Basophils Play a Protective Role in the Recovery of Skin Barrier Function from Mechanical Injury in Mice

Physical trauma disrupts skin barrier function. How the skin barrier recovers is not fully understood. We evaluated in mice the mechanism of skin barrier recovery after mechanical injury inflicted by tape stripping. Tape stripping disrupted skin barrier function as evidenced by increased transepidermal water loss. We show that tape stripping induces IL-1-, IL-23-, and TCRγδ+-dependent upregulation of cutaneous Il17a and Il22 expression. We demonstrate that IL-17A and IL-22 induce epidermal hyperplasia, promote neutrophil recruitment, and delay skin barrier function recovery. Neutrophil depletion improved the recovery of skin barrier function and decreased epidermal hyperplasia. Single-cell RNA sequencing and flow cytometry analysis of skin cells revealed basophil infiltration into tape-stripped skin. Basophil depletion upregulated Il17a expression, increased neutrophil infiltration, and delayed skin barrier recovery. Comparative analysis of genes differentially expressed in tape-stripped skin of basophil-depleted mice and Il17a-/- mice indicated that basophils counteract the effects of IL-17A on the expression of epidermal and lipid metabolism genes important for skin barrier integrity. Our results demonstrate that basophils play a protective role by downregulating Il17a expression after mechanical skin injury, thereby counteracting the adverse effect of IL-17A on skin barrier function recovery, and suggest interventions to accelerate this recovery.

The transcription factor NFIL3/E4BP4 regulates the developmental stage-specific acquisition of basophil function

BACKGROUND

Basophils are rare but important effector cells in many allergic disorders. Contrary to their early progenitors, the terminal developmental processes of basophils in which they gain their unique functional properties are unknown.

OBJECTIVE

We sought to identify a novel late-stage basophil precursor and a transcription factor regulating the terminal maturation of basophils.

METHODS

Using flow cytometry, transcriptome analysis, and functional assays, we investigated the identification and functionality of the basophil precursors as well as basophil development. We generated mice with basophil-specific deletion of nuclear factor IL-3 (NFIL3)/E4BP4 and analyzed the functional impairment of NFIL3/E4BP4-deficient basophils in vitro and in vivo using an oxazolone-induced murine model of allergic dermatitis.

RESULTS

We report a new mitotic transitional basophil precursor population (referred to as transitional basophils) that expresses the FcεRIα chain at higher levels than mature basophils. Transitional basophils are less responsive to IgE-linked degranulation but produce more cytokines in response to IL-3, IL-33, or IgE cross-linking than mature basophils. In particular, we found that the expression of NFIL3/E4BP4 gradually rises as cells mature from the basophil progenitor stage. Basophil-specific deletion of NFIL3/E4BP4 reduces the expression of genes necessary for basophil function and impairs IgE receptor signaling, cytokine secretion, and degranulation in the context of murine atopic dermatitis.

CONCLUSIONS

We discovered transitional basophils, a novel late-stage mitotic basophil precursor cell population that exists between basophil progenitors and postmitotic mature basophils. We demonstrated that NFIL3/E4BP4 augments the IgE-mediated functions of basophils, pointing to a potential therapeutic regulator for allergic diseases.

Biomarkers of Autologous Whole Blood Injection Efficacy in Patients with Chronic Spontaneous Urticaria with Autoreactivity: A Preliminary Study

INTRODUCTION

Chronic spontaneous urticaria (CSU) with autoreactivity is often resistant to antihistamines. Autologous whole blood injection (AWBI) has shown potential efficacy in the treatment of this disease, but it is controversial. It is necessary to screen patients who are suitable for this therapy in advance. This study aimed to identify biomarkers that predict the efficacy of AWBI treatment in CSU patients with autoreactivity.

METHODS

A total of 30 patients with autologous serum skin test-positive CSU treated with AWBI were included in this study; urticaria activity score (UAS7) was recorded and the treatment response was judged based on it. Levels of total serum IgE, anti-high-affinity IgE receptor (FcεRI) IgG, and basophils CD63 and FcεRI expressions, and D-dimer of all patients were determined and analyzed.

RESULTS

Baseline levels of total IgE, D-dimer, basophil FcεRI and CD63 expressions showed good correlations with UAS7 variations. D-dimer, basophil FcεRI and CD63 expressions changed significantly before and after AWBI treatment in AWBI responders, and the basophil FcεRI and CD63 expressions consistently and dynamically decreased in AWBI responders during the treatment. Baseline levels of total IgE, D-dimer, basophil FcεRI and CD63 expressions showed certain predictive values for AWBI response.

CONCLUSIONS

Baseline levels of total IgE, D-dimer, basophil FcεRI and CD63 expressions could be biomarkers of predicting AWBI efficacy in patients with CSU with autoreactivity.

Risk of Nephritis and Recurrence in Kimura Disease: A Retrospective Study

Background

Kimura disease (KD) presents a diagnostic challenge to clinicians because of its rarity and atypical symptoms in its early stages, and it is difficult to treat and prone to recurrence or involvement of other organs.

Aims and Objectives

This study aims to investigate the possible relevance of renal involvement and recurrence by analysing the clinical presentations, laboratory results, histopathological features, therapeutic data and follow-up results of KD.

Materials and Methods

A total of 27 patients diagnosed as KD in two hospitals from January 1999 to December 2021 were analysed retrospectively in this study based on the diagnosis of histopathology.

Results

KD mainly affected male more than female (8:1) with the onset age ranging from 3 to 58 years (median 29.8 years). The common initial symptoms included subcutaneous soft tissue or lymph node enlargement, non-specific skin lesions and proteinuria. One patient presented cough and expectoration as the first symptoms. KD patients often had high levels of serum immunoglobulin E (IgE) and basophils, which exhibited a significantly positive correlation with renal involvement and recurrence (p < 0.05). Early mass resection could prevent the development of nephritis and decrease the risk of relapse (p < 0.05).

Conclusion

KD should be noted in patients presenting with intractable and relapsing atopic skin lesions and (or) subcutaneous mass. Patients with high levels of serum IgE and blood basophils may be prone to developing KD-associated nephritis and predict a high risk of recurrence. Early surgical removal of the mass may result in a better prognosis.

Histamine elevation in familial Mediterranean fever: A study from the Juvenile Inflammatory Rheumatism cohort

BACKGROUND

Familial Mediterranean Fever (FMF) is the most frequent monogenic autoinflammatory disease (AID). Some patients have persistent symptoms despite colchicine intake. Mast cells (MC) are innate immune cells involved in inflammatory conditions including AID. Their activation is responsible for various symptoms such as abdominal pain, bloating and pruritus.

OBJECTIVE

Our objective was to evaluate features of a systemic MC activation in FMF adult patients.

METHODS

FMF adult patients prospectively filled a MC activation survey and usual MC mediators (tryptase and histamine in whole blood, plasma and urine) were measured. They were compared with a healthy control group (HC) and a systemic mastocytosis (SM) group. When digestive biopsies were realized during follow-up, MC infiltration in digestive mucosa was analyzed in FMF, in comparison with SM, Crohn disease (CD) and normal biopsies.

RESULTS

Forty-four FMF patients, 44 HC and 44 SM patients were included. Thirty-one (70%) FMF patients had symptoms of mast cell activation, versus 14 (32%) in the HC group (p = 0.0006). Thirty (68%) FMF patients had at least one elevated MC mediator: mainly whole blood histamine, in 19 (43%) and urinary histamine, in 14 (32%), which were significantly higher than in HC subjects. MC infiltration was comparable in FMF digestive biopsies, biopsies of CD and normal biopsies but was lower than in SM biopsies.

CONCLUSION

FMF patients show frequent symptoms of MC activation and an increase of blood or urinary histamine never described before in this disease. This suggests an implication of MC and possibly basophils in FMF pathophysiology.

Promises and Remaining Challenges for Further Integration of Basophil Activation Test in Allergy-Related Research and Clinical Practice

More than 20 years after having been initially proposed, the relevance and usefulness of basophil activation test (BAT) for the field of allergy research and testing were demonstrated on many occasions. Leveraging the fully open format of a flexible, whole blood-based functional assay, BAT has been shown to be equally important for fundamental research, clinical research, and diagnosis. Regardless of whether the focus of a study is on the characterization of the allergenic moiety, on the patient side, or on the study of the fundamental processes involved in the allergic disease or its treatment, BAT enables the gathering of very important insights. In spite of this, its full capabilities have yet to be leveraged. Various bottlenecks, including but not limited to assay logistics, robustness, flow cytometry access, and/or expertise, have indeed been limiting its development beyond experts and long-term users. Now, various initiatives, aiming at resolving these bottlenecks, have been launched. If successful, a broader use of BAT could then be contemplated. In such a situation, its more thorough integration in clinical practice has the potential to significantly change the allergic patient's journey.

A phase II study of Bruton's tyrosine kinase inhibition for the prevention of anaphylaxis

BACKGROUNDIgE-mediated anaphylaxis is a potentially fatal systemic allergic reaction for which there are no currently FDA-approved preventative therapies. Bruton's tyrosine kinase (BTK) is an essential enzyme for IgE-mediated signaling pathways and is an ideal pharmacologic target to prevent allergic reactions. In this open-label trial, we evaluated the safety and efficacy of acalabrutinib, a BTK inhibitor that is FDA approved to treat some B cell malignancies, in preventing clinical reactivity to peanut in adults with peanut allergy.METHODSAfter undergoing graded oral peanut challenge to establish their baseline level of clinical reactivity, 10 patients had a 6-week rest period, then received 4 standard doses of 100 mg acalabrutinib twice daily and underwent repeat food challenge. The primary endpoint was the change in patients' threshold dose of peanut protein to elicit an objective clinical reaction.RESULTSAt baseline, patients tolerated a median of 29 mg of peanut protein before objective clinical reaction. During subsequent food challenge on acalabrutinib, patients' median tolerated dose significantly increased to 4,044 mg (range 444-4,044 mg). 7 patients tolerated the maximum protocol amount (4,044 mg) of peanut protein with no clinical reaction, and the other 3 patients' peanut tolerance increased between 32- and 217-fold. 3 patients experienced a total of 4 adverse events that were considered to be possibly related to acalabrutinib; all events were transient and nonserious.CONCLUSIONAcalabrutinib pretreatment achieved clinically relevant increases in patients' tolerance to their food allergen, thereby supporting the need for larger, placebo-controlled trials.TRIAL REGISTRATIONClinicalTrials.gov NCT05038904FUNDINGAstraZeneca Pharmaceuticals, the Johns Hopkins Institute for Clinical and Translational Research, the Ludwig Family Foundation, and NIH grants AI143965 and AI106043.

Granulocyte development, tissue recruitment, and function during allergic inflammation

Granulocytes provide a fast innate response to pathogens and allergens. In allergy and anti-helminth immunity, epithelial cells of damaged barriers release alarmins like IL-25, IL-33, and thymic stromal lymphopoietin (TSLP) but also chemokines like CXCL1 or CCL11 to promote cell recruitment and inflammation. In addition, mast cells positioned at barrier tissue sites also quickly release mediators upon specifically sensing antigens through IgE bound to FcεR1 on their surface. Released mediators induce the recruitment of different granulocytes in a timely ordered manner. First, neutrophils extravasate from the blood vasculature to the side of alarmin release and promote a potent inflammatory response. Alarmins and activated mast cells further promote activation of ILC2s and recruitment of basophils and eosinophils, which inhibit neutrophil recruitment and enhance tissue type 2 immunity. In addition to their potent pro-inflammatory effector functions, granulocytes can also contribute to termination and resolution of inflammation. Here, we summarize the development and tissue recruitment of granulocyte subsets, and describe general effector functions and aspects of their increasingly appreciated role in limiting tissue damage. We further discuss targeting approaches for therapeutic interventions in allergic disorders.

Prognostic significance of circulating basophil counts in patients who underwent esophagectomy for esophageal cancer

PURPOSE

Recent reports have suggested that basophils influence allergic reactions and tumor immunity. In this study, we aimed to elucidate the association between preoperative circulating basophil (CB) counts and the outcomes of patients who underwent esophagectomy for esophageal cancer.

METHODS

A total of 783 consecutive patients who underwent esophagectomy for esophageal cancer were eligible. The clinicopathological factors and prognoses were compared between the groups stratified by the preoperative counts of CB.

RESULTS

There were more advanced clinical T and N stages in the low CB group than in the high CB group (P = 0.01 and = 0.04, respectively). The incidences of postoperative complications were comparable between the groups. The low CB count was associated with unfavorable overall and recurrence-free survivals (P = 0.04 and 0.01, respectively). In the multivariate analysis, low CB count was one of the independent prognostic factors for poor recurrence-free survival (HR 1.33; 95% CI 1.04-1.70; P = 0.02). In addition, hematogenous recurrence occurred more frequently in the low CB group than in the high CB group (57.6% vs. 41.4%, P = 0.04).

CONCLUSION

A preoperative low CB count was an unfavorable prognosticator in patients who underwent esophagectomy for esophageal cancer.

Mixtures of per- and poly-fluoroalkyl substances (PFAS) reduce the in vitro activation of human T cells and basophils

In the last decades, per- and poly-fluoroalkyl substances (PFAS), widely used industrial chemicals, have been in the center of attention because of their omnipotent presence in water and soils worldwide. Although efforts have been made to substitute long-chain PFAS towards safer alternatives, their persistence in humans still leads to exposure to these compounds. PFAS immunotoxicity is poorly understood as no comprehensive analyses on certain immune cell subtypes exist. Furthermore, mainly single entities and not PFAS mixtures have been assessed. In the present study we aimed to investigate the effect of PFAS (short-chain, long-chain and a mixture of both) on the in vitro activation of primary human immune cells. Our results show the ability of PFAS to reduce T cells activation. In particular, exposure to PFAS affected T helper cells, cytotoxic T cells, Natural Killer T cells, and Mucosal associated invariant T (MAIT) cells, as assessed by multi-parameter flow cytometry. Furthermore, the exposure to PFAS reduced the expression of several genes involved in MAIT cells activation, including chemokine receptors, and typical proteins of MAIT cells, such as GZMB, IFNG and TNFSF15 and transcription factors. These changes were mainly induced by the mixture of both short- and long-chain PFAS. In addition, PFAS were able to reduce basophil activation induced by anti-FcεR1α, as assessed by the decreased expression of CD63. Our data clearly show that the exposure of immune cells to a mixture of PFAS at concentrations mimicking real-life human exposure resulted in reduced cell activation and functional changes of primary innate and adaptive human immune cells.

Urticaria and basophils

Chronic spontaneous urticaria (CSU) is a common skin disease without an etiology in the vast majority of cases. The similarity of symptoms and pathology to allergen-induced skin reactions supports that skin mast cell IgE receptor activation is also involved in CSU. Accumulating evidence also supports a role for blood basophils in disease expression. Blood basopenia is noted in active CSU disease with the recruitment of blood basophils to skin lesion sites. Blood basophils further display altered IgE receptor mediated degranulation patterns in two phenotypes that improve in remission. In active CSU subjects, changes in IgE receptor signaling molecule expression levels accompany the altered degranulation function in blood basophils. The success of therapies targeting IgE in CSU patients have also shown that altered blood basophil phenotypes and enumeration have potential use as a disease biomarker.

The association between eosinophils (CD16+ eosinophils), basophils (CD203+ basophils), and CD23 B lymphocytes in patients with atopic dermatitis on dupilumab therapy: pilot study

BACKGROUND

Eosinophils, basophils, and the molecule CD23 on B cells are involved in the pathophysiology of atopic dermatitis (AD). The molecule CD23 is involved in the regulation of IgE synthesis and is expressed by activated B cells. The molecule CD16 is used to assess the activation of eosinophils and CD203 of basophils. The association between the count of eosinophils, basophils, CD16⁺ eosinophils, CD203⁺ basophils and the expression of the activation marker CD23 on B cells in patients with AD (with and without dupilumab therapy) is not described.

OBJECTIVE

The aim of this pilot study is to evaluate the association between the blood count of eosinophils, basophils, relative CD16⁺ eosinophils, relative CD203⁺ basophils, and the expression of molecule CD23 on B cells and on their subsets (total, memory, naive, switched, non-switched) in patients suffering from AD (with and without dupilumab therapy) and in control group.

METHODS

A total of 45 patients suffering from AD were examined; 32 patients without dupilumab treatment (10 men, 22 women, average age 35 years), 13 patients with dupilumab treatment (7 men, 6 women, average age 43.4 years), and 30 subjects as a control group (10 men, 20 women, average age 44.7 years). Immunophenotype was examined by flow cytometry in which monoclonal antibodies with fluorescent molecules were used. For statistical analysis we used non-parametric Kruskal-Wallis one-factor analysis of variance with post hoc by Dunn's test with Bonferroni modification and the Spearman's rank correlation coefficient; for coefficients higher than 0.41, we report R² (percent of variation explained).

RESULTS

The absolute count of eosinophils was significantly higher in patients with AD (with and without dupilumab) in comparison to healthy subjects. The difference in the relative count of CD16⁺ eosinophils in patients with AD (with and without dupilumab therapy) compared with control is not statistically significant. In patients with dupilumab therapy the significantly lower count of relative CD203⁺ basophils was confirmed compared with control. The higher association between the count of eosinophils (absolute and relative) and the expression of CD23 marker on B cells was confirmed in patients with dupilumab therapy; in contrast, this association was low in patients with AD without dupilumab therapy and in healthy subjects.

CONCLUSION

The higher association between the count of eosinophils (absolute and relative) and the expression of CD23 marker on B cells was confirmed in patients with AD under dupilumab therapy. It suggests that IL-4 production by eosinophils may play a role in B lymphocyte activation. The significantly lower count of CD203⁺ basophils has been demonstrated in patients with dupilumab therapy. This reduction of CD203⁺ basophil count may contribute to the therapeutic effects of dupilumab by reducing the inflammatory response and allergic reactions in patients with AD.

Biology of amphibian granulocytes - From evolutionary pressures to functional consequences

Granulocyte-lineage cells are important innate immune effectors across all vertebrates. Named for conspicuous secretory granules, granulocytes have historically been studied for their antimicrobial roles. Although versions of these cells are found in all vertebrate species examined to date, disparate environmental and physiological pressures acting on distinct vertebrate classes have shaped many of the facets dictating granulocyte biology. Immune pressures further determine granulopoietic constraints, ultimately governing granulocyte functions. For amphibians that inhabit pathogen-rich aquatic environments for some or all their lives, their unique granulocyte biologies satisfy many of their antimicrobial needs. Amphibians also occupy an intermediate position in the evolution of vertebrate immune systems, using combinations of primitive (e.g., subcapsular liver) and more recently evolved (e.g., bone marrow) tissue sites for hematopoiesis and specifically, granulopoiesis. The last decade of research has revealed vertebrate granulocytes in general, and amphibian granulocytes in particular, are more complex than originally assumed. With dynamic leukocyte phenotypes, granulocyte-lineage cells are being acknowledged for their multifaceted roles beyond immunity in other physiological processes. Here we provide an overview of granulopoiesis in amphibians, highlight key differences in these processes compared to higher vertebrates, and identify open questions.

Cellular mechanisms and effects of IL-4 receptor blockade in experimental conjunctivitis evoked by skin inflammation

Ocular surface diseases, including conjunctivitis, are recognized as common comorbidities in atopic dermatitis (AD) and occur at an increased frequency in patients with AD treated with biologics targeting IL-4 receptor α (IL-4Rα) or IL-13. However, the inflammatory mechanisms underlying this pathology are unknown. Here, we developed a potentially novel mouse model of skin inflammation-evoked conjunctivitis and showed that it is dependent on CD4+ T cells and basophils. Blockade of IL-4Rα partially attenuated conjunctivitis development, downregulated basophil activation, and led to a reduction in expression of genes related to type 2 cytokine responses. Together, these data suggest that an IL-4Rα/basophil axis plays a role in the development of murine allergic conjunctivitis. Interestingly, we found a significant augmentation of a number of genes that encode tear proteins and enzymes in anti-IL-4Rα-treated mice, and it may underlie the partial efficacy in this model and may represent candidate mediators of the increased frequency of conjunctivitis following dupilumab in patients with AD.

An Analysis of Eosinophil- and Basophil-Based Indices in Patients with Glioblastoma and their Correlation with Survival

BACKGROUND

Glioblastoma (GBM) is the most frequently diagnosed malignant brain tumor in adults. GBM is usually lethal within 24 months of diagnosis, despite aggressive multimodality treatment. Although it has been established that cancer-related inflammation is associated with worse outcomes, the role of eosinophils, basophils, atopy, and allergy in glioma biology is only gradually being delineated. In this study, we aimed to examine if eosinophil-based and basophil-based indices were altered in patients with GBM compared with healthy controls. We also aimed to study if there was any correlation between these indices and patient-related and tumor-related factors and survival.

METHODS

This study was a retrospective analysis of prospectively maintained databases. Data pertaining to patient-related and tumor-related factors, hemograms, and survival data were obtained from the electronic medical records of selected patients. Correlations between eosinophil-based and basophil-based indices and these factors were studied, as was the association with overall survival.

RESULTS

All the indices were altered in patients with GBM compared with normal healthy controls. The absolute eosinophil count was higher and the neutrophils/eosinophils ratio was lower in the better prognosis groups: those with better performance status; those without features of increased intracranial pressure or altered sensorium at presentation; those with ATRX-retained tumors that did not overexpress p53; and in the long-term survivors. The total lymphocyte count/basophils ratio and the absolute eosinophil count both independently predicted survival in a multivariate analysis.

CONCLUSIONS

The absolute eosinophil count was consistently higher in the better prognosis groups and is likely to be incorporated into prognostic models for GBM.

Urticaria and Angioedema: Understanding Complex Pathomechanisms to Facilitate Patient Communication, Disease Management, and Future Treatment

Chronic spontaneous urticaria (CSU) is primarily a T2-dominant disease with a complex genetic background. Skin mast cell activation can be induced not only via the IgE-FcεRI axis but also from several other distinct mechanisms, molecules, and receptors involved in CSU onset, persistence, and exacerbation. These include autoallergy, autoimmunity, central or peripheral neuroimmune dysregulation, activation of both extrinsic and intrinsic coagulation pathways, and microbial infections. Besides mast cells, recent reports suggest the active and direct involvement of basophils and eosinophils. Several biological characteristics or biomarkers have been linked with CSU's known endotypes and may help forecast therapeutic responses. The introduction of biologic therapy for CSU has been a major advance in the last 10 years. The cornerstone of angioedema (AE) pathogenesis is increased vascular permeability and plasma leakage into the deeper dermis and subcutis, either mediated by histamine or bradykinin (BK). C1-inhibitor deficiency, hereditary or acquired, is the primary cause of BK-mediated AE due to increased plasma BK concentration. Other complex conditions have been identified, with some likely involving contact system dysregulation and other putative mechanisms related to vascular endothelial dysfunction. The approval of multiple hereditary-AE-specific therapies for both prevention and acute attacks has revolutionized treatment of this disease. Any new knowledge of the pathogenesis of CSU and AE offers the opportunity to improve patient information, physician-patient communication, prediction of therapeutic responses, selection of precise tailor-made treatment for each patient, and exploration of novel treatment options for those who do not achieve disease control with current medications.

Comparative flow cytometry-based immunophenotyping analysis of peripheral blood leukocytes before and after fixation with paraformaldehyde

Flow cytometry based immunophenotyping provides prime insight into cellular population composition and characteristics, and is widely used in basic and clinical research. Challenges in processing peripheral blood samples in a timely manner necessitate protocol adaptations and utilization of fixatives. Fixation, however, may introduce artifacts to the flow cytometry readout. We performed a comparative flow cytometry immunophenotyping analysis of 13 immune cell populations in the whole blood using a staining protocol with and without fixation step. Freshly procured human peripheral blood samples were stained with a panel of 33 fluorochrome-conjugated antibodies. Samples were processed using a protocol with or without a paraformaldehyde-based fixation step, and matching sample pairs were analyzed by flow cytometry. Our results show that paraformaldehyde-based fixation, in comparison to matched unfixed samples, did not significantly affect population distribution and frequency for: B cells, Plasmablasts, Dendritic cells, NK cells, Granulocytes, Neutrophils, Eosinophils, or Hematopoietic Stem/Progenitor Cells. However, fixation led to significant marker shifts in the subpopulation distribution in CD4, T regulatory, CD8, Monocytes, and Basophils. These results indicate the importance of pre-experimental assessment of fixation-introduced artifacts in the flow cytometry output when considering the feasibility of fresh processing. This is especially important for samples analyzed using comprehensive exploratory immunoprofiling panels.

Targeting eosinophils by active vaccination against interleukin-5 reduces basophil counts in horses with insect bite hypersensitivity in the 2nd year of vaccination

Previously, virus-like particle (VLP)-based self-vaccinations targeting interleukin (IL)-5 or IL-31 have been suggested to treat equine insect bite hypersensitivity (IBH), a seasonal recurrent allergic dermatitis in horses. The IL-5-targeting equine vaccine significantly reduced blood eosinophil counts in horses, similar to human monoclonal antibodies targeting IL-5 or the IL-5 receptor alpha (IL-5Rα). Previous studies in humans have also reported an additional effect on reduction of basophil counts. The aim of the present study was to evaluate whether an equine anti-IL-5 vaccine affected blood basophil counts. Horses with IBH were followed in a 3-year trial consisting of a placebo administered in the 1st year, followed by vaccination using an equine (e)IL-5-VLP vaccine in the 2nd and 3rd years. There was a strong reduction in circulating eosinophil counts after vaccination against IL-5. Additionally, there were reduced basophil counts, but only in the 3rd year of the study, suggesting a bystander effect of the anti-IL-5 vaccine on basophil counts.

Association of peripheral basophils with tumor M2 macrophage infiltration and outcomes of the anti-PD-1 inhibitor plus chemotherapy combination in advanced gastric cancer

BACKGROUND

Although the anti-programmed death-1 (PD-1) inhibitor plus chemotherapy combination has been approved as the standard first-line treatment for advanced gastric cancer, a proportion of patients do not significantly benefit from this therapy. Who would respond poorly to this treatment and the underlying mechanisms of treatment failure are far from clear.

METHODS

We retrospectively analyzed the associations between the peripheral basophils at baseline and clinical outcomes in 63 advanced gastric cancer patients treated with anti-PD-1 plus chemotherapy and 54 patients treated with chemotherapy alone. Immunohistochemistry and immunofluorescence staining in gastric cancer samples were utilized to investigate the basophil-related immunophenotype.

RESULTS

The optimal cutoff of basophil count to distinguish responders to anti-PD-1 plus chemotherapy from non-responders was 20.0/μL. Compared with the low basophil group (≤ 20.0/μL, n = 40), the high basophil group (> 20.0/μL, n = 23) had a significantly lower objective response rate (ORR 17.4% vs. 67.5%, p = 0.0001), worse progression-free survival (median PFS 4.0 vs. 15.0 months, p = 0.0003), and worse overall survival (median OS not reached, p = 0.027). Multivariate analyses identified a basophil count of > 20.0/μL as an independent risk factor for a worse ORR (OR 0.040, 95% CI 0.007-0.241, p = 0.0004), worse PFS (HR 3.720, 95% CI 1.823-7.594, p = 0.0003) and worse OS (HR 3.427, 95% CI 1.698-6.917, p = 0.001). In contrast, there was no significant association between peripheral basophil counts and tumor response or survival in the chemotherapy-alone group (p > 0.05). In primary gastric cancer samples, we observed a correlation between higher peripheral basophil counts and the accumulation of tumor-infiltrating basophils (r = 0.6833, p = 0.005). Tumor-infiltrating basophils were found to be spatially proximate to M2 macrophages within TME and positively correlated with tumor M2 macrophage infiltration (r = 0.7234, p = 0.0023). The peripheral basophil counts also had a significant positive correlation with tumor-infiltrating M2 macrophage counts (r = 0.6584, p = 0.003). Further validation in tumor samples treated with the neoadjuvant anti-PD-1 inhibitor plus chemotherapy combination suggests that the peripheral basophils, tumor infiltration of basophils, and M2 macrophages were significantly more abundant in non-responders than in responders (p = 0.0333, p = 0.0007, and p = 0.0066, respectively).

CONCLUSIONS

The peripheral basophil count was observed to be a potential biomarker of anti-PD-1 efficacy for advanced gastric cancer. Moreover, basophils may induce an immune-evasive tumor microenvironment by increasing M2 macrophage infiltration, which could be a potential immunotherapeutic target for advanced gastric cancer.

miR-3934 regulates the apoptosis and secretion of inflammatory cytokines of basophils via targeting RAGE in asthma

Background

Several miRNAs are now known to have clear connections to the pathogenesis of asthma. The present study focused on the potential role of miR-3934 during asthma development.

Methods

miR-3934 was detected as a down-regulated miRNA in basophils by sequencing analysis. Next, the expression levels of miR-3934 in peripheral blood mononuclear cells of 50 asthma patients and 50 healthy volunteers were examined by RT-qPCR methods. The basophils were then treated with AGEs and transfected with miR-3934 mimics. The apoptosis levels were examined by flow cytometry assay; and the expression levels of cytokines were detected using the ELISA kits. Finally, the Western blot was performed to examined the expression of key molecules in the TGF-β/Smad signaling pathway.

Results

miR-3934 was down-regulated in the basophils of asthmatic patients. The expression of the pro-inflammatory cytokines IL-6, IL-8 and IL-33 was enhanced in basophils from asthmatic patients, and this effect was partially reversed by transfection of miR-3934 mimics. Furthermore, receiver operating characteristics analysis showed that miR-3934 levels can be used to distinguish asthma patients from healthy individuals. miR-3934 partially inhibited advanced glycation end products-induced increases in basophil apoptosis by suppressing expression of RAGE.

Conclusion

Our results indicate that miR-3934 acts to mitigate the pathogenesis of asthma by targeting RAGE and suppressing TGF-β/Smad signaling.

Sargahydroquinoic acid isolated from Sargassum serratifolium as inhibitor of cellular basophils activation and passive cutaneous anaphylaxis in mice

Basophils and mast cells are characteristic effector cells in allergic reactions. Sargahydorquinoic acid (SHQA), a compound isolated from Sargassum serratifolium (marine alga), possesses various biochemical properties, including potent antioxidant activities. The objective of the present study was to investigate inhibitory effects of SHQA on the activation of human basophilic KU812F cells induced by phorbol myristate acetate and A23187 (PMACI), a calcium ionophore. Furthermore, we confirmed the inhibitory effects of SHQA on the activation of rat basophilic leukemia (RBL)-2H3 cells induced by compound 48/80 (com 48/80), bone marrow-derived mast cells (BMCMCs) induced by anti-dinitrophenyl(DNP)-immunoglobulin E (IgE)/DNP-bovine serum albumin (BSA), DNP/IgE and on the reaction of passive cutaneous anaphylaxis (PCA) mediated by IgE. SHQA reduced PMACI-induced intracellular reactive oxygen species (ROS) and calcium levels. Western blot analysis revealed that SHQA downregulated the activation of ERK, p38, and NF-κB in a dose-dependent manner. Moreover, SHQA suppressed the production and gene expression of various cytokines, including interleukin (IL)-1 β, IL-4, IL-6, and IL-8 in PMACI-induced KU812F cells and IL-4 and tumor necrosis factor (TNF)- α in com 48/80-induced RBL-2H3 cells. It also determined the inhibition of PMACI, com 48/80- and IgE/DNP-induced degranulation by reducing the release of β -hexosaminidase. Furthermore, it attenuated the IgE/DNP-induced PCA reaction in the ears of BALB/c mice. These results suggest that SHQA isolated from S. serratifolium is a potential therapeutic functional food material for inhibiting effector cell activation in allergic reactions and anaphylaxis in animal model.

Eosinophils and associated parameters in different types of skin diseases related to elevated eosinophil levels

Background

Eosinophils, basophils, white blood cells (WBC), and immunoglobulin E (IgE) play major roles in the pathogenesis of atopic dermatitis (AD), bullous pemphigoid (BP), drug reaction with eosinophilia and systemic symptoms (DRESS), and hypereosinophilic syndrome (HES). This study aimed to describe these parameters in different skin diseases and provide further information concerning the underlying pathogenesis.

Methods

A cross-sectional study of blood test results, including WBC count, peripheral eosinophil count, peripheral basophil/WBC percentage, and IgE level, from 115 cases of AD, 75 cases of BP, 55 cases of DRESS, 119 cases of HES, and 621 healthy volunteers was performed in China. Data from before and after treatment and the population distribution of different diseases were compared and described.

Results

All participants showed increased peripheral eosinophil counts, eosinophil/WBC ratios, IgE levels, and decreased peripheral basophil counts, with variance among the different disease groups. Peripheral eosinophil counts in HES patients and IgE level in AD patients increased the most prominently. No significant correlation existed among eosinophils, basophils, and IgE. An obvious decrease in eosinophil count was demonstrated after treatment in all 4 diseases.

Conclusions

Eosinophils, basophils, and IgE exert functions in diverse skin diseases, presenting altered peripheral blood test results. In some cases, these changes are demonstrated only in the skin and not in the blood. Compared with the other parameters considered in this study, eosinophils seemed to be a better biomarker for treatment effects, regardless of the disease type.

Basophils in antihelminth immunity

It has been appreciated that basophilia is a common feature of helminth infections for approximately 50 years. The ability of basophils to secrete IL-4 and other type 2 cytokines has supported the prevailing notion that basophils contribute to antihelminth immunity by promoting optimal type 2 T helper (Th2) cell responses. While this appears to be the case in several helminth infections, emerging studies are also revealing that the effector functions of basophils are extremely diverse and parasite-specific. Further, new reports now suggest that basophils can restrict type 2 inflammation in a manner that preserves the integrity of helminth-affected tissue. Finally, exciting data has also demonstrated that basophils can regulate inflammation by participating in neuro-immune interactions. This article will review the current state of basophil biology and describe how recent studies are transforming our understanding of the role basophils play in the context of helminth infections.

Basophil-derived IL-4 promotes cutaneous Staphylococcus aureus infection

Superficial cutaneous Staphylococcus aureus (S. aureus) infection in humans can lead to soft tissue infection, an important cause of morbidity and mortality. IL-17A production by skin TCRγδ+ cells in response to IL-1 and IL-23 produced by epithelial and immune cells is important for restraining S. aureus skin infection. How S. aureus evades this cutaneous innate immune response to establish infection is not clear. Here we show that mechanical injury of mouse skin by tape stripping predisposed mice to superficial skin infection with S. aureus. Topical application of S. aureus to tape-stripped skin caused cutaneous influx of basophils and increased Il4 expression. This basophil-derived IL-4 inhibited cutaneous IL-17A production by TCRγδ+ cells and promoted S. aureus infection of tape-stripped skin. We demonstrate that IL-4 acted on multiple checkpoints that suppress the cutaneous IL-17A response. It reduced Il1 and Il23 expression by keratinocytes, inhibited IL-1+IL-23-driven IL-17A production by TCRγδ+ cells, and impaired IL-17A-driven induction of neutrophil-attracting chemokines by keratinocytes. IL-4 receptor blockade is shown to promote Il17a expression and enhance bacterial clearance in tape-stripped mouse skin exposed to S. aureus, suggesting that it could serve as a therapeutic approach to prevent skin and soft tissue infection.

Secondary basophilic leukemia in Ph-negative myeloid neoplasms: A distinct subset with poor prognosis

During progression of myeloid neoplasms, the basophil compartment may expand substantially and in some of these patients, a basophilic leukemia is diagnosed. In patients with Ph-chromosome+ chronic myeloid leukemia, acceleration of disease is typically accompanied by marked basophilia. In other myeloid neoplasms, secondary leukemic expansion of basophils is rarely seen. We report on 5 patients who suffered from a myelodysplastic syndrome, myeloproliferative neoplasm, or acute leukemia and developed a massive expansion of basophils during disease progression. In 4 of 5 patients, peripheral blood basophil counts reached 40%, and the diagnosis “secondary basophilic leukemia” was established. As assessed by flow cytometry, neoplastic basophils expressed CD9, CD18, CD25, CD33, CD63, PD-L1, CD123, and CLL-1. In addition, basophils were found to display BB1 (basogranulin), 2D7, tryptase and KIT. In 4 of 5 patients the disease progressed quickly and treatment with azacitidine was started. However, azacitidine did not induce major clinical responses, and all patients died from progressive disease within 3 Y. In in vitro experiments, the patients´ cells and the basophilic leukemia cell line KU812 showed variable responses to targeted drugs, including azacitidine, venetoclax, hydroxyurea, and cytarabine. A combination of venetoclax and azacitidine induced cooperative antineoplastic effects in these cells. Together, secondary basophilic leukemia has a poor prognosis and monotherapy with azacitidine is not sufficient to keep the disease under control for longer time-periods. Whether drug combination, such as venetoclax+azacitidine, can induce better outcomes in these patients remains to be determined in future clinical studies.

Immunoprofiling of early, untreated rheumatoid arthritis using mass cytometry reveals an activated basophil subset inversely linked to ACPA status

Background

Autoantibody production is a hallmark of rheumatoid arthritis (RA). Anti-citrullinated protein antibodies (ACPA) are highly disease-specific, and their presence is associated with more severe disease and poor prognosis compared to ACPA-negative patients. However, the immune cell composition associated with antibody-positive/negative disease is incompletely defined. Mass cytometry (MC) is a high-dimensional technique offering new possibilities in the determination of the immune cell composition in rheumatic diseases. Here, we set up a broad phenotyping panel to study the immune cell profile of early untreated RA to investigate if specific immune cell subsets are associated with ACPA+ versus ACPA− RA.

Methods

Freshly obtained PBMCs of early, untreated RA patients (8 ACPA+ and 7 ACPA−) were analysed using a 36-marker MC panel, including markers related to various immune lineages. Data were processed using Cytosplore for dimensional reduction (HSNE) and clustering. Groups were compared using Cytofast. A second validation cohort of cryopreserved PBMCs obtained from early RA patients (27 ACPA+ and 20 ACPA−) was used to confirm MC data by flow cytometry (FC). FC data were processed and analysed using both an unsupervised analysis pipeline and through manual gating.

Results

MC indicated no differences when comparing major immune lineages (i.e. monocytes, T and B cells), but highlighted two innate subsets: CD62L⁺ basophils (p = 0.33) and a subset of CD16⁻ NK cells (p = 0.063). Although the NK cell subset did not replicate by FC, FC replication confirmed the difference in CD62L⁺ basophil frequency when comparing ACPA+ to ACPA− patients (mean 0.32% vs. 0.13%; p = 0.01).

Conclusions

Although no differences in major lineages were found between early ACPA+ and ACPA− RA, this study identified the reduced presence of activated basophils in ACPA-negative disease as compared to ACPA-positive disease and thereby provides the first evidence for a connection between activated basophils and ACPA status.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-021-02630-8.

Autoimmune pancreatitis and pancreatic cancer: Epidemiological aspects and immunological considerations

Ordinary chronic pancreatitis is a well-known risk factor for pancreatic cancer, whereas such an association with autoimmune pancreatitis (AIP) is widely debated. Due to the rarity of the latter disorder, there are few specific clinical and epidemiological studies investigating the relation between AIP and pancreatic cancer, which do not seem to support it. However, these studies are affected by several limitations and, therefore, a link between AIP (and, specifically, type 1 AIP) and pancreatic cancer cannot be ruled out definitively on this basis. Moreover, several immunopathological aspects of type 1 AIP and, in general, immunoglobulin G4-related disease can create an immunological context that may impair the tumoral immunosurveillance and promote the pancreatic carcinogenesis and its progression. In detail, Th2 immunological dominance, type 2 macrophage polarization and basophil infiltration observed in type 1 AIP, may play a permissive role in creating a favorable immunological environment for pancreatic carcinogenesis, in addition to the immunosuppressive therapies that can be used in these patients.

Propolis suppresses cytokine production in activated basophils and basophil-mediated skin and intestinal allergic inflammation in mice

BACKGROUND

Propolis is a resinous mixture produced by honey bees that contains cinnamic acid derivatives and flavonoids. Although propolis has been reported to inhibit mast cell functions and mast cell-dependent allergic responses, the effect of propolis on basophil biology remains unknown. This study aimed to investigate the inhibitory effect of propolis on FcεRI-mediated basophil activation.

METHODS

To determine the inhibitory effect of propolis on basophil activation in vitro, cytokine production and FcεRI signal transduction were analyzed by ELISA and western blotting, respectively. To investigate the inhibitory effect of propolis in vivo, IgE-CAI and a food allergy mouse model were employed.

RESULTS

Propolis treatment resulted in the suppression of IgE/antigen-induced production of IL-4, IL-6 and IL-13 in basophils. Phosphorylation of FcεRI signaling molecules Lyn, Akt and ERK was inhibited in basophils treated with propolis. While propolis did not affect the basophil population in the treated mice, propolis did inhibit IgE-CAI. Finally, ovalbumin-induced intestinal anaphylaxis, which involves basophils and basophil-derived IL-4, was attenuated in mice prophylactically treated with propolis.

CONCLUSIONS

Taken together, these results demonstrate the ability of propolis to suppress IgE-dependent basophil activation and basophil-dependent allergic inflammation. Therefore, prophylactic treatment with propolis may be useful for protection against food allergic reactions in sensitive individuals.

An efficient and cost-effective method for the purification of human basophils

Human basophils are terminally differentiated granulocytes that are least abundant in the peripheral blood but play important roles in allergic diseases. Studies on human basophils are limited by the high cost on the isolation of human basophils by magnetic-activated cell sorting (MACS) for negative depletion of non-basophils, followed by CD123-based positive selection of basophils. Moreover, such CD123-based purification of basophils may be limited by blocking of the binding of IL-3/anti-CD123 to the surface CD123. Here we identified SSC^low CD4^- CD127^- HLA-DR^- CRTH2^high as unique markers for the identification of human basophils through stringent flow cytometric analysis of leukocytes from buffy coat. We established an efficient and cost-effective method for isolating human basophils from buffy coat based on positive magnetic selection of CRTH2⁺ cells followed by flow cytometric sorting of SSC^low CD4^- CD127^- HLA-DR^- CRTH2^high cells. Approximately 1 to 1.5 million basophils were isolated from one buffy coat with a purity of >97%. Basophils purified by this method were viable and efficiently responded to key regulators of basophils including IL-3 and anti-IgE. This method can be used for purifying human basophils for subsequent functional studies.

[The basophil: From control of immunity to control of leukemias]

The basophils, first described by Paul Ehlrich in 1879, are rare circulating cells, representing approximately 0.01 to 0.3% of the blood leukocytes. Until recently, these cells have been neglected because of their minority status among immune cells and because they show some similarities to mast cells residing in tissues. However, basophils and mast cells are now recognized as distinct cell lines and it appears that basophils have important and non-redundant functions, distinct from those of mast cells. On the one hand, basophils have beneficial contribution to protective immunity, in particular against parasitic infections. On the other hand, basophils are involved in the development of various benign and malignant pathologies, ranging from allergy to certain leukemias. Basophils interact with other immune cells or neoplastic cells through direct contacts or soluble mediators, such as cytokines and proteases, thus contributing to the regulation of the immune system but also to allergic responses, and probably to the process of neoplastic transformation. In this review, we will develop recent knowledge on the involvement of basophils in the modulation of innate and adaptive immunity. We will then describe the benign or malignant circumstances in which an elevation of circulating basophils can be observed. Finally, we will discuss the role played by these cells in the pathophysiology of certain leukemias, particularly during chronic myeloid leukemia.

Biologics for the Use in Chronic Spontaneous Urticaria: When and Which

Guidelines for the treatment of chronic spontaneous urticaria (CSU) recommend the use of the IgE-targeted biologic omalizumab in patients with antihistamine-refractory disease. The rationale for this is supported by the key role of IgE and its high-affinity receptor, FcεRI, in the degranulation of skin mast cells that drives the development of the signs and symptoms of CSU, itchy wheals, and angioedema. Here, we review the current understanding of the pathogenesis of CSU and its autoimmune endotypes. We describe the mechanisms of action of omalizumab, the only biologic currently approved for CSU, its efficacy and ways to improve it, biomarkers for treatment response, and strategies for its discontinuation. We provide information on the effects of the off-label use, in CSU, of biologics licensed for the treatment of other diseases, including dupilumab, benralizumab, mepolizumab, reslizumab, and secukinumab. Finally, we discuss targets for novel biologics and where we stand with their clinical development. These include IgE/ligelizumab, IgE/GI-310, thymic stromal lymphopoietin/tezepelumab, C5a receptor/avdoralimab, sialic acid-binding Ig-like lectin 8/lirentelimab, CD200R/LY3454738, and KIT/CDX-0159. Our aim is to provide updated information and guidance on the use of biologics in the treatment of patients with CSU, now and in the near future.

Biomarkers of the Severity of Honeybee Sting Reactions and the Severity and Threshold of Systemic Adverse Events During Immunotherapy

BACKGROUND

A biomarker that could identify individuals at high risk for severe honeybee sting allergic reaction and/or systemic adverse events (SAEs) during venom immunotherapy (VIT) would improve the management of patients with honeybee (HB) venom allergy.

OBJECTIVE

To identify biomarkers for risk of severe sting reactions or SAEs during VIT.

METHODS

We recruited 332 patients undergoing HB VIT. We ascertained predictors of the severity of the field-sting reaction and the severity and threshold of SAEs during VIT. We assessed the use of cardiovascular medications; baseline serum tryptase (BST) levels; specific IgEs to HB venom, rApi m 1, and rApi m 10; and basophil activation test (BAT) response.

RESULTS

Significant and independent predictors of a severe HB field-sting reaction were age (P = .008), an absence of skin symptoms (P = .001), BST (P = .014), and BAT response at an HB venom concentration of 0.1 μg/mL (P = .001). Predictors of severe SAEs during HB VIT were age (P = .025), BST (P = .006), and BAT response (P = .001). BAT response was also an individual and significant predictor of any SAEs and SAEs at a low cumulative allergen dose (median, 55 μg) during VIT build-up (P < .001). The use of β-blockers and angiotensin-converting-enzyme inhibitors and specific IgE levels were not associated with the severity of HB field-sting reactions or VIT SAEs.

CONCLUSIONS

BST and basophil activation are independent risk factors for severe HB sting anaphylaxis and SAEs during HB VIT. BAT response was the best biomarker for any SAEs and a lower threshold of SAEs during HB VIT. These risk factors can help guide recommendations for VIT and overcome systemic reactions to HB VIT.

Advanced Biomarkers: Therapeutic and Diagnostic Targets in Urticaria

Urticaria is a type of skin disease characterized by rapid onset of hives (superficial dermis edema, erythema, pruritus, or burning sensation). According to whether the natural course exceeds 6 weeks, urticaria can be divided into acute and chronic urticaria (CU). At present, the evaluation of CU activity mainly depends on the Urticaria Activity Score (UAS), but the evaluation indicators are relatively single, and we need more reliable experimental data for evaluation. We typically summarize advanced biomarkers and several related pathogenic pathways discovered in recent years on urticaria, including the cell adhesion/chemotaxis pathway, interleukin (IL)-6/Janus tyrosine kinase/STAT pathway, IL-17/IL-23 pathway, basophil- and mast cell-related pathway, coagulation/fibrinolysis-related pathways, single-nucleotide polymorphism, and some other pathways. This review aims to find appropriate biomarkers so that we can evaluate disease activity, discover novel therapeutic targets, and predict the patients' response more accurately to therapeutic agents.

A Comparative Study of Sex Distribution, Autoimmunity, Blood, and Inflammatory Parameters in Chronic Spontaneous Urticaria with Angioedema and Chronic Histaminergic Angioedema

BACKGROUND

Recurrent idiopathic histaminergic angioedema is currently classified as a subtype of angioedema, as well as a subtype of chronic spontaneous urticaria (CSU), based on the fact that both are mast cell-mediated and respond to the same treatments.

OBJECTIVE

In the present work, we sought to verify whether chronic histaminergic angioedema (CHA) is an entity distinct from CSU or represents a CSU subtype that lacks hives.

METHODS

We performed a prospective study comparing 68 CHA patients, angioedema without hives, with 63 CSU patients, with hives and angioedema, from whom we collected demographic and clinical data, as well as blood and serum markers.

RESULTS

We found key pathogenic features that differentiate CHA from CSU: gender distribution, basophil number, and antibodies against the IgE receptor. The male/female ratio in CHA was 0.78, whereas in CSU it was 0.36 (P = .0466). Basopenia was more often seen in CSU (n = 13 [20%]) than in CHA (n = 5 [7%]). Finally, 31.15% of CSU sera induced basophil activation, whereas no CHA sera were able to activate normal basophils. By contrast, nonspecific inflammation or immune markers, for example, erythrocyte sedimentation rate, C-reactive protein, or IgG antithyroid antibodies, were very similar between both groups. IgE anti-IL-24 could not be assessed because a control population did not differ from CSU.

CONCLUSIONS

Inclusion of CHA as part of the spectrum of CSU is an assumption not evidence-based, and when studied separately, important differences were observed. Until there is further evidence, CHA and CSU should not necessarily be considered the same disorder, and it is our opinion that review articles and guidelines should reflect that possibility.

Prognostic value of pretreatment circulating basophils in patients with glioblastoma

Accumulating evidence demonstrated that atopic diseases were inversely related to glioma susceptibility and associated with improved prognosis of patients with glioma. This study aimed to elucidate the impacts of basophils, one of the important effector cells in the pathobiology of atopic disease, on prognosis of patients with glioblastoma (GBM). A total of 268 patients were newly diagnosed with GBM and treated with operation at our institution from January 2010 to December 2017. The association between pre-operation circulating eosinophil, basophil, neutrophil, lymphocyte, monocyte count and GBM progression free survival (PFS) was investigated. Moreover, based on the results of multivariate analysis, a prognostic nomogram was established and evaluated. Kaplan-Meier method showed that basophils ≥0.015 × 10⁹/L (p = 0.015) and lymphocytes ≥1.555 × 10⁹/L (p = 0.005) were correlated with better PFS. Cox regression model showed that basophils ≥0.015 × 10⁹/L were an independent prognostic factor for PFS. Prognostic nomogram was established and the concordance index (C-index) for PFS prediction was 0.629. The calibration plots for the probability of 0.5-, 1- and 3-year PFS showed optimal consistency between the prediction by nomogram and actual observation. Increased pre-operation circulating basophils portend better PFS, which might be a useful and novel marker for the prognosis of GBM patients.

Modulating the Human Basophil Phenotype During Its Development and Maturation: Basophils Derived from In Vitro Cultures of CD34+ Progenitor Cells

Historically, the human basophil that is studied experimentally comes from peripheral blood. But there is evidence that only a short portion of the basophil life cycle related to IgE-mediated function occurs in the blood. The same evidence suggests that IgE-mediated functionality is present for 5-7 days in the bone marrow (or other tissues) during which the cell modulates its phenotype according to local conditions. It is suggested that to properly understand the nature of basophil behavior, a better understanding of its biology during maturation would be helpful. For example, one highly suggestive line of evidence for the relevance of understanding the maturation period is related to the change in basophil phenotype that occurs during treatment of patients with omalizumab. During this treatment, the intrinsic reactivity or sensitivity of the basophils is significantly increased despite, or perhaps because of, the dramatic reduction in FcεRI expression that accompanies this treatment. One of the critical signaling enzymes to increase expression selectively in basophils during treatment is SYK, which is one of the earliest signaling tyrosine kinases involved in translating the aggregation of FcεRI into secretion from the cell. Treatment with omalizumab increases SYK expression, and this observation focuses some attention of how SYK expression is regulated. It is possible that the key regulation occurs during maturation of the basophil. Regardless of the mechanisms operative in this particular treatment, understanding the process of maturation and the extrinsic factors that influence it may lead to better understanding of disease processes. Therefore, this chapter will discuss and present techniques to work with maturing human basophils.

Detection of Basophils and Other Granulocytes in Induced Sputum by Flow Cytometry

Flow cytometry is one of the most widely used techniques for the detection of surface markers on various cells, particularly the cells of the immune system, at a single-cell resolution. Modern flow cytometers can identify rare cell population in highly heterogeneous samples. Here we present a protocol that allows a precise detection of basophils as well as eosinophils and neutrophils in induced sputum samples. The identification of sputum basophils and other granulocytes contributes to a better understanding of the cellular network that promotes and regulates inflammation of the lower respiratory tract.

Histamine, mast cell tryptase and post-exercise hypotension in healthy and collapsed marathon runners

PURPOSE

Heat stress exacerbates post-exercise hypotension (PEH) and cardiovascular disturbances from elevated body temperature may contribute to exertion-related incapacity. Mast cell degranulation and muscle mass are possible modifiers, though these hypotheses lack practical evidence. This study had three aims: (1) to characterise pre-post-responses in histamine and mast cell tryptase (MCT), (2) to investigate relationships between whole body muscle mass (WBMM) and changes in blood pressure post-marathon, (3) to identify any differences in incapacitated runners.

METHODS

24 recreational runners were recruited and successfully completed the 2019 Brighton Marathon (COMPLETION). WBMM was measured at baseline. A further eight participants were recruited from incapacitated runners (COLLAPSE). Histamine, MCT, blood pressure, heart rate, body temperature and echocardiographic measures were taken before and after exercise (COMPLETION) and upon incapacitation (COLLAPSE).

RESULTS

In completion, MCT increased by nearly 50% from baseline (p = 0.0049), whereas histamine and body temperature did not vary (p > 0.946). Systolic (SBP), diastolic (DBP) and mean (MAP) arterial blood pressures and systemic vascular resistance (SVR) declined (p < 0.019). WBMM negatively correlated with Δ SBP (r = - 0.43, p = 0.046). For collapse versus completion, there were significant elevations in MCT (1.77 ± 0.25 μg/L vs 1.18 ± 0.43 μg/L, p = 0.001) and body temperature (39.8 ± 1.3 °C vs 36.2 ± 0.8 °C, p < 0.0001) with a non-significant rise in histamine (9.6 ± 17.9 μg/L vs 13.7 ± 33.9 μg/L, p = 0.107) and significantly lower MAP, DBP and SVR (p < 0.033).

CONCLUSION

These data support the hypothesis that mast cell degranulation is a vasodilatory mechanism underlying PEH and exercise associated collapse. The magnitude of PEH is inversely proportional to the muscle mass and enhanced by concomitant body heating.

Inflammatory and cardiometabolic markers at presentation with first episode psychosis and long-term clinical outcomes: A longitudinal study using electronic health records

Approximately one third of patients presenting with a first episode of psychosis need long-term support, but there is a limited understanding of the sociodemographic or biological factors that predict this outcome. We used electronic health records from a naturalistic cohort of consecutive patients referred to an early intervention in psychosis service to address this question. We extracted data on demographic (age, sex, ethnicity and marital status), immune (differential cell count measures and C-reactive protein (CRP)) and metabolic (cholesterol, triglycerides, glucose, glycated haemoglobin, blood pressure, body mass index (BMI)) factors at baseline, and subsequent need for long-term secondary (specialist) psychiatric care. Of 749 patients with outcome data available, 447 (60%) had a good outcome and were discharged to primary care, while 302 (40%) required follow-up by secondary mental health services indicating a worse outcome. The need for ongoing secondary mental healthcare was associated with high triglyceride levels (adjusted odds ratio/OR = 7.32, 95% CI 2.26-28.06), a low basophil:lymphocyte ratio (adjusted OR = 0.14, 95% CI 0.02-0.58), and a high monocyte count (adjusted OR = 2.78, 95% CI 1.02-8.06) at baseline. The associations for baseline basophil (unadjusted OR = 0.27 per SD, 95% CI 0.10-0.62) and platelet counts (unadjusted OR = 2.88, 95% CI 1.29-6.63) attenuated following adjustment for BMI. Baseline CRP levels or BMI were not associated with long-term psychiatric outcomes. In conclusion, we provide evidence that triglyceride levels and several blood cell counts measured at presentation may be clinically useful markers of long-term prognosis for first episode psychosis in clinical settings. These findings will require replication.

Chemokines during anaphylaxis: the importance of CCL2 and CCL2-dependent chemotactic activity for basophils

Background

The role of chemokines in anaphylaxis is unclear.

Methods

We prospectively recruited 49 patients presenting to the emergency department with an acute episode of anaphylaxis and 28 healthy subjects. We measured serum levels of the chemokines CCL2, CCL5, CCL7, CCL8, CCL11, CCL13, CCL17, CCL21, CCL22, CCL24, and CCL26, tryptase, the absolute number of circulating basophils, monocytes, lymphocytes, and PMNs, and whole blood FCER1A, CPA3 and HDC gene expression at two time points: during the anaphylactic episode and in convalescent samples collected approximately 3 months later. We then investigated the in vitro chemotactic activity of chemokines induced during anaphylaxis for the in vitro migration of the corresponding cells.

Results

Only CCL2 chemokine levels were significantly increased in anaphylaxis samples (median 514 pg/ml) compared to convalescent samples (284 pg/ml, P < 0.0001) and healthy subjects (279 pg/ml, P < 0.0001); there was no significant difference in any of the other chemokines. There was a significant positive correlation between the rates of increase of serum CCL2 (median [range]: 106.0% [− 44.7% to 557.4%]) and tryptase (133.8% [− 6.6% to 893.4%]; r = 0.68, P < 0.0001) and between the acute concentration of serum CCL2 and the acute concentration of serum tryptase (r = 0.77, P < 0.0001). The number of circulating basophils, but not other blood cells, significantly decreased during anaphylaxis (median 5.0 vs. 19.1 cells/µl in convalescent samples; P < 0.0001); a decrease in whole-blood gene expression of basophil markers (P ≤ 0.0018) confirmed these changes. Anaphylactic serum enhances the in vitro migration of basophils via CCL2-dependent chemotactic activity; in contrast, no CCL2-dependent chemotactic activity was observed for convalescent samples.

Conclusions

Our findings imply an important and specific role for CCL2-mediated chemotactic activity in the pathophysiology of human anaphylaxis.

Staphylococcal superantigen-like 12 induces the production of interleukin 4 in murine basophils

S. aureus is associated with atopic dermatitis (AD). Several staphylococcal products including cell wall components, protease, and exotoxins, are thought to be involved in allergic inflammation of AD via activating immune cells such as T cells and mast cells. None of the staphylococcal exotoxins has been reported to activate a primary IL-4 inducer, basophils, that are known to produce large amounts of IL-4 in response to allergens as well as IgE-independent stimuli such as mites and helminth proteases. In this study, we investigated the ability of staphylococcal superantigen-like (SSL) family to activate basophils. SSL12, reported its activity to activate mast cells, induced the production of IL-4 in bone marrow derived basophils. SSL12 also evoked the release of IL-4 in freshly isolated murine basophils in bone marrow cells, as the depletion of basophils by basophils-specific antibodies against high-affinity IgE receptor and CD49b diminished the responsiveness of bone marrow cells for SSL12. These results propose the novel immune regulatory activity of SSL12 by inducing IL-4 in basophils, that contributes to the development of allergic inflammation disorders and the immune evasion of the cocci.

Effects of omalizumab on basophils: Potential biomarkers in asthma and chronic spontaneous urticaria

Omalizumab is an anti-IgE humanized monoclonal antibody approved for the treatment of severe asthma and chronic spontaneous urticaria. Omalizumab binds free serum IgE and antagonizes its interaction with FcεRI, which is considered the main pharmacodynamic mechanism responsible for the clinical response to the treatment. The reduction of IgE serum concentration down-regulates the cellular expression of FcεRI on basophils. However, the biological events occurring on basophils during the therapy with omalizumab are multiple and complex. Here we review the current evidence regarding the specific biological effects of omalizumab on basophils in patients with asthma and chronic spontaneous urticaria. In addition to the modulation of IgE receptors, omalizumab may affect basophils homeostasis, intra-cellular signaling, cellular responsiveness/activation and cytokine release. These effects may be partially responsible for the clinical success of omalizumab and potentially provide useful biological markers for future assessment of the clinical response to the treatment. However, further investigation is required to better elucidate the role of basophils during the treatment with omalizumab.

Basophil Stimulation and Signaling Pathways

Despite the growing use of flow cytometry to analyze the functional characteristics of basophils, the intracellular signaling cascades that control their ability to elaborate various pro-allergic and inflammatory mediators and cytokines remain comparatively obscure. Additionally, some studies require the analysis of pro-allergic and inflammatory mediators, such as histamine, LTC₄, and various basophil-derived cytokines (e.g., IL-4 and IL-13). Elucidation of intracellular signaling proteins by Western blotting, cytosolic free calcium concentration by spectrofluorophotometry, and detection of mediator releases, as well as analysis of gene expressions by RT-PCR, generally requires relatively large numbers of purified basophils. In selected assays, flow cytometry enables the analysis of relatively low cell numbers and purity for the expression of intracellular signaling proteins or measurement of cytosolic free calcium concentrations by basophil-specific gating strategies. Unfortunately, many aspects of signal transduction relevant to human basophils cannot be readily extrapolated from the use of basophil or mast cell lines. This chapter therefore focuses on how to employ primary human basophils for studying mediator releases and signaling characteristics.

The Absolute Basophil Count

The absolute basophil count (cells/L) can be determined by manual counting of peripheral blood smears or using cell counting chambers as well as by automated hematology analyzers and fluorescence flow cytometry. Manual basophil counting of peripheral blood smears is currently regarded as the reference method, although the limitations of this method (distribution, observer, and statistical errors) are widely recognized. Automated hematology analyzers offer an advantage of larger numbers of counted cells and high throughput but are characterized by inconsistent analytical performance for basophil enumeration. Flow cytometric enumeration of circulating basophils using panels of monoclonal antibodies is being developed as novel candidate reference method for the absolute basophil count in peripheral blood. Basophil counting using fluorescence flow cytometry is characterized by high precision and statistical superiority. Emerging innovative technologies for absolute cell counts include imaging flow cytometry, mass cytometry, and on-chip blood counting, but their analytical performance for absolute basophil counts is yet to be established. Here, we describe various techniques for absolute basophil counting in peripheral blood including manual basophil counts in smears and hemocytometers and flow cytometric methodologies using double-platform, bead-based, and volumetric approaches.

Identification of Murine Basophils by Flow Cytometry and Histology

Here, we describe how murine basophils can be detected in vivo by flow cytometry and immunofluorescence staining. Basophils constitute a homogeneous population of CD4^-CD19^-CD49b⁺IgE⁺ cells in flow cytometric analysis. When IgE levels are low, one can also use anti-FcεRI or anti-CD200R3 antibodies instead of anti-IgE. For immunofluorescence staining, we use an anti-Mcpt8 antibody since Mcpt8 is a specific marker for murine basophils. We describe how to prepare the tissue to cut cryo-sections and how to perform the staining using a tyramide-based amplification kit.

Effectiveness and safety of benralizumab for severe asthma in clinical practice (J-BEST): a prospective study

Background

Benralizumab is a humanized, fucosylated, monoclonal antibody that targets the interleukin 5 (IL-5) α receptor. Several phase III trials have shown that benralizumab can significantly reduce the incidence of acute exacerbations and improve lung function in patients with severe asthma. However, there is a paucity of data from clinical practice. In this prospective study, we evaluated the effectiveness and safety of benralizumab for severe asthma in clinical practice.

Methods

This was a prospective, open-label, single-arm, single-center study in patients with severe asthma in clinical practice (UMIN000031951). Haematological, clinical, functional, and pharmacotherapeutic parameters were evaluated at baseline and at weeks 4 and 12 after initiation of benralizumab.

Results

Twenty-six patients were enrolled between May 2018 and March 2019. Both asthma quality of life questionnaire (AQLQ) score and asthma control test (ACT) score showed significant improvement over the study period. Forced expiratory volume in 1.0 second (FEV1) showed a significant increase at week 12 (baseline: 1.57 L; week 12: 1.75 L). Blood eosinophil and basophil counts were significantly decreased at week 12 compared to baseline. At week 12, the dose of regular oral corticosteroids (OCS) was significantly decreased from baseline as was the number of patients on need-based OCS. Benralizumab had no significant effect on fractional exhaled nitric oxide (FeNO) levels and total immunoglobulin E levels. Only one patient experienced mild headache during benralizumab therapy.

Conclusions

In this study, benralizumab conferred clinically significant benefits in patients with severe asthma with no short-term severe adverse events.

Circulating basophil count as a prognostic marker of tumor aggressiveness and survival outcomes in colorectal cancer

Background

Accumulating evidence demonstrated immune/inflammation-related implications of basophils in affecting tissue microenvironment that surrounded a tumor, and this study aimed to elucidate the clinical value of serum basophil count level.

Methods

Between December 2007 and September 2013, 1029 patients diagnosed with stage I–III CRC in Fudan University Shanghai Cancer Center meeting the essential criteria were identified. The Kaplan–Meier method was used to construct the survival curves. Several Cox proportional hazard models were constructed to assess the prognostic factors. A simple predictor (CB classifier) was generated by combining serum basophil count and serum carcinoembryonic antigen (CEA) level which had long been accepted as the most important and reliable prognostic factor in CRC.

Results

The preoperative basophils count < 0.025*10⁹/L was strongly associated with higher T stage, higher N stage, venous invasion, perineural invasion, elevated serum CEA level, and thus poor survival (P < 0.05). Moreover, multivariate Cox analysis showed that patients with low level of preoperative basophils count had an evidently poorer DFS [Hazard ratio (HR) = 2.197, 95% CI 1.868–2.585].

Conclusions

As a common immune/inflammation-related biomarker available from the blood routine examination, low level of preoperative serum basophil count was associated with aggressive biology and indicated evidently poor survival. Preoperative serum basophil count would be a useful and simple marker for the management of CRC patients.