Biomedical subjects

Q Hamid

Publications and source records attributed to Q Hamid.

At least 127 records · Page 7Linked to original sources

PubMed1996

An in vivo model of allergic inflammation: pulmonary human cell infiltrate in allergen-challenged allergic Hu-SCID mice.

CB.17 severe combined immunodeficient (SCID) mice were used to establish a model of allergic pulmonary inflammation. SCID mice were intraperitoneally reconstituted with 10(7) peripheral blood mononuclear cells (PBMC) from patients sensitive to Dermatophagoides pteronyssinus (Dpt) and 2 weeks later were exposed to Dpt aerosols. After Dpt nebulization, SCID mice engrafted with PBMC from Dpt-sensitive patients developed a specific human IgE response as well as an intense pulmonary infiltrate of human cells. In contrast, SCID mice reconstituted with PBMC from patients allergic to grass pollen or from non-allergic donors failed to produce IgE or to exhibit a similar inflammatory response. The level of the IgE production was dependent on the IgE level of the allergic donor. In the lungs of the same allergic SCID mice, 2 months after Dpt inhalation, the cell infiltrate contained CD45+, CD45RO+, CD20+ and HLA-DR+ human cells. They were located in perivascular and peribronchial areas and disseminated in the mouse lung parenchyma. Moreover, mRNA IL-5+ cells and eosinophils were found in peribronchial infiltrates. The observations indicate that humanized allergic SCID mice may develop, after nebulization with the relevant allergen, immune reactions similar to those observed in man and suggest that SCID mice may represent a useful model to analyze the regulatory mechanisms of IgE-associated allergic diseases.

Administration, Inhalation↗

PubMed1996

In vivo expression of IL-12 and IL-13 in atopic dermatitis.

Previous studies in atopic dermatitis (AD) have shown that acute and chronic skin lesions are associated with a TH2-type profile of cytokine expression. IL-12 and IL-13 are recently described cytokines, which possess TH1-and TH2-like actions, respectively. We have used the technique of in situ hybridization to examine the expression of IL-12 and IL-13 messenger RNA in skin biopsy specimens of acute and chronic skin lesions and uninvolved skin from patients with AD. When compared with normal control skin, the acute and chronic skin lesions and unaffected skin from patients with AD had significantly greater numbers of cells that were positive for IL-13 mRNA (p < 0.05). Acute AD skin lesions expressed a higher number of positive cells than those observed in chronic AD skin lesions (p < 0.05) or psoriasis skin lesions (p < 0.05) There was a significant increase in the numbers of IL-12 mRNA-positive cells in chronic skin lesions compared with acute lesions and uninvolved skin from patients with AD (p < 0.05). These data demonstrate that acute AD skin lesions are associated with an increased expression of IL-13 mRNA. In contrast, the relative increase in IL-12 mRNA in chronic AD skin lesions suggests a possible role for IL-12-producing cells in modulating chronic inflammation.

Acute Disease↗

PubMed1996

Venom immunotherapy modulates interleukin-4 and interferon-gamma messenger RNA expression of peripheral T lymphocytes.

The mechanism by which specific immunotherapy exerts its beneficial effect remains unclear. In order to evaluate the influence of venom immunotherapy on the T-cell cytokine pattern of allergic reactions, we studied interleukin-4 (IL-4) and interferon-gamma (IFN-gamma) mRNA expression of peripheral T lymphocytes from 12 patients undergoing rush venom desensitization, before treatment at Day 0 (D0), at Day 15 (D15) and Day 90 (D90) after treatment, and from seven controls. Antigen-specific T-cell proliferation was also determined. Cytokine mRNA expression was evaluated using in situ hybridization, 24 hr after culture of peripheral T cells with medium, venom, or an unrelated allergen. Allergen-induced T-cell proliferation decreased at D15 and D90 of rush immunotherapy (P < or = 0.02). In venom-stimulated cultures of the patient group, there was a decrease in IL-4 mRNA-positive cells at D15 and D90 (P < or = 0.001). Before desensitization, IFN-gamma mRNA expression was lower in patients than in controls and did not increase after in vitro allergen stimulation. In contrast, after immunotherapy, spontaneous IFN-gamma mRNA expression increased, but only at D90 (P < or = 0.001). The cytokine pattern observed at D90 after immunotherapy was similar to that observed in control subjects. In conclusion, venom immunotherapy induced an altered cytokine mRNA pattern in allergen-stimulated T cells which was dissociated from the early changes of allergen-induced T-cell responsiveness.

Adolescent↗

PubMed1996

Prednisolone treatment in asthma. Reduction in the numbers of eosinophils, T cells, tryptase-only positive mast cells, and modulation of IL-4, IL-5, and interferon-gamma cytokine gene expression within the bronchial mucosa.

We have tested the hypothesis that the beneficial effects of corticosteroids in asthma may result from reduction in the number of inflammatory cells infiltrating the bronchial mucosa with inhibition of cytokine gene expression. A randomized parallel group study was performed in 18 moderately severe asthmatic patients in whom an elective trial of corticosteroid treatment was indicated. Fiberoptic bronchoscopy was performed and bronchial biopsies taken from segmental carinae before and after 2 wk treatment with prednisolone (0.6 mg/kg/d) or matched placebo tablets. Immunohistology was performed on 6-microns cryostat sections using monoclonal antibodies. The number of cells expressing cytokine messenger RNA (mRNA) was assessed by in situ hybridization using S35-labeled riboprobes. When prednisolone- and placebo-treated groups were compared there was a decrease in airway methacholine responsiveness (p < 0.01) and an increase in FEV1 (p < 0.05) after prednisolone. This was accompanied by a reduction in CD3+ T lymphocytes (p < 0.05), "activated" EG2+ eosinophils (p < 0.02), and tryptase-only (mucosal-type) MCT cells (p < 0.02) but not MCTC (tryptase+chymase positive) cells in prednisolone-treated patients. In prednisolone-treated patients there was also a reduction in the number of cells expressing mRNA for interleukin-4 (IL-4, p < 0.01), and interleukin-5 (IL-5, p < 0.03) and an increase in cells expressing mRNA for interferon-gamma (IFN-gamma) (p < 0.01). These results support the view that corticosteroid treatment in asthma may act by modulation of cytokine expression with consequent inhibition of the local bronchial inflammatory infiltrate and tissue eosinophilia.

Adult↗

PubMed1996

Increased interleukin-10 messenger RNA expression in atopic allergy and asthma.

Interleukin-10 (IL-10) inhibits T-lymphocyte proliferation and production of cytokines. We have examined expression of IL-10 messenger RNA (mRNA) in atopic asthma and in allergen and tuberculin skin responses by in situ hybridization. The proportion of bronchoalveolar lavage (BAL) cells positive for IL-10 mRNA was increased in a group of 10 symptomatic asthmatics when compared with control subjects (17.5% versus 5.2% BAL cells positive; P < 0.001). In a separate group of six mild atopic asthmatics, there was an increased proportion of BAL cells positive for IL-10 mRNA 24 h after allergen inhalation challenge compared with diluent challenge BAL from the same subjects (24% versus 10%; P < 0.005). By simultaneous in situ hybridization and immunocytochemistry, IL-10 mRNA was localized to both CD3+ T cells and CD68+ alveolar macrophages in BAL, with a significantly more prominent T-cell signal in the symptomatic asthmatics compared with control subjects and after allergen challenge compared with diluent challenge of the mild asthmatic subjects. It has been suggested that IL-10 production is a late event after T-cell activation. To examine kinetics and specificity of IL-10 mRNA expression, skin biopsies were obtained from atopic, tuberculin-sensitive subjects at 1, 6, and 48 h after cutaneous injection of allergen or tuberculin. With both stimuli, there was an increase in IL-10 mRNA-positive cells at 6 h when compared with control sites injected with appropriate diluent which were biopsied 24 h after injection (P < 0.01 for allergen and P < 0.02 for tuberculin). These findings are compatible with the hypothesis that IL-10 mRNA is expressed in both macrophages and T lymphocytes in the airway in asthma and that IL-10 mRNA expression is induced from T lymphocytes in response to allergen. This response may also occur in other types of cell-mediated inflammation.

Adolescent↗

PubMed1996

Cytokine expression in the presence or absence of late airway responses after antigen challenge of sensitized rats.

To assess whether Th-2 cytokines are involved in the late airway response (LR) after antigen challenge, we evaluated cytokine mRNA expression in the lungs of two strains of rats before and 8 h after saline or antigen challenge: Brown Norway (BN) rats, high IgE producers that develop LR after antigen challenge and Sprague-Dawley (SD) rats, low IgE producers that develop little LR and no increased airway responsiveness after antigen challenge. Rats were sensitized with ovalbumin (OA) and 14 days later, lungs were obtained before or after OA challenge and measurement of lung physiology for 8 h. Lung tissue was either fixed for in situ hybridization or frozen for evaluation of mRNA expression by reverse transcription-polymerase chain reaction (RT-PCR). We examined mRNA expression for interleukin-4 (IL-4), and IL-5 (Th-2 cytokines) and IL-2 and interferon gamma (IFN-gamma, Th-1 cytokines). In situ hybridization showed that cells expressing IL-4 and -5 mRNA were increased in the airways of the lungs of BN rats after OA challenge (P < 0.05) and that cells expressing mRNA for IFN-gamma and IL-2 were higher in SD than in BN rats after antigen challenge (P < 0.05). Results from PCR showed that prior to antigen challenge, BN rats expressed in their lungs mRNA for IL-4 and -5 and SD rats expressed very little mRNA for IL-5 only. After antigen challenge most BN and SD rats expressed mRNA for IL-4 and -5 but expression of mRNA for IL-2 and IFN-gamma was only found in SD rats. In conclusion, rats that develop a LR after antigen challenge preferentially increase Th-2 cytokine expression in their lungs whereas those without LRs preferentially express Th-1 cytokines. Our results support the role of Th-2 cytokines in the LR and asthma.

Animals↗

PubMed1996

Eosinophil infiltration in nonallergic chronic hyperplastic sinusitis with nasal polyposis (CHS/NP) is associated with endothelial VCAM-1 upregulation and expression of TNF-alpha.

We studied potential mechanisms of eosinophil accumulation in nonallergic chronic hyperplastic sinusitis with nasal polyposis (CHS/NP). We measured expression of endothelial vascular cell adhesion molecule-1 (VCAM-1), which mediates selective eosinophil transendothelial migration, the cytokines interleukin (IL)-1 beta, TNF-alpha and IL-13 which upregulate VCAM-1 expression, and the chemokine RANTES which mediates lymphocyte, monocyte, and eosinophil chemotaxis in chronic hyperplastic sinusitis with nasal polyposis (CHS/NP) nasal polyps (nonallergic versus allergic) and middle turbinate biopsies from normal controls. By immunohistochemical staining, the density of EG2+ eosinophils was increased in both the nonallergic and allergic CHS/NP subgroups compared to normal controls. VCAM-1 expression was significantly increased in CHS/NP subjects compared to normal controls (P = 0.0005), with the highest intensity seen in nonallergic CHS/NP. By in situ hybridization, the densities of IL-1 beta, TNF-alpha, IL-13, and RANTES mRNA+ cells were all increased in nonallergic CHS/NP compared to normal controls (P = 0.009, 0.0005, 0.0005, and 0.001, respectively). In comparison to allergic CHS/NP, nonallergic CHS/NP had a significantly higher tissue density of TNF-alpha (P = 0.04) and a lower density of IL-13 (P = 0.005) mRNA+ cells. In general, VCAM-1 expression correlated strongly in CHS/NP with the density of TNF-alpha (R = .91, P = 0.0005) but not the density of IL-1 beta, IL-13, or RANTES mRNA+ cells. We conclude that upregulation of VCAM-1 and elaboration of RANTES may contribute to the marked accumulation of eosinophils in nonallergic CHS/NP. TNF-alpha may play a critical role in VCAM-1 upregulation in this nonallergic eosinophilic disorder.

Adult↗

PubMed1996

Evidence for major basic protein immunoreactivity and interleukin 5 gene activation during the late phase response in explanted airways.

Current evidence suggests that the events subsequent to antigen challenge in allergic asthmatics involve eosinophil activation and the synthesis of proinflammatory cytokines, in particular interleukin 5 (IL-5). However, little is known about how local inflammatory cell infiltration and activation are related to the changes in lung function following allergen exposure. We have developed a novel technique to investigate the local inflammatory events during late-onset allergic bronchoconstriction in lung explants from sensitized Brown-Norway (BN) rats. In this study we tested the hypothesis that the in vitro late airway response involves IL-5 gene activation and recruitment and activation of eosinophils. Explants were prepared from excised lungs of BN rats (n = 9) sensitized 2 wk previously to ovalbumin (OVA). Lungs were inflated with liquid agarose solution (2% wt/vol, 48 ml/kg) following perfusion with cold Ca2+/Mg(2+)-free Hanks' solution, and refrigerated briefly to gel the agarose, and 0.5- to 1.0-mm slices were prepared and cultured overnight at 37 degrees C. Airways were identified and challenged by direct application of OVA (20 micrograms). Cryostat sections of explants were immunostained for major basic protein (MBP) and IL-5 mRNA was detected by a 35S-uridine triphosphate-labeled probe and in situ hybridization. Explants harvested immediately prior to challenge showed little evidence of MBP and IL-5 mRNA expression. Explants harvested at 6 h which exhibited evidence of bronchoconstriction showed strong cell-associated immunostaining for MBP and high expression of IL-5 mRNA in the bronchial mucosa. colocalization studies performed in lung explants demonstrating late-onset airway responses suggested that the majority of IL-5 mRNA expression was not found in MBP-positive cells. When compared with explants from sham-sensitized rats (n = 4), there was a significant increase in MBP-positive and IL-5 mRNA-positive cells per millimeter of basement membrane of the airway. The presence of MBP immunoreactivity and IL-5 gene expression was not observed in explants taken from sensitized BN rats which did not undergo late-onset airway responses, indicating an association between inflammatory cell activation and airway constriction. The increase in MBP-positive cells several hours after OVA suggests activation, local recruitment, and/or differentiation of eosinophils. This study provides direct evidence for a temporal association between IL-5 expression, eosinophil infiltration, and the late response in individual cultured airways.

Allergens↗

PubMed1995

Dysregulation of interleukin 4, interleukin 5, and interferon gamma gene expression in steroid-resistant asthma.

In steroid-resistant (SR) asthma, there is a lack of clinical responsiveness to oral prednisone. Previous studies indicate that this may be explained by the effect of the combination of interleukin 2 (IL-2) and IL-4 on glucocorticoid receptor binding affinity. By contrast, steroid-sensitive (SS) asthmatics respond well to glucocorticoids, and this is accompanied by a decrease in the numbers of bronchoalveolar lavage (BAL) messenger RNA+ (mRNA+) cells expressing IL-4 and IL-5, and an increase in interferon gamma (IFN-gamma) transcripts. In the present study, we hypothesized that SR asthma is associated with alterations in T helper types 1/2 (Th2/Th1)-type cytokine gene expression. BAL was performed in six SR asthmatics and six SS asthmatics, before and after a 1-wk course of 40 mg daily prednisone. mRNA+ cells for IL-2, IL-4, IL-5, and IFN-gamma was measured by in situ hybridization using 35S-labeled RNA probes. Before prednisone therapy, there were significantly greater numbers of BAL cells (per 1,000) expressing IL-2 mRNA (p < 0.01) and IL-4 mRNA (p < 0.05) in SR asthmatics as compared with SS asthmatics, but no differences between the two groups in the numbers of BAL cells expressing IFN-gamma or IL-5 mRNA expression were observed. After a 1-wk course of prednisone, IL-2 expression was not altered in either group. However, SS asthmatics had a significant decrease in the numbers of BAL cells expressing mRNA for IL-4 (p < 0.01) and IL-5 (p < 0.001), and a rise in the numbers of IFN-gamma mRNA+ cells (p < 0.01). In contrast, after prednisone treatment, SR asthmatics had no significant change in either the number of BAL cells expressing mRNA for IL-4 or IL-5. Of note, there was an unexpected decrease in the numbers of IFN-gamma mRNA+ cells (p = 0.05). Our current findings indicate that SR asthma is associated with a dysregulation of the expression of the genes encoding for Th2/Th1 cytokines in airway cells and is compatible with the concept that a combination of IL-2 and IL-4 induce glucocorticoid (GR) binding affinity and T cell responsiveness to glucocorticoids.

Adult↗

PubMed1995

Evidence for distinct cytokine expression in allergic versus nonallergic chronic sinusitis.

BACKGROUND: The purpose of this study was to characterize the relationship between tissue cytokine expression and the cellular infiltrate present in chronic hyperplastic sinusitis with nasal polyposis (CHS/NP) and to compare the immunopathology and cytokine profile of patients with allergy versus patients without allergy. METHODS: Nasal polyp tissue samples from 12 patients with CHS/NP and nasal turbinate biopsy specimens from 10 normal control patients were examined for the expression of interleukin (IL)-4, IL-2, and interferon (IFN)-gamma cytokine messenger RNA (mRNA) species by in situ hybridization. These data were analyzed in conjunction with data previously reported for the cytokine mRNA species granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-3, and IL-5 and the immunocytochemical profile of the inflammatory cell infiltrate. Patients with allergy were distinguished from those without allergy on the basis of allergy skin tests. RESULTS: Tissue eosinophilia was a prominent feature of both allergic and nonallergic CHS/NP and correlated in both subgroups with the density of GM-CSF and IL-3 mRNA+ cells. In comparison with normal controls, patients with allergic CHS/NP had significantly higher CHS/NP had significantly higher tissue densities of GM-CSF, IL-3, IL-4, and IL-5 (p < or = 0.025). In contrast, patients with nonallergic CHS/NP had significantly higher tissue densities of GM-CSF, IL-3, and IFN-gamma (p < or = 0.001). The allergic and nonallergic subgroups showed distinct cytokine profiles with the most distinguishing cytokines of the allergic subgroup being IL-4 (p = 0.001) and IL-5 (p = 0.017) and of the nonallergic subgroup being IFN-gamma (p = 0.004). Furthermore, patients with allergic CHS/NP showed an increased density of CD3+ T lymphocytes compared with either controls or patients with nonallergic CHS/NP (p = 0.03). The density of CD3+ T lymphocytes was the only significant difference between patients with allergic and nonallergic CHS/NP. A clinical history of aspirin sensitivity was strongly correlated with nonallergic CHS/NP, as well as the nonallergic CHS/NP profile of cytokines, including IFN-gamma. CONCLUSION: We conclude that distinct mechanisms of eosinophilia exist in patients with allergic versus nonallergic CHS/NP. The allergic mechanism involves production of TH2-type cytokines, including GM-CSF, IL-3, IL-4, and IL-5, by infiltrating T lymphocytes. The nonallergic mechanism remains unknown but does involve production of GM-CSF, IL-3, and IFN-gamma. However, nonallergic eosinophilia is independent of IL-4 and IL-5, cytokines that contribute to tissue eosinophilia in allergic inflammation. Aspirin sensitivity is strongly correlated with nonallergic CHS/NP and production of the nonallergic CHS/NP profile of cytokines, including IFN-gamma.

Adolescent↗

PubMed1995

Phenotype of cells expressing mRNA for TH2-type (interleukin 4 and interleukin 5) and TH1-type (interleukin 2 and interferon gamma) cytokines in bronchoalveolar lavage and bronchial biopsies from atopic asthmatic and normal control subjects.

We investigated the phenotype of cells expressing messenger RNA encoding interleukin 4 (IL-4), IL-5, IL-2, and interferon gamma (IFN-gamma) in bronchoalveolar lavage (BAL) and bronchial biopsies (BX) from seven mild atopic asthmatic patients and nine nonasthmatic controls. Immunocytochemistry followed by in situ hybridization using either 35S- or digoxigenin-labeled riboprobes was performed on cytospins from BAL and BX, respectively. With BAL or BX, in situ hybridization alone showed significant increases in percentages of IL-2, IL-4, and IL-5 mRNA+ cells when asthmatics were compared to nonasthmatic controls. Double immunocytochemistry-in situ hybridization revealed that > 70% of IL-4 and IL-5 mRNA+ cells were activated T cells (CD3+). The remaining IL-4 and IL-5 mRNA+ signals were colocalized to tryptase+ mast cells, and activated eosinophils (EG2+). Rare IL-4 and IL-5 mRNA+ cells were observed in nonasthmatic controls, the majority being CD3+ cells, as were IL-2 and IFN-gamma mRNA+ cells (in both asthmatics and controls). A few IL-4 (< 8%) and IL-5 (< 5%) mRNA+ signals did not colocalize with any of the cells identified by immunocytochemistry. Thus, we provide further evidence that CD3+ T cells are the most abundant cells expressing IL-4 and IL-5 mRNA in BAL and BX from allergic asthma. Fewer, but detectable, numbers of tryptase+ mast cells and EG2+ eosinophils also expressed these transcripts.

Adult↗

PubMed1995

Peripheral blood CD4 but not CD8 t-lymphocytes in patients with exacerbation of asthma transcribe and translate messenger RNA encoding cytokines which prolong eosinophil survival in the context of a Th2-type pattern: effect of glucocorticoid therapy.

T-lymphocyte (T-LC)-derived cytokines have been implicated in asthma pathogenesis. Activation of peripheral blood CD4 but not CD8 T-LC and a Th2-type pattern of elevated cytokine mRNA expression in BAL fluid T-LC have been observed in asthmatics, but the principal source (CD4 or CD8 T-LC) of these cytokines is unknown. Our objective was to measure expression of Th1- and Th2-type cytokine mRNA and spontaneous secretion of IL-3, IL-5, and GM-CSF by peripheral blood CD4 and CD8 T-LC from asthmatics before and after oral glucocorticoid therapy and non-asthmatic controls. We used in situ hybridization to detect mRNA expression in isolated CD4 and CD8 T-LC, and an in vitro eosinophil survival assay to detect secretion of IL-3, IL-5, and GM-CSF in T-LC culture supernatants. Comparing the asthmatics with the controls, elevated percentages of CD4 T-LC expressed mRNA encoding IL-5, IL-4, and GM-CSF (P < 0.02) but not IL-3, IL-2, or IFN-gamma. In CD8 T-LC, mRNA expression was generally low with no significant differences between the groups. In the asthmatics, the percentages of CD4 T-LC expressing IL-5 mRNA correlated with disease severity and the numbers of peripheral blood eosinophils (P < 0.01). Culture supernatants of asthmatic CD4 but not CD8 T-LC exhibited significantly higher (P = 0.0003) eosinophil survival-prolonging activity compared with controls, in which low activity was detected. Inhibition with anti-cytokine antibodies suggested that GM-CSF, and to a lesser extent IL-5 and IL-3, could account for this activity. After oral glucocorticoid therapy of the asthmatics, lung function improved and the percentages of CD4 T-LC expressing mRNA encoding IL-3, IL-5, and GM-CSF but not IL-2, IL-4, or IFN-gamma were reduced (P < 0.04). Secretion of eosinophil survival-prolonging activity by the CD4 T-LC was also reduced (P = 0.004). We conclude that peripheral blood CD4 but not CD8 T-LC from asthmatics express cytokine mRNA in a Th2-type pattern and show elevated secretion of cytokines prolonging eosinophil survival. Glucocorticoid therapy of asthmatics is associated with a reduction in the percentages of CD4 T-LC expressing IL-3, IL-5, and GM-CSF mRNA and secretion of the corresponding proteins.

Adolescent↗

PubMed1995

Ozone stimulates synthesis of inflammatory cytokines by alveolar macrophages in vitro.

Ozone (O3) is one of the major irritant oxidant gases in photochemical smog. In the present study, the in vitro effect of low concentrations of O3 (0.1 to 1 ppm) was evaluated on cell viability and cytokine secretion by alveolar macrophages (AM) from guinea pigs and healthy subjects. Cell injury was estimated immediately after O3 exposure by evaluation of ATP cell content (measured by bioluminescence) and lactic dehydrogenase (LDH) release in the culture medium. No cytotoxic effect was found: the ATP cell content of both guinea pig AM and human AM did not significantly change after O3 exposure and similarly the LDH release in the culture medium was unchanged. AM-derived cytokines (tumor necrosis factor alpha [TNF alpha], interleukin-1 beta [IL-1 beta], interleukin-6 [IL-6], and interleukin-8 [IL-8]) were evaluated in AM supernatants. O3 exposure was associated with a significant increase in cytokine secretion, with a peak value at 0.4 ppm O3. The exposure of the guinea pig AM to 0.4 ppm O3 for 60 min increased the IL-6 activity by 252 +/- 60% and TNF activity by 202 +/- 35%. The increase in monokine production by the human AM was 443 +/- 208% for TNF alpha, 484 +/- 171% for IL-1 beta, 383 +/- 147% for IL-6, and 226 +/- 45% for IL-8 after a 60-min exposure to 0.4 ppm O3. Lowest O3 concentrations (0.1 and 0.2 ppm) only increased TNF alpha secretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗

PubMed1995

Granulocyte macrophage colony-stimulating factor contributes to enhanced monocyte survival in chronic atopic dermatitis.

Evidence suggesting that prolonged effector cell survival may contribute to perpetuation of inflammation prompted us to ask whether monocyte macrophages, the predominate inflammatory cell in the lesion of chronic atopic dermatitis (AD), exhibit enhanced survival in AD. Cultures of peripheral blood monocytes from patients with chronic AD, psoriasis, and from normal (NL) donors were examined for morphologic features and DNA fragmentation characteristic of cells undergoing the process of apoptosis (programmed cell death). Cultures of AD monocytes exhibited a significantly lower incidence of apoptosis than did cultures of NL monocytes (45 vs 68%, P < 0.01), or psoriatic monocytes (45 vs 80%, P < 0.01). Furthermore, AD monocytes were unresponsive to both IL-1, an inhibitor of apoptosis, and IL-4, an enhancer of apoptosis, in comparison to cultured NL monocytes. Of note, GM-CSF in a concentration-dependent fashion, decreased the incidence of apoptosis in NL monocyte cultures and rendered them unresponsive to these cytokines. These findings suggested that GM-CSF may enhance monocyte survival in AD. In support of this hypothesis, AD monocyte cultures produced fivefold more GM-CSF than did cultures of NL monocytes or psoriatic monocytes (P < 0.05). Additionally, there was a significantly greater number of GM-CSF mRNA expressing cells detected by in situ hybridization in biopsies of lesions of chronic AD than in acute AD or NL skin (P < 0.05). Finally, NL monocytes incubated with supernatants obtained from monocytes of AD patients exhibited significant inhibition of apoptosis, an effect that could be ablated by a neutralizing antibody to GM-CSF. Taken together, these data strongly suggest that increased production of GM-CSF by cells from patients with AD inhibits monocyte apoptosis and may contribute to the chronicity of this inflammatory disease.

Acute Disease↗

PubMed1995

Transfer of allergic airway responses with antigen-primed CD4+ but not CD8+ T cells in brown Norway rats.

Activated CD4+ helper T cells have been demonstrated in asthmatic airways and postulated to play a central role in eliciting allergic inflammation; direct evidence of their involvement seems to be lacking. We hypothesized that CD4+ T cells have the potential to induce allergic responses to antigen challenge, and tested this hypothesis in a model of allergic bronchoconstriction, the Brown Norway rat, using the approach of adoptive transfer. Animals were actively sensitized to either ovalbumin (OVA) or BSA and were used as donors of T cells. W3/25(CD4)+ or OX8(CD8)+ T cells were isolated from the cervical lymph nodes of sensitized donors and transferred to naive BN rats. 2 d after adoptive transfer recipient rats were challenged by OVA inhalation, and changes in lung resistance (RL), bronchoalveolar lavage (BAL) cells, and serum levels of antigen-specific IgE were studied. After OVA challenge recipients of OVA-primed W3/25+ T cells exhibited sustained increases in RL throughout the entire 8-h observation period and had significant bronchoalveolar lavage eosinophilia, which was detected by immunocytochemistry using an antimajor basic protein mAb. Recipients of BSA-primed W3/25+ T cells or OVA-primed OX8+ T cells failed to respond to inhaled OVA. OVA-specific immunoglobulin E was undetectable by ELISA or skin testing in any of the recipient rats after adoptive transfer. In conclusion, antigen-induced airway bronchoconstriction and eosinophilia were successfully transferred by antigen-specific W3/25+ T cells in Brown Norway rats. These responses were dependent on antigen-primed W3/25+ T cells and appeared to be independent of IgE-mediated mast cell activation. This study provides clear evidence for T cell mediated immune mechanisms in allergic airway responses in this experimental model.

Allergens↗

PubMed1995

Localization and characterization of endothelin-1 binding sites in the transplanted human lung.

The localization and characterization of endothelin-1 (ET-1) binding in sections of transplanted and control human lung tissues was investigated by in vitro autoradiography. Binding of [25I]ET-1 was saturable and specific, and demonstrated a single class of binding sites. Scatchard analysis of the data revealed a Kd of 0.52 +/- 0.15 nM and a Bmax of 61.17 +/- 4.5 amol/mm2 to normal lung parenchyma, and a Kd of 0.48 +/- 0.29 nM and a Bmax of 123.9 +/- 18.5 amol/mm2 to normal bronchial smooth muscle. In transplanted human lung, the binding characterizations were similar to those of normal lung. Scatchard analysis indicated high-affinity sites having a Kd of 0.8 +/- 0.19 nM and a Bmax of 153.6 +/- 9.2 amol/mm2 to lung parenchyma and a Kd of 0.59 +/- 0.21 nM and a Bmax of 141.77 +/- 14.6 amol/mm2 to bronchial smooth muscle. Binding in transplanted and control tissues was similar and was inhibited by co-incubation with an excess of unlabeled ETs (ET-1 > ET-2 > ET-3) but not by other unlabeled peptides. Binding was mainly localized to lung parenchyma, small blood vessels [muscular pulmonary artery (100-500 mm) and bronchial blood vessels], pulmonary veins, and bronchial smooth muscle. The specific binding in small blood vessels was lower in transplanted lung than in control lung. Less specific binding was found in elastic pulmonary vessels than in small blood vessels in both transplanted and control lungs. No binding was found in the cellular perivascular infiltrates of the transplanted lung. These results suggest that ET-1 acts intrinsically and that high-affinity receptors for it exist in transplanted lung both in the parenchyma and bronchial smooth muscle.

Adolescent↗

PubMed1995

Localization and characterization of endothelin-1 receptor binding in the blood vessels of human pulmonary tumors.

We have demonstrated endothelin-1 (ET-1) binding sites in the blood vessels of human pulmonary tumors by in vitro autoradiography. The blood vessels of the tumors were confirmed by immunostaining with von Willebrand factor. Specific [125I]ET-1 binding was identified in the blood vessels of all sizes in both tumor and stromal tissues. Nonspecific binding was observed in squamous cell carcinomas and in carcinoids. The ET-1 binding in blood vessels was specific, saturable, and time-dependent. The binding reached equilibrium at 120 min. Scatchard analysis of [125I]ET-1 binding to sections of blood vessels of squamous cell carcinoma indicated binding to a single class of binding sites, with a dissociation constant (Kd) of 0.16 nM and a maximal density of binding sites (Bmax) of 126 amol/mm2. The binding was competitively inhibited by ET-1 >> VIC > ET-2 > sarafotoxin (SRb) > ET-3 but not by other unrelated peptides. Our results provide evidence that ET-1 binding is localized in the blood vessels of pulmonary tumors and in stromal tissues surrounding the tumor nest. ET may play a role in the angiogenesis of tumor growth.

Autoradiography↗

PubMed1994

Histamine induces interleukin-8 secretion by endothelial cells.

It has been shown that histamine induces early changes on endothelial cells (EC), such as a transient expression of P-selectin and secretion and/or surface expression of early mediators (eg, prostacyclin [PG1(2)], platelet-activating factor [PAF], and leukotriene B4 [LTB4]). However, delayed effects of histamine on EC and particularly on cytokine production are undefined. In this study, the effect of histamine on interleukin (IL)-8 production by EC was evaluated using an enzyme-linked immunosorbent assay (ELISA) method and mRNA expression. The results showed that histamine increased the secretion and the mRNA expression of IL-8 by EC. Histamine-induced IL-8 production was (1) dose-dependent (at a dose > or = 10(-6) mol/L), (2) potentialized by costimulation with tumor necrosis factor (TNF)-alpha, (3) inhibited by H1 or H2 histamine receptor antagonists, and (4) significantly increased 4 hours after the initial stimulation. These data suggest that histamine may be involved in the control of the late inflammatory reaction associated to allergic disorders through IL-8 secretion by EC.

Cells, Cultured↗