Systemic activation of basophils and eosinophils: markers and consequences

Evidence of in vivo basophil activation in chronic idiopathic urticaria

BACKGROUND

Approximately 40% of chronic idiopathic urticaria (CIU) subjects have autoantibodies to either FcepsilonRIalpha or IgE. The effect of such autoantibodies on circulating basophil activation status is unknown.

OBJECTIVE

The expression of cell surface activation markers on basophils from CIU, non-allergic, and allergic subjects were compared. Further, the relationship between marker expression and serum factors reported in CIU, such as histamine-releasing activity (HRA) and immunoreactivity to FcepsilonRIalpha were examined.

METHODS

Peripheral blood was obtained from CIU, allergic, and non-allergic donors and fractionated by density gradients. Enriched basophils (1-12%) were analysed by flow cytometry for expression of activation markers including CD63, CD69, and CD203c. Dilutions of serum (5-50%) were analysed for HRA on basophils from a normal donor. Serum was tested for immunoreactivity by western blotting to a standard cell lysate prepared from an RBL-SX38 cell line transfected with human FcepsilonRIalpha.

RESULTS

CIU subjects (n=9) and allergic subjects (n=8) exhibited enhanced expression of CD63 and CD69, as compared with non-allergic subjects (n=7); however, no difference was seen among groups for CD203c expression. Five CIU and two non-allergic subjects had evidence of significant serum HRA (>20%), whereas two CIU, two allergic, and three non-allergic subjects had evidence of serum immunoreactivity to FcepsilonRIalpha. Serum HRA and serum immunoreactivity to FcepsilonRIalpha were not associated with enhanced surface marker expression.

CONCLUSION

Basophil activation marker expression is increased in CIU subjects and is not associated with serum factors. In addition, serum HRA and FcepsilonRIalpha immunoreactivity are not unique to CIU, or related to enhanced circulating basophil marker expression.

Significant correlation between the CD63 assay and the histamine release assay in chronic urticaria

BACKGROUND

Antibodies directed to the alpha subunit of the high affinity IgE receptor and the IgE molecule are proposed to be of pathogenetic relevance in a group of patients with chronic urticaria (CU). The diagnosis of autoimmune chronic urticaria (ACU) is difficult; the autologous serum skin test (ASST) seems to be a useful screening test, but reliable, additional confirmatory methods are needed.

OBJECTIVES

To assess the diagnostic value of a modified serum-induced basophil activation test, the CD63 expression assay, in the diagnosis of ACU by comparing the results of the CD63 assay with the results of the histamine release (HR) test, the ASST and serum levels of soluble CD40 ligand (sCD40L).

METHODS

Using basophils from an atopic (DA) and a nonatopic (DNA) donor the activity of sera of 72 patients with CU were measured in HR assay by enzyme-linked immunosorbent assay and in CD63 expression assay by flow cytometry. An ASST was carried out in all patients; in 30 of the 72 patients sCD40L was detected and correlations were derived between the different assays. Sera of 20 normal controls and 26 patients with systemic autoimmune diseases were also tested in the HR assay and in the CD63 expression assay.

RESULTS

Histamine-releasing activity was detected in the sera of 51% (DA) and 32% (DNA) of CU patients and 57% (DA) and 28% (DNA) of sera upregulated CD63 expression on the surface of basophils from the different donors. There was a significant correlation between the HR and the CD63 assays carried out on both donors, but the ASST showed a strong correlation with the HR assay only for basophils from the DA. The serum level of sCD40L was significantly higher in patients with CU compared with controls, but the difference between the autoimmune and the nonautoimmune groups was not significant.

CONCLUSIONS

The CD63 expression assay seems to be a reliable functional test in the diagnosis of ACU, particularly if highly sensitive donor basophils are used, but the determination of the sCD40L serum level was not sufficient to differentiate between the autoimmune and the nonautoimmune patient groups.

[Activated eosinophils: techniques to characterize them]

The deleterious role thought to be played by eosinophils in many situations is linked to their ability to secrete various inflammatory substances, mainly toxic proteins and lipid mediators, in body tissue. This ability is a particular feature of activated eosinophils, which have undergone numerous metabolic, functional, and phenotypic changes from their resting state. Characterizing the properties of these activated cells is an essential step in improving our understanding of their contributions to local inflammatory response, as both regulatory and effector cells. Improvements in existing methods as well as the development of new technical approaches have facilitated the ex vivo and in vitro study of activated eosinophils and their contribution to various disease states.

Circulating eosinophils in asthma, allergic rhinitis, and atopic dermatitis lack morphological signs of degranulation

BACKGROUND

In allergic diseases, eosinophils in affected tissues release granule proteins with cytotoxic, immunoregulatory, and remodelling-promoting properties. From recent observations, it may be assumed that eosinophils degranulate already in circulating blood. If degranulation occurs in the circulation, this could contribute to widespread systemic effects and provide an important marker of disease.

OBJECTIVE

To determine the degranulation status of circulating eosinophils in common allergic diseases.

METHODS

Using a novel approach of whole blood fixation and leucocyte preparation, the granule morphology of blood eosinophils from healthy subjects, non-symptomatic patients, symptomatic patients with asthma, asthma and Churg-Strauss syndrome, allergic rhinitis, and atopic dermatitis was evaluated by transmission electron microscopy (TEM) and eosinophil peroxidase (TEM) histochemistry. Plasma and serum levels of eosinophil cationic protein were measured by fluoroenzymeimmunoassay. Selected tissue biopsies were examined by TEM.

RESULTS

Regardless of symptoms, circulating eosinophils from allergic patients showed the same granule morphology as cells from healthy subjects. The majority of eosinophil-specific granules had preserved intact electron-density (96%; range: 89-98%), while the remaining granules typically exhibited marginal coarsening or mild lucency of the matrix structure. Abnormalities of the crystalline granule core were rarely detected. Furthermore, granule matrix alterations were not associated with any re-localization of intracellular EPO or increase in plasma eosinophil cationic protein. By contrast, eosinophils in diseased tissues exhibited cytolysis (granule release through membrane rupture) and piecemeal degranulation (loss of granule matrix and core structures).

CONCLUSION

In symptomatic eosinophilic diseases, circulating blood eosinophils retain their granule contents until they have reached their target organ.

Allergic bronchopulmonary aspergillosis in a patient with cystic fibrosis: diagnostic criteria when the IgE level is less than 500 IU/mL

BACKGROUND

Recently, the Cystic Fibrosis Foundation developed a consensus report recommending diagnostic criteria for allergic bronchopulmonary aspergillosis (ABPA) in patients with cystic fibrosis that includes a serum IgE level greater than 500 IU/mL as the "minimal diagnostic criterion."

OBJECTIVE

To describe a 7-year-old girl with ABPA whose serum IgE level increased to only 398 IU/mL.

METHODS

Total IgE and anti-Aspergillus serologic measurements were performed using enzyme-linked immunosorbent assay and standard laboratory techniques; HLA analysis was performed; interleukin 4 receptor alpha single nucleotide polymorphisms were performed using polymerase chain reaction and DNA sequencing; CD23+ B cells were measured using flow cytometry; and cytokine synthesis to Aspergillus purified antigens was assessed using flow cytometry.

RESULTS

A 7-year-old girl with cystic fibrosis who had mild pulmonary disease and well-controlled asthma developed pulmonary infiltrates, increased wheezing, and decreased pulmonary function. Additional studies demonstrated peripheral blood eosinophilia (eosinophil count, 1807 cells/mm3 [19%]) and an increase in IgE and IgG anti-Aspergillus serology; bronchoalveolar lavage revealed septate hyphae with 45 degrees branching subsequently identified as A fumigatus and pulmonary eosinophilia. Previous HLA typing revealed that the patient was HLA-DR2+, DRB*1501, HLA-DQ2-, a pattern associated with increased risk of ABPA. In addition, there was increased up-regulation of CD23 molecules by interleukin 4 stimulation on the patient's B cells, as observed in ABPA. The patient was treated with corticosteroids and itraconazole with resolution of symptoms and pulmonary infiltrates.

CONCLUSIONS

Examination of the pulmonary inflammatory response using bronchoalveolar lavage, genetic risk with HLA-DR2+DQ2- typing, and increased interleukin 4 sensitivity are useful adjunctive studies in the diagnosis of ABPA.

Activation of human eosinophils via P2 receptors: novel findings and future perspectives

A growing body of information indicates that release of intracellular nucleotides represents an important way to modulate several cell pathways in physiological or pathological conditions. Nucleotides released as a consequence of cell damage, cell stress, bacterial infection, or other noxious stimuli signal at a class of plasma membrane receptors--P2 receptors--activating diverse intracellular pathways in many tissues and organs. For example, nucleotides secreted in the airway system control chloride/liquid secretion, goblet cell degranulation, and ciliary beat frequency. Several studies indicate that nucleotides play a role in airway diseases through their action on multiple cell types, including mast cells, dendritic cells, neurons, and eosinophils. Recent work by us and other groups led to the identification and characterization of P2 receptors expressed by human eosinophils. In this review, we will summarize recent developments in this field and put forward a hypothesis about the role of P2 receptors in pathophysiological conditions where eosinophils are major players.

Effect of Mycobacterium vaccae on cytokine responses in children with atopic dermatitis

The increasing prevalence of atopic diseases over the last few decades is thought to be due to reduced exposure to environmental microbes that normally down-regulate allergic responses (hygiene hypothesis). We have shown previously that administration of the environmental microbe Mycobacterium vaccae ameliorates atopic dermatitis in school-age children at 3 months post-treatment. The present study tested the hypothesis that M. vaccae suppresses Th2-type cytokine activity and increases transforming growth factor (TGF)-beta(1) immunomodulatory activity in these children. Interleukin (IL)-4, IL-5, TGF-beta(1) and interferon (IFN)-gamma activity were assessed in resting and stimulated peripheral blood mononuclear cells (PBMC) isolated from 12 of the children who received M. vaccae in our original clinical trial. A cDNA expression array was used to examine a broader range of cytokine pathway transcripts. There were no significant changes in either Th2-type or TGF-beta(1) activity. A 5- to 10-fold increase in Th1-type activity was found at 1 month post-M. vaccae administration (P < 0.05), but it had returned to baseline by 3 months. The results do not support the hypothesis that M. vaccae reduces Th2-type or increases TGF-beta(1) activity of PBMC isolated from children with atopic dermatitis. The transient surge in IFN-gamma at 1 month is unlikely to explain any improvement in eczema score at 3 months.

Immunopathogenesis of allergic bronchopulmonary aspergillosis in cystic fibrosis

Allergic bronchopulmonary aspergillosis (ABPA) is a hypersensitivity lung disease mediated by an allergic late-phase inflammatory response to Aspergillus fumigatus antigens. ABPA is characterized by markedly elevated Aspergillus-specific and total IgE levels and eosinophilia, and manifested by wheezing, pulmonary infiltrates, and bronchiectasis and fibrosis, which afflict asthmatic and cystic fibrosis (CF) patients. We propose that ABPA develops in genetically susceptible CF patients due to HLA-DR2 and DR5 restriction, increased sensitivity to IL-4 stimulation, and increased A. fumigatus allergen-specific Th2 CD4+ T-cell-mediated responses. In addition, A. fumigatus proteases play a role in facilitation of antigen transport across the epithelial cell layer by damaging the epithelial integrity and by a direct interaction with epithelial cell surface receptors, resulting in pro-inflammatory cytokine production and corresponding inflammatory responses.

Assays for measuring in vitro basophil activation induced by recombinant allergens

The diagnosis of type I allergy is essentially based on clinical data, skin tests, and measurements of allergen-specific IgE. However, the determination of specific IgE per se does not permit a definitive conclusion concerning the response of effector cells to the respective allergen(s) and consecutive clinical symptoms in all patients. In an attempt to overcome this problem, a number of basophil-activation assays have been developed during the last few years. Today, allergen-induced activation of blood basophils can be employed as a specific and reliable measure of IgE-dependent responses in sensitized individuals. Using recombinant allergens and basophil-specific markers, these novel assays appear to serve as simple and useful tests in component-resolved diagnosis of type I allergies. In the current article, the biochemical, functional, and technical background of these basophil tests is discussed.

Effects of Prostaglandin D2and 5-Lipoxygenase Products on the Expression of CD203c and CD11b by Basophils

Basophils are important in allergic diseases such as asthma because they produce a variety of inflammatory mediators. Activation of these cells with IgE and N-formyl-methionyl-leucyl-phenylalanine results in a variety of responses, including increased surface expression of CD203c and CD11b and release of histamine. Although considerable information is available on the effects of eicosanoids on neutrophils, eosinophils, and monocytes, less is known about their effects on basophils. In the present study, we examined the effects of various eicosanoids on the above basophil responses. Of the naturally occurring eicosanoids tested, prostaglandin D(2) (PGD(2); EC(50), 10 nM) was by far the most potent activator of CD203c expression, with other prostanoids having little effect. This response was mediated by the DP(2) receptor/chemoattractant receptor-homologous molecule expressed on Th2 cells because it was shared by the selective agonist 15R-methyl-PGD(2) (EC(50), 3 nM). The 5-lipoxygenase products leuko-triene B(4) and 5-oxo-6,8,11,14-eicosatetraenoic acid also stimulated CD203c expression but to a lesser extent than PGD(2), whereas leukotriene D(4) was inactive. Neither PGD(2) nor 5-oxo-6,8,11,14-eicosatetraenoic acid stimulated histamine release or CD63 expression on basophils. Both PGE(2) and the DP(1) receptor agonist BW245C [(4S)-(3-[(3R,S)-3-cyclohexyl-3-hydroxypropyl]-2,5-dioxo)-4-imidazolidineheptanoic acid] strongly inhibited DP(2) receptor-mediated CD203c expression. The DP(1) receptor antagonist BWA868C [3-[(2-cyclohexyl-2-hydroxyethyl)amino]-2,5-dioxo-1-(phenylmethyl)-4-imidazolidine-heptanoic acid] enhanced PGD(2)-induced CD203c expression, suggesting that interaction of PGD(2) with DP(1) receptors can limit activation of basophils by this prostaglandin. In conclusion, PGD(2) is the most potent inducer of basophil CD203c expression among eicosanoids and may be a key mediator in asthma and other allergic diseases. The balance between DP(1) and DP(2) receptors may be important in determining the magnitude of basophil responses to this prostaglandin.

In vitro assays for the diagnosis of IgE-mediated disorders

Advances in technology have provided new laboratory tools for the quantitation of allergen-specific IgE antibodies in serum and on the surface of basophils. This review examines the evolution from qualitative IgE antibody assays of the late 1960s to the present-day, third-generation, automated and quantitative allergen-specific IgE assays. The latest technology trend is toward microarrays in which crude or purified native and recombinant allergens can be spotted in microdot arrays on silica chips to permit extensive panels of specific IgE measurements to be performed with small quantities of serum. Although these technologies hold promise, their diagnostic performance requires further assessment once their technical details have been optimized. Potential abuses of this newer IgE antibody technology include the use of allergosorbent specificities (eg, especially food and drugs) that lack validation, application of IgE antibody measurements in the diagnosis of non-IgE-dependent disorders (eg, aspirin sensitivity), and modification of IgE antibody assays to measure food-specific IgG antibody for which there is no clinical indication. Basophil mediator release assays have evolved to include flow cytometric methods that can quantitatively detect the presence of cell surface-bound allergen-specific IgE antibodies. Assays for histamine and leukotriene C 4 released after in vitro basophil activation are now more accurate and standardized. Current analytic methods for IgE antibodies provide more quantitative and reproducible measurements of IgE than ever before, although still with less sensitivity that traditional skin testing. The current challenge is to translate the quantitative IgE antibody results into a more accurate diagnosis of allergic disease.

Basophil CD63 expression assay on highly sensitized atopic donor leucocytes-a useful method in chronic autoimmune urticaria

BACKGROUND

The autoimmune subclass of chronic idiopathic urticaria (CU) has been characterized by the occurrence of biologically relevant IgG antibodies against the IgE molecule or the alpha chain of the high-affinity Fcepsilon receptor (FcepsilonRIalpha) on basophils and mast cells. These antibodies are usually detected by autologous serum skin testing and confirmed by histamine release studies, immunoblotting, or enzyme-linked immunosorbent assay, but not always.

OBJECTIVES

To detect autoantibodies to the FcepsilonRIalpha in sera of CU patients by a modified serum-induced basophil activation test measured by flow cytometry (FCM) and to evaluate the relationship between the in vitro functional test, the autologous serum skin test (ASST), and the serum levels of IgE, eosinophil cationic protein (ECP) and antithyroid antibodies.

METHODS

Sera of 30 patients with CU and 26 patients with systemic autoimmune diseases (systemic lupus erythematosus, dermatomyositis) were tested for CD63 activation marker expression on basophils by FCM. Leucocytes from two highly sensitized atopic donors (D(A1,) D(A2)) and one non-atopic donor (D(NA)) were incubated with patients' sera and double-labelled with anti-IgE and anti-CD63 antibodies. Subsequently, the percentage of CD63-expressing basophils was determined by using FCM. In all CU patients an ASST was carried out and the serum IgE, and ECP levels and antithyroid antibodies were evaluated.

RESULTS

Twelve patients had a positive ASST and 14 patients a positive CD63 expression assay. There was a strong correlation between the ASST and CD63 assay. Sera from patients with systemic autoimmune diseases did not raise positive CD63 expression on basophils. There was a moderate negative correlation between the occurrence of atopic serum markers (IgE, ECP) and the ability of sera to induce CD63 expression on basophil cells of D(A2) (P < 0.05). The female sex was preponderant and antithyroid antibodies were more frequent.

CONCLUSIONS

Our new technical observation demonstrates that basophils of highly sensitized atopic donors can be successfully used without priming with IL-3 for the in-vitro flow cytofluorimetric diagnosis of CU. With this investigation the characterization of the autoimmune origin of CU is based on an objective in vitro technique.

Eosinophils and atopic dermatitis

In spite of the progress regarding the description of immunological phenomena associated with atopic dermatitis (AD), the pathogenesis of this disease still remains unclear. The presence of eosinophils in the inflammatory infiltrate of AD has long been established. Eosinophil numbers as well as eosinophil granule protein levels in peripheral blood are elevated in most AD patients and appear to correlate with disease activity. Moreover, eosinophil granule proteins, which possess cytotoxic activity, are deposited in the skin lesions. These observations indicate a role of eosinophils in the pathogenesis of AD. Furthermore, AD is associated with increased production of T helper 2 cytokines including interleukin (IL)-5, which specifically acts on eosinophils, resulting in accelerated eosinophilopoiesis, chemotaxis, cell activation, and delayed apoptosis. Therefore, IL-5 is an interesting target for experimental therapy in this inflammatory disorder of the skin. Such studies might result in new insights into the pathogenetic role of eosinophils in AD.

In vitro allergy diagnosis: should we follow the flow?

During the last 5 years, an increasing number of studies have demonstrated that flow cytometric quantification of in vitro basophil activation can be a quite performant and reliable tool to measure IgE-dependent allergen-specific responses in allergic patients. So far, most assays have used CD63 as a basophil activation marker and native allergen extracts for stimulation. However, other basophil markers and recombinant allergens have recently been introduced. The technique has been applied for the diagnosis of allergy to pollen, house dust mite, food, natural rubber latex, hymenoptera venom and drugs. In addition, the technique has proven to be useful in non-IgE-mediated reactions such as hypersensitivity to drugs as well as detection of auto-antibodies in chronic urticaria. This review will focus on some specific issues: (1) principles of flow cytometric analysis of in vitro-activated basophils, (2) general technical aspects of the technique (including passive sensitization), (3) clinical applications and (4) recommendations for further development and evaluation of the technique.

Identification of granulocyte subtype–selective receptors and ion channels by using a high-density oligonucleotide probe array

BACKGROUND

During inflammation, neutrophils, basophils, and eosinophils release cell type-specific mediators and proteases through signaling molecules, such as G protein-coupled receptors and ion channels. As such, ion channels and receptors, including G protein-coupled receptors, are common drug targets.

OBJECTIVE

We sought to identify, for the first time, ion channels and receptors preferentially expressed by each granulocyte subtype.

METHODS

Using GeneChip, we compared approximately 20,000 transcripts present in 7 leukocyte types, platelets, mast cells, and fibroblasts to identify granulocyte subtype-selective transcripts for receptors and ion channels. Granulocyte subtype-selective transcripts were chosen on the basis of several conditions, such as the transcript having a 5-fold or greater expression level compared with the maximum level of other leukocytes.

RESULTS

Fifty-one transcripts were chosen to be preferentially expressed by each granulocyte subtype. Seventeen of the 51 transcripts have not been previously reported as granulocyte subtype selective. Among the 17 receptors and ion channels, 6 were basophil selective, eosinophil selective, or both and were not highly expressed by other organs, indicating that they might be potential targets for antiallergy drugs.

CONCLUSION

Use of this database of potential cell type-selective drug targets should minimize the efforts required for pharmaceutical development.

Familial eosinophilia: a benign disorder?

Familial eosinophilia (FE) is an autosomal dominant disorder characterized by marked eosinophilia and progression to end organ damage in some, but not all, affected family members. To better define the pathogenesis of FE, 13 affected and 11 unaffected family members (NLs) underwent a detailed clinical evaluation at the National Institutes of Health (NIH). No clinical abnormalities were more frequent in the family members with FE compared with the NLs. There was, however, a decreased prevalence of asthma in family members with FE compared with unaffected family members. Eosinophil morphology as assessed by either light or transmission electron microscopy was normal in family members with and without FE. Although levels of eosinophil-derived neurotoxin (EDN) and major basic protein (MBP) were elevated in patients with FE compared with NL, levels of both granule proteins were lower than in nonfamilial hypereosinophilic syndrome (HES). Similarly, increased surface expression of the activation markers CD69, CD25, and HLA-DR was detected by flow cytometry on eosinophils from patients with FE compared with NL, albeit less than that seen in HES. These data suggest that, despite prolonged marked eosinophilia, FE can be distinguished from HES by a more benign clinical course that may be related to a relative lack of eosinophil activation.

Treatment of Churg-Strauss syndrome with high-dose intravenous immunoglobulin

BACKGROUND

In some patients with Churg-Strauss syndrome (CSS), especially those with myocardial or neural involvement, conventional treatment with corticosteroids with or without cyclophosphamide is not effective.

OBJECTIVE

To examine the effects of intravenous high-dose immunoglobulin (IVIG) in patients with CSS who showed poor responsiveness to conventional treatment.

METHODS

We consecutively selected patients with CSS who showed any organ involvement despite corticosteroid treatment with or without cyclophosphamide. The diagnosis was based on the classification criteria of the American College of Rheumatology. IVIG therapy was performed with a dose of 400 mg/kg of immunoglobulin daily for 5 days. Neuropathy was evaluated with the manual muscle strength test and by the skin temperature of affected sites. Cardiac function was examined with ejection fraction by echocardiography and 2 imaging tests of myocardium (iodine 123 metaiodobenzylguanidine and thallium 201).

RESULTS

The manual muscle strength test results were improved, and the skin temperature of both hands and legs was increased by IVIG therapy. In 5 patients with heart failure, the mean +/- SD ejection fraction of the left ventricle increased from 35.2% +/- 13.9% to 61.0% +/- 10.1% (P < .02). The uptake of iodine 123 metaiodobenzylguanidine of the myocardium increased, indicating that the myocardial viability was improved. The thallium 201 images revealed the presence of perfusion defects, which were improved by IVIG therapy.

CONCLUSIONS

Patients with CSS who are resistant to corticosteroid treatment with or without cyclophosphamide may be treated effectively with IVIG therapy.

Tissue Eosinophilia in Pemphigoid Gestationis: Association with Eotaxin and Upregulated Activation Markers on Transmigrated Eosinophils

PROBLEM

We studied chemotactic cytokines and activation of skin-homed eosinophils in pemphigoid gestationis, a rare autoimmune bullous disease of late pregnancy.

METHOD OF STUDY

Eotaxin and interleukin (IL)-5 were analysed in patients' blister fluid and serum by enzyme-linked immunosorbent assay. Lesional tissue was investigated for eotaxin deposition by immunohistochemistry. Adhesion molecules and activation markers on tissue eosinophils were analysed by immunofluorescence staining.

RESULTS

Eotaxin was elevated in serum of two pemphigoid gestationis patients compared with nine healthy pregnant women. Blister fluid contained even higher amounts of eotaxin and in addition IL-5. Eotaxin was mainly expressed in subepidermal tissue in close proximity to eosinophils that expressed high levels of adhesion molecules (CD11b, CD11c, CD18 and CD49d) and the activation marker HLA-DR.

CONCLUSIONS

High local levels of eotaxin and IL-5 as present in the blister fluid correspond to the high state of activation of the infiltrated eosinophils.

Allergic reactions occurring during anaesthesia: diagnostic approach

Anaphylactic and anaphylactoid reactions to anaesthetic and associated agents used during the perioperative period have been increasingly reported during the last 3 decades. The frequency of life-threatening hypersensitivity reactions occurring during anaesthesia has been estimated to vary between 1/1.000 and 1/25.0000 procedures, with muscle relaxants being involved in almost three quarters of the cases. The mortality from these reactions is in the range of 3-6%. Nowadays, natural rubber latex also accounts for a significant number of perioperative anaphylaxis, particularly in children. Clinical manifestations do not allow to differentiate between IgE-mediated anaphylaxis and anaphylactoid reactions resulting from non-specific mediator release. Successful management of these patients requires multidisciplinary approach and includes prompt recognition and stabilisation of the acute event by the attending anaesthetist, determination of the responsible agent(s) with avoidance of subsequent administration of incriminated compound(s). The latter is based upon correct identification of the responsible drug and potentially cross-reactive compounds by the allergist and requires a detailed review of the anaesthetic report as well as appropriate in vitro and in vivo allergy tests. At present, the overall performance of skin tests makes them the "gold standard" for diagnosis of muscle relaxant-induced perioperative hypersensitivity reactions. In addition, given their good negative predictive value, skin tests have been proven to be a useful tool to tailor the appropriate therapeutic alternative. For other compounds diagnosis is more difficult but newer techniques such as analysis of in vitro activated basophils can be helpful.

The release of basogranulin in response to IgE-dependent and IgE-independent stimuli: validity of basogranulin measurement as an indicator of basophil activation

BACKGROUND

Basogranulin, the novel basophil granule protein recognized by the monoclonal antibody BB1, can be released by stimulation with anti-IgE antibody or calcium ionophore. However, the kinetics and regulation of its secretion are unknown.

OBJECTIVE

We quantified basogranulin and histamine release in response to a range of stimuli to assess whether basogranulin secretion is a reliable marker of basophil activation.

METHODS

Isolated peripheral blood basophils were stimulated with anti-IgE antibody, calcium ionophore, N -formyl-Met-Leu-Phe, and complement C5a. The released basogranulin and histamine were quantified by dot blotting with BB1 and a fluorometric method, respectively. Basogranulin localization was confirmed by flow cytometry.

RESULTS

Both basogranulin and histamine displayed a bell-shaped response curve when basophils were challenged with anti-IgE. Half-maximal release occurred within 30 seconds. Basogranulin levels were maximal by 15 minutes, whereas those for histamine continued increasing to 30 minutes. Wortmannin, a PI3-K inhibitor, suppressed the release of both mediators. Basophils from donors with the "nonreleaser" phenotype secreted neither mediator in response to anti-IgE. Non-IgE-dependent stimuli released both mediators in parallel in a concentration-dependent manner. The correlation between the relative amounts of each mediator released was highly significant (r =.901, P <.0001, n = 87). Flow cytometry revealed that some of the secreted basogranulin adhered to the cell surface.

CONCLUSIONS

Basogranulin is secreted along with histamine in response to both FcepsilonR I-related and unrelated stimuli. It is therefore a valid marker of basophil activation and could provide the basis for an immunoassay that distinguishes between basophil and mast cell activation.

Analysis of gene expression in peripheral blood eosinophils from patients with atopic dermatitis by differential display

To identify the genes related to atopic dermatitis (AD), we compared gene expression in eosinophils from AD patients and healthy volunteers. RNA was prepared from peripheral blood eosinophils. Gene expression was monitored by fluorescent differential display (DD) and real-time RT-PCR. Eighteen new sequences, including expressed sequence tags (ESTs), were expressed at higher levels in eosinophils from AD patients than in those from healthy volunteers. The functions of most of these genes are unknown. We found no correlation between the expression of a particular gene and clinical markers such as the number of eosinophils and the amount of IgE. Multivariate analysis of the gene expression data in each sample showed a very high coefficient of correlation among the copy numbers of each gene. The genes under investigation were also expressed in cultured blood eosinophils after IL-4, IL-5 and IFN-gamma stimulation. We were able to predict the function of some of the sequences by scanning for homologies within either the human or mouse genome databases. The mouse counterpart of one of these genes, intersectin 2, was expressed dramatically, as measured by ear edema, in 1-fluoro-2,4-dinitrobenzene-induced mouse contact dermatitis and in NC/Nga mouse dermatitis.

Advances in mechanisms of allergy

This review summarizes selected "mechanisms of allergy" articles appearing between 2001 and 2002 in the Journal of Allergy and Clinical Immunology (JACI). Papers chosen include those dealing with human eosinophil and basophil biology from life to death, as well as studies with animal models of allergic disease, including knock-out mice, Brown Norway rats, and ovalbumin (OVA)-sensitized and challenged BALB/c mice, that further our understanding of mechanisms of allergic diseases. When appropriate, articles from other journals have been included to supplement the topics being presented.

Cutting edge: histamine inhibits IFN-alpha release from plasmacytoid dendritic cells

Plasmacytoid dendritic cells (DC) are professional APC and a major source of type I IFN following viral infection. We previously showed that histamine alters the cytokine profiles of maturing monocyte-derived DC resulting in a change from Th1 to Th2 in their T cell polarizing function. In this study, we show that human plasmacytoid DC, activated by either CpG oligodeoxynucleotides or viral infection, also respond to histamine through H2 receptors, leading to a marked down-regulation of IFN-alpha and TNF-alpha and a moderate switch in their capacity to polarize naive T cells. Our findings provide an explanation for low levels of type I IFN frequently observed in atopic individuals.

4. IgE, mast cells, basophils, and eosinophils

IgE, mast cells, basophils, and eosinophils constitute essential elements in allergic inflammation. Allergen-specific IgE, synthesized in response to allergens in the environment and in susceptible individuals, becomes fixed to high-affinity receptors on cellular membranes, especially of mast cells and basophils. If these receptor-bound IgE molecules are aggregated on reexposure to specific allergen, these mast cells and basophils produce mediators that result in the allergic response. Principal among the cells drawn to sites of mediator release is the eosinophil.

Role of acid back-diffusion, glutathione, oxyradical, and histamine in antral hemorrhagic ulcer in rats: the protective effect of lysozyme chloride and antioxidants

The pathogenesis of gastric antral hemorrhage and ulceration is unclear. This paper first proposes that antral hemorrhagic ulcers produced in rats are associated with attenuation of defensive parameters (such as mucosal glutathione levels and histamine release, as well as aggravation of aggressive factors) including gastric acid back-diffusion and oxyradical generation. The protective effects of lysozyme chloride and antioxidants on this ulcer model were also evaluated. After being deprived of food for 24 hours followed by refeeding for 1 hour, rats were injected with 1.0 mol HCl/L intragastrically under potent analgesia of diethylether-anesthesia to induce antral ulcer. Control rats received a normal saline solution only. Rats were then given free access to water and food for 4 days. Before the experiment began, rats were again deprived of food for 24 hours. Following anesthetization, their stomachs were irrigated for 3 hours with either normal saline or a physiological acid solution containing 100 mmol HCl/L and 54 mmol NaCl/L. Aggravation of various aggressive and defensive parameters in antral mucosa was observed in refed rats that had received 1.0 mol HCl/L. A high relationship of mucosal glutathione level (r = -0.8754, P <.05) or lipid peroxides generation (r = 0.8198) to antral ulceration was obtained in those ulcerated rats. Intragastric lysozyme chloride (50-200 mg/kg) injected three times daily produced a dose-dependent attenuation of various gastric parameters in the acid-irrigated stomachs of antral ulcer rats. Intraperitoneal injections of various antioxidants, including exogenous glutathione, allopurinol, or dimethylsulfoxide also attenuated antral ulcer. In conclusion, the imbalance of aggressive factors, such as acid back-diffusion and oxyradicals-as well as defensive factors including glutathione and histamine-is important in modulating antral hemorrhagic ulcers that can be ameliorated by lysozyme chloride or antioxidants in rats.

Validation of a two-color flow cytometric assay detecting in vitro basophil activation for the diagnosis of IgE-mediated natural rubber latex allergy

BACKGROUND

IgE-dependent triggering of basophils not only elicits the release of different mediators but also the up-regulation of certain markers, e.g. CD63, which can be detected by flow cytometry. We intended to investigate if flow cytometric analysis of basophil activation could be a valuable tool in the diagnosis of latex allergy, and to evaluate if the basophil activation test (BAT) could be helpful in determining the clinical significance of a positive latex IgE in individuals with negative history and negative latex skin test. Additionally we aimed to determine the role of cross-reactive carbohydrate determinants (CCDs) in causing positive latex IgE without apparent clinical significance.

METHODS

Twelve healthy controls without a history of latex hypersensitivity with a negative latex IgE and skin test (group 1), 24 individuals without a history of latex hypersensitivity with a negative latex IgE and skin test but with other inhalant allergies (group 2), and 29 latex allergic patients with a compelling history of latex allergy with a positive latex IgE and prick test (group 3) were enrolled. The diagnostic performances of the BAT were further evaluated in 13 individuals with a history of latex allergy but with negative specific IgE and/or skin test (group 4). Twenty-four individuals with positive latex IgE without apparent clinical relevance, i.e. without history of latex hypersensitivity and negative latex skin tests, were also analyzed (group 5). The putative role of CCDs causing positive latex IgE results without apparent clinical significance was evaluated by quantification of IgE for bromelain.

RESULTS

According, to the receiver operating characteristics(ROC)-generated threshold value of 17% between latex allergic patients and the pooled group of nonlatex allergic individuals, the sensitivity and specificity of the basophil activation test was 93.1% and 91.7%, respectively. In healthy controls, allergic patients without latex hypersensitivity and latex allergic patients the number of positive BATs was 0/12, 3/24 and 27/29, respectively. In the individuals with an evocative history of latex allergy but with negative latex IgE and/or skin test the BAT was positive in all 13 cases. Twenty of 24 individuals without apparent latex allergy but with positive latex IgE had a negative BAT. IgE for bromelain was positive in 1/19 sera from group 2, 1/24 sera from group 3, none of the 8 sera from group 4, but in 16/18 sera from group 5, respectively.

CONCLUSION

Flow cytometric analysis of activated basophils seems a highly sensitive and specific tool for diagnosing latex allergy. In addition, the technique might help to determine the clinical relevance of positive IgE quantification in the absence of overt latex allergy. CCDs of natural rubber latex allergens were confirmed to mimic latex sensitization.

Recombinant allergens promote expression of CD203c on basophils in sensitized individuals

BACKGROUND

Traditionally, the diagnosis of type I allergies is based on clinical data, skin test results, and laboratory test results with allergen extracts. During the past few years, several attempts have been made to refine diagnostic assays in clinical allergy by introducing recombinant allergens and novel markers of IgE-dependent cell activation.

OBJECTIVES

We have identified the ectoenzyme CD203c as a novel basophil antigen that is upregulated on IgE receptor cross-linkage. In this study we applied CD203c and a panel of recombinant allergens to establish a novel basophil test that allows for a reliable quantification of IgE-dependent responses at the effector cell level.

METHODS

Patients allergic to birch (Bet v 1, n = 15; Bet v 2, n = 8) and grass (Phl p 1, n = 15; Phl p 2, n = 10; Phl p 5, n = 14) pollen allergens, as well as 10 nonallergic donors, were examined. Basophils were exposed to various concentrations of recombinant allergens for 15 minutes and then examined for expression of CD203c by means of flow cytometry. CD203c upregulation was correlated with the increase in CD63.

RESULTS

Exposure to recombinant allergens resulted in a dose-dependent increase in expression of CD203c on peripheral blood basophils in sensitized individuals, whereas no increase was seen in healthy control subjects. The effects of the recombinant allergens on CD203c expression were also time dependent. There was a good correlation between allergen-induced upregulation of CD203c and upregulation of CD63 (R = 0.76).

CONCLUSION

Flow cytometric quantitation of CD203c on blood basophils exposed to recombinant allergens is a useful approach to determine the allergic state in sensitized individuals and represents a basis for a sensitive novel allergy test.

Expression and function of histamine receptors in human monocyte-derived dendritic cells

BACKGROUND

Histamine is a well-known mediator eliciting different responses in immune and nonimmune cells, but its role in modulating dendritic cell (DC) functions has been marginally investigated.

OBJECTIVE

The purpose of this investigation was to analyze whether human monocyte-derived DCs express functional histamine receptors according to their maturation stage.

METHODS

DCs were derived from monocytes and used as immature or LPS-differentiated cells. DCs were tested for histamine receptor expression, chemotaxis, cytokine release, and the capacity to induce T-cell differentiation in response to specific histamine receptor agonists.

RESULTS

Immature and mature DCs expressed the mRNA for H1, H2, and H3 histamine receptors. Histamine induced intracellular Ca2+ transients, actin polymerization, and chemotaxis in immature DCs. Maturation of DCs resulted in the loss of these responses. In maturing DCs, however, histamine dose-dependently enhanced intracellular cAMP levels and stimulated IL-10 secretion while inhibiting production of IL-12. As a consequence, histamine might contribute to the impairment of generation of allogeneic type 1 responses via maturing DCs. Specific histamine receptor agonists or antagonists revealed that Ca2+ transients, actin polymerization, and chemotaxis of immature DCs were due to stimulation of H1 and H3 subtypes. Modulation of IL-12 and IL-10 secretion by histamine involved the H2 and H3 receptors exclusively.

CONCLUSIONS

Our study suggests that histamine has important biological effects on DC activities, opening the possibility that histamine released during inflammatory or immune responses could regulate DC functions and ultimately favor type 2 lymphocyte-dominated immunity.

Activation markers of human basophils: CD69 expression is strongly and preferentially induced by IL-3

BACKGROUND

The biological functions of basophils are precisely regulated by various cytokines in vitro, but little is known about surface markers that are upregulated during the cytokine-mediated activation process.

OBJECTIVE

It has been well established that CD69, CD44, and CD54 represent "activation markers" for cytokine-mediated eosinophil activation. The objective of this study was to elucidate the expression and regulation of these molecules in human basophils in vitro as well as in vivo.

METHODS

Basophils were purified from venous blood by means of density gradient centrifugation followed by negative selection. Surface expression was analyzed by means of flow cytometry. We also studied the expression of CD69, CD44, and CD54 on basophils in bronchoalveolar lavage fluid and blood specimens from patients with asthma.

RESULTS

CD44 and CD54 were constitutively expressed on basophils and moderately upregulated by IL-3. On the other hand, CD69 expression was only weakly observed in freshly isolated basophils, but IL-3 induced extremely high levels of expression. Surface CD69 appeared rather slowly in comparison with CD63 and CD11b, and the induction of expression was completed within 24 hours. Basophil CD69 had no functional relevance, but it did have biological relevance. Whole blood basophils from asthmatic individuals expressed significantly higher levels of CD69 than did those from normal individuals. Furthermore, bronchoalveolar lavage fluid basophils showed higher levels of CD69 expression than did blood basophils from the same donors.

CONCLUSION

CD69 expression on basophils was preferentially and strongly upregulated by IL-3. CD69 on basophils might be useful as an in vitro as well as in vivo marker of activation of these cells by IL-3.

Lack of association between atopic eczema/dermatitis syndrome and polymorphisms in the promoter region of RANTES and regulatory region of MCP-1

BACKGROUND

Chemokines play an important role in the pathophysiology of atopic eczema/dermatitis syndrome (AEDS) and allergy. Recently polymorphisms in the promoter region of RANTES (regulated on activation normal T cell expressed and secreted) and in the gene regulatory region of MCP-1 (monocyte chemoattractant protein-1) have been found, which increase the expression of these chemokines. The - 403A allele of the RANTES promoter region was found associated with AEDS in German children. We investigated whether the presence of these polymorphisms was associated with AEDS or allergy in Hungarian children.

METHODS

One hundred and twenty-eight children with AEDS, 102 allergic children without AEDS and 303 children of comparable ages without allergic disorders were screened for genotype with a PCR-based assay.

RESULTS

There were no significant differences in the frequency of these polymorphisms, or in the distribution of genotypes between the groups. The total IgE concentration, the white blood cell count and the blood eosinophil cell count did not differ between the genotypes.

CONCLUSION

In this cohort of Hungarian children there was no association between - 28G, and - 403A alleles in the RANTES promoter, - 2518G polymorphism in the distal regulatory region of the MCP-1 and AEDS, or allergy.

Polymorphism in the gene regulatory region of MCP-1 is associated with asthma susceptibility and severity

BACKGROUND

Chemokines play an important role in the pathophysiology of asthma and allergy. Recently, polymorphisms in the gene regulatory region of monocyte chemoattractant protein 1 (MCP-1) and in the promoter region of RANTES have been found; these polymorphisms increase the expression of the chemokines.

OBJECTIVE

We investigated whether the presence of the polymorphisms was associated with atopy or asthma and whether these alleles influenced the severity of asthma in affected individuals.

METHODS

Three groups of subjects-160 children with asthma (disease severity being classified according to the Global Initiative for Asthma guidelines, modified for children), 151 children with nonasthmatic but allergic phenotype, and 303 children without allergic or asthmatic disorders-were screened with a PCR-based assay for genotyping.

RESULTS

The frequency of the -2518G polymorphism in the gene regulatory region of MCP-1 was significantly higher in asthmatic children than in controls (P <.001; odds ratio [OR] = 2.0 [1.4-2.6]) and nonasthmatic atopic children (P <.001; OR = 2.0 [1.4-2.9]). The MCP-1 G/G genotype correlated with asthma severity. In asthmatic children, the MCP-1 -2518G allele was also associated with an increased blood eosinophil level. The promoter polymorphisms in the RANTES gene did not have a detectable effect on the susceptibility to asthma or allergy or on the blood eosinophil count.

CONCLUSION

In this cohort of children, there are associations between carrying G at -2518 of the MCP-1 gene regulatory region and the presence of asthma as well as between asthma severity and homozygosity for the G allele. In asthmatic children, the MCP-1 -2518G polymorphism correlated with increased eosinophil levels. This variant of MCP-1 might belong to the predictor gene set for asthma.

Segmental bronchoprovocation in allergic rhinitis patients affects mast cell and basophil numbers in nasal and bronchial mucosa

Mast cells and basophils are cells that play an important role in the initiation and control of allergic inflammation in asthma and rhinitis. This study was undertaken to determine the presence and dynamics of mast cells and basophils in the nasal and bronchial mucosa of allergic rhinitis patients after segmental bronchial provocation (SBP). Eight nonasthmatic, grass pollen-allergic rhinitis patients and eight healthy controls were included. Bronchial and nasal biopsies, as well as blood samples, were taken before (T(0)) and 24 h (T(24)) after SBP. Immunohistochemical staining was performed for mast cells (tryptase and chymase; phenotypes MC(T), MC(TC), MC(C)) and basophils (BB1). In the bronchial mucosa, the number of BB1(+) cells increased significantly (p < 0.05) in allergic rhinitis patients after SBP. In the nasal mucosa, the numbers of MC(C) and MC(TC) cells decreased significantly, whereas the numbers of [BB1(+)] cells increased significantly in allergic rhinitis patients after SBP (p < 0.05). In blood, the number of basophils decreased (p < 0.05) and the level of interleukin (IL)-5 increased (p < 0.05) in atopic patients after SBP. No significant changes could be observed in healthy controls. This study shows that SBP in nonasthmatic allergic rhinitis patients reduces numbers of mast cells in the nose as a result of enhanced degranulation. At the same time, there is evidence for an influx of basophils from the blood into the nasal and bronchial mucosae.

History and future perspectives of treating asthma as a systemic and small airways disease

Asthma is an inflammatory disorder in which the small airways of the lung play an important role. There is also evidence for the systemic nature of asthma. No current method adequately measures small airways function alone. Therefore, a combination of functional and clinical parameters should be used to ensure that patients with asthma are adequately treated with due consideration of the small airways. Previously therapeutic strategies have focused on bronchodilation and attenuation of airway inflammation. While early oral therapies had the advantage of reaching the small airways and treating the systemic aspect of asthma, they were associated with serious side-effects. Inhaled therapies were therefore developed to limit these effects. However, inhaled therapies have the disadvantage of limited penetration into the peripheral airways and an inability to treat the systemic component of asthma. They are also associated with local and systemic side-effects. The future for asthma treatment is likely to be a systemically administered medication with few side-effects targeting disease-specific mediators. The leukotriene receptor antagonists and anti-IgE monoclonal antibodies are examples of such therapies and the emergence of other new strategies is awaited.

Allergy to dermatophagoides in a group of Spanish gypsies: genetic restrictions

BACKGROUND

Spanish gypsies have traditionally lived as nomads, a reason why few epidemiological studies were done in this ethnic group. However, the high prevalence of asthmatic diseases demonstrated in a population residing in the North of Spain induces us to analyse whether it was due to the influence of genetic loci previously implicated in other population studies as causing the disorders.

METHODS

DRB1* and DQB1* HLA class II, TCR-Valpha8.1, FcepsilonRI-beta Rsa I exon 7 and intron 2, TNF-beta (LTalpha-Nco I) and CD14, were tested for association with asthma and atopy by multiple regression analysis, in 5 families comprising 87 individuals.

RESULTS

Significant associations were found with DQB1*02 (p = 0.02) and DQB1*0301 (p = 0.008) and elevated levels of total serum IgE. A negative association (p = 0.02) was found between total serum IgE and DRB1*14. FcepsilonRI-beta Rsa I-In2 allele 1 was associated with high levels of total serum IgE (p = 0.04). Levels of Der p 1 IgE antibodies were negatively associated with DRB1*11-DQB1*0301 (p = 0.007), and positively with TCR Valpha-8 allele 1 (p = 0.04) and with FcepsilonRI-beta Rsa I-In2 allele 1 (p = 0.009).

CONCLUSIONS

Our results do not show any association between asthma and the genetic loci studied although they do suggest the existence of multiple genetic influences on the allergic response in these families.

The spectrum of olive pollen allergens

Olive pollen is one of the most important causes of seasonal respiratory allergy in Mediterranean countries, where this tree is intensely cultivated. Among the high number of protein allergens detected in this pollen, 8 - Ole e 1 to Ole e 8 - have been isolated and characterized. Ole e 1 is the most frequent sensitizing agent, affecting more than 70% of the patients suffering of olive pollinosis, although others, such as Ole e 4 and Ole e 7, have also been shown to be major allergens. In this context, the prevalence of many olive pollen allergens seems to be dependent on the geographical area where the sensitized patients live. Some of the olive allergens have been revealed as members of known protein families: profilin (Ole e 2), Ca(2+)-binding proteins (Ole e 3 and Ole e 8), superoxide dismutase (Ole e 5) and lipid transfer protein (Ole e 7). No biological function has been demonstrated for Ole e 1, whereas Ole e 4 and Ole e 6 are new proteins without homology to known sequences from databases. cDNAs encoding for Ole e 1, Ole e 3 and Ole e 8 have been overproduced in heterologous systems. The recombinant products were correctly folded and exhibited the functional activities of the natural allergens. In addition to the Oleaceae family, other species, such as Gramineae or Betulaceae, contain pollen allergens structurally or immunologically related to those of the olive tree. This fact allows to detect and evaluate antigenic cross-reactivities involving olive allergens. The aim of this research is the development of new diagnostic tools for olive pollinosis and new approaches to improve the classical immunotherapy.