Studies on histamine metabolism in intrinsic bronchial asthma

Effect of autogenic bacterial antigens on the production of histamine releasing factor by mononuclear cells from intrinsic asthmatic patients

The production of histamine releasing factor (HRF) by mononuclear cells (MNC) from intrinsic asthmatic patients has previously been reported. In this study, we investigated the effect of preincubation of lymphocytes with autogenic killed bacteria upon the production of HRF. Bacteria were isolated from the sputum, and nasopharyngeal swab obtained from patients and control subjects. MNC from intrinsic asthmatics and healthy controls were preincubated with killed bacteria for 4 h, then washed and cultured for 18 h. HRF activity of the cell-free supernatants was assayed in the histamine release test using basophils from normal subjects. We found that MNC from the patients spontaneously produce significant amounts of HRF. Preincubation of the cells with autogenic bacterial antigens enhanced HRF production in 12 of 25 patients and only in one of 15 control subjects. No specific bacterial strain was identified as having the sole stimulatory property for HRF production; rather, individual susceptibility predisposes to the ability to produce HRF in response to some common bacteria. When MNC from healthy subjects were preincubated with bacterial antigens isolated from the patients, no enhancement in HRF production was observed. We concluded that MNC from some intrinsic asthmatics are specifically sensitized to certain bacterial antigens and release HRF upon contact with these antigens.

Plasma elevations of histamine and a prostaglandin metabolite in acute asthma

Recent studies of laboratory-provoked asthma have suggested that asthma is an inflammatory disease of lower airways. The purpose of this study was to measure the systemic elaboration of 2 bronchoconstrictive inflammatory mediators during naturally acquired acute asthma utilizing a prospective, serial-sampling protocol. Plasma levels of 13,14-dihydro-15-keto-PGF2 alpha and histamine were measured by radioimmunoassay and radioenzymatic assay, respectively, in 23 children with acute asthma. Mean PG metabolite and histamine values (pg/ml) before (167 +/- 72, 1,029 +/- 378) and 10 to 90 min after (377 +/- 145, 1,000 +/- 489) initial therapy were significantly higher than those of the same children after resolution of asthma (2.9 +/- 0.2, 260 +/- 42) and those of normal children (4.3 +/- 0.9, 240 +/- 14). Peak PG metabolite levels were significantly higher in children who presented with PEFR values (% predicted) less than 40% (1,234 +/- 432) compared with those who presented with greater than 40% (404 +/- 296), and in children with post-therapy improvement in PEFR of less than 20% (1,281 +/- 470) compared with those with greater than 20% (365 +/- 226). Histamine levels were significantly higher in children with post-therapy improvement in PEFR of less than 20% (2,560 +/- 1,600) compared with those with greater than 20% (475 +/- 100), and in hospitalized (3,915 +/- 1,910) compared with nonhospitalized (408 +/- 130) children. Significant differences were not observed on the basis of corticosteroid dependence, allergic disposition, or type of initial therapy. These data suggest a role for histamine and PGF2 alpha in the pathogenesis of airway inflammation in acute asthma.

Histamine release induced by bacteria. A new mechanism in asthma?

Bacteria release histamine from human basophil leukocytes and mast cells. The release can be caused by an immunological (IgE-dependent) mechanism, but mostly we found a non-immunological (lectin-mediated) mechanism which indicates that mediator release triggered by bacteria can occur without the person being sensitized to the micro-organism in question. Both bacteria and bacterial products such as endotoxins potentiate basophil histamine release caused by allergens in allergic patients or by bacteria in persons sensitized to the micro-organisms. It is therefore tempting to speculate that bacteria and their products might be of importance for asthma by their capacity to release histamine and to potentiate mediator release.

Bronchial hyperreactivity after treatment with sodium cromoglycate in atopic asthmatic patients not exposed to relevant allergens

The bronchial hyperreactivity, measured as the responsiveness to histamine, was studied in 14 atopic patients before, during, and after 4 wk of treatment with sodium cromoglycate (SCG) and placebo in a double-blind, randomized, crossover study. The patients were not exposed to relevant allergens during the study. The variations in provocation concentrations corresponding to 20% decrease in FEV1 (PC20) were small during both placebo and active drug treatment. After SCG treatment, PC20 increased (less responsiveness) in nine of the 14 patients, especially in those with low PC20 values. The difference between placebo and active drug treatment was not statistically significant. Although SCG has a mediator-inhibiting effect, this study gave no support for the assumption that inhibition of mediator release leads to a reduction of the bronchial hyperreactivity in atopic asthmatic subjects who are not exposed to relevant allergens.

Bacterial histamine release by immunological and non-immunological lectin-mediated reactions

The mechanisms of bacteria-induced histamine release were examined in vitro in human leukocytes and rat mast cells. Three types of bacterial responders were found. In persons with IgE-bearing basophilocytes bacterial histamine release could be triggered by two different mechanisms, an IgE-dependent mechanism where removal of IgE abolished the release and a non-immunological mechanism where this was not the case. In responders with no IgE-bearing cells bacterial histamine release was caused by a non-immunological mechanism. The non-immunological mechanism was further substantiated by release in isolated mast cells from germ-free rats. These experiments suggest a direct interaction between bacteria and target cell, and experiments with multi-washed bacteria and bacteria cell wall preparations indicate the possibility of the bacteria wall interacting with the target cell. It is probable that the non-immunological mechanism depends on lectin-mediated reactions, since bacteria-induced histamine release was inhibited by lectin-binding sugars as is release caused by plant lectins.

Lectin-mediated reactions in histamine release caused by bacteria

The bacteria-induced release of histamine was studied in human basophil leukocytes and in isolated rat mast cells. Whole bacteria of Staph. aureus caused release in a 98% pure population of peritoneal mast cells from germ-free rats, indicating a non-immunological mechanism and a direct interaction between the bacteria and the target cells. Probably the bacterial cell wall interacts with the cell membrane, since a preparation of the bacterial cell wall caused a dose-dependent release of histamine from basophil leukocytes similar to that induced by whole bacteria, and repeated washing of whole bacteria did not change the release. Inhibition studies by lectin-binding sugars indicate that aminosugars on the bacterial surface of Staph. aureus interact with lectins on the basophil cell membrane leading to histamine release.

Quantitative determination of 1,4-methyl-imidazoleacetic acid in urine by high performance liquid chromatography

A reversed phase ion-pair high performance liquid chromatographic (HPLC) method for quantitative determination of the major histamine metabolite 1,4-methyl-imidazoleacetic acid (1,4-MIAA) in urine is described. The sample handling is minimal as the sample only has to be centrifuged and diluted before analysis, in contrast to earlier gas chromatographic and thin-layer chromatographic methods. The method correlates well with a thin-layer chromatographic determination (r = 0.79, n = 15), and results from analysis of urine from different patients suffering from mastocytosis, chronic urticaria, atopic dermatitis and asthma are presented together with samples from normal individuals. Most of the patients analysed showed increased excretion of 1,4-MIAA compared with the controls. Future applications of the method, including analysis on patients with food allergy and patients with abnormalities in their histamine metabolism, are discussed.

Eosinophil diamine oxidase activity in acute inflammation in humans

Eosinophil diamine oxidase, histaminase, activity was assayed in acute inflammatory states and correlated to disease activity. Correlation to serum and urine histamine, metabolites of histamine and granulocyte histamine metabolizing enzymes was also studied. Using a radiochromatagraphic assay, diamine oxidase, histaminase, activity was determined in human peripheral blood eosinophils from patients with acute inflammatory states including active asthma, cold-induced urticaria and parasitic infestation; eosinophils from non-active asthmatic patients and normals were used as controls. Eosinophils were purified over a metrizamide discontinuous (16-30%) gradient. Total eosinophils were purified over a metrizamide discontinuous (16-30%) gradient. Total eosinophil histaminase activity was increased two- to three-fold in patients with active disease and returned to lower levels in eosinophils from patients without active disease or with treated disease. Thus, the induction of eosinophil histaminase might be a control mechanism for the inflammation induced by histamine during these acute inflammatory states.

Intrinsic asthma and bacterial histamine release

In this study of intrinsic asthma (IA) in children the pathogenic role of bacteria in respiratory disease was elucidated by a basophil histamine liberation technique. Several strains of bacteria caused release of histamine from peripheral leukocytes in vitro. Normal, non-infectious and non-atopic children frequently responded in a similar fashion, although positive responses were less frequent. It seems that two different mechanisms of bacterial histamine release exist: interaction with the basophil-bound IgE and a direct interaction with the cell surface. It is suggested that the histamine release takes place only in the lung of IA patients, where a defective pulmonary barrier could permit the bacteria to enter, but not in healthy individuals.

Studies on hypersensitivity to bacterial antigens in intrinsic asthma

Twelve children, aged 4 to 14 years, with moderate to severe intrinsic asthma (IA) were studied. Symptom-Score charts were used to confirm the relationship of acute respiratory tract infections to exacerbations of asthma. Hypersensitivity to eight commonly occurring bacteria from the normal flora of the upper respiratory tract was studied by skin test, by crossed immunoelectrophoresis, and by basophil histamine release in vitro, using ultrasonicates of the bacteria as antigens. Skin tests were all negative. All children contained low titers of precipitating antibodies against most of the bacteria, but in this respect they did not differ from normal children. In contrast, release of histamine was induced in leukocytes from the IA children by all, or most sonicates, while such reactions, were less frequent in control children. The pattern of responses indicated an element of specificity. These was no correlation to precipitating antibodies, or to the microbial flora of the children. Positive responses were characterized by low values of maximal histamine release, and by a tendency to fluctuations with time. Because of these fluctuations, and because the IA children and control children were tested on separate occasions, we cannot be certain as to the real difference between these two groups. Our studies do, however, demonstrate that water-soluble constituents of all the bacterial strains tested were capable of causing the release of histamine in vitro, but that this phenomenon is not restricted to IA. The clinical significance of these findings awaits further investigations on the mechanism(s) of release in vitro by such agents.

Studies on histamine metabolism in allergen-induced asthma

The excretion of histamine (Hi) and it metabolite methyhistamine (MeHi) was determined in separated fractions of urine up to 12h after standardized allergen provocations in 18 adult patients with defined extrinsic bronchial asthma. The main histamine metabolite, methylimidazoleacetic acid (MeImAA), was measured in six of the patients. After positive provocations (decrease in FEV1 greater than 20%) the excretion of Hi was significantly increased during 3h and that of MeHi during 4h after challenge. Negative provocations (decrease in FEV1 less than 20%) were not followed by any changes in the excretion of Hi and MeHi. MeImAA excretion increased in five out of six patients after positive provocation. It was calculated that the increased excretion of Hi and its metabolites after a positive provocation corresponded to a release of about 1 mg histamine in the body or about 1 microgram/g lung tissue if all histamine was liberated in the lung. Pretreatment with two anti-allergic drugs, disodium cromoglycate and ICI 74.917, giving significant allergen protection, resulted in a smaller increase of the excretion of both Hi and MeHi, indicating an inhibition of histamine release in vivo.

Histamine-induced bronchospasm. Its reproducibility and usage in clinical evaluation of the sub-threshold bronchodilating dose of a new beta-agonist, KWD 2131

The reproducibility of the histamine challenge in seven asymptomatic patients with extrinsic asthma, provoked four times each with 1-2 weeks interval, was investigated. The method was thereafter used in order to find the sub-threshold bronchodilating dose of a new beta-agonist KWD 2131 with a preferably anti-allergic property. Selection of patients and methodology of the histamine challenge procedure were carefully standardized. Histamine was administered during quiet breathing at 3-min intervals in a step-wise cumulative manner up to a point where greater than 20% decrease in FEV 1.0 was reached. The pooled intra-individual standard deviation was 4.6% in FEV 1.0, 5.0% in PEFR, and 4.7% in FVC. Pretreatment with KWD 2131, before histamine challenge, showed that the subthreshold dose for bronchodilatation was 0.5 mg in nine patients and 0.25 mg in three patients compared with 1 mg in patients with intrinsic asthma. It was important to perform individualized dose-titration of the sub-threshold bronchodilating dose of KWD 2131 before initiation of a subsequent allergen provocation study.

Metabolism of 14C-histamine given intrabronchially to asthmatic patients

14C-histamine was administered intrabronchially to asthmatic patients and controls. The urinary excretion of total radioactivity, 14C-histamine and its radioactive metabolites was measured. It was found that the excretion of total radioactivity was complete within 24 h. The excretion rate was equal to that observed after intravenous injection of 14C-histamine, indicating a rapid penetration of the bronchial mucosa. However, the diuresis seemed to be of importance for the excretion rate. Histamine inactivation by methylation was more pronounced after intrabronchial than after intravenous administration.