Double blind placebo controlled exposure to molds: exposure system and clinical results.

UNLABELLED: The objective was to develop an experimental setup for human exposure to mold spores, and to study the clinical effect of this exposure in sensitive subjects who had previously experienced potentially building-related symptoms (BRS) at work. From three water-damaged schools eight employees with a positive histamine release test to Penicillium chrysogenum were exposed double- blinded to either placebo, approximately 600,000 spores/m3 air of P. chrysogenum or approximately 350,000 spores/m3 of Trichoderma harzianum for 6 min on three separate days. A statistically significant rise in symptoms from mucous membranes appeared from the 9-graded symptom scale after exposure to T. harzianum or placebo. Dichotomizing the data, whether the participants experienced at least a two-step rise on the symptom scale or not, gave borderline increase in mucous membrane symptoms after exposure to P. chrysogenum. In conclusion this is, to our knowledge, the first study to successfully conduct a human exposure to a highly controlled dose of fungal material aerosolized directly from wet building materials. This short-term exposure to high concentrations of two different molds induced no more reactions than exposure to placebo in eight sensitive school employees. However, a statistical type II error cannot be excluded because of the small sample size. PRACTICAL IMPLICATIONS: In this double blind, placebo controlled study of mold exposure changes in symptoms, objective measurements and blood samples were small and mostly non-significant, and at the same level as after placebo exposure. The developed exposure system based on the Particle-Field and Laboratory Emission Cell (P-FLEC) makes it possible to deliver a precise and highly controlled dose of mold spores from water-damaged building materials, imitating realistic field exposure conditions. The present experiment is too small to rule out an effect of mold exposure; long-term experimental exposure studies on larger number of subjects are needed.

Gastric mucosal cytokine responses in Helicobacter pylori-infected patients with gastritis and peptic ulcers. Association with inflammatory parameters and bacteria load.

Helicobacter pylori is an important pathogen in gastroduodenal inflammation and ulceration. Several mechanisms have been proposed to explain its role. We studied the cytokine production patterns in situ in gastric mucosal biopsies from H. pylori-positive and H. pylori-negative patients with dyspepsia. Immunohistochemistry with monoclonal antibodies was used. The study showed enhanced expression of interleukin (IL) -8, IL-10 and interferon-gamma (IFN-gamma) in H. pylori infection and a significant association was found between these cytokines and the following parameters: bacteria load, chronic inflammation and activity. These parameters were significantly correlated with the cell markers CD19 and CD56. The study indicates a dual effect of H. pylori on the Th1 response, i.e. a stimulation of the response verified by increased IFN-gamma and a feed-back verified by an increase of the counterinflammatory IL-10, which may dampen the inflammatory and cytotoxic effect of the Th1 response. Furthermore, the study confirms the connection between increase of IL-8 and inflammatory activity in gastric mucosa in H. pylori infection.

Serum IgE specific to indoor moulds, measured by basophil histamine release, is associated with building-related symptoms in damp buildings.

OBJECTIVE: To study the relationship between basophil histamine release (HRT) to indoor moulds, indicating specific IgE, and building-related symptoms (BRS), asthma, and hay fever in individuals working in damp and mouldy buildings. METHODS: A cross-sectional study was performed among 86 school staff members, who on average had worked 143 months (range: 3-396) in moist buildings with mould growth in the constructions. A questionnaire concerning mucous membrane symptoms, facial skin symptoms, central nervous system symptoms, hay fever, and asthma was fulfilled by the participants, and blood samples were taken. Eight mould species growing on building constructions were identified and cultivated to obtain allergenic materials for testing. The presence in serum of IgE specific to moulds was verified by histamine release test (HRT) based on passive sensitization of basophil leukocytes. The validity of the method was confirmed by parallel testing of patients allergic to grass- and birch pollen and by the shift from positive to negative response after removal of serum IgE and by using sham sensitization. RESULTS: The prevalence of most BRS was between 32% and 62%. Positive HRT, showing serum IgE specific to one or more of the moulds, was observed in 37% of the individuals. The highest frequency of positive HRT was found to Penicillium chrysogenum and then to Aspergillus species, Cladosporium sphaerospermum and Stachybotrys chartarum. A significant association was found between most BRS and positive HRT, whereas no association was observed between positive HRT to moulds and self reported hay fever or asthma. CONCLUSION: Positive HRT to indoor moulds, showing the presence in serum of IgE specific to the fungi, was found to be related to BRS in individuals working in damp and mouldy buildings. Whether the association is of causal character is a question for further studies. The test may be useful in the evaluation and study of possible mould induced BRS.

Examination of serum IgE specific to pig protein in pig farmers by histamine release test.

Pig farmers are susceptible to a number of occupational hazards which may lead to respiratory symptoms. Therefore, inhalation allergy to pig was examined in pig farmers, including 40 farmers with work-related respiratory symptoms and 40 farmers without these symptoms. The presence in serum of IgE specific to pig protein was examined by the histamine release test, based on passive sensitization of basophil leukocytes with the farmers' serum. This test showed pig-specific IgE in a highly selected group of pig farmers in a previous study. In the present study of nonselected farmers, no swine-specific IgE was found in their serum. The results are thus in accordance with previous studies of nonselected populations of pig farmers tested by RAST and skin prick test. It can therefore be concluded that IgE-sensitization to pig protein is not a common phenomenon in pig farmers.

Evaluation of IgE-sensitization to fungi in HIV-positive patients with eczematous skin reactions.

BACKGROUND: Human immunodeficiency virus infection is associated with declining immune function and polyclonal B-cell activation leading to elevated IgE-levels. In selected patient categories, increased total IgE may be associated with allergic diseases. Furthermore, a significant number of patients with low CD4+ cell numbers have various skin manifestations, eg, eczema and dermatophytosis. Patients with chronic fungal infections and a tendency to produce increased levels of specific IgE may become allergic and IgE-mediated mechanism may contribute to inflammatory reactions in the skin. OBJECTIVE: This study investigates IgE-sensitization of patients infected with human immunodeficiency virus to a panel of fungal extracts of Candida albicans, Fusarium moniliforme, Penicillium notatum, Pityrosporum ovale, and Trichophyton rubrum. METHODS: Fifteen HIV-positive patients with eczematous skin manifestations and five non-atopic healthy controls were evaluated by basophil histamine release and skin prick test with fungal extracts. The extracts were separated by sodium dodecylsulfate-polyacrylamide gel electrophoresis under reducing conditions and analyzed by IgE-immunoblotting with sera from the patients and controls. RESULTS: Thirteen of 15 patients (87%) released histamine to one or more of the fungi. Skin prick test was positive to one or more fungi in 7 (47%) patients. Patient sera revealed binding to a wide range of IgE-binding components present in the fungal extracts. The IgE response was most often directed against a 46-kD main protein in the Candida albicans extract. There was no correlation between total serum IgE, CD4+ cell counts, and frequency of IgE-sensitization to fungi. CONCLUSION: The human IgE response in HIV-infected patients appears to be polyspecific and may be directed against various fungi of which Candida albicans may be an important allergen. It is possible that the sensitization is due to frequent infections with Candida albicans in this patient population. No unspecific fungal reactions were noted among control patients. These results suggest that allergen-specific IgE-mediated mechanism may contribute to the pathogenesis of the eczematous skin reaction in HIV-infected patients.

Chlamydia pneumoniae and possible relationship to asthma. Serum immunoglobulins and histamine release in patients and controls.

Chlamydia pneumoniae (C.pn.) is claimed to be of importance for the development of bronchial asthma in previously healthy individuals. This is a new and speculative theory. Earlier studies have mainly focused on C.pn. and exacerbation of asthma. If this new theory were true, one would expect titres of C.pn.-specific IgG to be higher or more common in patients compared with controls. It would also seem probable that pathobiological mechanisms as found in connection with other microorganisms could be demonstrated, i.e. presence of C.pn.-specific IgE and the capability of C.pn. to induce or enhance histamine release from basophil leukocytes. We therefore examined C.pn.-specific IgE, IgG and IgM in sera from 22 adults with bronchial asthma and 25 healthy controls. IgE was verified by passive sensitization of basophils from umbilical cord blood. The prevalence of IgE was approx. 69% and IgG approx. 23% in both groups. IgG-titres were between 1:16 and 1:64 in both groups. No IgM was found. Further, C.pn. could neither induce nor enhance histamine release from basophil leukocytes of patients or controls. We conclude that patients with bronchial asthma and healthy controls do not differ in relation to 1) C.pn.-specific IgE in sera, 2) the capability of C.pn. to induce or enhance histamine release from basophil leukocytes, since no such effect was found, or 3) previous C.pn. infection judged by the presence of specific IgG antibodies. Our results cannot support the theory that C.pn. is a cause of adult-onset asthma.

The in vivo and in vitro effects of rhG-CSF on allergic, haematological and biochemical variables.

UNLABELLED: The objective was to evaluate the influence of treatment with rhG-CSF on allergic indexes. This was done by open trial of 5 days' treatment with rhG-CSF (5 microg/kg/day s. c.). 10 patients (6 men), aged 28 to 54 years, with rhinoconjunctivitis due to grass pollen allergy, participated in the investigation. Main measures were blood count, basophil histamine release, skin test and conjunctival provocation test. RESULTS: The treatment resulted in significant increases in numbers of neutrophils (590%), basophils (280%), eosinophils (250%) and lymphocytes (71%). Total blood histamine was increased, but basophil histamine releasability was decreased. Serum alkaline phosphatase increased 92% and serum lactate dehydrogenase increased 35% (both significant). There were no significant changes in the skin tests and the conjunctival provocation tests. Two months after the treatment all tests had returned to baseline levels. Five of the patients (50%) reported side effects, one withdrew. In conclusion treatment with rhG-CSF increases the number of circulating blood cells other than neutrophils without causing changes in indexes of allergic reactivity.

The indoor microfungus Trichoderma viride potentiates histamine release from human bronchoalveolar cells.

Trichoderma viride (Tv) is often found in damp and mouldy buildings where people complain of adverse health effects including mucosal/respiratory symptoms. Inhaled spores can reach the alveoli and may interact with the airway epithelium. An interaction with the mucosal mast cells was studied in cells obtained by bronchoalveolar lavage (BAL) from 18 individuals. The fungal spores were found to trigger histamine release from the BAL cells, but relatively high concentrations (0.1-2 mg/ml) were needed. A similar dose response was obtained in basophil histamine release. The Tv-induced mediator release was caused by non-immunological (non-IgE-dependent) mechanisms since the histamine release was not changed by removal of IgE from the basophils before exposure of the cells to the spores. However, in very low concentrations (0.1 ng/ml) the fungal spores were found to potentiate IgE-mediated histamine release triggered by anti-IgE antibody in suspensions of BAL cells. Potentiation was also obtained in basophil histamine release, but relatively high concentrations of Tv (10(-2) mg/ ml) were needed. Our in vitro experiments show that mucosal mast cells from the airways are highly sensitive to the potentiating effect of Tv. Although inhalation studies are needed to determine the in vivo effect of the spores, the results suggest reinforcement of mediator release to be a mechanism in the adverse health implications observed in mouldy buildings.

Basophil-bound IgE and serum IgE directed against Haemophilus influenzae and Streptococcus pneumoniae in patients with chronic bronchitis during acute exacerbations.

The investigation includes 12 patients hospitalized with acute exacerbations of chronic bronchitis (CB) and infected in the lower respiratory tract with Haemophilus influenzae (HI) or Streptococcus pneumoniae (SP). Eight patients were infected the HI, three with SP, and one patient with both species. Basophil-bound IgE and serum IgE directed against these species were examined using the patients' own bacterial isolates. All patients showed IgE-mediated histamine release when their peripheral leukocytes were incubated in vitro with the infecting species, indicating basophil-bound IgE directed against their own bacterium. No IgE-mediated response was obtained in the control group of 12 healthy individuals. Bacteria-specific IgE in serum was demonstrated by immunofluorescence assay and further verified by passive sensitization. There was a positive serum titre in seven of nine patients housing HI and in all SP-infected patients but not in the control group. No synchronism was found between a positive response in the histamine release test and the immunofluorescence assay by parallel testing during the test period. This may be due to a time delay between production of serum IgE and its fixation to the cell surface. The results indicate a potential for a bacteria-specific IgE-mediated immune response in CB. Thus, by triggering mediator release, bacteria may be involved in the pathogenesis of exacerbations in CB.

Haemophilus influenzae release histamine and enhance histamine release from human bronchoalveolar cells. Examination of patients with chronic bronchitis and controls.

Haemophilus influenzae (H. influenzae), Streptococcus pneumoniae (S. pneumoniae) and Branhamella catarrhalis (B. catarrhalis) are often found in the lower respiratory tract of patients with chronic bronchitis. Earlier studies have shown that bacteria induce mediator release from human basophils and parenchymal lung mast cells. In this study the capability of bacteria to trigger or potentiate histamine release from superficially located mast cells in the airway epithelium was studied in cell suspensions obtained by bronchoalveolar lavage in patients with chronic bronchitis (CB). In approximately half of the patients H. influenzae and Staphylococcus aureus (S. aureus) were found to trigger histamine release, whereas no response was obtained by S. pneumoniae or B. catarrhalis. The mediator release was caused by a non-IgE-dependent mechanism. At lower concentrations of H. influenzae causing no histamine release the bacterium was found to enhance IgE-mediated histamine release triggered by anti-IgE antibody. The synergy was more pronounced in patients with CB than in controls. Since H. influenzae is found in the lower respiratory tract of the patients but not in normal individuals, the infection here may via histamine release lead to harmful effects on the airways of importance for precipitation and exacerbation of chronic bronchitis.