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Factors determining spontaneous histamine release from human basophils purified with Percoll gradients and Dynabeads.

Identification of factors influencing histamine release from purified and cultured basophil leukocytes is important for proper interpretation of results obtained on histamine release. This paper describes factors that influence spontaneous histamine secretion from human basophil leukocytes purified on Percoll gradients, followed by negative selection with Dynabeads. Anti-IgE and recombinant human interleukin-3 were used as model stimulants, and the purified basophil leukocytes were stimulated for 10 min and 6 h. The effect of the following conditions was examined: Percoll temperature, cell-suspension density, and serum in the media. The results showed that low Percoll temperature, high cell-suspension density, and the presence of serum in the media decreased spontaneous histamine release and increased maximal net histamine release upon stimulation.

Antibodies, Anti-Idiotypic↗

The CD63 basophil activation test in Hymenoptera venom allergy: a prospective study.

BACKGROUND: The basophil activation test (BAT), which relies on flow cytometric quantitation of the allergen-induced up-regulation of the granule-associated marker CD63 in peripheral blood basophils, has been suggested to be a useful approach in detecting responsiveness to allergens. The purpose of this study was to establish the usefulness of the BAT with regard to the clinical history and current diagnostic tools in Hymenoptera venom allergy using a prospective study design. METHODS: Fifty-seven consecutive patients allergic to Hymenoptera venom as defined by a systemic reaction after an insect sting, and 30 age- and sex-matched control subjects with a negative history were included. The degree and nature of sensitization was confirmed by skin testing, specific immunoglobulin E (IgE), serum tryptase levels and BAT. In the nonallergic control group only analysis of specific IgE and BAT were performed. Correlation of BAT, skin test and specific IgE, respectively, with the clinical history in the allergic group was termed as sensitivity and in the control group as specificity. RESULTS: Twenty one of 23 (91.3%) bee venom allergic patients and 29 of 34 (85.3%) patients allergic to wasp and hornet venom tested positive in BAT. The overall sensitivity of BAT, specific IgE and skin tests were 87.7, 91.2 and 93.0%, respectively. The overall specificities were 86.7% for BAT and 66.7% for specific IgE. No correlation between the severity of clinical symptoms and the magnitude of basophil activation was observed. CONCLUSION: The BAT seems to be an appropriate method to identify patients allergic to bee or wasp venom with a comparable sensitivity to standard diagnostic regimens. The higher specificity of BAT as compared with specific IgE makes this test a useful tool in the diagnosis of Hymenoptera venom allergy.

Animals↗

Histamine release from cord blood basophils is influenced by plasma IgE concentration, osmolarity, gestational age at birth and atopic disposition.

To characterize the normal values of histamine release from basophil leucocytes in cord blood after stimulation with both IgE-mediating and non-IgE-mediating secretagogues, a population of 1,684 newborn infants was studied using a microfiber-based method for detecting histamine release. A wide variation in anti-IgE and Concanavalin A-induced histamine release in the population was found. An increase in osmolarity in the release media selectively enhanced the maximal IgE-mediated histamine release, in addition to an increase in sensitivity in the dose response for anti-IgE and Concanavalin A. Both anti-IgE and Concanavalin A mediated histamine release were found to be significantly associated with the concentration of IgE in cord blood. Furthermore, an increased sensitivity to the IgE-mediated response and a close correlation between anti-IgE and Concanavalin A histamine release were found in the group of newborns with high IgE levels. Gestational age at birth and histamine release after stimulation with both IgE-mediating, and non-IgE mediating secretagogues were found to be significantly related, thus suggesting a continuing maturation of the human basophil leucocytes in the last weeks of gestation. Parental atopic disposition also affected basophil releasability in cord blood.

Basophils↗

Eosinophils and basophilic cells in sputum and nasal smears taken from infants and young children during acute asthma.

To examine the increase in eosinophils and basophilic cells in the respiratory areas of infants and young children with asthma (n = 111), we analyzed the numbers of eosinophils and basophilic cells in sputum and nasal smears. The number of children with eosinophilia grades of 2+ or greater (> or = 11 cells/five fields in x1000 magnification) in sputum and nasal smears, respectively, in each age group was as follows: 33% and 21% under 1 year, 59% and 64% at 1 year, and 79-80% and 75-78% at 2-3 years. An increased infiltration of basophilic cells according to age was also observed. Infiltration of these cells began earlier than the appearance of IgE antibodies to mite in blood.

Acute Disease↗

An increase in basophils in a case of acute myelomonocytic leukaemia associated with marrow eosinophilia and inversion of chromosome 16.

A patient with acute myelomonocytic leukaemia (M4 subtype) with pericentric inversion of chromosome 16, inv(16)(p13q22), and a marked basophilia is described. Results from transmission electron microscopy suggested that the basophils were immature. Clinically, although leukaemic cells had a tendency to infiltrate a number of tissues and organs, such as skin, gingiva, liver and lung, the patient was successfully treated with chemotherapy. The increase in basophils accompanied by marrow eosinophilia may be the result of abnormal differentiation of leukaemic cells that have the capacity to differentiate into both the eosinophilic and basophilic pathways.

Adult↗

Pharmacological modulation of IL-6 and IL-8 secretion by the H1-antagonist decarboethoxy-loratadine and dexamethasone by human mast and basophilic cell lines.

Mast cells and basophils are central effector cells of allergic reactions and are involved in inflammatory diseases. These cell types produce an array of mediators including a broad spectrum of cytokines. In order to examine whether antiallergic drugs modulate the release of these mediators, we have investigated the influence of dexamethasone and decarboethoxy-loratadine (DEL), the active metabolite of the H1-blocking agent loratadine, on the release of IL-6 and IL-8 by the human mast cell line HMC-1 and the human basophilic cell line KU812 by ELISA. Dexamethasone (10(-6)-10(-11) M) or Del (10(-5)-10(-14) M) were added to the cells either 1 h prior to or simultaneously with PMA and Ca-ionophore A23187. When preincubated with the cells, DEL dose-dependently suppressed IL-6 release by up to 40% and IL-8 release by up to 50%. Dexamethasone potently suppressed secretion of both cytokines if simultaneously added to the cells with the stimuli by up to 60% and after preincubation by up to 80%. Since both antihistamines and glucocorticoids are used for treatment of allergic diseases, the findings reported here indicate that these drugs may modulate allergic reactions via inhibition of cytokine release from mast cells and basophils.

Basophils↗

Histamine release reaction of basophils in chronic granulocytic leukaemia. Induction by heterologous anti-immunoglobulin E, concanavaline A, and phytohaemagglutinin; effect of heavy water.

Basophils possess membrane bound IgE molecules, and immunological activation leads to a secretory process with cell degranulation and histamine release. Heterologous anti IgE, concanavaline A, and phytohaemagglutinin are potent non-cytotoxic releasing agents. They operate by a mechanism similar to that of immunological activation. Heavy water is not a histamine releasing inducer but it increases histamine release of the cells. We studied the histamine release reaction of leukaemic basophils in 10 patients and found a physiological response such as that previously reported with normal human basophils.

Antibodies, Anti-Idiotypic↗

Inhibition of IgE-dependent histamine release from human peripheral blood basophils by humanized Fab fragments that recognize the membrane proximal domain of the human Fc epsilon RI alpha-chain.

BACKGROUND: Inhibition of the interaction between IgE and the alpha-chain of Fc epsilon RI (Fc epsilon RI alpha) is a straightforward strategy to develop therapeutic reagents for IgE-mediated allergic diseases. OBJECTIVE: The purpose of this study is the humanization of CRA2 and/or CRA4, mouse anti-human Fc epsilon RI alpha monoclonal antibodies (mAbs) which recognize the IgE-binding membrane proximal immunoglobulin-like domain of Fc epsilon RI alpha. METHODS: The two mAbs were humanized by CDR grafting onto human V region frameworks encoded by human germline V and J genes. The activities of the recombinant antibodies to bind Fc epsilon RI alpha and inhibit IgE binding to Fc epsilon RI alpha were analyzed by flow cytometry and ELISA. Human peripheral blood basophils were pretreated with the Fab fragments of the humanized CRA2 and stimulated with IgE and an anti-IgE polyclonal antibody. The released histamine was measured. RESULTS: The humanized CRA2 had almost the same activities of binding and inhibition of IgE binding to Fc epsilon RI alpha as the original mouse CRA2. Although the Fc epsilon RI-binding activity was maintained following humanization of the CRA4 light chain V region, it was lost by the humanization of the CRA4 heavy chain V region. Pretreatment of human peripheral blood basophils with the Fab fragments of the humanized CRA2 inhibited their subsequent degranulation activated by cross-linking of the Fc epsilon RI. CONCLUSION: In the humanized CRA2, all amino acid residues except CDR are replaced with the residues encoded by human germline genes. The humanization of CRA2 might be an important step in the development of immunotherapy to manipulate the IgE network in which mast cells, basophils, and various types of Fc epsilon RI alpha expressing cells are involved.

Amino Acid Sequence↗

A new combined test with flowcytometric basophil activation and determination of sulfidoleukotrienes is useful for in vitro diagnosis of hypersensitivity to aspirin and other nonsteroidal anti-inflammatory drugs.

BACKGROUND: We assessed whether nonsteroidal anti-inflammatory drugs (NSAIDs) may provoke blood basophil activation in vitro in aspirin- and NSAID-hypersensitive patients, as detected by a flowcytometric technique using the CD63 marker--flowcytometric basophil activation test (FAST) assay--in addition to the sulfidoleukotriene (sLT) release--the cellular allergen stimulation test (CAST). METHODS: Sixty aspirin- and/or NSAID-hypersensitive patients were studied. Thirty control patients without history and negative provocation challenge were also included. The percentage of activated basophils after in vitro stimulation with NSAIDs at 3 different concentrations was evaluated by an anti-CD63 phycoerythrin conjugate (FAST assay) and the amount of sLTs released in the cell supernatant by ELISA (CAST assay). RESULTS: For aspirin, the FAST indicated a sensitivity of 41.7%, a specificity of 100%, a positive predictive value of 100% and a negative predictive value of 99.4%; for paracetamol 11.7 and 100%, for metamizol 15 and 100%, for diclofenac 43.3 and 93.3%, and for naproxen 54.8 and 74.1%. Many patients showed positive tests to more than 1 NSAID. When considering the first 4 NSAIDs, the global sensitivity increased to 66.7%, while the specificity remained at 93.3%. The addition of the CAST results still increased the sensitivity up to 73.3%, but with a decrease of the specificity to 71.4%. CONCLUSIONS: The FAST shows a high percentage of positive reactions, which may reach 60-70% when 4 NSAIDs are tested and even 88% when the test is performed within 1 month of the last clinical drug exposure and reaction. The test has a high specificity above 90%. The addition of sLT determinations yields additional information in a few isolated cases. It is suggested that this test, when properly used, may help avoid some cumbersome and dangerous provocation challenges.

Adult↗

In vitro analysis of birch-pollen-associated food allergy by use of recombinant allergens in the basophil activation test.

BACKGROUND: Basophil activation is associated with the expression of CD63. In birch-pollen-associated food allergy to celery, carrot and apple, Bet v 1, Api g 1, Dau c 1 and Mal d 1 are major allergens. Recombinant allergens have not yet been used in the CD63-based basophil activation test (BAT). OBJECTIVE: To evaluate the feasibility of using recombinant allergens in the BAT in the diagnosis of allergy to apple, carrot and celery and to compare results with routine tests, i.e. skin prick tests (SPTs) and specific IgE. METHODS: Thirty-two patients with an oral allergy syndrome induced by apple, carrot or celery and 22 controls were studied. SPTs were performed with native foods. Specific IgE was determined by the CAP method and basophil activation by flowcytometry upon double staining with anti-IgE/anti-CD63 monoclonal antibodies after incubating with purified recombinant Bet v 1, Bet v 2, Api g 1, Dau c 1 and Mal d 1. RESULTS: By the combined use of the BAT and the CAP method, sensitization to Bet v 1 and Bet v 2 was detected in 100 and 25% of all subjects, respectively. Sensitivity of specific IgE for apple, carrot and celery was 60, 70 and 75% with corresponding specificities of 64, 86 and 82%. Sensitivity of the BAT for Mal d 1, Dau c 1 and Api g 1 was 75, 65 and 75% with corresponding specificities of 68, 100 and 77%. CONCLUSIONS: The BAT using recombinant allergens provides a valuable new in vitro method for the detection of sensitization to foods. Although double-blind placebo-controlled food challenges remain the gold standard to confirm food allergy, the CD63-based BAT with recombinant allergens may supplement routine tests for allergy diagnosis.

Allergens↗

Detection of basophil sensitization by IgE antibodies to nuclear antigens in connective tissue diseases.

Responses of the IgE type to various nuclear antigens have been explored using the human basophil degranulation test (HBDT) to single (SS) and double-stranded (DS) deoxyribonucleic acid (DNA), nuclear ribonucleoprotein (nRNP), and Sm antigens. This study was conducted on systemic lupus erythematosus (SLE) patients as compared to rheumatoid arthritis (RA) polymyositis (PM), scleroderma (SCL) and mixed connective tissue disease (MCTD). SLE and MCTD patients showed a high level of basophil degranulation to the four antigens. Degranulation to nRNP protein was higher in MCTD than in SLE cases. HBDT to the four antigens were constantly negative in control donors and in RA, PM and SCL. Basophil degranulation to DS-DNA in SLE was blocked by previous exposure of the blood to anti-human-IgE antiserum. These results exemplify the specificity of the HBDT, making this simple and fast test a useful tool in the diagnosis of connective tissue diseases.

Antigens↗

Platelet augmentation of IgE-dependent histamine release from human basophils and mast cells.

A factor(s) from human platelets enhances IgE-mediated histamine release from human basophils and mast cells. This effect is directly related to the platelet number; at physiological platelet/leukocyte ratios (40:1), the enhancement was 66 +/- 11%. Platelet stimulation by thrombin more than doubled the enhancement, to 172 +/- 10% at 40:1. Mast cell release was also enhanced by platelets although the magnitude was more limited (86 +/- 13% at 40:1 with thrombin). Direct basophil/platelet contact was unnecessary in that platelet supernatants were fully active; a direct platelet factor/basophil interaction is suggested, however, by the fact that basophils purified 100-fold with respect to other leukocytes were enhanced by the platelet factors. The appearance of platelet-enhancing activity is associated with the release of an alpha-granule marker (PF4) rather than with products of arachidonic acid metabolism (thromboxane B2). The platelet factor(s) responsible for these effects are not dialyzable, are heat stable and do not appear to be identical to PF4 or platelet-derived growth factor (PDGF). Since anti-IgE-stimulated basophils cause PF4 release and this correlates with the release of enhancing factor, we suggest that a pro-inflammatory feed forward relationship exists. Together with our previous data showing that platelets are activated in vivo during antigen challenge of allergic asthmatic subjects, these results suggest that platelets may be important in modulating IgE-mediated allergic reactions in man.

Basophils↗

Inhibitability and enhanceability of basophil histamine release in asthmatic and normal subjects.

Circulating human basophils contain histamine, a potent mediator of inflammation. Previous in vitro studies have shown that histamine 'releasability' in asthmatic subjects differs from normal subjects but have not evaluated possible differences in the immunopharmacological control of the release of this mediator which might account for these differences. The purpose of the present study was to examine the immunopharmacologic control of basophil histamine release in 14 asthmatics and 10 normal subjects who were characterized by pulmonary function tests, allergic status (skin tests and serum IgE levels) and nonspecific airways reactivity to methacholine and histamine. Basophils were stimulated with anti-IgE, and the inhibitory effects of the H2 agonist, dimaprit, and dibutyryl cyclic AMP (dbcAMP), as well as the enhancing properties of 5-hydroperoxyeicosatetraenoic acid (5-HPETE) and indomethacin on the modulation of histamine release, were investigated. Although no statistically significant differences were seen in the percent histamine release triggered by anti-IgE in these two groups, enhancement of histamine release by 5-HPETE was more consistent in the asthmatic subjects (10 of 10) than in control subjects (6 of 8). The percent increase in histamine release produced by 5-HPETE in asthmatic subjects averaged 3.9 +/- 1.3% using 0.03 micrograms anti-IgE/ml and 4.8 +/- 3.2% using 0.1 microgram anti-IgE/ml (p less than 0.002, Wilcoxon's signed rank test), and averaged 3.0 +/- 4.3 and 3.1 +/- 5.3%, respectively, in control subjects (p greater than 0.10).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Appearance of basophilic cells/mast cells and IgE antibodies in liquid human cell cultures.

Maturation of basophils/mast cells as well as formation of IgE antibodies are parts of the immune response to antigens. We have analyzed these important constituents of the allergic inflammatory response in vitro, cultivating human peripheral blood cells from allergic and normal individuals. Mesenteric lymph nodes were also cultured from two normals. In liquid cultures of peripheral blood cells, the number of small basophils initially present decreased and large basophilic cells appeared over a 2-week period. In normals, the maturation of large basophils from precursor cells could be stimulated with supernatants from peripheral blood cell cultures from atopic individuals stimulated with the relevant allergen. The IgE levels declined in cultures of peripheral blood, whereas the IgE antibodies in cultures of cells from a mesenteric lymph node from one of the nonallergic individuals increased during the 2-week period. In separate cultures, the IgE formation could not be reproducibly stimulated by antigen or mitogen. The study shows the possibility to stimulate the maturation of basophil/mast cell precursor cells present in the blood of allergic and healthy individuals with antigen-induced factors. In contrast, the IgE formation by blood cells was difficult to stimulate.

Basophils↗

Surface membrane traffic in guinea pig basophils exposed to cationic ferritin.

Surface membrane traffic patterns can be influenced by a number of factors, including the functional state of the cell. We used transmission electron microscopy to investigate the fate of surface membrane in guinea pig basophils exposed to cationized ferritin (CF) in vitro. CF bound to the plasma membrane and was internalized on the membranes of vesicles and vacuoles, a process that was particularly prominent at the uropod of basophils exhibiting a polarized ('motile') configuration. The vesicles/vacuoles moved to the Golgi area, or, in the case of degranulating basophils, were observed in continuity with the degranulation sac, a structure formed largely by the fusion of individual cytoplasmic granule membranes. However, CF-positive vesicles were never observed to fuse directly with the membranes of intact cytoplasmic granules.

Animals↗

The role of 5-lipoxygenase pathway activation in basophil histamine release.

This study was performed to evaluate the role of products of the 5-lipoxygenase pathway in histamine release from human basophils. AA-861, a specific inhibitor of 5-lipoxygenase, did not inhibit anti-IgE-induced histamine release from human basophils with 6 +/- 11% inhibition at 10(-6)M. Neither was there a marked inhibition of histamine release induced by ionophore A23187 and formyl-L-methionyl-L-leucyl-L-phenylalanine with 16 +/- 10 and 11 +/- 6% inhibition respectively at 10(-6)M of AA-861. In contrast, AA-861 enhanced 12-0-tetradecanoyl-phorbol-13-acetate-induced histamine release with 20 +/- 3% at 10(-6)M. These results suggest that 5-lipoxygenase activation may not play a role in basophil histamine release.

Basophils↗

Activation of basophils and mast cells for mediator release.

Biochemical events involved in both IgE-dependent and IgE-independent mediator release from basophils and mast cells were analyzed. The results revealed that bridging of IgE receptors activates a variety of membrane-associated enzymes, such as serine protease, phospholipase C, methyltransferases and adenylate cyclase, resulting in the stimulation of phosphatidylinositol (PI) turnover and a transient increase in both phospholipid methylation and intracellular cAMP. Mobilization of intracellular Ca2+ monitored by Quin-2 fluorescence is detected within 5 s after antigen challenge and appears to be the earliest intracellular change detectable after receptor bridging. Stimulation of PI turnover results in the generation of inositol 1,4,5-triphosphate (IP3) and of 1,2-diacylglycerol (DAG), which in turn activates protein kinase C. Evidence was obtained that the guanyl nucleotide (GTP)-binding protein Ni is not involved in the transduction of IgE-mediated triggering signals for mediator release. Although the sequence of enzyme activation following receptor bridging is not clear, the results suggest that the mobilization of intracellular Ca2+ is a crucial initial signal in the IgE-mediated activation of basophils and mast cells. In the mediator release induced by IgE-independent stimuli, enzymes involved in the mediator release are different from one stimulus to another. The results indicate the presence of multiple biochemical pathways for mediator release from basophils and mast cells.

Animals↗

Circulating basophil counts in atopic individuals.

Absolute numbers of circulating basophils were measured in 55 atopic and 35 non-atopic individuals, using a flow cytometer for automated cell counting. They were significantly elevated in the atopic group (p less than 0.001), but the total leucocyte count was not significantly different between the two groups. Eosinophil counts, which correlated with the number of basophils for both populations, were also significantly raised in the atopic group (p less than 0.001). Individual variation in absolute basophil counts was not detected in sequential samples taken at daily intervals over 5 days, in 5 atopics and 4 non-atopics. In addition, no significant variation was detected in 6 atopics and 5 non-atopics over a period of up to 20 months.

Adolescent↗