additionally, in lymphocytes, all 19 piRNAs were upregulated. [ABSTRACT FROM AUTHOR]

Background: There is a need for searching for biomarkers indicating patients who will benefit the most from treatment with omalizumab for chronic spontaneous urticaria (CSU). The aim of this study was to assess whether the eosinophil/neutrophil/platelet/basophil-to-lymphocyte ratio (ELR, NLR, PLR, BLR) may predict the response to omalizumab treatment of chronic spontaneous urticaria. Methods: A retrospective data analysis of CSU patients treated s-c with 300 mg of omalizumab every four weeks under the drug program was carried out. NLR, ELR, PLR and BLR, DLQI, UAS-7, CRP, anti-TPO and tIgE were assessed before (V0) and after three (V3) and six months (V6) of treatment. Results: Among 52 patients with CSU, 21 were responders, 24 were partially responders and 6 were non-responders to treatment with 300 mg omalizumab every four weeks. An amount of 18 patients had features of type I autoallergic CSU (CSUaiTI) and 34 patients had autoimmunity type IIb CSU with mast cell-directed activating autoantibodies (CSUaiTIIb). NLR, ELR, PLR and BLR indices did not change during a six-month-course of biological treatment. Initial values of ELR and BLR were significantly correlated with the initial tIgE level and anti-TPO/IgE ratio. Initial values of NLR, ELR and BLR were significantly correlated with initial CRP. Comparisons between type I autoallergic CSU (CSUaiTI) and autoimmunity type IIb CSU (CSUaiTIIb) revealed that the absolute number and percentage of eosinophils, basophils, BLR and tIgE were significantly higher in type CSUaiTI and anti-TPO and anti-TPO/IgE were significantly lower in type CSUaiTI. Conclusions: NLR, ELR, PLR and BLR do not change significantly during six months of omalizumab treatment and do not appear to be useful in predicting its efficacy. [ABSTRACT FROM AUTHOR]

Aims: Benralizumab, a humanized, afucosylated monoclonal antibody against the interleukin 5 receptor, α subunit, causes rapid depletion of eosinophils by antibody‐dependent cellular cytotoxicity. We investigated the pharmacokinetic and pharmacodynamic effects of benralizumab in patients with chronic rhinosinusitis with nasal polyps (CRSwNP) from the phase III OSTRO trial. Methods: Patients received a placebo or 30 mg of benralizumab by subcutaneous injection every 8 weeks (first three doses every 4 weeks) to week 48; a subset of patients continued in an extended follow‐up period to assess treatment durability to week 80. Serum benralizumab concentrations and blood eosinophil and basophil counts were assessed to week 80. Biomarker assessments were performed on nasal polyp tissue biopsies at week 56 and nasal lining fluid at weeks 24 and 56 to examine changes in immune cells and inflammatory mediators. Results: Among 185 patients in this analysis, 93 received benralizumab. Serum benralizumab concentrations reached a steady state by week 24 (median concentration 385.52 ng mL−1); blood eosinophils were almost fully depleted and blood basophils were reduced between weeks 16 and 56. Nasal polyp tissue eosinophils decreased with benralizumab from 57.6 cells mm−2 at baseline to 0 cells mm−2 at week 56 (P <.001 vs placebo), and tissue mast cells were numerically reduced. In nasal lining fluid, eosinophil‐derived neurotoxin was significantly reduced at weeks 24 and 56 (P <.001) and interleukin‐17 at week 56 (P <.05) with benralizumab. Conclusion: Benralizumab treatment led to rapid, sustained, nearly complete depletion of eosinophils from blood and nasal polyp tissue in patients with CRSwNP. [ABSTRACT FROM AUTHOR]

Background: Diagnosis of asthma and chronic obstructive pulmonary disease (COPD) becomes difficult in a primary healthcare center due to ambiguous interpretation of spirometry and lack of facility to access established biomarkers. While routine hematological indices are easily available and accessible. The study aimed to evaluate the role of different hemogram indexes in males in COPD, asthma, and healthy smokers. Materials and Methods: Lung function tests and complete blood count (CBC) were done for 50 male subjects each from asthma, COPD, and healthy smokers. Multivariate analysis (MVA) was performed on blood indices data set. Receiver operating characteristic (ROC) curve was plotted to observe the performance of indexes. Pearson correlation was used to establish association between the lung function and blood indices. Results: Most of the indices were elevated in COPD. Whereas, asthma patients showed a significant increase in eosinophil basophil ratio (EBR), lymphocyte‐monocyte ratio (LMR), and mean platelet volume‐platelet count ratio (MPR). Orthogonal (O)‐ Partial Least‐Squares Discriminant Analysis (PLSDA) and variable importance in projection (VIP) score established EBR, neutrophil‐lymphocyte ratio (NLR) and LMR, as discriminants for asthma. Whereas, Systemic Inflammatory Response Index (SIRI), NLR and EBR were the key variables for COPD. NLR (r = −0.73, p < 0.001) and SIRI (r = −0.71, p < 0.001) were found to be negatively correlated with forced expiratory volume in 1 s (FEV1) percentage of the predicted value (%pred) in asthma and COPD, respectively. EBR showed the sensitivity and specificity of 96% and 86% respectively in asthma. NLR was having sensitivity of 82% and 90% specificity in COPD. Conclusion: Our study in males shows routine hematological indices as being cost‐effective, feasible, and seem to have tremendous potential as screening markers among chronic respiratory diseases in a primary healthcare center. [ABSTRACT FROM AUTHOR]

In vitro cell activation through specific IgE bound to high-affinity receptors on the basophil surface is a widely used strategy for the evaluation of IgE-mediated immediate hypersensitivity reactions to betalactams. Cellular activation requires drug conjugation to a protein to form a large enough structure displaying a certain distance between haptens to allow the cross-linking of two IgE antibodies bound to the basophil's surface, triggering their degranulation. However, no information about the size and composition of these conjugates is available. Routine in vitro diagnosis using the basophil activation test uses free amoxicillin, which is assumed to conjugate to a carrier present in blood. To standardize the methodology, we propose the use of well-controlled and defined nanomaterials functionalized with amoxicilloyl. Silica nanoparticles decorated with PAMAM–dendrimer–amoxicilloyl conjugates (NpDeAXO) of different sizes and amoxicilloyl densities (50–300 µmol amoxicilloyl/gram nanoparticle) have been prepared and chemically characterized. Two methods of synthesis were performed to ensure reproducibility and stability. Their functional effect on basophils was measured using an in-house basophil activation test (BAT) that determines CD63+ or CD203chigh activation markers. It was observed that NpDeAXO nanocomposites are not only able to specifically activate basophils but also do so in a more effective way than free amoxicillin, pointing to a translational potential diagnosis. [ABSTRACT FROM AUTHOR]

Background Methods Results Conclusions The α‐Gal syndrome (AGS) is an emerging allergy to mammalian food caused by IgE‐mediated reactions to the carbohydrate galactose‐α‐1,3‐galactose (α‐Gal). Mammalian food sources contain α‐Gal, but the amount differs. The objective of this study was to investigate the allergenic potency of various foods of mammalian origin among AGS patients.Twenty‐six AGS patients were included. Food extracts from innards, lean meats, processed meat products, milk, and whey were analyzed. Immunoblot, ELISA, immunofluorescence, and basophil activation test were used to determine the α‐Gal content, characterize IgE binding, and assess foods' allergenicity.The determined amount of α‐Gal, IgE reactivity to food extracts, and food extract potencies to activate patients' basophils correlated well with each other. Pork and beef kidney showed the highest allergenicity. Beef liver and bacon showed allergenicity comparable to that of lean meats. Game meat seemed to have a higher allergenic potency than meats from farm‐raised animals. The processed meat products liver pâté and black pudding, despite lower α‐Gal content, demonstrated moderate allergenicity. Milk showed the lowest allergenicity. IgE reactivity to food extracts was highly similar for all patients and strongly dominated by the α‐Gal epitope.The allergenic potency of mammalian meat depends on the origin of the meat, the different cuts, and type of processing, with innards posing the greatest risk to AGS patients. Even processed mammalian meat constitutes a risk. Dairy products show the lowest risk. This study highlights the importance of analyzing even more foods to improve the management of AGS. [ABSTRACT FROM AUTHOR]

Allergen-stimulated basophils secrete leukotriene C4 (LTC4), acting on the cysteinyl leukotriene receptor (CysLTR2) in neurons, activating neuronal signaling that mediates acute itch exacerbation in atopic dermatitis (AD). CXCR2+ basophils recruited to the kidney release interleukin (IL)-6, which recruits type 17 T helper (T H 17) cells, contributing to the pathogenesis of renal fibrosis. Targeting CXCR2+ basophils might be considered a therapeutic strategy in renal fibrosis. In mouse bone marrow granulocyte–monocyte progenitors, high expression of E-cadherin on myeloid progenitors marks an early population of pro-basophil and mast cell progenitors, which is committed to the basophil and mast cell fates. Lung-resident basophils establish a lung-specific function influenced by IL-33 and granulocyte–macrophage colony-stimulating factor (GM-CSF), which are crucial for maintaining alveolar macrophage development and function. Basophils serve as multifunctional regulators in either maintaining homeostasis or contributing to disease pathogenesis. Recent findings highlight their diverse lineage-priming stages and involvement in disorders across organs such as the skin, lung, kidney, and heart, suggesting systemic influence and potential heterogeneous subpopulations. However, the underlying mechanisms of basophil differentiation and heterogeneity remain unclear, meriting further investigation, particularly when developing possible therapeutic strategies for relevant disorders. Basophils, rare granulocytes, have long been acknowledged for their roles in type 2 immune responses. However, the mechanisms by which basophils adapt their functions to diverse mammalian microenvironments remain unclear. Recent advancements in specific research tools and single-cell-based technologies have greatly enhanced our understanding of basophils. Several studies have shown that basophils play a role in maintaining homeostasis but can also contribute to pathology in various tissues and organs, including skin, lung, and others. Here, we provide an overview of recent basophil research, including cell development, characteristics, and functions. Based on an increasing understanding of basophil biology, we suggest that the precise targeting of basophil features might be beneficial in alleviating certain pathologies such as asthma, atopic dermatitis (AD), and others. [ABSTRACT FROM AUTHOR]

Upon first exposure to cetuximab, hypersensitivity reactions can occur. We aimed to assess the utility of the basophil activation test (BAT) to alpha-gal and cetuximab for predicting severe reactions. We prospectively recruited 38 patients and evaluated sIgE to alpha-gal in all patients before the first application of cetuximab. In all alpha-gal-sensitized patients, we evaluated skin tests to meat extracts, gelatine, and cetuximab and performed BAT with alpha-gal and cetuximab. In 24% (9/38) of patients, sIgE to alpha-gal was >0.10 kUA/L, and 8/9 reacted to the cetuximab. Basophil activation tests with alpha-gal were positive in all sensitized patients and were higher in those with severe reactions (18.3% in grade 4 [n = 4] vs. 1.8% in grade 2 [n = 3] or no reaction [n = 1] at 3.3 ng/mL of alpha-gal; p = 0.03). All patients with severe grade 4 reactions had a positive CD63 BAT response to cetuximab compared to patients with moderate or no reaction, who all had negative BAT (57.7% vs. 0.9% at 500 µg/mL, 63.2% vs. 4.1% at 100 µg/mL, 58.2% vs. 2.7% at 10 µg/mL, and 32.1% vs. 3.3% at 1 µg/mL of cetuximab, respectively; p ≤ 0.001). In summary, before initiating cetuximab treatment, sIgE to alpha-gal should be assessed in all patients. To predict the severity of the reaction and to assess the risk of cetuximab-induced anaphylaxis, we should perform BATs with alpha-gal or more discriminative BATs with cetuximab. [ABSTRACT FROM AUTHOR]

In Australia, neuromuscular blocking agents are the leading cause of perioperative anaphylaxis. Current investigation of suspected anaphylaxis includes tryptase levels, serum immunoglobulin E (IgE) levels, and skin testing, including intradermal testing and skin prick testing. The gold standard for the diagnosis of a hypersensitivity reaction is a challenge test, but this poses a risk to patient safety. An alternative test, known as the basophil activation test (BAT) is a form of cellular in vitro testing using flow cytometry to measure the degree of basophil degranulation within a sample of blood following exposure to an allergen. This acts as a surrogate marker for mast cell and basophil activation, thereby identifying IgE-mediated allergy. It is most commonly used to supplement equivocal findings from initial in vitro testing to assist in confirming the diagnosis of a hypersensitivity reaction and identify the causative agent. We present a case series in which five patients with suspected anaphylaxis underwent a BAT, demonstrating its role and limitations in allergy testing within Australia. [ABSTRACT FROM AUTHOR]

Type I hypersensitivity reactions can result in pulmonary inflammation via increasing the bronchospasm and mucous secretions in the airways of lungs; however, the participation of neutrophils in pulmonary inflammation mediated by type I hypersensitivity reactions are incompletely understood. The present study thus aimed to examine the association between neutrophil recruitment and lung inflammation in patients with type I hypersensitivity reactions. For this purpose, blood samples, that were obtained from 128 individuals with type I hypersensitivity reactions and 40 individuals who served as the controls, were analyzed to measure the levels of immunoglobulin E (IgE), basophils, neutrophils, platelet distribution width (PDW) and red blood cell distribution width (RDW). Moreover, sputum neutrophils were also measured in both the patients and the controls. In addition, consolidation areas were identified by specialist radiologist staff. The results revealed a significant increase in the levels of IgE and basophils corresponding to 91 and 79%, respectively, in patients with type I hypersensitivity reactions. The present study also observed a marked increase in the number of neutrophils in the blood and sputum of patients. Moreover, the results revealed that the levels of PDW and RDW were significantly increased in the patients. In addition, a marked association (y=1.3061x+0.3546) (R²=0.7067) between the infiltrated neutrophils and the consolidation area in the lungs. On the whole, the present study demonstrates a notable association between neutrophil recruitment and lung inflammation in patients with type 1 hypersensitivity reactions; thus, neutrophils may prove useful as a therapeutic target for protection against pulmonary inflammation. Moreover, the presence of neutrophils in sputum may also be used as a biomarker of pulmonary inflammation mediated by type I hypersensitivity reactions. [ABSTRACT FROM AUTHOR]

Immunological dysregulation plays a fundamental role in the inflammatory aspects of endometriosis. Circulating blood leukocytes, one of the most abundant immune cell populations in the human body, have been shown diagnostic significance in some diseases. Nevertheless, the association between peripheral blood leukocyte counts and endometriosis remains unexplored to date. We analyzed two targeted study cohorts: a tertiary center cohort (Endometriosis at Oxford University (ENDOX) Study: 325 cases/177 controls) and a large-scale population study (UK Biobank (UKBB): 1537 cases/6331 controls). In both datasets, peripheral venous blood sample results were retrieved, and counts of leukocyte subpopulations, including neutrophils, lymphocytes, monocytes, eosinophils, and basophils, were analyzed. Logistic regression models were used to investigate the association of leukocyte subtype alterations with endometriosis status, adjusting for confounding factors. We demonstrate that a higher blood basophil level is associated with increased odds of endometriosis. This association was first discovered in the ENDOX cohort (basophils >0.04 × 109/L: OR 1.65 (95% CI: 1.06–2.57), Ptrend = 0.025) and replicated in the UKBB dataset (basophils >0.04 × 109/L: OR 1.26 (95% CI: 1.09–1.45), Ptrend = 0.001). Notably, women with basophil counts in the upper tercile had significantly increased odds of having stage III/IV endometriosis (ENDOX study: OR = 2.30, 95% CI (1.25–4.22), Ptrend = 0.007; UKBB study (OR = 1.40, 95% CI (1.07–1.85), Ptrend = 0.015). None of the other leukocyte subtypes showed an association. Our findings suggest an association between inflammatory responses and the pathogenesis of endometriosis; future studies are warranted to investigate whether the association is causal.

For the first time, an analysis of leukocyte changes in the organs of the immune system (pronephros, mesonephros, and spleen) of the Baikal omul Coregonus migratorius (Georgi, 1775) (Salmoniformes: Coregonidae) infected with Dibothriocephalus dendriticus (Nitsch, 1824) (syn. Diphyllobothrium dendriticum) (Cestoda: Diphyllobothriidea) is presented in natural habitat conditions. In the pronephros of infected fish, the number of poorly differentiated neutrophils (myelocytes and metamyelocytes) was significantly higher than in uninfected fish, which indicated inflammatory processes. D. dendriticus triggered the immunoregulatory processes in the body of infected fish, as evidenced by the decrease in the total number of lymphocytes and prolymphocytes (B-lymphocytes) in the pronephros and the increase in prolymphocytes in the spleen. The other effector elements (cells of the monocyte–macrophage lineage, basophils, and eosinophils) were barely involved in antiparasitic defense. [ABSTRACT FROM AUTHOR]

Acute promyelocytic leukemia is a rare form of acute myeloid leukemia in which immature promyelocytes abnormally proliferate in the bone marrow. In most cases, the disease is characterised by the translocation t(15;17) (q24;q21), which causes the formation of PML::RARA, an oncogenic fusion protein responsible for blocking myeloid differentiation and survival advantage. Here, we present a case of acute promyelocytic leukemia with two unusual features: basophilic differentiation and a three-way translocation involving chromosomes 12, 15 and 17. In the few cases reported, basophilic differentiation was associated with a poor prognosis. In contrast, our patient responded promptly to the standard treatment with all-trans-retinoic acid (ATRA) and arsenic trioxide (ATO) and obtained complete remission. To our knowledge, this is the first report of basophilic acute promyelocytic leukemia with the three-way translocation t(12;17;15) (p13; q24;q21).

Abstract Background Patients suffering from chronic spontaneous urticaria (CSU) are typically classified as type I or type IIb autoimmune CSU, but further patient stratification is hindered by the lack of biomarkers. Objectives We investigated whether the histamine content of individual basophils differ between patient subtypes in CSU to evaluate its potential as a biomarker. Methods A total of 101 patients diagnosed with CSU were included in the study. The histamine content per circulating basophil was derived from the basophil count in peripheral blood and levels of total cellular blood histamine. These measures, together with results from the serum‐induced basophil histamine release assay (s‐BHRA), were correlated to information on demographics, clinical characteristics, patient reported outcomes and laboratory analyses. Results The histamine content per basophil was significantly different between s‐BHRA positive and ‐negative patients (0.175 vs. 1.40 pg/cell, p

Sysmex DI-60 enumerates and classifies leukocytes. Limited research has evaluated the performance of Sysmex DI-60 in abnormal samples, and most focused on leukopenic samples. We evaluate the efficacy of DI-60 in determining white blood cell (WBC) differentials in normal and abnormal samples in different WBC count. Peripheral blood smears (n = 166) were categorised into normal control and disease groups, and further divided into moderate and severe leucocytosis, mild leucocytosis, normal, mild leukopenia, and moderate and severe leukopenia groups based on WBC count. DI-60 preclassification and verification and manual counting results were assessed using Bland–Altman and Passing–Bablok regression analyses. The Kappa test compared the concordance in the abnormal cell detection between DI-60 and manual counting. DI-60 exhibited notable overall sensitivity and specificity for all cells, except basophils. The correlation between the DI-60 preclassification and manual counting was high for segmented neutrophils, band neutrophils, lymphocytes, and blasts, and improved for all cell classes after verification. The mean difference between DI-60 and manual counting for all cell classes was significantly high in moderate and severe leucocytosis (WBC > 30.0 × 109/L) and moderate and severe leukopenia (WBC < 1.5 × 109/L) groups. For blast cells, immature granulocytes, and atypical lymphocytes, the DI-60 verification results were similar to the manual counting results. Plasma cells showed poor agreement. In conclusion, DI-60 demonstrates consistent and reliable analysis of WBC differentials within the range of 1.5–30.0 × 109. Manual counting was indispensable in examining moderate and severe leucocytosis samples, moderate and severe leukopenia samples, and in enumerating of monocytes and plasma cells. [ABSTRACT FROM AUTHOR]

Background: The introduction of biological drugs in the management of chronic rhinosinusitis with nasal polyps (CRSwNP) is allowing new and increasingly promising therapeutic options. This manuscript aims to provide a multicenter trial in a real-life setting on Mepolizumab treatment for severe uncontrolled CRSwNP with or without comorbid asthma. Methods: A retrospective data analysis was jointly conducted at the Otolaryngology–Head and Neck Surgery departments of La Sapienza University and San Camillo Forlanini Hospital in Rome. Both institutions participated by sharing clinical information on patients with CRSwNP treated with Mepolizumab. Patients were evaluated before starting Mepolizumab, at six months and at twelve months from the first drug administration. During follow–up visits, patients underwent endoscopic evaluation, quality of life assessment, nasal symptoms assessment, and blood tests to monitor mainly neutrophils, basophils, eosinophils, and IgG, IgA, and IgE assay. Results: Twenty patients affected by CRSwNP and treated with Mepolizumab were enrolled (12 females and 8 males with a mean age of 63.7 years). Sixteen patients (80%) had concomitant asthma. During follow-up, a gradual improvement in nasal polyp score, quality of life and nasal symptoms, assessed by SNOT-22 and VAS and loss of smell measured by olfactory VAS, was found. Regarding blood tests, eosinophils decreased gradually, while other blood parameters showed no statistically significant changes. Conclusions: Mepolizumab has been shown to be effective in the therapeutic management of patients with CRSwNP. Further studies are needed to support our findings and better understand the underlying immune pathways to predict patients' response to biological treatment in CRSwNP. [ABSTRACT FROM AUTHOR]

This document summarizes a study on the presence of food allergens in blood and its potential impact on adverse transfusion reactions (ATRs). The study found that the reactivity of basophil activation test (BAT) varied depending on the time between ingestion and blood collection, as well as the type of donor and food ingested. Patients with high levels of food-specific IgE were more likely to have a higher BAT response. However, the study did not verify the identification and concentration of allergens in donor blood, and future studies should further investigate the relationship between allergen content in blood products and the risk of developing ATRs. [Extracted from the article]

Acute promyelocytic leukemia is a rare form of acute myeloid leukemia in which immature promyelocytes abnormally proliferate in the bone marrow. In most cases, the disease is characterised by the translocation t(15;17) (q24;q21), which causes the formation of PML::RARA, an oncogenic fusion protein responsible for blocking myeloid differentiation and survival advantage. Here, we present a case of acute promyelocytic leukemia with two unusual features: basophilic differentiation and a three-way translocation involving chromosomes 12, 15 and 17. In the few cases reported, basophilic differentiation was associated with a poor prognosis. In contrast, our patient responded promptly to the standard treatment with all-trans-retinoic acid (ATRA) and arsenic trioxide (ATO) and obtained complete remission. To our knowledge, this is the first report of basophilic acute promyelocytic leukemia with the three-way translocation t(12;17;15) (p13; q24;q21). [ABSTRACT FROM AUTHOR]

In the past two decades, we witnessed the evolution of the basophil activation test (BAT) from mainly research applications to a potential complementary diagnostic tool to document IgE‐dependent allergies. However, BAT presents some technical weaknesses. Around 10%–15% of tested patients are non‐responders, BAT can be negative immediately post‐reaction and the use of fresh basophils, ideally analysed within 4 h of collection, restricts the number of tests that can be performed per sample. The need for fresh basophils is especially limiting when conducting batch analyses and interlaboratory comparisons to harmonize BAT methodology. These limitations significantly hinder the wider application of BAT and urge the development of alternative testing, such as the mast cell activation test (MAT). The essential difference between BAT and MAT is the heterogeneity of the starting material used to perform the assays. Mast cells are tissue‐resident, so cannot be easily accessed. Current alternative sources for functional studies are generating primary human mast cells, differentiated from donor progenitor cells, or using immortalized mast cell lines. Hence, the methodological approaches for MAT are not only vastly different from BAT, but also different among MAT protocols. This review summarizes the advantages and disadvantages of BAT and MAT assays, dedicating special attention to elucidating the key differences between the cellular sources used and provides an overview of studies hitherto performed comparing BAT and MAT in the diagnosis of IgE‐mediated food and drug allergies. [ABSTRACT FROM AUTHOR]

Background: Clinical trials showed the efficacy of 300 mg/4 weeks of omalizumab (OMA) during 6 months in patients with severe chronic spontaneous urticaria (CSU). Nevertheless, in real life, many patients require higher doses and/or longer treatment. This study assesses the real‐life performance of OMA in severe CSU and identifies factors associated with the response. Methods: CSU patients eligible for OMA were recruited prospectively. Clinical data and a blood test were collected before OMA initiation. Urticaria Activity Score 7 (UAS7) was calculated at baseline and every 3 months during OMA treatment. CSU control was defined as UAS7 <7 points. This work was partially sponsored by OMA manufacturer. Results: Eighty‐nine adults (19.1% males) with severe CSU were recruited. Median duration of CSU prior to OMA initiation was 2 years, and median severity by UAS7 at baseline was 24 points (range 10–42 points). OMA controlled 94.4% of patients, but 17.9% of responders required doses >300 mg/4 weeks. A blood basophil count >20 cells/μL (OR 13.33; 95% CI 3.32–52.63; p <.001) and the absence of hypothyroidism (OR 3.65; 95% CI 0.78–16.95; p =.099) were identified as predictive factors to achieve control with 300 mg/4 weeks. Twelve patients were able to stop OMA during the study (responders in remission, RR). RR had received OMA for a median of 29 months (12–53 months). Conversely, 32 patients had been on OMA for >29 months at the end of the study (active responders, AR). AR had received OMA for a median of 45 months (30–100 months). There were no significant differences in clinical or analytical factors between RR and AR patients. Conclusions: Low blood basophil count and the presence of hypothyroidism might serve as biomarkers for the controller dose of OMA in severe CSU patients. [ABSTRACT FROM AUTHOR]

A 10-year-old neutered male Maltese dog was presented for an investigation of lymphocytosis. The dog was up-to-date on vaccinations and deworming. Physical examination did not reveal any significant abnormalities. A complete blood cell count (CBC) showed mild leukocytosis with moderate lymphocytosis, basophilia, and moderate neutropenia, but no significant left shift or toxic change. Serum biochemistry and urinalysis were unremarkable. All performed tests for infectious agents common in this geographical region were negative. No significant abnormalities were found on abdominal ultrasound examination. Multiparametric flow cytometry of peripheral blood showed a CD8+ T-cell lymphocytosis, and PCR for antigen receptor rearrangement revealed a clonal expansion of the T-cell receptor gamma chain genes. A clinical diagnosis of chronic lymphocytic leukemia (CLL) was made, and follow-up was recommended. On Day 48 post-presentation, the CBC showed mild non-regenerative anemia (NRA), moderate leucocytosis due to moderate to marked lymphocytosis, basophilia, and a marked increase in hyposegmented neutrophils with mild toxic change in the absence of neutrophilia or neutropenia. Treatment with chlorambucil and prednisolone was initiated. On Days 87 and 197 post-presentation, the CBC showed mild NRA, with progressively decreasing numbers of hyposegmented neutrophils. The dog remained without clinical signs. Basophilia and probable pseudo-Pelger–Huët anomaly were possibly secondary to CLL. To the authors' knowledge, this is the first report of these two hematologic conditions secondary to CLL in dogs. Recognition of a pseudo-Pelger–Huët anomaly is clinically relevant to avoid misinterpretation as a marked left shift due to severe inflammation and prevent unnecessary urgent therapeutic actions. [ABSTRACT FROM AUTHOR]

Background: Chronic infection by Loa loa remains an unsolved immunological paradox. Despite harboring subcutaneously migrating adult worms and often high densities of microfilariae, most patients experience only relatively mild symptoms, yet microfilaricidal treatment can trigger life-threatening inflammation. Here, we investigated innate cell populations hypothesized to play a role in these two faces of the disease, in an endemic population in Gabon. Methodology/Principal findings: We analyzed numbers and activation of eosinophils and basophils, as well as myeloid-derived suppressor cell (MDSC) subsets and associated circulating cytokine levels by flow cytometry in sex- and age-matched L. loa-uninfected (LL-), -amicrofilaraemic (MF-) and -microfilaraemic (MF+) individuals (n = 42), as well as microfilaraemic individuals treated with albendazole (n = 26). The percentage of eosinophils was lower in LL- (3.0%) than in the combined L. loa-infected population, but was similar in MF+ (13.1%) and MF- (12.3%). Upon treatment of MF+, eosinophilia increased from day 0 (17.2%) to day 14 (24.8%) and had decreased below baseline at day 168 (6.3%). Expression of the eosinophil activation marker CD123 followed the same pattern as the percentage of eosinophils, while the inverse was observed for CD193 and to some extent CD125. Circulating IL-5 levels after treatment followed the same pattern as eosinophil dynamics. Basophil numbers did not differ between infection states but increased after treatment of MF+. We did not observe differences in MDSC numbers between infection states or upon treatment. Conclusions/Significance: We demonstrate that both chronic infection and treatment of L. loa microfilaraemia are associated with eosinophil circulation and distinct phenotypical activation markers that might contribute to inflammatory pathways in this setting. In this first ever investigation into MDSC in L. loa infection, we found no evidence for their increased presence in chronic loiasis, suggesting that immunomodulation by L. loa is induced through other pathways. Author summary: Loiasis–also called African eye worm for its most pathognomonic feature–is a disease caused by the helminth Loa loa, affecting over ten million people in Central and West Africa. While L. loa seems to successfully evade an effective immune response in chronic infection, treatment can lead to severe inflammation upon rapid death of L. loa larvae in the blood. Here, we investigated different subsets of immune cells hypothesized to play a role in L. loa-mediated immune modulation in chronically infected individuals and upon treatment of individuals with circulating larvae. We found that eosinophils–an important cell population in the immune response to helminths–increase in numbers and are activated in both L. loa-infection and its treatment. Myeloid-derived suppressor cells can suppress immune responses in cancer and some other infectious diseases but have never been investigated in loiasis. We hypothesized that they are involved in immunosuppression by L. loa but found no evidence thereof. Better understanding of immunomodulation in chronic loiasis may ultimately improve the management of this neglected disease. [ABSTRACT FROM AUTHOR]

Imidazole peptides possess multiple functions, including antioxidant effects, although their biological activities are largely unclear. Their production in humans and animals suggests their physiological roles and validates their safety for pharmaceutical or supplemental use. This study investigated the in vitro anti-anaphylactic potential of two histidine-containing dipeptides, carnosine and anserine in mast cells and basophils. Carnosine and anserine reduced mast cell degranulation elicited by anti-ovalbumin monoclonal IgE and ovalbumin or ionomycin in rat basophilic leukemia RBL2H3 cells without affecting cell viability. In contrast, interleukin-4 production following stimulation was enhanced in the presence of carnosine. Carnosine and anserine strongly inhibited Akt phosphorylation and moderately inhibited ERK phosphorylation. However, these peptides enhanced the increase in phosphorylated JNK levels upon IgE stimulation. The phosphorylation levels of p38 were not affected by carnosine or anserine. To determine the effect of carnosine on basophils, we established a method for detecting IgE-dependent activation in primary cultured mouse splenic basophils via CD63 expression for the first time. Carnosine treatment significantly reduced the increase in CD63 surface expression, a marker of degranulation, in mouse splenic basophils stimulated with anti-IgE. Flow cytometory analysis revealed that mean fluorescence intensities for non-stimulated, anti-IgE-stimulated, and carnosine-pre-treated/anti-IgE-stimulated basophils were 3853 ± 320, 5548 ± 282, and 3853 ± 203, respectively. The findings indicate carnosine and anserine suppress mast cell and basophil IgE-dependent degranulation. The proposed mechanism of the inhibitory effect is the suppression of the activation of phosphoinositide 3-kinase–Akt. Carnosine and anserine may exert anti-anaphylactic effects under physiological and pathological conditions and serve as safe potential drug candidates. [ABSTRACT FROM AUTHOR]

The clinical course following a first episode of schizophrenia (FES) is often characterized by recurrent relapses, resulting in unfavorable clinical and functional outcomes. Inflammatory dysregulation has been implicated in relapse risk; however, the predictive value of inflammatory blood cells in clinically remitted patients after a FES has not been previously explored. In this study, we closely monitored 111 patients in remission after a FES until relapse or a three-year follow-up endpoint. The participants were recruited from the multicenter 2EPS Project. Data on inflammatory blood cells and ratios were collected at baseline and at the time of relapse or after three years of follow-up. Monocyte counts (OR = 1.91; 95 % CI = 1.07–3.18; p = 0.009) and basophil counts (OR = 1.09; 95 % CI = 1.01–1.12; p = 0.005) at baseline were associated with an increased risk of relapse, while the platelet-lymphocyte ratio (OR = 0.98; 95 % CI = 0.97–0.99; p = 0.019) was identified as a protective factor. However, after adjusting for cannabis and tobacco use during the follow-up, only monocyte counts (OR = 1.73; 95 % CI = 1.03–2.29; p = 0.027) and basophil counts (OR = 1.08; 95 % CI = 1.01–1.14; p = 0.008) remained statistically significant. ROC curve analysis indicated that the optimal cut-off values for discriminating relapsers were 0.52 × 10^9/L (AUC: 0.66) for monocytes and 0.025 × 10^9/L (AUC: 0.75) for basophils. When considering baseline inflammatory levels, no significant differences were observed in the inflammatory biomarkers at the endpoint between relapsers and non-relapsers. This study provides evidence that higher monocyte and basophil counts measured at remission after a FES are associated with an increased risk of relapse during a three-year follow-up period. • First study to investigate the association between peripheral inflammatory cells after a first episode of schizophrenia, and relapse risk. • Higher monocyte and basophil count at baseline increase the risk of relapse. • Inflammatory blood cells exhibited limited predictive capability for relapse. [ABSTRACT FROM AUTHOR]

Background: The basophil activation test is an emerging clinical tool in the diagnosis of cow's milk allergy (CMA). The aim was to assess the association between the basophil allergen threshold sensitivity to the major milk protein casein (casein‐specific CD‐sens), the levels of milk‐ and casein‐specific Immunoglobulin E antibodies (IgE‐ab), and the severity of allergic reactions at milk challenges. Methods: We enrolled 34 patients aged 5–15 (median 9) years who underwent a double‐blind placebo‐controlled milk‐challenge (DBPCMC) as screening before inclusion in an oral immunotherapy study for CMA. The severity of the allergic reaction at the DBPCMC was graded using Sampson's severity score. Venous blood was drawn before the DBPCMC. Milk‐ and casein‐specific IgE‐ab were analyzed. Following in vitro stimulation of basophils with casein, casein‐specific CD‐sens, was determined. Results: Thirty‐three patients completed the DBPCMC. There were strong correlations between casein‐specific CD‐sens and IgE‐ab to milk (rs = 0.682, p <.001), and between casein‐specific CD‐sens and IgE‐ab to casein (rs = 0.823, p <.001). There was a correlation between the severity of the allergic reaction and casein‐specific CD‐sens level (rs = 0.395, p =.041) and an inverse correlation between casein‐specific CD‐sens level and the cumulative dose of milk protein to which the patient reacted at the DBPCMC (rs = −0.418, p =.027). Among the 30 patients with an allergic reaction at the DBPCMC, 67% had positive casein‐specific CD‐sens, 23% had negative casein‐specific CD‐sens, and 10% were declared non‐responders. Conclusion: Two thirds of those reacting at the DBPMC had positive casein‐specific CD‐sens, but reactions also occurred despite negative casein‐specific CD‐sens. The association between casein‐specific CD‐sens and the severity of the allergic reaction and cumulative dose of milk protein, respectively, was moderate. [ABSTRACT FROM AUTHOR]

Chronic spontaneous urticaria (CSU) is an inflammatory skin disorder that manifests with itchy wheals, angioedema, or both for more than 6 weeks. Mast cells and basophils are the key pathogenic drivers of CSU; their activation results in histamine and cytokine release with subsequent dermal inflammation. Two overlapping mechanisms of mast cell and basophil activation have been proposed in CSU: type I autoimmunity, also called autoallergy, which is mediated via IgE against various autoallergens, and type IIb autoimmunity, which is mediated predominantly via IgG directed against the IgE receptor FcεRI or FcεRI-bound IgE. Both mechanisms involve cross-linking of FcεRI and activation of downstream signaling pathways, and they may co-occur in the same patient. In addition, B-cell receptor signaling has been postulated to play a key role in CSU by generating autoreactive B cells and autoantibody production. A cornerstone of FcεRI and B-cell receptor signaling is Bruton tyrosine kinase (BTK), making BTK inhibition a clear therapeutic target in CSU. The potential application of early-generation BTK inhibitors, including ibrutinib, in allergic and autoimmune diseases is limited owing to their unfavorable benefit-risk profile. However, novel BTK inhibitors with improved selectivity and safety profiles have been developed and are under clinical investigation in autoimmune diseases, including CSU. In phase 2 trials, the BTK inhibitors remibrutinib and fenebrutinib have demonstrated rapid and sustained improvements in CSU disease activity. With phase 3 studies of remibrutinib ongoing, it is hoped that BTK inhibitors will present an effective, well-tolerated option for patients with antihistamine-refractory CSU, a phenotype that presents a considerable clinical challenge. [ABSTRACT FROM AUTHOR]

Background: Asparaginase (ASNase) is a crucial part of acute leukemia treatment, but immune responses to the agent can reduce its effectiveness and increase the risk of relapse. Currently, no reliable and validated biomarker predicts ASNaseinduced hypersensitivity reactions during therapy. We aimed to identify predictive biomarkers and determine immune cells responsible for anaphylaxis using a murine model of ASNase hypersensitivity. Methods: Our preclinical study uses a murine model to investigate predictive biomarkers of ASNase anaphylaxis, including anti-ASNase antibody responses, immune complex (IC) levels, ASNase-specific binding to leukocytes or basophils, and basophil activation. Results: Our results indicate that mice immunized to ASNase exhibited dynamic IgM, IgG, and IgE antibody responses. The severity of ASNase-induced anaphylaxis was found to be correlated with levels of IgG and IgE, but not IgM. Basophils from immunized mice were able to recognize and activate in response to ASNase ex vivo, and the extent of recognition and activation also correlated with the severity of anaphylaxis observed. Using a multivariable model that included all biomarkers significantly associated with anaphylaxis, independent predictors of ASNase-induced hypersensitivity reactions were found to be ASNase IC levels and ASNase-specific binding to leukocytes or basophils. Consistent with our multivariable analysis, we found that basophil depletion significantly protected mice from ASNase-induced hypersensitivity reactions, supporting that basophils are essential and can be used as a predictive marker of ASNase-induced anaphylaxis. Conclusions: Our study demonstrates the need for using tools that can detect both IC- and IgE-mediated hypersensitivity reactions to mitigate the risk of ASNase-induced hypersensitivity reactions during treatment. [ABSTRACT FROM AUTHOR]

Background: Flow cytometry-based basophil activation tests (BAT) have been performed with various modifications, differing in the use of distinct identification and activation markers. Established tests use liquid reagents while a new development involves the use of tubes with dried antibody reagents. The aim of this pilot study was to compare these two techniques in patients with insect venom allergy. Methods: Seventeen patients with an insect venom allergy were included in the study. The established "BAT 1" utilizes conventional antibody solutions of anti-CCR3 for basophil identification and anti-CD63 to assess basophil activation, whereas "BAT 2" uses dried anti-CD45, anti-CD3, anti-CRTH2, anti-203c and anti-CD63 for identification and activation measurement of basophils. Negative and positive controls as well as incubations with honey bee venom and yellow jacket venom at three concentrations were performed. Results: Seven patients had to be excluded due to low basophil counts, high values in negative controls or negative positive controls. For the remaining 10 patients the overall mean (± SD) difference in activated basophils between the two tests was 0.2 (± 12.2) %P. In a Bland-Altman plot, the limit of agreement (LoA) ranged from 24.0 to -23.7. In the qualitative evaluation (value below/above cut-off) Cohen's kappa was 0.77 indicating substantial agreement. BAT 2 took longer to perform than BAT 1 and was more expensive. Conclusion: The BAT 2 technique represents an interesting innovation, however, it was found to be less suitable compared to an established BAT for the routine diagnosis of insect venom allergies. [ABSTRACT FROM AUTHOR]

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by anti-nuclear autoantibodies whose production is promoted by autoreactive T follicular helper (TFH) cells. During SLE pathogenesis, basophils accumulate in secondary lymphoid organs (SLO), amplify autoantibody production and disease progression through mechanisms that remain to be defined. Here, we provide evidence for a direct functional relationship between TFH cells and basophils during lupus pathogenesis, both in humans and mice. PD-L1 upregulation on basophils and IL-4 production are associated with TFH and TFH2 cell expansions and with disease activity. Pathogenic TFH cell accumulation, maintenance, and function in SLO were dependent on PD-L1 and IL-4 in basophils, which induced a transcriptional program allowing TFH2 cell differentiation and function. Our study establishes a direct mechanistic link between basophils and TFH cells in SLE that promotes autoantibody production and lupus nephritis. Basophils have been implicated in systemic lupus erythematosus (SLE), as evidenced by the fact that basophil-deficient mice do not develop the disease. Here, the authors demonstrate that PD-L1 and IL-4 expression in basophils promotes the pathogenic accumulation of follicular helper T cells in patients with SLE and murine models. [ABSTRACT FROM AUTHOR]

There is a need for accessible biomarkers to refine the treatment of patients with nonmuscle invasive bladder cancer (NMIBC). This 2-center retrospective study evaluates the circulating basophil count as a biomarker for patients receiving Bacillus-Calmette Guérin (BCG) for NMIBC. We found higher circulating basophils independently predicted both recurrence and progression, highlighting its potential as a biomarker for patients with NMIBC. Purpose: To predict recurrence and progression in non-muscle-invasive bladder cancer (NMIBC) patients receiving bacillus Calmette-Guérin (BCG), we evaluated circulating basophils as a biomarker that could be detected from the complete blood count. Patients and Methods: We use a pooled cohort of patients from the Centre Hospitalier Universitaire de Québec-Université Laval (2016-2020) and the Vancouver General Hospital (2010-2018) where a complete blood count was available before transurethral resection of bladder tumor (TURBT) of a high-grade NMIBC and subsequent BCG. Descriptive statistics described the cohort based on the dichotomous presence or absence of basophils on the complete blood count. Kaplan-Meier estimates and a log-rank test compared recurrence-free survival (RFS) and progression-free survival (PFS), with multivariable cox regression analysis used to estimate proportional hazard ratios. Results: The study cohort included 261 patients, with a median follow-up of 31.5 months (interquartile range 18.1-45.0 months). The median age was 74.0 years and 16.8% were female. Circulating basophils were detectable in 49 (18.9%) patients. Both RFS and PFS were significantly lower in patients with detectable basophils. Multivariable analysis demonstrated detectable basophils were an independent predictor of both recurrence (HR = 1.85; 95% confidence interval [CI] 1.20-2.85; P = .01) and progression (HR = 2.29; 95% CI 1.14-4.60; P = .02). Conclusion: Our results confirm that baseline levels of circulating basophils are an immunological biomarker to predict recurrence and progression of NMIBC. [ABSTRACT FROM AUTHOR]

Drug hypersensitivity reactions (DHRs) to platinum-based compounds (PCs) are on the rise, and their personalized and safe management is essential to enable first-line treatment for these cancer patients. This study aimed to evaluate the usefulness of the basophil activation test by flow cytometry (BAT-FC) and the newly developed sIgE-microarray and BAT-microarray in diagnosing IgE-mediated hypersensitivity reactions to PCs. A total of 24 patients with DHRs to PCs (20 oxaliplatin and four carboplatin) were evaluated: thirteen patients were diagnosed as allergic with positive skin tests (STs) or drug provocation tests (DPTs), six patients were diagnosed as non-allergic with negative STs and DPTs, and five patients were classified as suspected allergic because DPTs could not be performed. In addition, four carboplatin-tolerant patients were included as controls. The BAT-FC was positive in 2 of 13 allergic patients, with a sensitivity of 15.4% and specificity of 100%. However, the sIgE- and BAT-microarray were positive in 11 of 13 DHR patients, giving a sensitivity of over 84.6% and a specificity of 90%. Except for one patient, all samples from the non-allergic and control groups were negative for sIgE- and BAT-microarray. Our experience indicated that the sIgE- and BAT-microarray could be helpful in the endophenotyping of IgE-mediated hypersensitivity reactions to PCs and may provide an advance in decision making for drug provocation testing. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to determine the staining conditions and appropriate fan1 start time (FAN1ST) for Sysmex SP-50 to produce blood smears (BS) that reflect the true lymphocyte morphology of patient samples. Methods: Using different start times of fan1, we obtained a set of 84 blood smear slides from 21 blood samples and measured 10,920 lymphocyte areas, which were then converted to compare lymphocyte sizes. We also performed a leukocyte differential count using Sysmex DI-60 on 202 blood smear slides prepared before and after the change in staining conditions and compared the results. Results: The mean lymphocyte sizes at FAN1ST 0 second, 5 seconds, 10 seconds, and 30 seconds were 12.55 µm, 12.14 µm, 11.27 µm, and 10.50 µm, respectively. The mean differences in the pre-classification of neutrophils, lymphocytes, monocytes, eosinophils, and basophils in DI-60, according to the SP-50 staining conditions, were 0.88, -1.58, -0.24, 0.37, and 0.07, respectively. Conclusions: Wright-Giemsa staining of blood smears prepared on the SP-50 showed that changing the pH of the concentrated phosphate buffer to 6.6 and adjusting the staining time did not affect the results of the leukocyte differential count. However, since fan1 was used to dry the blood smear on the SP-50 and the lymphocyte size gradually decreased as the start time was delayed, it was necessary to set a start time for fan1 that did not affect the lymphocyte size. [ABSTRACT FROM AUTHOR]

Antigen-specific IgG2 and IgG3 are rarely measured in food allergy clinical trials despite known function in preventing mast cell and basophil activation. Our objective was to determine whether measuring peanut-specific IgG2 and IgG3 levels would correlate with peanut allergy status. Peanut-specific IgG subclasses were measured via ELISA assays in Learning Early About Peanut allergy (LEAP) trial participants at 5 years of age and were correlated with peanut allergy vs peanut sensitization vs non-peanut allergic and peanut consumption vs peanut avoidance. Peanut-specific IgG1, IgG2, IgG3, and IgG4 levels were significantly different between participants with peanut allergy vs peanut sensitization vs non-peanut allergic, and a multivariate logistic regression model and stepwise selection found that IgG1 most closely associated with peanut allergy status. Similarly, all subclasses differentiated those consuming vs those avoiding peanut, but subsequent modeling found that IgG4 most closely associated with consumption status. Amongst the peanut-specific IgG subclasses, IgG1 was the best biomarker for peanut allergy, while IgG4 was the best biomarker for peanut antigen exposure in this highly atopic cohort. Our study did not find added value from evaluating peanut-specific IgG 2 and 3 as biomarkers of peanut allergy, although they did correlate with peanut allergy. Subsequent studies should assess the value of adding IgG subclasses to multivariate models predicting peanut allergy status.

This article discusses the role of CCR3 expression in chronic spontaneous urticaria (CSU), a condition characterized by persistent itching and hives. The study found that CCR3 expression is decreased on basophils and eosinophils in patients with CSU compared to healthy individuals. This suggests that reduced CCR3 expression may be a marker of active disease in CSU, rather than disease severity. The study also explores the potential mechanisms behind this decrease in CCR3 expression and highlights the need for further research on the role of CCR3 in the pathogenesis of CSU. [Extracted from the article]

This article discusses the effects of benralizumab, a medication used to treat severe eosinophilic asthma, on basophils, a type of white blood cell. The study found that benralizumab reduced the percentage and activation of basophils in patients with severe eosinophilic asthma. The medication did not cause basophil degranulation or promote allergic reactions. Additionally, the study identified changes in the miRNA profile of basophils after benralizumab treatment. These findings suggest that benralizumab may have a dual benefit in reducing both eosinophils and basophils in patients with severe eosinophilic asthma. [Extracted from the article]

The article discusses the potential reasons behind the "nonreleaser" basophil status observed in the basophil activation test (BAT) used for allergy diagnosis. It suggests that a self-activating mechanism in the patient's serum may be responsible for this state. The researchers conducted experiments using blood and serum samples from sensitized individuals and found a strong connection between serum-induced basophil degranulation and the nonreleaser state in BAT. However, more research is needed to fully understand the mechanisms and clinical implications of basophil self-activation. Another article by Gal et al. explores the relationship between two tests used to diagnose chronic urticaria, a skin condition characterized by hives. The study found a significant correlation between the CD63 assay and the histamine release assay, indicating that both tests can effectively diagnose the condition. This research provides valuable insights for medical professionals and researchers studying chronic urticaria. [Extracted from the article]

Background: Symptoms in patients with systemic mastocytosis (SM) are associated with an increase in mast cell burden and release of mast cell–derived mediators. The most frequent presentation of SM is indolent SM (ISM), with moderate symptoms and prognosis. Basophil numbers in these patients are generally normal. However, when examining basophil activation in patients with ISM, we noted an abnormal response to N-formylmethione-leucyl-phenylalanine (fMLP). Objective: Our aim was to compare basophil responsiveness to fMLP and anti-IgE in healthy volunteers and patients with ISM and relate the findings to fMLP receptor (FPR) expression. Methods: Basophils isolated from peripheral blood of 15 patients with ISM and 14 healthy volunteers were stimulated with fMLP or anti-IgE. CD63 expression to assess basophil activation and expression of FPRs were assessed by flow cytometry. Results: Baseline expression of CD63 on basophils was similar between the healthy volunteers and patients with ISM. fMLP induced higher expression of CD63 on basophils from patients with ISM, whereas responses to anti-IgE were similar between groups. Basophils from patients with ISM also had higher fMLP1 receptor (FPR1) expression, wheresas FPR2 and FPR3 were not detected. fMLP blocked the binding of anti-FPR1 antibody to FPR1, consistent with the conclusion that fMLP signals through FPR1. Conclusions: Level of fMLP-induced basophil activation is higher in patients with ISM, which is associated with an increase in FPR1 expression. Further investigation is needed to determine why FPR1 expression is elevated, whether such expression might serve as an additional surrogate marker in the diagnosis of ISM, and whether enhanced responses of basophils to fMPL might have some relationship to unexplained episodes of mediator release.

Aging is a time-dependent progressive physiological process, which results in impaired immune system function. Age-related changes in immune function increase the susceptibility to many diseases such as infections, autoimmune diseases, and cancer. Different metabolic pathways including glycolysis, tricarboxylic acid cycle, amino acid metabolism, pentose phosphate pathway, fatty acid oxidation and fatty acid synthesis regulate the development, differentiation, and response of adaptive and innate immune cells. During aging all these pathways change in the immune cells. In addition to the changes in metabolic pathways, the function and structure of mitochondria also have changed in the immune cells. Thereby, we will review changes in the metabolism of different innate immune cells during the aging process. [ABSTRACT FROM AUTHOR]

Diagnosing immediate drug hypersensitivity reactions (IDHRs) can pose a significant challenge and there is an urgent need for safe and reliable tests. Evidence has emerged that the basophil activation test (BAT), an in vitro assay that mirrors the in vivo response, can be a complementary test for many drugs. In this position paper, members of Task Force (TF) "Basophil activation test in the evaluation of Drug Hypersensitivity Reactions" from the European Academy of Allergy and Clinical Immunology (EAACI) present the data from a survey about the use and utility of BAT in IDHRs in Europe. The survey results indicate that there is a great interest for using BAT especially for diagnosing IDHRs. However, there are still main needs, mainly in the standardization of the protocols. Subsequently consensus‐based recommendations were formulated for: (i) Technical aspects of BAT in IDHRs including type of sample, management of drugs, flow cytometry protocols, interpretation of the results; and (ii) Drug‐specific aspects that should be taken into account when performing BAT in relation to betalactams, neuromuscular blocking agents, fluoroquinolones, chlorhexidine, opioids, radio contrast media, chemotherapeutics, biological agents, nonsteroidal anti‐inflammatory drugs, COVID vaccine, and excipients. Moreover, aspects in the evaluation of pediatric population have also been considered. All this indicates that BAT offers the clinician and laboratory a complementary tool for a safe diagnostic for IDHRs, although its place in the diagnostic algorithm depends on the drug class and patient population (phenotype, geography, and age). The standardization of BAT is important for generalizing this method beyond the individual laboratory. [ABSTRACT FROM AUTHOR]