Search PubMed⌕ Search

Biomedical subjects

S Rak

Publications and source records attributed to S Rak.

At least 55 records · Page 3Linked to original sources
PubMed1997

Specific induction of interleukin-4-producing cells in response to in vitro allergen stimulation in atopic individuals.

BACKGROUND AND OBJECTIVE: CD4+ T cells can be divided into two major subsets, T helper (TH)1 and TH2 cells. Interleukin-4 (IL-4) is produced by TH2 cells and induces switching of immunoglobulin (Ig) M/IgG to IgE. Interferon-gamma (IFNgamma) produced by TH1 cells counteracts the IgE-promoting effects of IL-4. In this study we wanted to investigate whether the number of IL-4-producing cells could be a direct measurement of allergen exposure in vitro, and whether this was correlated to the elevated serum IgE-levels seen in atopic persons. METHODS: We compared the number of IL-4- and IFNgamma-producing cells using an enzyme-linked immunospot assay (ELISPOT) in response to allergens from birch and cat in peripheral mononuclear cells from atopic and healthy individuals. RESULTS: In the two sensitized groups there was an increase in the number of IL-4-producing cells in response to the specific allergen which was not seen in the healthy group (1/20000 cells and 1/200000 cells, respectively, P < 0.001 for birch). In criss-cross experiments where birch-sensitized individuals were stimulated with cat allergen, no IL-4-producing cells were seen, indicating a high degree of specificity. In individual subjects, the elevated numbers of IL-4-producing cells were significantly correlated with their allergen-specific serum IgE levels. When allergen was combined with a suboptimal dose of PHA, there was a synergistic increase in the number of allergen-induced IL-4-producing cells (1/4000 cells) in the atopic donors, which was not seen with the number of IFNgamma-producing cells. CONCLUSIONS: Allergen-specific IL-4 producing cells in a peripheral blood mononuclear cell (PBMC) culture can be detected by ELISPOT and the response can synergistically be enhanced by suboptimal concentrations of PHA.

Adult↗
PubMed1997

Nitrogen dioxide exposure enhances asthmatic reaction to inhaled allergen in subjects with asthma.

We investigated whether exposure to a low level (490 micrograms/m3) of nitrogen dioxide (NO2) affects bronchial responsiveness to allergen and enhances allergen-induced increase in airway responsiveness to histamine. Eighteen subjects with asthma and allergy to pollen were exposed at rest to either purified air or NO2 for 30 min followed 4 h later by an allergen inhalation challenge. Responsiveness to histamine was measured the day after. Lung function during NO2 exposure and allergen challenge was measured by plethysmography and after exposure by a portable spirometer hourly. The order of exposure to NO2 and air was randomized and separated by at least 2 wk. The asthmatic reaction during the late phase was enhanced by NO2, and peak expiratory flow after allergen challenge was on average 6.6% lower (p = 0.02) after NO2 than after air exposure. The number of subjects having a late asthmatic reaction (fall in FEV1 > 15%) was seven after air and 10 after NO2 (NS). Peripheral blood samples were analyzed for differential cell counts before and after NO2/allergen and serum levels of eosinophil cationic protein (ECP). NO2 effect on lung function was neither associated with an increase in eosinophil numbers nor with ECP levels. NO2 did not affect lung function before allergen challenge, early asthmatic reaction, and allergen-induced increase in responsiveness to histamine. These results indicate that short exposure to an ambient level of NO2 followed several hours later by allergen inhalation enhances allergen-induced late asthmatic reaction.

Administration, Inhalation↗
PubMed1997

IL-13 mRNA and immunoreactivity in allergen-induced rhinitis: comparison with IL-4 expression and modulation by topical glucocorticoid therapy.

The allergen-induced late nasal response (LNR) is associated with high expression of interleukin-4 (IL-4) and IL-5 messenger RNA (mRNA) in the nasal mucosa, suggesting a role for Th2-type cytokines in the development of the LNR. Moreover, topical corticosteroid-mediated inhibition of the LNR is accompanied by inhibition of IL-4, but not IL-5, mRNA expression, IL-13 shares a number of functions with IL-4, including IgE switching and vascular cell adhesion molecule-1 (VCAM-1) upregulation. We investigated the expression of IL-13 mRNA and immunoreactivity in nasal biopsies from 10 normal subjects and 20 subjects with allergic rhinitis. IL-4 mRNA expression was examined in the same subjects. The allergic rhinitis patients were randomized to receive a 6-wk treatment with either topical fluticasone propionate (n = 10) or placebo (n = 10) nasal spray twice daily. A nasal biopsy was taken before treatment and 24 h after local nasal allergen provocation with a grass-pollen extract. Before treatment, there was no significant difference between the allergic rhinitis patients and controls in the expression of IL-13 mRNA and immunoreactivity. After allergen provocation, we observed a significant increase in IL-13 mRNA-positive and immunoreactive cells at 24 h only in subjects given placebo (P < 0.001). Inhibition of the LNR after corticosteroid treatment was associated with a marked decrease in allergen-induced IL-13 mRNA-positive (P < 0.001) and immunoreactive cells (P < 0.001). In subjects given placebo, 76.9 +/- 5.5% of IL-13 mRNA-positive cells observed after allergen were CD3+, whereas 11.2 +/- 2.7% coexpressed immunoreactivity for mast-cell tryptase. In these subjects, increases in cells expressing IL-13 mRNA were greater than for IL-4 mRNA (P = 0.001), and double in situ hybridization studies revealed that 100% of the IL-4 mRNA-positive cells coexpressed IL-13 mRNA, whereas 66.6 +/- 10.5% of IL-13 mRNA-positive cells coexpressed IL-4 transcripts after allergen challenge. The results of this study suggest that IL-13 expression is a prominent feature of the LNR, and that inhibition of the LNR following steroid therapy may be partly attributable to inhibition of IL-13 expression.

Administration, Intranasal↗
PubMed1996

Identification of IL-5 and RANTES as the major eosinophil chemoattractants in the asthmatic lung.

The study was carried out to identify those molecules that are important in vivo in the attraction of eosinophil granulocytes to the lungs of patients with asthma. Asthmatic patients with birch pollen allergy had lavages performed before and during the pollen season, and the chemotactic activity of the bronchoalveolar lavage fluid was tested against normal eosinophils. The activity was significantly increased during the pollen season as compared with the activity before the pollen season (p less than 0.01). Neutralizing antibodies to IL-2, IL-5 and IL-8, leukemia inhibitory factor, and to RANTES were added to the bronchoalveolar lavage fluid. Antibodies to IL-5 and RANTES, but not to IL-2 and IL-8 or leukemia inhibitory factor, significantly inhibited the chemotactic activity for eosinophils (p less than 0.001). It is concluded that IL-5 and RANTES are important chemoattractants in the lungs of patients with allergic asthma. The effect of IL-5 may be that of a cofactor to the chemotactic molecules, of which RANTES may be one of the most important in allergic asthma.

Adolescent↗
PubMed1996

Oxygen radical production by blood eosinophils is reduced during birch pollen season in allergic patients.

BACKGROUND: The eosinophil granulocyte takes part in allergic inflammatory diseases, like asthma and rhinitis. The aim of this study was to investigate the oxidative metabolism of the blood eosinophils and neutrophils from birch pollen allergic patients, during and after exposure to their allergen. METHODS: Thirteen birch pollen allergic patients, with seasonal symptoms of rhinitis, with or without asthma, were followed. The cells were purified using a percoll gradient and the MACS system. The eosinophil purity in all samples was > 95%. The oxidative metabolism of both the PMN and the eosinophils was measured by means of a chemiluminescence (CL) assay, with luminol or lucigenin as the amplifier, and using PMA (16 nM) as the activator. RESULTS: In relative terms, the lucigenin CL by the eosinophils was 5-10-fold higher than that of the PMN, P = 0.002. The eosinophils of the birch pollen allergic patients produced less oxygen radicals during the season, compared to the reference group, measured both with luminol CL and lucigenin CL, P = 0.01 and P = 0.02 respectively. Out of season, there was no difference. There was also no difference, during either period, between patients and references in PMN CL. Separating the eosinophils into hypodense and normodense fractions, showed a decreased oxidative metabolism by the hydrodense eosinophils. CONCLUSION: We conclude that the eosinophils of birch pollen allergic patients have reduced production of oxygen radicals when the patients are exposed to their allergen, which could depend on higher amounts of hypodense eosinophils in the blood during season.

Adult↗
PubMed1994

Influence of prolonged treatment with topical corticosteroid (fluticasone propionate) on early and late phase nasal responses and cellular infiltration in the nasal mucosa after allergen challenge.

We have examined the effect of prolonged treatment with topical corticosteroid on allergen-induced early and late nasal responses and the associated inflammatory cell infiltrate in grass pollen sensitive allergic rhinitics. Following a randomized double-blind 6 week treatment period with fluticasone propionate 200 micrograms aqueous nasal spray twice daily or matched placebo spray, nasal provocation was performed using Timothy grass pollen extract. Nasal symptoms were recorded at intervals from 0 to 24 h. Nasal biopsies were performed before treatment and at 24 h after allergen and processed for immunohistology. When corticosteroid-treated patients were compared with the placebo group there was an approximately 50% decrease in the size of the early (0-60 min) response and almost complete inhibition of late (1-24 h) nasal symptoms after allergen challenge. After allergen challenge markedly fewer T lymphocytes and CD25+ (interleukin-2 receptor bearing) cells were observed in both the epithelium and submucosa in fluticasone treated patients compared with the placebo group. Significantly less total and activated eosinophils were observed, particularly within the nasal epithelium. Submucosal mast cell counts were decreased, whereas increased numbers of submucosal neutrophils were observed. These results confirm that topical corticosteroid treatment inhibits allergen-induced early and late nasal responses. This may possibly occur following a decrease in T lymphocytes and/or mast cells and their products and a consequent reduction in tissue eosinophilia.

Administration, Topical↗
PubMed1994

Topical glucocorticosteroid (fluticasone propionate) inhibits cells expressing cytokine mRNA for interleukin-4 in the nasal mucosa in allergen-induced rhinitis.

Allergen-induced late nasal responses are associated with recruitment and activation of T lymphocytes and eosinophils and preferential mRNA expression for T-helper type 2 (Th2) cytokines. We tested the hypothesis that topical corticosteroids may inhibit late responses by inhibiting cells expressing mRNA for Th2 cytokines. A randomized double-blind placebo-controlled trial of topical corticosteroid (fluticasone propionate) was performed in 48 adult grass pollen-sensitive patients. Nasal biopsies were taken at baseline and repeated 24 hr after local nasal allergen provocation following 6 weeks treatment with either fluticasone propionate 200 micrograms or placebo nasal spray twice daily. Baseline mRNA expression for interleukin-4 (IL-4) (P = 0.01) and IL-5 (P = 0.002) was higher in the patients than in normal controls. Topical corticosteroid treatment significantly inhibited immediate nasal symptoms, with almost complete inhibition of the late response following allergen challenge. This was associated with a marked decrease in the allergen-induced increases in cells expressing mRNA for IL-4 (P = 0.002) but not for IL-5. Inhibition of the late response was also accompanied by decreases in CD25+ cells, presumed T lymphocytes and eosinophils. A significant correlation was observed between the decreases in IL-4 mRNA+ cells and in eosinophils after treatment (r = 0.46, P < 0.05). These results suggest that prolonged treatment with topical corticosteroid inhibits allergen-induced early and late nasal responses and the associated tissue eosinophilia, and that, at least in part, this may result from inhibition of cells expressing mRNA for IL-4.

Administration, Topical↗
PubMed1994

T lymphocytes and mast cells express messenger RNA for interleukin-4 in the nasal mucosa in allergen-induced rhinitis.

We have investigated the phenotype of interleukin-4 (IL-4) mRNA+ cells in the nasal mucosa of six subjects with allergic rhinitis before and 24 hr after local allergen provocation with grass pollen extract. Serial cryostat sections were cut from paraformaldehyde-fixed snap-frozen nasal biopsies, and immunocytochemistry (APAAP) followed by in situ hybridization performed on the same sections. For immunocytochemistry, antibodies against CD3, tryptase, major basic protein (MBP) and CD68 were used to identify T cells, mast cells, eosinophils and macrophages, respectively. Hybridization studies were performed using a digoxigenin-labelled IL-4 riboprobe. Nitroblue tetrazolium (NBT) and X-phosphate-5-bromo-4-chloro-3-indoly phosphate (BCIP) served as chromogens to detect hybridization IL-4 mRNA signals. Significant increases in T lymphocytes and eosinophils and in the number of IL-4 mRNA+ cells were observed after allergen challenge. Double immunocytochemistry/in situ hybridization demonstrated that the majority of IL-4 mRNA+ cells after allergen challenge were CD3+ (73.7% +/- 1.6). Lower numbers of IL-4 mRNA hybridization signals were co-localized to tryptase+ cells (26.0% +/- 1.6). In contrast, no IL-4 mRNA hybridization signals were co-localized to either eosinophils or macrophages. These results indicate that after allergen challenge T cells are the principal cellular source of IL-4 mRNA transcripts during human late nasal responses, with a lesser contribution from mast cells.

Adult↗
PubMed1993

The effect of immunotherapy on T-cell subsets in peripheral blood and bronchoalveolar lavage fluid in pollen-allergic patients.

The effect of immunotherapy (IT) on T-cell subsets in peripheral blood and bronchoalveolar lavage fluid (BAL) was examined in 15 patients with rhinoconjunctivitis and asthma caused by sensitivity to birch pollen. They were treated with IT for 3 years. Seven patients were treated with highly standardized birch-pollen extract (Pharmacia, Sweden). Eight untreated patients served as controls. Histamine challenge, blood sampling, and BAL were performed before (January, February), and at the peak of, the birch-pollen season (May). The subpopulations of T cells in peripheral blood and BAL fluid were investigated by immunocytochemistry and flow cytometry. During the birch-pollen season, the percentage of CD3+ and CD4+ cells of blood mononuclear cells in the IT patients increased significantly (P < 0.03 and P < 0.02, respectively). The percentage of CD8+ cells remained unaltered. In control patients, no changes of T-cell subsets in the peripheral blood were observed. T-cell subsets in BAL did not change during the season in relation to preseasonal values for either IT-treated or non-IT-treated patients.

Adolescent↗
PubMed1993

Effects of immunotherapy on the inflammation in pollen asthma.

Seasonal asthma is a natural model of airway inflammation where amount of airborne antigen have direct impact and correlates to the clinical disease and degree of inflammation. Bronchial hyperresponsiveness (BHR) is an indirect measure of the degree of airway inflammation and the seasonal increase paralleling clinical disease has been shown in a number of studies. Using a model of seasonal asthma in birch pollen sensitive individuals we intended to prove the anti-inflammatory potential of immunotherapy (IT). Forty birch pollen-allergic patients, 20 IT-treated and 20 untreated participated in a series of studies. BHR expressed as PC20 histamine increased in all patients during the season although most in untreated controls; the difference between the groups was p < 0.07. The level of eosinophil cationic protein (ECP) rose in untreated, but not IT-treated, patients during the season (p < 0.05). Significant increase in eosinophil chemotactic activity (ECA) in serum of untreated patients during the season was noted. IT-treatment abrogated this response. After 2 years of treatment bronchoalveolar lavage (BAL) was performed on 12 patients (6 in each group). IT-treatment prevented seasonal rise of eosinophil numbers in peripheral blood (PB) and the lung while in the untreated group the increase was significant in both compartments (p < 0.05 and p < 0.01, respectively). At the same time, significant increment in ECP and ECA levels in BAL were recorded in untreated patients compared with IT-treated (p < 0.05, p < 0.01, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Asthma↗
PubMed1993

T cells are the principal source of interleukin-5 mRNA in allergen-induced rhinitis.

We have investigated the phenotype of interleukin-5 (IL-5) mRNA+ cells in the nasal mucosa of subjects with allergic rhinitis. Serial cryostat sections were cut from paraformaldehyde-fixed snap-frozen nasal biopsies from six patients, before and 24 h after local allergen provocation with grass pollen. Immunocytochemistry (APAAP) was followed by in situ hybridization on the same sections. For immunocytochemistry, antibodies against CD3, tryptase, and major basic protein (MBP) were used to identify T cells, mast cells, and eosinophils, respectively. Hybridization studies were performed using a Digoxigenin-labeled IL-5 riboprobe. Nitroblue tetrazolium (NBT) and X-phosphate-5-bromo-4-chloro-3- indoly phosphate (BCIP) served as chromogens to detect hybridized IL-5 mRNA signals. The majority of IL-5 mRNA+ cells were CD3+ (83.2%), whereas the remainder were either tryptase+ (11.3%) or MBP+ (5.4%). In contrast, only a few IL-5 mRNA+ cells were observed in nasal biopsies before challenge, all of which were co-localized to CD3+ cells. These results indicate that CD3+ cells are the principal cellular source of IL-5 transcripts in the nasal mucosa 24 h after allergen-induced late-phase nasal responses.

Adult↗
PubMed1993

[Current aspects of asthma].

Knowledge of the pathophysiology and aetiology of asthma has expanded greatly during recent years, and hopes are strong that within the foreseeable future it will be possible to alleviate asthmatic symptoms even more effectively. This review covers some of this new knowledge, and presents viewpoints on the practical clinical management of asthma patients.

Adrenal Cortex Hormones↗
PubMed1991

The effect of immunotherapy on eosinophil accumulation and production of eosinophil chemotactic activity in the lung of subjects with asthma during natural pollen exposure.

Two groups of birch pollen--allergic patients with seasonal rhinoconjunctivitis and asthma were followed during two consecutive birch-pollen seasons, one group, N = 10, during a season with high pollen load, and one group, N = 15, during a season of low pollen load. Half the patients were treated with immunotherapy (IT) for 3 and 4 years, respectively. The other half of the patients served as control group (non-IT). Bronchoalveolar lavage (BAL) was performed once before each season and once during the pollen season. Eosinophil (EOS) numbers in BAL were increased (p less than 0.01) during the season with high pollen load but not in the season with a low pollen load, and this increment was absent in the IT-treated group. Also, the EOS cationic protein levels were raised in the non-IT-treated group during the season with a high pollen load. The levels of EOS and neutrophil chemotactic activity were raised in BAL in both seasons in the non-IT-treated group compared with the IT-treated group (p less than 0.02, p less than 0.003, p less than 0.04, and p less than 0.005 in high- and low-load pollen season, respectively). Serum and BAL eosinophil chemotactic activity (ECA) were positively correlated (p less than 0.001). We conclude that there is an influx of active EOSs into the lung of pollen-allergic patients with asthma during a pollen season, which may be abrogated by IT. Furthermore, the generation of ECA appears to be an extremely sensitive marker of antigenic exposure, and the potent inhibition of the generation of ECA by IT may provide a clue as to the mechanism of this treatment.

Adolescent↗
PubMed1991

Neutrophil function in chronic bronchitis.

This study was initiated with the question: Do defects in neutrophil functions predispose patients with chronic bronchitis to their recurrent bacterial infections? Forty five patients with chronic bronchitis and recurrent bacterial infections were studied. A number of aspects of neutrophil functions reflecting migratory and phagocytic functions and oxidative metabolism were measured in vitro, once in all 45 patients and 3 times in 22 patients over a period of 6 months. A great number of abnormalities was found on the first occasion with a complete normalization for all variables except one at the end of the observation period. The number of infectious exacerbations was significantly higher (p less than 0.05) at the start of the observation period i.e. October-November, as compared to the end, i.e. April-May. The oxidative metabolism, as reflected by lucigenin-enhanced chemiluminescence, was significantly reduced (p less than 0.001) also at the period of few infections, suggesting a primary defect of the neutrophil. Smoking was shown to adversely affect luminol-enhanced chemiluminescence and the chemokinetic activity of the patients' cells. We conclude that most variables were altered in a way which was anticipated from the study of individuals with acute bacterial infections. The probable primary defect in oxidative metabolism of the neutrophils in addition to the acquired defects as a consequence of smoking may add to the predisposition of some individuals to their recurrent bacterial infections.

Adult↗
PubMed1990

Immunotherapy abrogates the generation of eosinophil and neutrophil chemotactic activity during pollen season.

In a group of 40 birch pollen-allergic patients with a history of rhinoconjunctivitis and wheezing during the pollen season, 20 were immunotherapy (IT) treated preseasonally with birch-pollen extract (Pharmacia, Uppsala, Sweden). Blood samples for determination of the levels of heat-labile eosinophil chemotactic activity (HL-ECA), heat-labile neutrophil chemotactic activity (HL-NCA), and heat-stable neutrophil chemotactic activity were collected before the season, at the beginning of the study, at the start of the season, at the peak, at the end, and after the birch-pollen season. The symptoms from rhinoconjunctivitis and airways, peak expiratory flow, and use of medication were recorded throughout the season. Significant increases of HL-ECA and HL-NCA were observed in untreated compared with IT-treated patients at the start of the season (p less than 0.0001 for both activities) and at the peak of the birch-pollen season (p less than 0.0005 and p less than 0.01, respectively). At the end of the season, HL-ECA levels were not significantly different between the patient groups, whereas HL-NCA levels were still higher in untreated patients (p less than 0.005). We conclude that IT completely abrogates the generation of HL-ECA and HL-NCA during a pollen season.

Adolescent↗
PubMed1989

The formation of eosinophil and neutrophil chemotactic activity during a pollen season and after allergen challenge.

Heat-stable (HS) and heat-labile (HL) neutrophil chemotactic activities (NCAs) have been demonstrated in serum after allergen challenge of subjects with asthma. In this investigation, we have studied the possible occurrence of similar activities in 20 atopic individuals on natural exposure to allergen, that is, during the birch-pollen season. Since eosinophil accumulation is a hallmark of an ongoing allergic inflammation in the respiratory tract also, the possible production of eosinophil chemotactic activity (ECA) was examined in serum after allergen challenge and at natural exposure to pollen. Both HL-NCA and HL-ECA were produced to a significant extent (p less than 0.001) during the season, with the peak of activities occurring simultaneously with the peak pollen count. HL-ECA was produced after allergen challenge of subjects with asthma in the laboratory, as has been demonstrated for NCA previously. The activity of the HS-NCA was unaltered during season. Gel-filtration studies of the major HL-NCA and HL-ECA indicated a molecular weight for both activities of 100 to 150,000, and the activities produced during season cochromatographed with the HL-NCA and HL-ECA produced after allergen challenge in the laboratory, suggesting that all these activities are due to one and the same molecule. The results suggest that the heat-labile chemotactic activity found in serum of atopic subjects and subjects with asthma after allergen exposure may be involved in the attraction of eosinophils and neutrophils to the site of allergic inflammation.

Asthma↗
PubMed1988

The effect of immunotherapy on bronchial hyperresponsiveness and eosinophil cationic protein in pollen-allergic patients.

The effect of immunotherapy (IT) on bronchial response to histamine and on eosinophil cationic protein (ECP) in 40 birch pollen-allergic patients with a history of rhinoconjunctivitis and wheezing during the birch season was examined. Twenty patients started IT with birch extract (Pharmacia, Uppsala, Sweden) before the season. The other 20 patients were not treated with IT. Histamine-challenge tests were performed before, at the start, at pollen peak, at the end, and after the birch-pollen season. Blood samples for determination of ECP were collected at the same time. Skin prick tests and nasal provocation tests were also performed before and after the season. A significant increase in bronchial hyperresponsiveness was noted in the group treated with IT and in the untreated group during the season. The increase was greatest in the untreated group with the maximal difference between the two groups at the end of the pollen season (p less than 0.07). IT treatment was followed by significantly less medication and higher peak expiratory flow values. The levels of ECP increased during the season in untreated patients (p less than 0.05) but not in patients treated with IT. The ECP levels of patients from both groups correlated significantly with histamine sensitivity (p less than 0.001).

Allergens↗