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

Is the analysis of histamine and/or interleukin-4 release after isocyanate challenge useful in the identification of patients with IgE-mediated isocyanate asthma?

Isocyanates are a well-known and frequent cause of occupational asthma. The implementation of specific inhalation challenges (SICs) is the gold standard in asthma diagnosis supporting occupational case history, lung function testing, specific skin prick tests and the detection of specific IgE. However, the diagnosis is not always definitive. An interesting new approach, analyses of individual genetic susceptibilities, requires discrimination between a positive SIC reaction arising from IgE-mediated immune responses and one from other pathophysiological mechanisms. Hence, additional refinement tools would be helpful in defining sub-classes of occupational asthma and diagnosis. We used total IgE levels, specific IgE and SIC results for sub-classification of 27 symptomatic isocyanate workers studied. Some mutations in glutathione S-transferases (GSTs) are suspected either to enhance or to decrease the individual risk in the development of isocyanate asthma. Our patient groups were assessed for the point mutations GSTP1*I105V and GSTP1*A114V as well as deletions (null mutations) of GSTM1 and GSTT1. There seems to be a higher risk in developing IgE-mediated reactions when GSTM1 is deleted, while GSTT1 deletions were found more frequently in the SIC positive group. Blood samples taken before SIC, 30-60 min and 24h after SIC, were analyzed for histamine and IL-4, classical markers for the IgE-mediated antigen-specific activation of basophils or mast cells. We suggest that the utility of histamine measurements might provide an additional useful marker reflecting isocyanate-induced cellular reactions (although the sampling times require optimization). The promising measurement of IL-4 is not feasible at present due to the lack of a reliable, validated assay.

Endotoxin-stimulated innate immunity: A contributing factor for asthma

Exposure to airborne endotoxin in infancy may protect against asthma by promoting enhanced T(H)1 response and tolerance to allergens. On the other hand, later in life, it adversely affects patients with asthma. Endotoxin binding to receptors on macrophages and other cells generates IL-12, which inhibits IgE responses. It also generates cytokines like IL-1, TNF-alpha, and IL-8, which cause inflammation. These signal transduction pathways resemble those leading to the generation of cytokines, such as IL-4, IL-13, and IL-5, which are responsible for the inflammation of IgE-mediated allergic disease. The main difference seems to be that endotoxin recruits neutrophils, but IgE recruits eosinophils, and the details of the tissue injury from these granulocytes differ. Sources of airborne endotoxin include many agricultural dusts, aerosols from contaminated water in many industrial plants, contaminated heating and air-conditioning systems, mist-generating humidifiers, and damp or water-damaged homes. Acute inhalation of high concentrations of endotoxin can cause fever, cough, and dyspnea. Chronic inhalation of lesser amounts causes chronic bronchitis and emphysema and is associated with airway hyperresponsiveness. Airborne endotoxin adversely affects patients with asthma in 3 ways: (1) by increasing the severity of the airway inflammation; (2) by increasing the susceptibility to rhinovirus-induced colds; and (3) by causing chronic bronchitis and emphysema with development of irreversible airway obstruction after chronic exposure of adults. The most effective management is mitigating exposure. The potential of drug treatments requires further clinical investigation.

Beneficial effect of Helicobacter pylori eradication in dermatologic diseases

BACKGROUND

A relationship between skin diseases, particularly rosacea and chronic urticaria, and H. pylori infection has been suggested.

METHODS

We preformed a prospective evaluation of the effect of H. pylori eradication in patients with a variety of chronic skin diseases. Patients were followed monthly for at least one year after cure of the infection. The effect of therapy was scored using a three point scale: complete remission (> 90% improvement), partial remission (50-90% improvement) or no improvement (< 50 improvement). The relationship between response and anti-H. pylori Ig G and E to specific H. pylori antigens was analyzed by Western blot analysis.

RESULTS

Eighty-eight H. pylori-infected patients with skin disease were enrolled. Treatment was successful in 73% of patients with chronic urticaria as 23% (6 of 26) had complete and 50% had partial remission. Sixty-two percent (18 of 29) with pruritus cutaneus had partial remission as well as 30% with prurigo chronica multiformis had complete remission. Western blotting was done on 24 patients with skin disease and a 44K H. pylori antigen was detected by Ig E analysis in 100% (5 of 5) patients with complete remission compared to 23% (3 of 13) in those without skin disease.

CONCLUSIONS

These results suggest it may be prudent to test patients with chronic urticaria, prurigo chronica multiformis, pruritus cutaneus, and eczema nummulare for H. pylori infection and to eradicate the infection in those whose test is positive.

A case of prurigo and lichenified plaques successfully treated with proton pump inhibitor

A case of prurigo and lichenified plaques successfully treated with proton pump inhibitor is presented. She presented with pruritic eruptions, which showed marked lichenification and prurigo nodules, on her trunk and extremities. She had been treated with steroid ointment and H1-histamine receptor antagonist without success. Laboratory examinations revealed increased eosiophils and elevated lactate dehydrogenase. The skin biopsy specimen showed moderate acanthosis with spongiosis and lymphocytic and eosinophilic infiltration into the upper dermis. Because of vomiting and epigastralgia, endoscopical examination was performed, and an ulcer was found at the angle of her ventricle. A biopsy specimen disclosed a benign gastric mucosa with moderate inflammation within the lamina propria, and organisms consistent with Helicobacter pylori. Treatment for gastric ulcer with proton pump inhibitor (omeprazole) and aluminium hydroxide gel improved her eruptions and her pruritus resolved. She was discharged with complete cure of her eruption and ventricular ulcer. Our case indicates that gastric lesions induced by Helicobacter pylori infection may play an important role in dermatological diseases. Proton pump inhibitors including omeprazole are one of the choices for the treatment of some dermatological diseases including prurigo and lichenified plaques.

Susceptibility of asthmatic children to respiratory infection

OBJECTIVE

A case-control study of patients with pneumonia was conducted to investigate whether wheezing diseases could be a risk factor.

METHODS

A random sample was taken from a general university hospital in S. Paulo City between March and August 1994 comprising 51 cases of pneumonia paired by age and sex to 51 non-respiratory controls and 51 healthy controls. Data collection was carried out by two senior paediatricians. Diagnoses of pneumonia and presence of wheezing disease were independently established by each paediatrician for both cases and controls. Pneumonia was radiologically confirmed and repeatability of information on wheezing diseases was measured. Logistic regression analysis was used to identify risk factors.

RESULTS

Wheezing diseases, interpreted as proxies of asthma, were found to be an important risk factor for pneumonia with an odds ratio of 7.07 (95% CI = 2.34-21.36), when the effects of bedroom crowding (odds ratio = 1.49 per person, 95% CI = 0.95-2.32) and of low family income (odds ratio = 5.59 against high family income, 95% CI = 1.38-22.63) were controlled. The risk of pneumonia attributable to wheezing diseases is tentatively calculated at 51.42%.

CONCLUSION

It is concluded that at practice level asthmatics should deserve proper surveillance for infection and that at public health level pneumonia incidence could be reduced if current World Health Organisation's guidelines were reviewed as to include comprehensive care for this illness.

Bronchoalveolar lavage findings suggest two different forms of childhood asthma

BACKGROUND

It seems plausible that children with atopy and persistent asthma symptoms will, like their adult counterparts, have chronic airways inflammation. However, many young children with no other atopic features have episodic wheezing that is triggered solely by viral respiratory infections. Little is known as to whether airways inflammation occurs in these two asthma patterns during relatively asymptomatic periods.

METHODS

Using a non-bronchoscopic bronchoalveolar lavage (BAL) procedure on children presenting for an elective surgical procedure, this study has investigated the cellular constituents of BAL fluid in children with a history of atopic asthma (AA) non-asthmatic atopic children (NAA) or viral associated wheeze (VAW).

RESULTS

A total of 95 children was studied: 52 with atopic asthma (8.0 years, range 1.1-15.3, 36 male), 23 with non-asthmatic atopy (median age 8.3 years, range 1.7-13.6, 11 male) and 20 with VAW (3.1 years, range 1.0-8.2, 13 male). No complications were observed during the lavage procedure and no adverse events were noted post-operatively. Total lavage fluid recovered was similar in all groups and the total cell numbers were higher in the VAW group. Eosinophil (P < or = 0.005) and mast cell (P < or = 0.05) numbers were significantly elevated in the group with atopic asthma.

CONCLUSIONS

During relatively asymptomatic periods there is on-going airways inflammation, as demonstrated by eosinophil and mast cell recruitment, in children with asthma and atopy but not in children with viral associated wheeze or atopy alone. This strongly suggests that there are different underlying pathophysiological mechanisms in these two groups of children who wheeze.

Assessment of a strategy for the control of respiratory diseases in children

A programme for the control of respiratory diseases in children was conceived for the State of S. Paulo, Brazil, in 1986. Its progress thereafter and the epidemiology of the diseases concerned are examined. Apart from an inquiry into the 64 existing State local health authorities, a sample of 18,255 cases of children assisted by the programme at different levels, including both in-patient and outpatient care, is analysed. Each case record included information about identification (child, doctor and health facility), reasons for calling, diagnoses made and outcome of treatment. Further data were also sought from hospitals and from State mortality records. The programme was found to be poorly implemented in the State but, where implemented, it showed itself capable of resolving problems (only 0.5% of the cases could not be handled) as also of changing ongoing trends (more than 50% reduction in hospital admission rates). Individual assessment of each item of the programme indicated its bottlenecks. Regarding the epidemiology of respiratory diseases, it is observed that the major burden to health services comes from children aged less than five, and that the most important diseases are wheezing illnesses and pneumonia. Moreover, they were found to be significantly associated (p = 0.000) so that a child in the community presenting wheezing diseases is 5 times more likely to develop pneumonia than a child with any other respiratory diagnosis. Similarly, among the under five deaths it was found that the risk for pneumonia is 3 times greater for children who died presenting wheezing diseases than it is for children with any other sort of diagnosis. In conclusion, the programme is deemed to be efficient and effective but its efficacy is marred by administrative flaws. The successful control of respiratory problems in childhood is related to a proper appreciation of the importance of wheezing diseases.

Branhamella catarrhalis colonization in preschool asthmatics

Branhamella catarrhalis has been associated with exacerbations of chronic bronchitis and asthma in adults. To investigate the possible role of B. catarrhalis in asthma of early childhood, we took posterior pharyngeal swabs from 24 normal children, 20 well asthmatics, and 20 acutely wheezy asthmatics, all between 1 and 4 years of age. On culture, 33% of the normal children were colonized with B. catarrhalis; colonization rates in the well asthmatics (70%) and in the wheezy asthmatics (75%) were significantly higher than in normals. The nature of this association requires further study.

Basophil-bound and serum immunoglobulin E directed against Helicobacter pylori in patients with chronic gastritis

The immunoglobulin (Ig) E immune response in patients with Helicobacter pylori-associated chronic gastritis has been evaluated. Of 26 patients with H. pylori infection, 22 (84%) tested positive for basophil-bound specific IgE (determined by the histamine release test) and 18 (69%) for serum specific IgE (determined by an enzyme-linked immunosorbent assay). In contrast, only 1 of 17 persons in whom the bacterium was not detected presented cell-bound and serum specific IgE. In the 4 histamine release test--positive but enzyme-linked immunosorbent assay--negative patients, removal of antibody from the basophil surface by acid elution showed that histamine release occurred through an IgE-dependent mechanism. When normal basophils, passively sensitized with serum from IgE-positive patients, were exposed to the H. pylori antigen, a significant release was observed, confirming the class specificity of the response. Inhibition experiments with bacteria other than H. pylori showed that the IgE antibody was specifically directed against this organism. The percentage of antigen-induced histamine release did not correlate with serum specific IgE level. However, the response of basophils to antigenic challenge was proportional to IgE-dependent cellular releasability. This finding suggests that target cell sensitivity may be the most important factor in determining the entity of biological response to the antigenic challenge. The ability of H. pylori to induce a specific IgE immune response could answer key questions regarding the mechanisms inducing gastric inflammation.

Influenza A virus potentiates bacteria-induced histamine release. Examination of normal individuals and patients allergic to bacteria

Influenza A virus was found to enhance basophil histamine release induced by Escherichia coli, Salmonella enteritidis, Staphylococcus aureus, Streptococcus pneumoniae and Streptococcus sanguis, but did not per se release histamine. This potentiating effect of the virus was seen both when the bacteria-induced mediator release was IgE-dependent (i.e. patient allergic to bacterium) and when the bacterium caused histamine release by a non-immunological mechanism independent of IgE (putative sugar-lectin mediated). Also histamine release induced by other immunological and non-immunological stimuli, such as anti-IgE, calcium ionophore or agarose beads was enhanced in the presence of the virus. The potentiating effect of the virus on bacteria-induced mediator release might be of importance for the conversion from latent to manifest asthma in upper respiratory tract infections.

Virus enhances IgE- and non-IgE-dependent histamine release induced by bacteria and other stimulators

Histamine release from human basophil leukocytes was triggered by Staph. aureus, Salmonella enteritidis, non-haemolytic streptococci, or E. coli. Influenza A virus was found to enhance the mediator release and the effect was caused by synergism, since the virus did not induce release of histamine per se. This potentiating effect of the virus was seen both when the bacteria-induced histamine release was IgE-dependent (i.e. patient sensitized to the bacterium) and when the bacterium caused mediator release by a non-immunological mechanism independent of IgE (putative sugar-lectin mediated). Histamine release induced by anti-IgE and calcium ionophore or agarose-beads was also enhanced in the presence of the virus. These findings indicate that influenza A virus potentiates both IgE- and non-IgE-mediated histamine release induced by bacteria and other stimulators.

Histamine and mast cell distribution in the intestinal wall of the germ free and conventional rats. Influence of the mode of sterilization of the diet

The influence of the mode of sterilization of the diet (gamma-irradiation vs. autoclaving) on the histamine and mast cells distribution in the intestinal mucosa, was studied in germ free (GF) and conventional (CV) rats. Interactions between the diet and the digestive microflora were observed. Histamine concentration and mast cells counts are higher in CV rats small intestine than in GF's. The differences are increased with the irradiated diet. At the opposite in the hindgut, these values are higher in GF than in CV rats, especially in the rats fed the steam sterilized diet. The variations in the wall histamine contents and in the mucosal mast cells counts due to the diet and/or the microflora do not appear to be always correlated.

Staphylococcus aureus and influenza A virus stimulate human bronchoalveolar cells to release histamine and leukotrienes

Mediator release was examined from superficially lying cells in the airway epithelium obtained by bronchoalveolar lavage (BAL) in 13 non-atopic individuals. The BAL-cells were incubated (20 min, 37 degrees C) with Staphylococcus (Staph.) aureus or with human influenza A virus Staph. aureus was found to release histamine from cells from 7 of the 13 individuals and influenza A virus in 3 of 5 persons. Furthermore, Staph, aureus stimulated the BAL-cells to release leukotriene B4 in 7 of 11 subjects, whereas no release was found by influenza A virus in 7 examined persons. When cells from 4 persons were stimulated with Staph. aureus no release of leukotriene C4 was found. The mediator release caused by bacteria and virus might be of importance for the exacerbation of bronchial asthma in upper respiratory tract infections, since histamine is assumed to increase the epithelial permeability with entrance of allergens and other insulting particles, and leukotriene B4 facilitates airway inflammation.

Influenza A virus enhances Staphylococcus aureus-induced basophil histamine release in normal individuals and patients with intrinsic asthma

Influenza A virus was found to enhance Staphylococcus aureus-induced histamine release in human leukocyte suspensions, but did not per se release histamine. This potentiating effect was found to be similar in cells from normal individuals and from patients with intrinsic asthma. The enhancement of mediator release could be due to viral neuraminidase on the surface of the virus, since a similar potentiating effect was caused by a purified neuraminidase preparation obtained from Vibrio cholerae, and the effect of virus as well as of the purified neuraminidase was completely abolished by a potent neuraminidase inhibitor. The potentiating effect of virus on bacteria-induced mediator release might be of importance for the conversion from latent to manifest asthma in upper respiratory tract infections.

Histamine distribution in the gastrointestinal wall of germ free and conventional chicken: evidence of the role of the digestive microflora

The digestive microflora produces a decrease of the mucosal histamine content in the wall of the chicken colon but has no significant incidence in the upper part of the digestive tract. The anatomical and physiological particularities of the chicken digestive tract permitted to observe that wall histamine concentration depends on different factors. Endogenous factors control the wall histamine content in the proventriculus, independantly of the diet and/or of the presence of a microflora. Diet has a specific incidence upon the gastrointestinal wall of the host in the crop and in the colon. The colon microflora decreases the effect of the diet essentially when the chicken are fed a semi synthetic diet. Interactions between the diet and the microflora could induce physiopathological manifestations.

Induction of histamine release from rat mast cells and human basophilic granulocytes by clinical Escherichia coli isolates and relation to hemolysin production and adhesin expression

We investigated the role of 27 disease-relevant Escherichia coli strains isolated from humans in the induction of histamine release from rat peritoneal mast cells and human basophilic granulocytes. Our data indicated that only the hemolysin-positive (HLY+) bacteria and the hemolysin-positive culture supernatants induced histamine release. For the latter, the hemolysin activity determined the degree of histamine secretion. Incubation of the target cells with washed HLY+ bacteria revealed a different secretory response. For the rat mast cells, histamine release paralleled expression of hemolysin activity, with the exception of strain S98 (O75:K5:H- HLY+), which induced less histamine, although its hemolysin activity was relatively high. No correlation between histamine secretion and hemolysin activity was observed when human basophils were stimulated with the HLY+ bacteria. Large amounts of histamine were still released, even when the hemolysin activity declined to zero. Our results support the potent role of the E. coli hemolysin as a pathogenicity factor in bacterial infection.

Virus enhances histamine release from human basophils

Histamine release from human basophil leukocytes was triggered by Staph. aureus or by complement activation caused by endotoxins isolated from E. coli or Salmonella bacteria. Influenza A virus was found to enhance the mediator release and the effect was caused by synergism, since the virus itself did not release histamine. The potentiating effect of the virus was abolished by a potent neuraminidase inhibitor. Furthermore, a purified neuraminidase preparation obtained from Vibrio cholerae caused a similar potentiating effect, which was also abolished by the neuraminidase inhibitor. These findings indicate that the neuraminidase on the surface of influenza A virus is responsible for the potentiating effect of the virus on basophil histamine release.

Histamine release from human adenoidal and mesenteric mast cells induced by bacterial antigens

The histamine-releasing capability of Staphylococcus aureus antigens was examined in human adenoidal and mesenteric mast cells obtained by enzymic dispersion of tissues from non-allergic patients. Both populations of mast cells released histamine after challenge with bacterial protein in concentrations between 5-500 micrograms/ml. The release was dependent on the dose, temperature and metabolic energy. The maximum release was observed at 15 min after challenge. The present results suggest that Staphylococcus aureus antigens release histamine from human adenoidal and mesenteric mast cells via a non-cytotoxic, active secretory process.

Role of cell-bound hemolysin as a pathogenicity factor for Serratia infections

The hemolytic activities of clinical isolates of Serratia marcescens, of Serratia liquefaciens, and of Escherichia coli strains containing a cloned hemolysin gene of S. marcescens were determined. Hemolysis was induced only by cells and not by spent media. The hemolytically active bacteria induced the release of the leukotriene C4 and of much less leukotriene B4 from polymorphonuclear leukocytes, the release of histamine from rat mast cells, and chemoluminescence of neutrophils. The hemolytic activity was correlated with the response of the leukocytes, but quantitative differences were recorded with regard to the release of the inflammatory mediators. Therefore, other factors in addition to the hemolysin contribute to the stimulation of leukotriene generation and histamine release. It is concluded that the hemolysin via these inflammatory mediators can increase vascular permeability, edema formation, and granulocyte accumulation and thus contributes to the pathogenicity of Serratia species.

Bacteria and their products peptidoglycan and teichoic acid potentiate antigen-induced histamine release in allergic patients

Histamine release was examined in leukocyte suspensions from patients allergic to grass pollen, mite or cat dander or to bacteria (antigen). When the cells were challenged with specific antigen plus bacteria to which the person was not sensitized, these bacteria were found to potentiate the allergic histamine release. The potentiating effect by bacteria might be due to the bacterial cell wall components, peptidoglycan and teichoic acid, which mimic the effect of bacteria.