High spontaneous release of histamine in vitro from leukocytes of persons hypersensitive to food.

In vitro studies of antigenic release of histamine from peripheral leukocytes (basophils) have been done in more than 600 allergic children. Ordinarily only about 5% to 10% of the histamine content of leukocytes will leak out or be released "spontaneously" during incubation of suspensions in vitro, without the addition of antigen. A small percentage of children were found to have leukocytes that released 25% to 100% of the histamine content spontaneously during incubation. The significance of this was not apparent until recently, when studies were concentrated on children suspected of hypersensitivity reactions to foods, among whom a much greater prevalence of spontaneous histamine release from leukocytes was encountered. Of children proved by a double-blind food challenge to react with manifestations of immediate hypersensitivity, 100% had leukocytes that consistently released over 25% (usually between 50% and 100%) of the histamine content spontaneously without the addition of antigen. Such high spontaneous histamine release appears to be characteristic of persons with clinical evidence of hypersensitivity to food.     

Pharmacologic modulation of spontaneous histamine release

In a previous study from our laboratory (Akagi and Townley) we reported that basophils from asthmatic patients off medication show spontaneous histamine release (SHR) significantly higher than asthmatic patients on chronic medication. Both groups of asthmatics showed significantly higher SHR than normal subjects. These findings led us to test the in vitro effect of various therapeutic agents on SHR. Theophylline exerted the most pronounced inhibitory effect on SHR (P less than .005). The effects of isoproterenol and PGE1 were significant (P less than .005) but less than theophylline. These in vitro findings led us to evaluate the effect of a single dose, orally administered bronchodilator on in vitro SHR from asthmatic subjects. The effect of theophylline 250 mg and metaproterenol 20 mg on pulmonary function and SHR was evaluated on separate study days. Four of the eight asthmatic subjects showed greater than 10% SHR. The baseline value of SHR in the same individuals on two different study days showed significant correlation (r = .82). A single dose of metaproterenol or theophylline increased the pulmonary function but failed to influence the SHR. Although SHR occurs in asthmatic subjects, it is not influenced by single dose bronchodilation.     

Mite-allergen exposure and spontaneous histamine release in monosensitive and polysensitive mite-allergic patients

Forty-three patients allergic to mites and suffering mainly from asthma were recruited: 25 were mite-monosensitive and 18 were polysensitive, as determined by skin tests and specific serum IgE determinations with various allergens. In vitro spontaneous histamine release (SHR) by washed blood basophils was measured once or several times for each patient. Throughout this study, the mean periods of high and low mite-allergen exposure were defined on the basis of relative indoor humidity and temperature data. For the mite-monosensitive patients, there was a significant increase in mean SHR during the season of high mite-allergen exposure as compared to the months of lower mite-allergen presence ( P < 0.002). No significant difference between mean SHR values was observed when comparing the monosensitive group during the season of high mite-allergen exposure with polysensitive patients (allergic to mite and pollen) during the period of exposure to both allergens. Differences in mean SHR reported here emphasize the positive relationship between intense allergen exposure and the in vitro SHR increase in blood basophils of mite-allergic patients.     

Automated histamine analysis for in vitro allergy testing. II. Correlation of skin test results with in vitro whole blood histamine release in 82 patients.

The recently developed sensitive, automated histamine assay system was applied for in vitro allergy testing. The simplified method for histamine release from whole heparinized blood was used. Aliquots of blood and allergen were incubated for one hour at 37 degrees C, and each supernatant was then analyzed for histamine release. Nine common pollen and environmental allergens were used at three 10-fold dilutions for in vitro testing with the use of 20 ml of blood. Intradermal skin tests were correlated with the whole blood histamine release in 82 patients who had received no immunotherapy. A scoring system for the histamine results was developed to take into consideration the results with multiple allergen concentrations. When the skin test was strongly positive (greater than or equal to 3 + at 100 protein nitrogen units [PNU]/ml), the whole blood histamine release was positive in 89% of the tests. In contrast, when the skin test was negative ( less than 1 + at 100 PNU/ml), the histamine release was also negative in 99.8% of the cases. When the skin test was 1 +, the histamine release from whole blood was positive in 6% of the tests; and when the skin test was 2+, the whole blood results were positive in 32%. The accuracy, precision, and sensitivity of the automated histamine assay allow its application for the clinical study of allergic patients.     

Seasonal increase of spontaneous histamine release in washed leucocytes from rhinitis patients sensitive to grass pollen.

The spontaneous histamine release (SHR) in basophils from patients sensitive to grass pollen has been studied before and during the 1987 grass pollen season. Nineteen patients were recruited on seasonal rhinitis symptoms, positivity for cutaneous tests and for serum-specific IgE with grass pollen. At the time of the biological investigations the patients were following a clinical trial of hyposensitization, including placebo, calcium phosphate and aluminium hydroxide-adsorbed grass pollen extract treatments. During the pollen season, grass pollen counts and clinical scores were checked over a 40-day period. Mean SHR was significantly higher during the pollen period than before, for the whole population of 19 patients (10.9% and 4.6%; P less than 0.005) as well as when the high SHR responders were excluded (5.5% and 3.6%; P less than 0.01). No significant correlation existed between SHR and clinical scores or treatments. SHR could be inhibited at 4 degrees C, in absence of CA++ or of oxidative metabolism and thus originated from cells actively secreting histamine.     

Increased in vitro histamine release by radiographic contrast media in patients with history of incompatibility.

This study was designed to compare in vitro leucocyte histamine release in patients with a history of previous radiographic contrast media (RCM) reactions and normal controls. Peripheral leucocytes of ten patients with a positive history of RCM imcompatibility and nineteen normal volunteers were stimulated in vitro with different RCM in different concentrations and the amount of histamine released was measured in the supernatant. There was a significant increase in histamine release induced by RCM in low doses (0.02-0.1 M) in the patients as compared to the normals. At the high doses (0.2-0.3 M), no significant differences were found. Leucocytes from four of the patients were stimulated preferentially by the dye responsible for the incompatibility. Six patients showed no such preference. The increased "releasability" of the patients' leucocytes could not be transferred by serum. Normal leucocytes, when incubated with serum from "high releasing" patients did not show increased histamine release after stimulation with the respective dye. It is suggested that an excessive non-immunological response of basophil leucocytes to RCM stimulation might, in part, account for the adverse clinical reactions observed. Furthermore, leucocyte histamine release might be a useful diagnostic tool for detecting patients with a high risk of developing contrast media reactions.     

In vitro histamine and serotonin release studies in atopic dermatitis.

6 patients suffering from severe atopic dermatitis with high serum IgE were investigated. 3 of the patients had elevated plasma histamine levels (1.5-2.0 ng/ml). Compared to 9 nonatopic normal volunteers, the patient showed increased in vitro histamine release from peripheral leukocytes after stimulation with iothalamate and methacholine: while there was no significant histamine release at a methacholine concentration of 10(-4) M in normals, 4 of the patients with atopic dermatitis showed measurable histamine release under these conditions in vitro. The uptake of radiolabeled serotonin by platelets in vitro was decreased in 2 of the patients. There was no significant difference in serotonin release induced in vitro by different concentrations of thrombin, epinephrine and methacholine; 2 patients showed an increased platelet release reaction after iodipamide stimulation. It is concluded that a general tendency to release vasoactive mediators, even after 'nonimmunologic' stimulation, might play a role in the pathogenesis of atopic dermatitis.     

Concanavalin A induced histamine release from human basophils in vitro.

The site of interaction for concanavalin A (Con-A)-induced histamine release from human basophils was studied in vitro. Blocking the epsilon one determinant (D leads to 1) of IgE with high concentrations of monomer (Fab) anti-Depsilon1 does not significantly inhibit the quantity of histamine released by suboptimum concentrations of Fc specific anti-IgE. This indicates that the monomer anti-Depsilon1 does not have the capacity to sterically hinder the bridging of all of the determinants in the Cepsilon3 and Cepsilon4 domains (Fc'-epsilon-region) of IgE. The monomer anti-Depsilon1 does effectively inhibit release induced by suboptimum concentrations of Con-A. The data indicate that for suboptimum concentrations, Con-A activation is IgE mediated and takes place in the proximity of Depsilon1 and not at the membrane receptor for IgE.     

Autonomic function in hemodialyzed patients.

The authors have studied the autonomic function in a group of 34 regular hemodialyzed patients and in a group of 24 normal volunteers with simple, non-invasive and repeteable techniques. To evaluate autonomic function Valsalva manoeuvre, cold pressor test, mental stress test, tilt test, diving reflex test, systolic-time intervals and plasma catecholamines levels were used in all subjects. Uremic patients on maintenance hemodialysis were studied the day after hemodialysis. The response to cold pressor test, mental stress test, tilt test and plasma catecholamines levels resulted normal in all uremic patients, even if 17 out of 34 patients showed an abnormal response to the Valsalva manoeuvre (Valsalva ratio lesser than 1.40). In these patients an alteration of diving reflex and/or a pathological systolic-time interval was found. The authors suggest that sympathetic function is normal in regular hemodialyzed patients and that the abnormal response to the Valsalva manoeuvre is probably due to a defect in the vagal control of the heart and/or an alteration of cardiac performance.     

Polistes wasp hypersensitivity: diagnosis by venom-induced release of histamine in vitro.

Polistes wasps cause a majority of Hymenoptera-induced anaphylactic reactions in Texas. Using the in vitro release of histamine from basophils of patients allergic to Polistes stings, we have studied the cross-reactivity of venoms from three species of Polistes wasps as well as the cross-reactivity among Polistes, honeybee, and Vespula maculifrons (yellow jacket) venoms. Venom collected by an extrusion technique from Pollistes exclamans, Pollistes apachus, and Pollistes carolina caused release of histamine in seven Polistes-sensitive individuals. The dose-response curves from all three Polistes species were quite similar, suggesting extensive cross-reactivity among these species. None of these patients showed significant release of histamine from leukocytes exposed to yellow jacket or honeybee venom. We conclude that a source of Polistes venom is available for further study and possibly for therapy. It appears that any of three local common species of Polistes wasps could be used. Our studies confirmed earlier reports that Hymenoptera sensitivity if often genus-specific.     

Effect of norepinephrine on in vitro histamine release from rat mast cells.

The effect of norepinephrine on compound 48/80-induced histamine release from rat peritoneal mast cells, was studied in an in vitro system. It was found that norepinephrine, within the concentration range 10(-5)--10(-3) M, exerts a significant, dose-related, repressive effect. This effect is greatly potentiated by the beta-antagonist practolol (10(-3) M), throughout the concentration range of 10(-11)--10(-3) M norepinephrine. Methoxyamine, a selective alpha-adrenergic agonist, also represses histamine release in a dose-dependent manner; however, it is not as potent as norepinephrine. The present results would seem to suggest that the repressive effect on histamine release, observed within a low concentration range of norepinephrine, may be due to alpha-adrenoceptor mechanisms.     

Modulation of the spontaneous histamine release by adrenergic and cholinergic drugs

Experiments have been reported on the possible modulation of the spontaneous histamine release by adrenergic and cholinergic drugs.Adrenergic drugs increase the spontaneous histamine release in vivo, and in neoplastic mast cells, in vitro. The mechanism of histamine release appears to be dependent upon the activation of alpha-adrenoceptors.Cholinergic drugs activate the release of histamine in many secretory processes in vivo; in vitro, acetylcholine is one of the most powerful histamine releasers in isolated purified rat mast cells.The release of histamine evoked by acetylcholine in rat mast cells is a calcium-requiring, temperature-dependent exocytosis. The physiological relationship of the sympathetic, parasympathetic and histamine-containing cells are discussed.Lecture held at the Sixth Annual Meeting of the European Branch of the Histamine Club, London, April 20–22, 1977.     

Impaired basophil histamine release from allergic patients

A few patients (6–7%) with a verified type I allergic reaction do not respond with histamine release after challenge of their basophils with specific antigen (non-responding basophils from allergic patients). Sera from these non-responding patients were used for passive sensitization of responding cells from healthy controls. When these sensitized cells were challenged with specific antigen, histamine release was observed indicating that the non-responding allergic patients have circulating antigen-specific IgE capable of binding to Fc-receptors on the basophils. These findings suggest the possibility that non-responding basophils have impaired cell functions. We therefore examined the influence of enhanced IgE receptor stimulation on histamine release in non-responding basophils. This was made by stimulating protein kinase C activity by a phorbol ester (phorbol 12-myristate 13-acetate). When the non-responding cells were incubated with the phorbol ester and challenged with either anti-IgE or specific antigen, the cells released histamine.These findings support the hypothesis that the unresponsiveness of basophils in some allergic patients is associated with impaired IgE receptor complex activation or subcellular functioning and not with a lack of cell-bound IgE.