Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “BASOPHILS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 469 records · Page 26Linked to original sources
PubMed1986

Potentiation of human basophil histamine release by protamine: a new role for a polycation recognition site.

Protamine is an arginine-rich basic polypeptide that stimulates histamine release from rat mast cells but not from human basophils. In this report, we show that protamine causes a non-cytolytic potentiation of IgE-mediated histamine release from human basophils. A direct effect of protamine on basophils was supported by results obtained using cell preparations containing 35-65% basophils. The potentiation occurred at all concentrations of antigen that initiated release and was most pronounced at antigen concentrations that alone stimulated minimal histamine release. The kinetics of potentiated release were parallel to those for IgE-mediated histamine release, and addition of protamine did not overcome the block caused by antigenic desensitization. Staging experiments indicated that enhancement occurred only when protamine and antigen were added together in a single step reaction. Protamine also potentiated release stimulated by eosinophil granule major basic protein or poly-L-lysine, but inhibited release initiated by poly-L-arginine; poly-L-arginine stimulated release was also inhibited by polymyxin B. Arginine-rich histone mimicked the protamine effect, while lysine-rich histone, polymyxin B, and compound 48/80 had minimal or no effect on IgE-mediated release. These results suggest that a polycation recognition site on human basophils similar to that described for rat mast cells may mediate potentiation of basophil secretory events by arginine-rich basic polypeptides.

Basophils↗
PubMed1992

Cultured human cord blood cells spontaneously produce a factor with basophil-promoting activity.

Cord blood is a source for pluripotential stem cells capable of differentiating into various hemopoietic cell lines in the presence of suitable specific growth factors. Without additional growth factors, cultured cord blood cells give rise to large numbers of basophils. We have recently defined a human basophil growth promoting factor, designated as interleukin-3-like activity (IL-3-LA), produced spontaneously by human monocytes and lymphocytes. In order to explain the phenomenon of spontaneous basophil development in cord blood cultures, we studied the relationship between basophil production and IL-3-LA release in these cultures. IL-3-LA produced by cord blood mononuclear cells increased from day 3 to day 14 and then decreased gradually by day 35. Basophil development was observed from day 14 on (33% +/- 6.4) and peaked on day 21 (51% +/- 7.4). Histamine release followed the same pattern i.e., 10 +/- 3.4 ng/ml on day 14, and 23 +/- 6.5 ng/ml on day 21. It is suggested that IL-3-LA spontaneously released by cord blood mononuclear cells induces basophil development in these cultures.

Basophils↗
PubMed1994

The effect of exercise on basophil histamine release in patients with bronchial asthma.

There is increasing evidence for the role of basophils in allergic bronchial asthma. We studied the potential role of basophils in the pathogenesis of post-exercise-induced bronchoconstriction by measuring the histamine release from basophils both spontaneously and following ConA, FMLP, anti-IgE and TPA treatment. Two groups of patients with allergic asthma were studied: group I consisted of 8 patients with an exercise-induced fall in FEV1 of 20% or more, and group II had 7 patients with bronchial asthma who had less than a 5% fall in FEV1 following exercise. The mean spontaneous histamine release (SHR%) from basophils for group I was significantly larger than that of group II both before as well as at 5-10 and 60 min following exercise. The SHR% at baseline was 25 +/- 10 in group I (mean +/- SD) and 15 +/- 5 in group II (mean +/- SD). At 5-10 min following exercise it was 24 +/- 6 in group I and 11 +/- 2 in group II, while at 60 min following exercise it was 24 +/- 6 in group I and 17 +/- 2 in group II. There was no significant difference between the two groups in the effect of ConA, FMLP, anti-IgE or TPA treatment on basophil histamine release. The enhanced bronchoconstriction by exercise did not affect histamine release either spontaneously or following those 4 stimuli. It was concluded that, although patients with exercise-induced asthma have a greater degree of spontaneous histamine release, this is not affected by induced bronchoconstriction, a finding which does not support a role for basophils in exercise-induced asthma.

Adolescent↗
PubMed1985

Induction of systemic and local basophil and eosinophil responses in guinea pigs by the feeding of the tsetse fly Glossina morsitans.

Guinea pigs infested with Glossina morsitans weekly for 5 weeks exhibited marked peripheral blood basophil and eosinophil responses to each infestation, with a dominant cutaneous basophil response to challenge infestation. G. morsitans feeding was completed within 3--10 min, depending upon prior exposure, and flies were reluctant to feed and probed longer on hyperexposed animals. Blood basophil responses exhibited the greatest increases over controls (up to 12-fold) compared to eosinophils (up to 3-fold). After the first and third infestations, both basophil and eosinophil levels increased, whereas after the second and fourth infestations both cell types declined. Greatest blood basophil responses developed after the first infestation with levels ranging from 0 to 14 +/- 9 cells/mm3 in infested animals to 0 and 2 +/- 2 cells/mm3 in uninfested controls. Eosinophilia increased with each infestation where levels ranged from 57 +/- 23 cells/mm3 after the first tsetse feeding to 110 +/- 20 cells/mm3 after the fourth infestation; compared to 11 +/- 11 to 50 +/- 12 cells/mm3 in uninfested controls. Fly-feeding sites were marked by hemorrhages, and probing behavior resulted in a line of small hemorrhages when the underside of the skin was examined. Histologically, G. morsitans feeding sites in naive guinea pigs 24 h post-infestation were dominated by mononuclear cells (93% of the infiltrate) with a weak granulocyte component, of which eosinophils were dominant (1.3%). Tsetse feeding sites in guinea pigs exposed 3 times previously were again dominated by mononuclear cells (57% of the infiltrate), but granulocytes comprised a significant part of the response (43% of the infiltrate) where basophils were dominant (25%).

Animals↗
PubMed1994

Haemopoietic stem cells and basophils.

In a recent paper it was argued that all stem cells are small motile cells, the haemopoietic stem cell being no exception. Although haemopoietic stem cells arise and mature in an extravascular milieu, they are present in small numbers in the peripheral circulation, where they have a lymphocyte-like appearance, and in the peripheral circulation their fate can be linked to the development of basophils. The basophil is a cell shrouded in mystery, and one of the most mysterious aspects of the basophil is its small numbers in bone marrow, a finding which does not fit in with a marrow origin. A simple experiment provides an alternative explanation as to how they develop. If peripheral blood smears are prevented from drying out, after a few hours new basophils develop from a lymphocyte-like cell. The findings suggest that the basophil may arise, not in the marrow, but in the peripheral circulation, and may represent an aberrant development of the haemopoietic stem cell caused by the plasma. The pathology of the basophil supports this view.

Animals↗
PubMed1991

Leukotriene C4 formation by enriched human basophil preparations from normal and asthmatic subjects.

Numbers of circulating basophils are increased in asthmatic subjects, compared to normal subjects. Basophil enriched cell preparations from normal and asthmatic subjects were challenged in vitro with the calcium ionophore A23187, anti-IgE, or opsonized zymosan to study leukotriene C4 formation, histamine release, and prostaglandin D2 formation. No prostaglandin D2 formation by basophils was observed. Furthermore, opsonized zymosan was not capable of inducing any mediator formation or release from basophils. At optimal stimulation conditions no differences were found between basophils from normal and asthmatic subjects concerning A23187 or anti-IgE induced leukotriene C4 formation or histamine release. A23187 and anti-IgE induced leukotriene C4 formation were in the range of 1-20 and 0.6-4.8 pmol/10(6) basophils respectively.

Antibodies, Anti-Idiotypic↗
PubMed2003

Carbon monoxide modulates the response of human basophils to FcepsilonRI stimulation through the heme oxygenase pathway.

We report the effects of exogenous and endogenous carbon monoxide (CO) on the immunological activation of human basophils. Hemin (1-100 microM), a heme oxygenase substrate analogue, significantly increased the formation of bilirubin from partially purified human basophils, thus indicating that these cells express heme oxygenase. This effect was reversed by preincubating the cells for 30 min with Zn-protoporphyrin IX (100 microM), a heme oxygenase inhibitor. Hemin (100 microM) also decreased immunoglobulin G anti-Fcepsilon (anti-IgE)-induced activation of basophils, measured by the expression of a membrane granule-associated protein, identified as cluster differentiation protein 63 (CD63), and by histamine release. These effects were reversed by Zn-protoporphyrin IX (100 microM), by oxyhemoglobin (HbO(2)), a CO scavenger (100 microM), and by 1H-[1,2,4]oxadiazolo[4,3-a] quinoxalin-1-one (ODQ), an inhibitor of the soluble guanylyl cyclase (100 microM). Exposure of basophils to exogenous CO (10 microM for 30 min) also decreased their activation, while nitrogen (N(2)) was ineffective. HbO(2) and ODQ reversed the inhibition, reversing both membrane protein CD63 expression and histamine release to basal values. Both hemin and exogenous CO significantly raised cGMP levels in basophils and blunted the rise of calcium levels caused by immunological activation. This study suggests that CO increases cGMP formation, which in turn induces a fall in intracellular Ca(2+) concentration, thereby resulting in the inhibition of human basophil activation.

Antibodies, Anti-Idiotypic↗
PubMed2002

Spontaneous and cytokine induced basophil adhesion evaluated by microtiter assay.

We have developed a microtiter assay for evaluating basophil spontaneous adhesion to extracellular matrix (ECM) proteins exemplified by fibronectin and cytokine induced basophil adhesion to bovine serum albumin (BSA). The percentage of basophils adhering to either ECM or BSA was quantified by the histamine content of the adhering basophils. The spontaneous adhesion to fibronectin was higher than to laminin and collagen type I. Both spontaneous adhesion to fibronectin and interleukin-3 (IL-3), interleukin-5 (IL-5), granulocyte/macrophage colony stimulating factor (GM-CSF) induced adhesion to BSA increased with time between 5 and 45 min. The histamine release in both spontaneous and induced basophil adhesion was lower than 3.1%. This microtiter assay is simple and reproducible and can be applied for basic and clinical studies using a limited number of partially purified basophils.

Animals↗
PubMed1983

Purification of human basophils by negative selection.

Enriched populations of human basophils were prepared using a combination of negative selection techniques. First, a 2-step discontinuous gradient was made using 65% and 55% isotonic Percoll. Purification of plasma basophils by centrifugation through the gradient increased basophils from 0.96 +/- 0.55% to 14.6 +/- 7.9% (n = 9). In 5 other experiments a second step was added in which contaminating mononuclear cells were removed using a panning technique. In this technique, Percoll separated cells were treated with anti-T-cell antibodies. Contaminating T-cells were selectively removed by adherence to a petri dish coated with affinity purified goat anti-mouse IgG. Basophil purity was increased to 34 +/- 15% using this step. These experiments demonstrated that negative selection techniques can yield an increase in basophil purity 50-100-fold. The purified basophils contained the expected quantity of histamine (1.36-1.54 pg/basophil) and released the same amount of histamine in response response to different concentrations of goat anti-human IgE Fc as did unpurified cells.

Antibodies, Monoclonal↗
PubMed1995

Histamine release from human basophils induced by platelet activating factor: the role of extracellular calcium, interleukin-3, and granulocyte-macrophage colony-stimulating factor.

Although we have demonstrated that platelet activating factor (PAF) directly induces histamine release from human basophils, other studies have failed to report similar effects. In an attempt to understand the variability of these results, we examined the effect of some factors that could influence the basophils' response to PAF such as, extracellular Ca2+ and cytokines (interleukin-3 and granulocyte-macrophage colony-stimulating factor [GM-CSF]). The secretion of histamine induced by PAF was optimal when the cells were incubated in Ca2+ for 2 to 5 minutes, whereas it declined at longer time intervals up to 15 minutes. If cytochalasin B (5 micrograms/ml) was coincubated with PAF (1 mumol/L) to enhance the secretory response, histamine release was maximal at time 0 and decreased in parallel with the time of the basophils' exposure to Ca2+, like 0.1 microgram/ml anti-IgE-induced histamine secretion but unlike 1 mumol/L formyl-methionyl-leucyl-phenylalanine-induced histamine secretion. We found that there is synergy between interleukin-3 (1 to 3 ng/ml) and PAF (1 mumol/L) for secretion of histamine from human basophils (p < 0.05) and that GM-CSF (10 ng/ml) significantly (p < 0.02) potentiates the secretion of histamine activated by PAF (1 mumol/L). Our results demonstrate that: (1) the kinetics of the interaction between Ca2+ and the activation pathway that leads to histamine secretion are central events in the release reaction elicited by PAF in human basophils, and (2) interleukin-3 and GM-CSF can potentiate the secretory response of human basophils stimulated by PAF.

Antibodies, Anti-Idiotypic↗
PubMed1997

Expression of high-affinity IgE receptors (Fc epsilon RI) on peripheral blood basophils, monocytes, and eosinophils in atopic and nonatopic subjects: relationship to total serum IgE concentrations.

BACKGROUND: High-affinity IgE receptors (Fc epsilon RI) have been identified on peripheral blood basophils, monocytes, and eosinophils; but the relative receptor expression on these cells and their relationship to atopy are unclear. OBJECTIVE: The aim of this study was to compare Fc epsilon RI expression on these cell types and assess their relationship to total serum IgE concentrations in subjects with atopic asthma, rhinitis, or dermatitis compared with nonatopic control subjects. METHODS: Flow cytometry was used to evaluate Fc epsilon RI expression by determining the specific mean fluorescence of the binding of two anti-Fc epsilon RI alpha-chain monoclonal antibodies (15-1, which competes with IgE for receptor binding, and 22E7, which is noncompetitive). RESULTS: Compared with basophils Fc epsilon RI expression (determined by 22E7 specific mean fluorescence) was greatly reduced on monocytes and was only detectable on eosinophils in a small minority of subjects. Nevertheless, Fc epsilon RI expression on all three cell types was significantly increased in atopic patients compared with nonatopic control subjects (p < 0.0001 for basophils, p = 0.003 for monocytes, and p = 0.039 for eosinophils). Fc epsilon RI expression on both basophils and monocytes in all subjects correlated significantly with serum IgE concentrations (r = 0.86 and 0.55, respectively; p < 0.001). For each subject, and on all three cell types, the specific mean fluorescence after 22E7 staining was greater than with 15-1, implying some degree of receptor occupancy. CONCLUSION: Fc epsilon RI expression on peripheral blood monocytes was considerably less than on basophils and barely detectable on eosinophils. Elevated Fc epsilon RI expression was observed in atopic subjects with all three cell types, suggesting a role for these receptors in IgE-mediated allergic inflammation. The possibility of common regulatory mechanisms was suggested by the correlation of Fc epsilon RI expression on basophils and monocytes with serum IgE concentrations.

Adult↗
PubMed1999

Basophils from patients with allergic asthma show a primed phenotype.

BACKGROUND: IL-3, IL-5, and GM-CSF are not able to induce histamine release in purified basophils of nonallergic donors. However, we have recently found that preincubation with 2 micromol/L thapsigargin, which induces a rise in intracellular free calcium ions, renders human basophils extremely sensitive for IL-3, IL-5, or GM-CSF, leading to enhanced histamine release. Histamine release was also induced in the reverse order (first cytokine and then thapsigargin). OBJECTIVE: Because these cytokines are supposed to be increased in allergic inflammation, we examined whether basophils of patients with allergic asthma showed an enhanced response to thapsigargin. METHODS: We measured the histamine release induced by thapsigargin in a group of allergic asthmatic subjects (n = 24) and compared this response with those of 3 control groups. The control groups consisted of healthy control subjects (group 1, n = 21); patients with a nonallergic, nonasthmatic lung disease (group 2, n = 22); and patients with nonallergic asthma (group 3, n = 9). RESULTS: There was no difference in spontaneous histamine release. Also, no significant difference in histamine release was found when anti-IgE or formyl-methionyl-leucyl-phenylalanine was used as a stimulus. Histamine release induced by IL-3 alone or a combination of IL-3 and thapsigargin also did not differ. In contrast, basophils from the group with allergic asthma showed a significantly higher percentage of histamine release induced by thapsigargin (38.2% +/- 13.2%) than did basophils from the 3 control groups (healthy control subjects, 22.5% +/- 6.9%; subjects with lung disease, 24.9% +/- 8.9%; subjects with nonallergic asthma 15.0% +/- 3.0%; all mean +/- SD). CONCLUSION: These data indicate that basophils in peripheral blood of subjects with allergic asthma have a primed phenotype and that thapsigargin-induced histamine release is a practical tool to study this phenomenon.

Adult↗
PubMed1999

Validation of a flow cytometric assay detecting in vitro basophil activation for the diagnosis of muscle relaxant allergy.

BACKGROUND: Anaphylactic reactions during anesthesia are mainly the result of muscle-relaxant (MR) drugs. Skin tests, serologic detection of specific IgE, and in vitro leukocyte histamine release are used to investigate MR allergy. OBJECTIVE: We describe a new assay that is based on the detection by flow cytometry of the altered expression of plasma membrane molecules of MR-activated basophils. METHODS: For this assay, which we have named the BASIC assay, basophils are incubated in vitro with MR, after which they are fixed and then triple labeled with fluorescein-conjugated anti-CD63, tandem dye R-phycoerythrin-cyanin 5.1 conjugated anti-CD45, and R-phycoerythrin conjugated anti-IgE. The resulting B asophils' A ltered S urface I mmunofluorescence is detected by flow C ytometry (BASIC). RESULTS: Forty-one patients who had an allergic reaction during general anesthesia and 23 control subjects without such a history were studied. All included subjects' basophils were tested in the BASIC assay with at least 4 MR: suxamethonium, gallamine, vecuronium, and pancuronium. After reaction of the basophils of the MR-allergic patients with MRs, increased surface expression of CD63 and CD45 and decreased expression of IgE were detected. Increased expression of CD63 was observed most frequently and it was stronger than the alteration of the 2 other markers. Cross-reactivity between MRs commonly occurred. MRs diluted 10(-1) activate the basophils of the control subjects, suggesting that at relatively high concentrations MRs are also nonspecific basophil activators. CONCLUSION: In the diagnosis of MR allergy, the BASIC assay has a good specificity but a low sensitivity, and it correlates strongly with skin test results. It is currently appraised for the diagnosis of anaphylactic reaction induced by other classes of drugs.

Adult↗
PubMed2000

Inhibition of basophil histamine release by tyrosine kinase and phosphatidylinositol 3-kinase inhibitors.

It has been demonstrated that tyrosine kinase (TK) and phosphatidylinositol 3-kinase (PI3-K) are involved in IgE-mediated stimulation of human basophils; conversely, little is known about the biochemical pathways activated by IL-3 and GM-CSF. The aim of this study was to evaluate the effects of TK and PI3-K inhibitors on basophil histamine release induced by anti-IgE, IL-3 and GM-CSF. Since IL-3 and GM-CSF cause histamine release from normal human basophils only when the inhibitory effect of extracellular Na(+) has been removed, peripheral blood leukocytes were suspended in isotonic solutions containing either 140 mM NaCl or 140 mM N-methyl-D-glucamine(+). After stimulation with anti-IgE, IL-3 or GM-CSF, histamine release was measured by an automated fluorometric method. The effects of preincubation with four different TK inhibitors (AG-126, genistein, lavendustin A, tyrphostin 51) and one PI3-K inhibitor (wortmannin) were evaluated. AG-126, genistein and lavendustin A exerted a significant dose-dependent inhibitory effect on basophil histamine release induced by anti-IgE (either in high or in low Na(+) medium), IL-3 and GM-CSF. Among the TK inhibitors, lavendustin A exerted the most potent activity, followed by AG-126 and genistein. Tyrphostin 51 caused a weak inhibition of histamine release induced by IL-3, GM-CSF and anti-IgE in a low Na(+) medium, but not in a physiological Na(+)-containing medium. The PI3-K inhibitor wortmannin exerted the most effective inhibitory activity on the histamine release induced by the three agonists. The combined effects of lavendustin A and wortmannin were less than additive, suggesting that TK and PI3-K are involved in the same activation pathway in human basophils. These results suggest a possible role of TK and PI3-K in basophil histamine release induced by anti-IgE, IL-3 and GM-CSF. TK and PI3-K are indeed potential therapeutic targets for antiallergic drugs.

Androstadienes↗
PubMed1993

Induction of human IgE synthesis in B cells by mast cells and basophils.

Immunoglobulin E (IgE) is central to the induction of allergic diseases through its binding to the high-affinity receptor (Fc epsilon R1) on mast cells and basophils. Crosslinking by allergens of the bound IgE leads to the release of various inflammatory mediators. IgE production by B cells requires a physical interaction with T cells, involving a number of surface adhesion molecules, as well as the soluble factors interleukin-4 (IL-4) and IL-13 (ref. 5) produced by T cells, basophils and mast cells. Here we report that, in the presence of IL-4, mast and basophilic cell lines can provide the cell contact signals that are required for IgE synthesis. The human cell lines HMC-1 (mast) and KU812 (basophilic) both express the ligand for CD40 (CD40L) which is shown to be responsible for the IgE production. Moreover, freshly isolated purified human lung mast cells and blood basophils are also shown to express CD40L and to induce IgE production. This evidence suggests that mast cells and basophils may therefore play a key role in allergy not only by producing inflammatory mediators, but also by directly regulating IgE production independently of T cells.

Animals↗
PubMed2004

Effects of phosphodiesterase inhibitors on interleukin-4 and interleukin-13 generation from human basophils.

The aim of the present study was to determine whether inhibition of cyclic nucleotide phosphodiesterase (PDE) modulates the stimulated generation of the cytokines, interleukin-4 (IL-4) and IL-13, from human basophils. This was addressed by evaluating the effects of both nonselective and selective inhibitors of PDEs on the generation of cytokines from basophils. The nonselective PDE inhibitors, isobutyl-methylxanthine (IBMX) and theophylline, attenuated the IgE-mediated generation of IL-4 and IL-13 and, also, the release of histamine from basophils. The effects of the isoform-selective inhibitors, 8-methoxymethyl-IBMX (PDE 1 inhibitor), siguazodan (PDE3 inhibitor), rolipram (PDE4 inhibitor), denbufylline (PDE4 inhibitor), Org 30029 (mixed PDE3 and 4 inhibitor) and zaprinast (PDE5 inhibitor), were studied. Of these selective compounds, only rolipram, denbufylline and Org 30029 inhibited the IgE-dependent generation of IL-4, IL-13 and histamine from basophils to a statistically significant (P<0.05) degree. The effects of isoform-selective inhibitors on basophils activated by IL-3 were evaluated. The IL-3-induced generation of IL-4, IL-13 and histamine was inhibited to a statistically significant (P<0.05) extent, only by compounds that act as inhibitors of PDE4. These data suggest that inhibition of PDE4 can regulate the generation of cytokines from human basophils.

Basophils↗
PubMed2003

Measurement of basophil-activating capacity of grass pollen allergens, allergoids and hypoallergenic recombinant derivatives by flow cytometry using anti-CD203c.

BACKGROUND: The assessment of the basophil-activating potential is an important aspect in the development of improved preparations for specific immunotherapy. The aim of the study was to evaluate the suitability of CD203c expression as a measure of basophil activation to compare allergoids with original allergen extracts, and recombinant hypoallergenic allergen derivatives with recombinant wild-type and natural allergens. METHODS: Heparinized whole blood samples from grass pollen allergic subjects were stimulated with grass pollen allergens and allergen derivatives followed by labelling of the basophils with PE-conjugated anti-CD203c. After lysis of the erythrocytes and fixation, the basophils were detected by flow cytometry. In some experiments, histamine release was determined simultaneously. RESULTS: Grass pollen allergoids revealed a 10-10 000-fold reduction of basophil-activating capacity measured by CD203c expression. The deletion mutant DM4 of rPhl p 5b showed stronger hypoallergenic characteristics in a range of 50-10 000-fold reduction, whereas a combination mutant of rPhl p 5b and Phl p 6 revealed less hypoallergenic features. Histamine release experiments led to a similar outcome as CD203c measurement. CONCLUSIONS: The measurement of CD203c expression on basophils by flow cytometry provides a rapid and sensitive method for the estimation of the allergic or hypoallergenic features of allergen preparations. The results demonstrated the hypoallergenicity of grass pollen allergoids and of the rPhl p 5b variant DM4, which may be a candidate in future preparations for specific immunotherapy.

Adult↗
PubMed1999

Detection of allergen-induced basophil activation by expression of CD63 antigen using a tricolour flow cytometric method.

In the field of allergy diagnosis, most in vitro functional tests are focused on basophils. Nevertheless, the very small number of circulating basophils limits these experiments and their clinical benefit remains controversial. As flow cytometry is a valuable tool for identifying cell populations, even at low concentrations, we developed a tricolour flow cytometric method for the study of allergen-induced basophil activation. Identification of cells was based both on CD45 expression and on the presence of IgE on the cell surface, since basophils express high-affinity receptors for IgE (Fc epsilon RI). Cell activation upon allergen challenge was assessed by the expression of CD63 antigen on the plasma membrane. Basophil isolation and activation (with the chemotactic peptide formyl-methionyl-leucyl-phenylalanine) were validated in 32 non-allergic patients. In 12 allergic patients, basophil stimulation by a relevant allergen was in most cases positive (10/12). Furthermore a concentration-dependent hook effect was observed. Of the allergic and non-allergic patients, none showed non-specific activation with an irrelevant allergen (specificity 100%). Overall, our preliminary results, even in a small population, suggest that this is a reliable and valuable method for the diagnosis of allergies complementing specific allergen IgE and skin test results. Obviously, additional clinical studies are needed to validate these first results.

Adolescent↗