Inhibition of basophil activation by histamine: a sensitive and reproducible model for the study of the biological activity of high dilutions.

BACKGROUND: At the beginning of this series of experiments we were looking for a model based on the use of purified commercially available compounds based on a fully described and accepted pharmacological model to study of the biological effect of high dilutions. Negative feedback induced by histamine, a major pro-inflammatory mediator, on basophils and mast cells activation via an H2 receptor me these criteria. The simplest way of measuring basophil activation in the early 1980's was the human basophil activation test (HBDT). OBJECTIVES: Our major goal was first to study the biological effect of centesimal histamine dilutions beyond the Avogadro limit, on the staining properties of human basophils activated by an allergen extract initially house dust mite, then an anti-IgE and N-formyl-Met-Leu-Phe (fMLP). Technical development over the 25 years of our work led us to replace the manual basophil counting by flow cytometry. The main advantages were automation and observer independence. Using this latter protocol our aim was to confirm the existence of this phenomenon and to check its specificity by testing, under the same conditions, inactive analogues of histamine and histamine antagonists. More recently, we developed an animal model (mouse basophils) to study the effect of histamine on histamine release. METHODS AND RESULTS: For the HBDT model basophils were obtained by sedimentation of human blood taken on EDTA and stained with Alcian blue. Results were expressed in percentage activation. Histamine dilutions tested were freshly prepared in the lab by successive centesimal dilutions and vortexing. Water controls were prepared in the same way. For the flow cytometric protocol basophils were first labeled by an anti-IgE FITC (basophil marker) and an anti-CD63 (basophil activation marker). Results were expressed in percentage of CD63 positive basophils. Another flow cytometric protocol has been developed more recently, based on basophil labeling by anti-IgE FITC (fluorescein isothiocyanate) and anti-CD203 PE (another human basophil activation marker). Results were expressed in mean fluorescence intensity of the CD203c positive population (MFI-CD203c) and an activation index calculated by an algorithm. For the mouse basophil model, histamine was measured spectrofluorimetrically. The main results obtained over 28 years of work was the demonstration of a reproducible inhibition of human basophil activation by high dilutions of histamine, the effect peaks in the range of 15-17CH. The effect was not significant when histamine was replaced by histidine (a histamine precursor) or cimetidine (histamine H2 receptor antagonist) was added to the incubation medium. These results were confirmed by flow cytometry. Using the latter technique, we also showed that 4-Methyl histamine (H2 agonist) induced a similar effect, in contrast to 1-Methyl histamine, an inactive histamine metabolite. Using the mouse model, we showed that histamine high dilutions, in the same range of dilutions, inhibited histamine release. CONCLUSIONS: Successively, using different models to study of human and murine basophil activation, we demonstrated that high dilutions of histamine, in the range of 15-17CH induce a reproducible biological effect. This phenomenon has been confirmed by a multi-center study using the HBDT model and by at least three independent laboratories by flow cytometry. The specificity of the observed effect was confirmed, versus the water controls at the same dilution level by the absence of biological activity of inactive compounds such as histidine and 1-Methyl histamine and by the reversibility of this effect in the presence of a histamine receptor H2 antagonist.

Pre-lethal anaphylaxis to carboxymethylcellulose confirmed by identification of specific IgE--review of the literature.

BACKGROUND: Carboxymethylcellulose (CMC) is used extensively in the pharmaceutical and food industries on account of its various properties. Anaphylactic reactions are rare. It has been reported principally after intra-articular infiltration of sustained-release corticosteroids containing CMC and, very rarely, after barium enema. METHODS: A case of pre-lethal anaphylactic shock after barium enema was studied by prick-test, intra-dermal reaction (IDR), leukocyte histamine release test (LHRT), basophil activation test (BAT), cystein-leukotriene release test (CAST) and dot-blot analysis. RESULTS: IDR to CMC was positive at a concentration of 10 microg/ml. BAT and CAST were positive. Specific IgE were identified using dot-blot analysis. DISCUSSION: This is the third report of CMC-specific IgE and the second of anaphylaxis to CMC associated with a barium suspension in contact with GI tract mucosa. CMC as an excipient in medicinal products may therefore be a risk factor for severe anaphylaxis after injection or following contact with GI tract mucosa. Sensitization and allergic reactions by CMC in food additives have to be considered.

Improvement of flow cytometric analysis of basophil activation inhibition by high histamine dilutions. A novel basophil specific marker: CD 203c.

BACKGROUND: Histamine is known to elicit a negative feedback effect on anti-IgE and allergen-induced basophil activation. A series of experiments performed between 1981 and 1995 using a manual method showed biological activity of highly diluted histamine. Most of the experiments used histamine in the range 10(-30) (15C)-10(-36) M (18C). These results were confirmed by automated flow cytometry, but this method is based on the selection of basophils by anti-IgE and analysis of basophil activation by anti-CD 63, showing significant but relatively low inhibition (approximately 14%), insufficient to convince the scientific community of the reality of the phenomenon. OBJECTIVE: We investigated if the use of CD 203c, a basophil specific, earlier marker than CD 63 of the activation cascade, increased the sensitivity of the method, testing two target histamine dilutions, 10(-4) (2C) and 10(-32) M (16C). METHODS: Basophils, obtained from buffy coats, were pre-incubated with the histamine dilutions and activated by two agonists: anti-IgE and fMLP (formyl-methionyl-leucyl-phenylalanine peptide). Basophil activation was stopped with EDTA. The cells were labelled with anti-IgE, anti-CD 13 and anti-CD 14 for basophil selection, and anti-CD 63 and anti-CD 203c for basophil activation. Results were expressed in up-regulation percentage for CD 63 or mean intensity of fluorescence (MFI) for CD 203c. RESULTS: Histamine 10(-4) M (2C) and histamine 10(-32) M (16C) were capable of inhibiting both IgE-dependent (anti-IgE) and IgE-independent (fMLP) basophil activation. The percentage inhibition depended on the activation marker used. The highest inhibition for histamine dilution 16C was observed with CD 203c (38%, P<0.001), approximately half the inhibition observed with histamine 2C (73%). CONCLUSION: These new flow cytometric protocols confirmed that high dilutions of histamine may inhibit basophil activation and that the inhibitory effect is not restricted to IgE-dependent activation. The use of CD 203c instead of CD 63 increased the magnitude of the response.

[Immuno-biological diagnosis of food allergy]. / Diagnostic immuno-biologique de l'allergie alimentaire.

Food allergy is becoming more frequent, with 6% of asthmatics reporting an isolated food allergy, and 5 to 6% of atopic dermatitis patients also have either a single or multiple true food allergy. There is value in immuno-biological diagnosis by: Measurement of total serum IgE. Measurement of mono-allergen-specific IgE, following a measurement by a multi-allergen of the Trophatope type. A study of elimination of foods for 2 or 3 months followed by their re-introduction. Oral provocation tests in a hospital environment under clinical control and subsequent measurement of the mediators:-Plasma histamine, tryptase, and urinary methylhistamine to give proof of responsibility of the food allergen. Nowadays, it is perfectly possible to include in diagnosis the new technologies of the test of activation of basophils/or lymphocytes by means of flow cytometry.

[Evaluation of the reproducibility of the MAST technique for pneumoallergens and food allergens. Biological study]. / Evaluation de la fiabilité de la technique MAST pour les pneumallergènes et les trophallergènes. Etude biologique.

MAST-Cla reagent is used in France for now 10 years for the specific IgE determinations. Due to the different modifications of the manufactoring process we checked here the actual sensitivity of this test as compared to the results obtained by the CAP RAST RIA. The mean sensitivities related to the class 1 limit obtained by successive dilutions of the tested sera were respectively for the major aero-allergens and food allergens 0.40 kUI/l and 0.49 kUI/l. Four major allergens (grass pollen, house dust mite, egg yolk and milk) we observed a low background for 10 control subjects, the mean values (n = 6) related to a low concentration of grass pollen specific IgE (0.5 kUl/l) being significant (p < 0.01).

[A case of coconut oil allergy in an infant: responsibility of "maternalized" infant formulas]. / Un cas d'allergie à l'huile de noix de coco chez un nourrisson: responsabilité des laits maternisés.

The case is presented here of a baby of 8 months fed from her birth with maternal milks. The first milk induced a severe gastro-intestinal disorder which disappeared when a second milk was used. A third milk caused a relapse. The only common allergen was coconut, which was physico-chemically modified in the second milk. Demonstration of the responsibility of coconut oil was based on positive re-introduction tests, positive skin tests for coconut and maternal milk that were negative for cow's milk and peanut and by specific IgE tests which were positive in comparison with negative controls.

[Importance of studying deficiencies of IgG subclasses (IgG2 and IgG4) in immuno-allergologic practice]. / Intérêt de la recherche d'un déficit en sous-classes d'IgG (IgG2 et IgG4) en pratique immuno-allergologique.

Levels of the sub-classes of immunoglobulins IgG2 and IgG4 have been established by radial diffusion with monoclonal antibodies in 150 subjects. 49 (42 adults and 7 children) showed either a low level of IgG2 (less than 0.42 g/l n = 11) or a reduced level of IgG4 (less than 0.05 g/l n = 38). A single patient had a double deficit, 38 subjects had a superinfection of which 17 had a severe form and in 77% of these cases a level of IgG4 of less than 0.05 g/l.

Hymenoptera venom immunotherapy. I. Induction of T cell-mediated immunity by honeybee venom immunotherapy: relationships with specific antibody responses.

The specific cell-mediated and humoral immune responses of 14 children allergic to honeybee venom were studied. An 8-day rush venom immunotherapy induced an increase in T proliferative (p less than 0.04) and T suppressive (p less than 0.003) cell-specific activities. Antibody variations, an increase in specific IgG4 (p not equal to 0.05), and a decrease in specific IgE (p less than 0.01) were observed 1 year later. Initial high T suppressive cell activity prevents T proliferative cell increase during rush venom immunotherapy. High initial levels of specific IgG1 and specific IgG4 have opposing effects on the increase in T suppressive cell activity, the former being positively correlated with intensive increase (r = 0.840; p less than 0.005), the latter negatively with T suppressive cell increase (r = -0.709; p less than 0.001). These data indicate that there are interrelationships between the cell-mediated immunity and the antibody responses in honeybee allergy.