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J Sainte-Laudy

Publications and source records attributed to J Sainte-Laudy.

At least 19 recordsLinked to original sources
PubMed2006

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.

Antibodies, Anti-Idiotypic↗
PubMed2006

Flow-assisted allergy diagnosis: current applications and future perspectives.

Physicians predominantly rely upon quantification of serum-specific immunoglobulin E (IgE) and/or skin test to confirm clinically suspected IgE-mediated allergy. However, for various reasons, identification of the offending allergen(s) and potentially cross-reactive structures is not always straightforward. Flow-assisted allergy diagnosis relies upon quantification of alterations in the expression of particular basophilic activation markers. Actually, upon challenge with a specific allergen, basophils not only secrete quantifiable bioactive mediators but also upregulate the expression of different markers which can be detected efficiently by flow cytometry using specific monoclonal antibodies. Currently, the technique has been applied in the investigation of IgE-mediated allergy caused by classical inhalant allergens, food, Hevea latex, hymenoptera venoms and drugs. It is also appreciated; the technique proves valuable in the diagnosis of non-IgE-mediated (anaphylactoid) reactions such drug hypersensitivity and the detection of autoantibodies in certain forms of chronic urticaria. This review will not address immunologic features, characteristics and general pitfalls of flow-assisted analysis of in vitro-activated basophils as summarized elsewhere. After a recapitulation of the principles and some specific technical issues of flow-assisted analysis of in vitro-activated basophils, we principally focus on the current clinical and research applications of the basophil activation tests. Personal experience of both research groups is provided, where appropriate. Finally, a viewpoint on how the field might evolve in the following years is provided.

Cell Separation↗
PubMed2004

Histamine dilutions modulate basophil activation.

BACKGROUND: In order to demonstrate that high dilutions of histamine are able to inhibit basophil activation in a reproducible fashion, several techniques were used in different research laboratories. OBJECTIVE: The aim of the study was to investigate the action of histamine dilutions on basophil activation. METHODS: Basophil activation was assessed by alcian blue staining, measurement of histamine release and CD63 expression. Study 1 used a blinded multi-centre approach in 4 centres. Study 2, related to the confirmation of the multi-centre study by flow cytometry, was performed independently in 3 laboratories. Study 3 examined the histamine release (one laboratory) and the activity of H(2) receptor antagonists and structural analogues (two laboratories). RESULTS: High dilutions of histamine (10(-30)-10(-38) M) influence the activation of human basophils measured by alcian blue staining. The degree of inhibition depends on the initial level of anti-IgE induced stimulation, with the greatest inhibitory effects seen at lower levels of stimulation. This multicentre study was confirmed in the three laboratories by using flow cytometry and in one laboratory by histamine release. Inhibition of CD63 expression by histamine high dilutions was reversed by cimetidine (effect observed in two laboratories) and not by ranitidine (one laboratory). Histidine tested in parallel with histamine showed no activity on this model. CONCLUSIONS: In 3 different types of experiment, it has been shown that high dilutions of histamine may indeed exert an effect on basophil activity. This activity observed by staining basophils with alcian blue was confirmed by flow cytometry. Inhibition by histamine was reversed by anti-H2 and was not observed with histidine these results being in favour of the specificity of this effect We are however unable to explain our findings and are reporting them to encourage others to investigate this phenomenon.

Alcian Blue↗
PubMed2004

Allergy to nickel in dental alloys.

A case of oral allergy to dental alloys is presented, highlighting the interest of dosage of salivary nickel and of flow cytometry showing a selective CD4+ activation. The discrepancy between the rarity of oral allergy to dental alloys and the frequency of nickel sensitization and nickel-induced contact dermatitis leads to discuss the mechanisms of oral tolerance.

Adult↗
PubMed2002

[Specific antibodies to iodinated contrast media. Research techniques, specificity].

Immuno-allergology of iodine contrast products is much discussed, the main questions posed by these molecules particularly concern the existence of specific IgE and their frequency, the specificity of the antibodies, involvement of the iodine atoms and their routes of sensitisation. Our preliminary study on 6 cases of urticaria (5) and erythema (1) after use of ioxaglate and with positive search for ioxaglate-specific IgE (2.3 to 6.7) after coupling to Sepharose (Baldo and Fisher technique). The results of this technique are expressed with reference to a pool of serum of subjects who had no contact with these contrast products. The threshold of positivity was 2, the mean of the results from 10 subjects who were exposed lay between 1.37 +/- 0.42. Inhibition of specific IgE by ioxaglate was positive in 6 cases. In 2/3 cases inhibition by potassium iodide was also observed. Several published studies in favour of the existence of specific IgE of close specificity, the inhibitions of specific IgE presented were mostly only observed for the contrast product used. An hypothesis would be that the ionic molecules have a greater capacity to induce the synthesis of specific IgE than non-ionic molecules because of their affinity for carrier proteins. The inhibitions seen with mineral iodine in this short study do not permit total elimination of the participation of the iodine atom at the antigenic site.

Animals↗
PubMed2001

[Acetylsalicylic acid: hypersensitivity, intolerance, or allergy?].

After a century of therapeutic use of acetyl salicylic acid (ASA), the different mechanisms involved leading to the therapeutic activity and to the various clinical reactions (even life threatening) observed in patients sensitive to ASA or in general to the non steroidal anti-inflammatory drugs (NSAID's) are still to be discovered or confirmed. During the last century a lot of scientific results have been published in favour of a wide panel of mechanism including an humoral (IgE and/or IgG) or a cellular (lymphocytes) immune reaction, inhibition of the cyclooxygenases, a cellular activation (mast cells, basophils, eosinophils and platelets), a competition at the serum albumin level and an activation of the complement cascade. In general the same actors than in the anaphylactic reaction are found (mediators, cellular activation and amplification systems). It is clear today that these reactions for which an accurate diagnosis is mandatory cannot be explained by a single mechanism, which is the case of a lot of other allergens.

Anaphylaxis↗
PubMed2000

Diagnosis of venom allergy by flow cytometry. Correlation with clinical history, skin tests, specific IgE, histamine and leukotriene C4 release.

BACKGROUND: Potent allergens such as hymenoptera venoms are capable of inducing severe and life threatening clinical reactions. Percentage of false negative results obtained by the usual diagnostical methods is comprised between 10 and 25%. OBJECTIVE: Evaluation of the sensitivity and the specificity of cellular tests and particularly evaluation of a new flow cytometric method. METHODS: Forty-five allergic patients having experienced a local, a systemic reaction or an anaphylactic shock and 10 controls having undergone hymenoptera stings without clinical reactions were selected on the basis of the clinical history, skin tests and specific IgE. Three cellular tests were performed on the same cell suspensions and in the presence of 2 ng/mL of rIL3: histamine release (RIA), leukotriene C4 release (ELISA) and basophil activation test (flow cytometry after double anti-IgE FITC, anti-CD63 PE labelling). RESULTS: As compared to the clinical history, sensitivities of skin tests, specific IgE, flow cytometry, histamine release and leukotriene release were, respectively; 85%, 88%, 100%, 89% and 100%. Flow cytometric analysis of basophil activation showed a significant decrease of the mean fluorescence density and number of IgE positive cells and a significant increase of the number of CD63 positive cells. The 10 controls tested by flow cytometry were negative. CONCLUSION: As compared to the clinical history and to the other parameters tested here, flow cytometry showed a high sensitivity and a high specificity. The excellent correlation observed between this method and the other cellular tests such as histamine and leukotriene release are in favour of the specificity of flow cytomery and in favour of the use of this method for venom allergy diagnosis.

Adolescent↗
PubMed2000

[Importance of blood tests for the diagnosis of drug allergies].

This work is devoted to the study of 22 dossiers of persons who have presented with clinical signs following taking a drug. The study was confined to patients in whom the symptoms had as origin a hypersensitivity (true or non-specific by histamine release). This study has allowed analysis of the value of several serological tests (measurement of leukotrienes, activation of basophils and T specific lymphocytes) in diagnosis and so to define the path to take that is best adapted to each case. The conclusion presents an agreement between the suspected diagnosis, after allergy enquiry and prick-tests, and the results of serological tests.

Adolescent↗
PubMed1999

Human basophil activation measured by CD63 expression and LTC4 release in IgE-mediated food allergy.

BACKGROUND: IgE-dependent basophil activation induced by an allergen elicit the release of LTC4 and the expression of the CD63 membrane marker. OBJECTIVE: The aim of this study was to check if flow cytometric analysis of basophil activation could be applied to food allergy diagnosis and if this method paralleled LTC4 release. METHODS: Patients were selected by the clinical history, skin tests, and provocation tests. Basophil activation induced by food extracts was studied in 24 control subjects and in 27 patients having a food allergy by LTC4 release test (LRT) and by flow cytometric anti-IgE+, CD63 + cell counting (BAT = basophil activation test). In case of negative anti-IgE response a passive blood donor basophil passive sensitization step was added to LRT and BAT. Leucocyte histamine release test was performed in 11 patients. RESULTS: Basophil activation test was positive in 18/31 cases and LRT in 22/34 cases for food-allergic patients and, respectively, in 1/33 and 1/35 cases for the controls. A correlation was observed between specific IgE, BAT, and LRT. Basophil activation test and LRT performed after passive sensitization had an excellent sensitivity only for specific IgE levels ranging between 3.5 and 35 KU/L. CONCLUSION: The present study shows that allergen-induced LTC4 release and anti-IgE, antiCD63 bicolor flow cytometric analysis of basophil activation may be used for food allergy diagnosis. Both tests have a good sensitivity and specificity. Basophil activation test and LRT are more efficient than histamine release test in case of high spontaneous histamine release, frequently observed in case of food allergy.

Adolescent↗