House dust mite asthma

Fifty asthmatics, candidates for hyposensitization with the house dust mite Dermatophagoides pteronyssinus (Dp), went through a series of allergy tests to evaluate the sensitivity of different organs to Dp. All patients were exposed to bronchial challenge with histamine and bronchial, nasal and conjunctival challenge with Dp, skin prick test (SPT) with Dp, analyses for Dp-specific histamine release from blood cells (HR) and for anti-Dp-IgE in serum (RAST). Results from 40 patients reacting positively in all tests were further analysed. Sensitivity to Dp in the various organs did not parallel, but a fair correlation was demonstrated between pulmonary allergen sensitivity and HR (r = 0.65, P less than 0.001), and between pulmonary sensitivity to allergen and to histamine (r = 0.47, P less than 0.001). Combined variations in HR and in (unspecific) bronchial sensitivity to histamine explained 53% of the variation in bronchial sensitivity to the allergen. This parameter showed less correlation to RAST and SPT (r = 0.31 and r = 0.35, P greater than 0.05). The results indicate that bronchial allergen challenge cannot be replaced by similar challenge of other organs, since the sensitivity of the mucosa in different organs of the same patient seems unrelated. Diagnosis should therefore be based on challenge of the organ with dominating clinical importance. In our selected group of patients, however, it was indicated that a substitution of the result of bronchial allergen challenge by measurement of unspecific bronchial reactivity, together with information on the general allergen sensitivity on a cellular level, might be possible. The unpleasant symptoms of the immediate and late bronchial reactions to allergen challenge could thereby be avoided.     

Hyposensitization in asthmatics with mPEG-modified and unmodified house dust mite extract

Forty-six adult asthmatics allergic to D. pteronyssinus (Dp) participated in a 2-year study. Thirty-one underwent hyposensitization (HS-group). Fifteen were treated with Dp-extract (Dp-group), and 16 with a similar extract modified by monomethoxypolyethylene glycol with reduced allergenicity (mPEG-Dp-group). Fifteen patients served as controls. Dp-specific antibodies and histamine release from blood basophils were determined and compared with Dp-sensitivity in lungs and skin. In addition, IgG and IgE against the major allergen Der p I were followed in a subgroup. Dp-specific IgG, IgG1, and IgG4 increased significantly in both HS-treated groups after 1 and 2 years (median: 2.5- to 11.6-fold). IgG4 was not induced if maintenance dose during the first year was less than 20,000 BU. Median skin sensitivity decreased 4.4- to 8.2-fold after 1 year and 7.4- to 21.4-fold after 2 years. Der p I specific IgG response was unrelated to the occurrence or change in IgE with the same specificity. The mPEG-Dp-extract tended to have less effect on skin sensitivity and immunological parameters, differences reaching statistical significance for skin sensitivity only. In the HS-group, the decrease in bronchial sensitivity was significantly correlated to a decrease in IgE (r = 0.36), IgG1/IgG4 (r = 0.49), Dp-specific histamine release (r = 0.58), and to an increase in Dp-specific IgG4 (r = -0.36) and IgG4/IgE (r = -0.48). In patients improving clinically, Dp-specific IgG4/IgE increased, and median Dp-specific IgE was reduced to 80% compared with an increase to 150-160% seen in the unchanged or deteriorated group (P less than 0.05). Findings indicate an improvement of effect, if the allergen dose is sufficient to reduce specific IgE and/or induce an IgG and especially IgG4 response.     

Spontaneous histamine release from washed leukocytes and whole blood in atopic and non-atopic individuals

The ability of basophils from patients with allergic rhinitis, extrinsic asthma, chronic idiopathic urticaria and atopic dermatitis to release histamine spontaneously in vitro was studied. Spontaneous release in the presence and absence of 30% D2O was investigated from both washed leukocytes and whole blood. Compared with controls histamine release (HR) from washed leukocytes was significantly enhanced in allergic rhinitis patients only, whereas in the other groups only a certain percentage of patients was found to have high spontaneous HR. In whole blood experiments HR in all groups was within the normal range. Our data indicate that enhanced spontaneous mediator release from washed basophils in vitro does not necessarily prove this mechanism to be of pathophysiological relevance in vivo.     

Juxtacellular histamine concentration governs histamine release from rat peritoneal mast cells

Isolated rat peritoneal mast cells release histamine when superfused with isoosmotic salt or sucrose solutions. The release was ascribed by us to an intracellular ion exchange between potassium and histamine at granule sites, resulting from a flux of cytoplasmic potassium across the granules secondary to the disturbance of the ‘state of equilibrium’ at the cell surface caused by the superfusion (Uvnäs et al. 1989). In the present article is shown that the histamine releasing effect is counteracted by the addition of histamine to the superfusion fluid. The inhibition is concentration-dependent and accompanied by concomitant changes in the potassium efflux. A 50% inhibition of the histamine release requires an external histamine concentration of 40 μm and extrapolation of the equilibrium curve hints at a total inhibition at concentrations around 170 μm. The observations are taken to indicate that reduction of the juxtacellular histamine concentration caused by the superfusion disturbs the histamine equilibrium at the mast cell surface resulting in the activation of the histamine secretory mechanism. In other words, the secretory activity of the mast cell is checked by the juxtacellular concentration of histamine. When the juxtacellular histamine is removed e.g. on isolation procedures, other experimental situations such as superfusion, or by consumption in vivo the mast cell delivers histamine to restore the juxtacellular equilibrium.     

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.     

Validated safety predictions of airway responses to house dust mite in asthma

BACKGROUND: House dust mite (HDM) is the most common aeroallergen causing sensitization in many Western countries and is often used in allergen inhalation challenges. The concentration of inhaled allergen causing an early asthmatic reaction [provocative concentration of inhaled allergen causing a 20% fall of forced expiratory volume in 1 s (FEV(1))(PC(20) allergen)] needs to be predicted for safety reasons to estimate accurately the severity of allergen-induced airway responsiveness. This can be accomplished by using the degree of non-specific airway responsiveness and skin sensitivity to allergen. OBJECTIVE: We derived prediction equations for HDM challenges using PC(20) histamine or PC(20) methacholine and skin sensitivity data obtained from patients with mild to moderate persistent asthma and validated these equations in an independent asthma population. METHODS: PC(20) histamine or PC(20) methacholine, skin sensitivity, and PC(20) allergen were collected retrospectively from 159 asthmatic patients participating in allergen challenge trials. Both the histamine and methacholine groups (n=75 and n=84, respectively), were divided randomly into a reference group to derive new equations to predict PC(20) allergen, and a validation group to test the new equations. RESULTS: Multiple linear regression analysis revealed that PC(20) allergen could be predicted either from PC(20) methacholine only ((10)log PC(20) allergen=-0.902+0.741.(10)log PC(20) methacholine) or from PC(20) histamine and skin sensitivity (SS) ((10)log PC(20) allergen=-0.494+0.231.(10)log SS+0.546.(10)log PC(20) histamine). In the validation study, these new equations accurately predicted PC(20) allergen following inhalation of HDM allergen allowing a safe starting concentration of allergen of three doubling concentrations below predicted PC(20) allergen in all cases. CONCLUSION: The early asthmatic response to inhaled HDM extract is predominantly determined by non-specific airway responsiveness to methacholine or histamine, whereas the influence of the cutaneous sensitivity to HDM appears to be rather limited. Our new equations accurately predict PC(20) allergen and hence are suitable for implementation in HDM inhalation studies.     

Bacteria-induced histamine release from human bronchoalveolar cells and blood leukocytes

Histamine release induced by Staphylococcus aureus was examined in cells obtained by bronchoalveolar lavage (BAL) in non-atopic individuals. Approximately half of the individuals responded with mediator release to the bacterium, and the release was found to be time- and concentration dependent. No difference was found between the patients who responded and those who did not respond in regard to age, sex, smoker/non-smoker, % recovery of BAL-fluid, total cell count, differential cell counts, histamine content per mast cell, or diagnoses. Also stimulation of the BAL-cells with the calcium-ionophore A23187 resulted in histamine release. S. aureus-induced histamine release from basophils was examined in leukocyte suspensions obtained from the same individuals, and in all experiments release was found. The dose-response curves were similar to those obtained with BAL cells. The bacteria-induced mediator release from superficially lying cells in the airways epithelium might be of importance for the precipitation or exacerbation of bronchial asthma in respiratory tract infections.     

Basophil histamine release in the diagnosis of house dust mite and dander allergy of asthmatic children

The aim of the study is to compare the glass fibre-based basophil histamine release test with skin test (Phazet), RAST (Phadebas) and bronchial provocation test in children with allergic asthma. The study comprised 68 selected children with a case history of extrinsic allergic asthma to danders (cat and dog) and house-dust mite. Skin prick test, RAST, and histamine release were performed in all children and the bronchial provocation test was used as a reference of "true allergic asthma". A total of 81 allergen bronchial challenges were performed and 44 children experienced 49 positive provocations. In 2.9% (2/68) of the children histamine release could not be performed due to technical difficulties (low histamine release with anti-IgE). Concordances in the range 76-87% were observed with no significant difference between the tests. The highest concordance (87%) was found between histamine release and bronchial provocation test followed by skin prick test vs bronchial provocation (84%) and RAST vs bronchial provocation (80%). The sensitivity and specificity were calculated for each test. All tests showed sensitivities in the range 90-94% and no significant difference between them was observed. The specificity of histamine release, skin prick test, and RAST was 0.78, 0.69, and 0.63, respectively. The specificity of histamine release was better than RAST demonstrated by 95% confidence intervals. In conclusion, it was found that the histamine release test is a convenient diagnostic method and the study indicates a diagnostic value comparable to the common diagnostic methods in clinical allergy.     

Hyposensitization in asthmatics with mPEG modified and unmodified house dust mite extract

In a 2-year study, 46 asthmatics with verified allergy to the house dust mite D. pteronyssinus (Dp) were included either as controls (Ctls) or receiving hyposensitization (HS) with unmodified or monomethoxypolyethylene glycol (mPEG) modified Dp-extract. Patients were monitored by annual challenges with histamine in bronchi, and Dp allergen in bronchi, nose and conjunctiva. mPEG-modified extract was not inferior to unmodified Dp-extract; both were to some extent able to improve tolerance to Dp and histamine in bronchi and to Dp in nose and eyes. During the 1st year, the bronchial sensitivity to Dp decreased significantly in the HS groups but not in the Ctls. During the 2nd year, improvement was more pronounced in the Ctl group. The relative increase in Dp or histamine tolerance did not differ significantly between groups after either 1 or 2 years; the only exception was conjunctival sensitivity, which in the Ctl group was unchanged, and a 10-fold increase in tolerance in the HS groups. No direct benefit was seen on late-phase bronchial reactions. In patients with improved pulmonary symptoms a tendency was seen towards reduced sensitivity to histamine and Dp. Variation within groups was extensive.     

Measurement of PC20 histamine with the use of two different nebulizers and measurement of FEV1 and PEF

Histamine challenge was performed in 19 patients using two nebulizers (PARI and Wright) and FEV1 and PEF were measured to determine PC20 histamine. FEV1 and PEF gave identical PC20 histamine values. The PARI nebulizer gave PC20 histamine values that were 2.5 doubling concentrations lower than the Wright nebulizer. The reproducibility of histamine challenge with the PARI nebulizer was studied in 15 patients and the results suggested that the challenge was reproducible within one doubling concentration of histamine.     

Influence of bronchial allergen challenge on histamine release by human basophils

BACKGROUND: Basophils can be primed by cytokines such as interleukin (IL) -3, IL-5 or granulocyte macrophage-colony stimulating factor (GM-CSF). It has been described that the concentrations of these cytokines are enhanced at sites of allergic inflammation as well as systemic in allergic asthma. OBJECTIVE: To investigate the priming status of basophils as detected by thapsigargin-induced histamine release during bronchial allergen challenge. METHODS: Ten subjects allergic to house dust mite were challenged via an aerosol delivery system. Spontaneous leucocyte histamine release as well as histamine release induced by various stimuli was measured in vitro at several time points. In addition, lung function parameters, serum IL-5 and blood eosinophil counts were evaluated. RESULTS: We found no effect of bronchial allergen challenge upon spontaneous leucocyte histamine release, nor upon histamine release induced by anti-immunoglobulin (Ig) E, house dust mite extract, C5a, fMLP, IL-3, PMA+ thapsigargin or IL-3+ thapsigargin. However, the priming status of basophils as measured by thapsigargin-induced histamine release was enhanced at 24 h after bronchial allergen challenge. Analysis of the individual data showed a heterogeneous initial response (30 min, 6 h) followed by a predominant increase at 24 h after allergen challenge. This increase in the thapsigargin-induced histamine release correlated with the increase in serum IL-5 levels at 24 h after allergen challenge. CONCLUSION: The priming status of human basophils as measured by thapsigargin-induced histamine release is enhanced 24 h after allergen challenge.     

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.     

Stability of histamine dihydrochloride in solution

Histamine dihydrochloride (HC) is one of the bronchoconstrictors used for bronchial challenge. Information on the activity of HC dilutions during storage is desirable (4). Activity, bacterial, and fungal contamination of stored HC dilutions were tested after storage at 20 degrees, 4 degrees, and -18 degrees C. HC dilutions with a concentration of and below 0.25 mg/ml have a significantly reduced activity after 1 month's storage at 20 degrees C and should at present be used within 1 week to ensure the presence of the expected activity. The activity of HC dilutions stored at 4 degrees C or -18 degrees C was stable for at least 6 months. Upon delivery from a pharmacy we detected no bacterial or fungal contamination of HC dilutions by means of the method used. Before 3 months' storage, and independently of storage temperature, bacterial contamination was not found. After 3 months' storage, bacterial contamination was found in HC dilutions with a concentration below 0.5 mg/ml. No fungi were isolated. HC dilutions with a concentration of 0.25 mg/ml and below should not be stored for more than 1 month and should be used within 1 week of opening.     

Changes in protein kinase C activity during histamine release from activated rat mast cells

Rat mast cells were challenged with compound 48/80 or calcium ionophore A23187, and protein kinase C activity in the cell pellets and the amount of histamine release into the supernatant were measured. After stopping the reaction, rat mast cells were lysed in a medium which prevents alterations in phosphorylation and dephosphorylation during sample processing. Histamine was significantly released from compound 48/80-stimulated mast cells at 30 s after the stimulation. In parallel with this, protein kinase C activity in the cell pellets increased at 30 s and 1 min and returned to basal value 3 min after the stimulation. When mast cells were incubated with various concentrations of 48/80 for 30 s, the amount of histamine release and protein kinase C activity increased dependently on the concentration of 48/80. Significant histamine release from A23187-stimulated mast cells was found at 1 min after the stimulation. Also protein kinase C activity in the cell pellets increased at 1 min and returned to basal value 5 min after the stimulation. A reduction of cytosolic protein kinase C activity was observed upon 48/80 treatment in a time- and concentration-dependent manner. Further, staurosporine, a potent inhibitor of protein kinase C, inhibited 48/80-induced histamine release in parallel with the inhibition of protein kinase C activity. These findings suggest that transient increase of protein kinase C activity may be involved in the mast cell activation process.     

Affinity of IgE antibody to antigen influences allergen-induced histamine release.

BACKGROUND: Although affinity of an antibody for an antigen is recognized to be an important factor in determining its biological effects, little is known about the relevance of such affinity of IgE antibodies to the functional response. OBJECTIVES: To investigate the effect of IgE antibody affinity to Der p 2 on Der p 2-induced histamine release from human basophils. METHODS: The most probable value of the dissociation constant (Kd) of IgE antibody to Der p 2 was calculated and histamine release by Der p 2-challenged leucocytes was used to evaluate the biological efficacy of the IgE antibody. RESULTS: The most probable Kd value of IgE antibody to Der p 2 ranged from 5.6 to 177.8 pM in 14 asthmatic patients sensitive to Der p 2. A significant correlation was observed in Der p 2-induced histamine release between the sensitivity and the Kd value for Der p 2-specific IgE antibody (rs = 0.797, P = 0.0040), suggesting that the higher the affinity, the lower the amount of allergen required for the release of a specific level of histamine. CONCLUSION: Apart from the changes associated with the reactivity, the sensitivity of histamine release is closely related to the affinity of IgE antibody for its antigen.     

Bronchial mucosal structure after histamine inhalation

Previous studies have shown an increased number of inflammatory cells and an increased level of hyaluronan in the bronchoalveolar lavage (BAL) fluid, 24 h after the inhalation of histamine. In the present report, the influence of histamine inhalation on the bronchial mucosa was, therefore, investigated in 20 subjects. Scanning electron microscopy (SEM) revealed that small areas of the mucosal surface were altered or lacked cilia more frequently in the bronchial biopsies taken 24 h after the inhalation of histamine than in the control biopsies. In contrast, light and transmission electron microscopy revealed no increase in epithelial damage and no changes in the subepithelial morphology. The results indicate that inhalation of histamine does not significantly alter the structure of the bronchial mucosa, which means that bronchial biopsies can be taken for routine morphological examination within 24 h after a histamine test. When using the biopsies in research, one should consider the possible influence of the histamine test.     

Effect of astemizole on antigen-mediated histamine release from the blood of patients with allergic rhinitis

The main objective of this study was to test the effectiveness of astemizole in vitro in blocking the release of histamine from blood of patients with allergic rhinitis. The results of this investigation indicated that astemizole inhibited allergen-mediated histamine release from blood basophils of patients with this allergic disorder. The inhibition by astemizole (33-156 mumol) was immediate, requiring no pre-incubation of the cells, and was dose-dependent, with maximal inhibition of about 91%. The relatively high potency of astemizole in inhibiting the immunologic release of histamine may provide an additional measure in the treatment of allergic rhinitis with this H1-receptor antagonist.     

Assessment of histamine release from basophils in whole blood by benzylpenieilloyl poly-L-lysine in penicillin-sensitized patients

Histamine release from basophil granulocytes in whole blood by benzylpenicilloyl poly-L-lysine (PPL) was investigated in 7 patients with penicillin allergy. All patients presented with systemic immediate hypersensitivity reactions after i.v. administration of penicillin G. Total histamine (of 7 patients) ranged from 27.5 ng/ml to 62.1 ng/ml (mean 43.2 ng/ml). The spontaneous histamine release ranged from 0.15% to 5.1% (mean 1.8%) of the total content. Addition of PPL in various concentrations resulted in values between 0.8 and 9.6%. Although PPL is a reliable allergen for prick- and intradermal testing in the diagnosis of penicillin allergy--demonstrating a histamine liberation in the skin--the in vitro experiment using the same allergen showed no histamine release above 10%. Using a threshold of 5% out of 7 patients, 4 (57%) would show a positive histamine release. Therefore it might indicate that in penicillin allergy a threshold of 5% must be used. In addition, basophils in whole blood and skin mast cells may be activated differently.     

Effect of nitrendipine on histamine release from human basophil leukocytes

The effect of the new calcium antagonist nitrendipine on in vitro basophil activation was evaluated in 10 subjects. The histamine release induced by calcium ionophore A23187, f-met peptide and anti-IgE was inhibited, in a dose-dependent fashion, by nitrendipine in the concentration range of 1-100 microM. The activity of this calcium antagonist seems complex and related to an interference with calcium at multiple sites. At concentrations higher than 200 microM, nitrendipine causes histamine release from basophil leukocytes. This histamine secretion is likely to be due to a cytotoxic effect, since it is associated with an increase in LDH levels in the cell supernatant.     

Characterization of purification-associated reduction in IgE-dependent histamine release from rat peritoneal mast cells

Histamine release from purified rat peritoneal mast cells (PMC) was examined and compared to that from a non-purified preparation (PEC). Both PEC and PMC released similar amounts of histamine upon stimulation with compound 48/80, calcium ionophore A23187 and substance P. In contrast, IgE-dependent histamine release from PMC caused by antigen, anti-IgE and concanavalin A was very low compared to that of PEC. The reduced IgE-dependent histamine release from PMC, however, was recovered when PMC was reconstituted with non-mast cells (NMC) present in the peritoneal cavity. The effect was time-dependent and reached a plateau in 30 min. NMC from both sensitized and non-sensitized rats recovered the reduced histamine release from PMC dose-dependently. The potentiating effect of NMC was observed even in the presence of excess amount of phosphatidylserine. Supernatants of NMC and a mixture of PMC and NMC incubated for 1 hr at 37°C, however, failed to potentiate the histamine release. These results demonstrate that IgE-dependent histamine release from rat peritoneal mast cells is upregulated by other cells present in the peritoneal cavity, and that the mechanism involved is distinct from that of phosphatidylserine.