Biomedical subjects

Q Hamid

Publications and source records attributed to Q Hamid.

At least 91 records · Page 5Linked to original sources

PubMed1998

Association of increased CD4+ T-cell infiltration with increased IL-16 gene expression in atopic dermatitis.

BACKGROUND: The mechanisms involved in the initiation and the maintenance of skin inflammation in atopic dermatitis (AD) are poorly understood. Previous studies have demonstrated increased numbers of infiltrating CD4+ T cells in acute lesions compared with normal control skin. IL-16 is a cytokine that has selective chemotactic activity for CD4+ cells. OBJECTIVE: We sought to examine whether IL-16 expression might be upregulated in acute versus chronic AD. METHODS: We investigated the expression of IL-16 mRNA in skin biopsy specimens from acute and chronic skin lesions, as well as from the uninvolved skin of patients with AD and normal skin. Cryostat sections from 4% paraformaldehyde-fixed skin biopsy specimens were processed for in situ hybridization by using cRNA coding for IL-16 mRNA. Numbers of infiltrating CD4+ and CD8+ cells were also determined by immunocytochemistry. RESULTS: There were positive signals for IL-16 mRNA both in the basal layer of the epidermis and in the dermis of AD skin biopsy specimens from all subjects studied. The numbers of epidermal and dermal IL-16 mRNA+ cells were significantly increased in acute skin lesions compared with chronic (P <.01) and uninvolved (P <.001) skin lesions and compared with normal skin (P <.001). The number of CD4+ cells was significantly increased in acute skin lesions compared with chronic (P <.01) skin lesions and uninvolved skin (P <.01) and compared with normal skin (P <.01). Significant correlations were found between the numbers of CD4+ cells and the numbers of epidermal (r = 0.82, P <.001) and dermal (r = 0.71, P <.001) IL-16 mRNA+ cells. CONCLUSION: The results demonstrate that upregulation of IL-16 mRNA expression in acute AD is associated with increased numbers of CD4+ cells, suggesting that IL-16 may play a role in the initiation of skin inflammation, presumably through recruitment of CD4+ cells.

Biopsy↗

PubMed1998

Interleukin-6 expression in chronic sinusitis: colocalization of gene transcripts to eosinophils, macrophages, T lymphocytes, and mast cells.

Chronic sinusitis in allergic (ACS) and nonallergic (NCS) patients is characterized by persistent inflammation and subepithelial fibrosis of the sinus mucosa. The inflammatory infiltrate is rich in T lymphocytes, monocyte/macrophages, plasma cells, and eosinophils. Th2-type cytokines are thought to regulate inflammatory cell recruitment, activation, survival, and the release of tissue-damaging mediators. Interleukin-6 is a proinflammatory Th2-type cytokine that stimulates fibroblast proliferation and collagen synthesis. Expression of interleukin-6 has been reported in pulmonary fibrosis and a number of other conditions associated with fibrotic tissue changes. In vitro studies have indicated that interleukin-6 is produced by macrophages, T cells, eosinophils, mast cells, and other cell types. Here we examined interleukin-6 messenger RNA and immunoreactivity in the sinus epithelium and subepithelium of subjects with ACS and NCS by in situ hybridization and immunocytochemistry, performed on sinus biopsy and polyp sections obtained from patients. Nasal turbinate biopsy specimens from normal volunteers were used as controls. Interleukin-6 messenger RNA and immunoreactivity were expressed by a significantly greater proportion of epithelial and subepithelial cells in ACS and NCS subjects than in normal controls. There was no difference in epithelial or subepithelial interleukin-6 expression between ACS and NCS patients. Colocalization studies revealed that macrophages, T cells, eosinophils, and mast cells are sources of interleukin-6 messenger RNA in ACS and NCS. The numbers of interleukin-6 messenger RNA-positive cells coexpressing immunoreactivity for the mast-cell marker were significantly greater in ACS than in NCS subjects. The results of this study suggest a role for interleukin-6 in the inflammatory response of chronic sinusitis.

Adult↗

PubMed1998

Comparison of inflammatory cell profile and Th2 cytokine expression in the ethmoid sinuses, maxillary sinuses, and turbinates of atopic subjects with chronic sinusitis.

Chronic sinusitis is a common disease characterized by persistent inflammation of the sinus mucosa. This study was undertaken to investigate immunopathologic findings in biopsy specimens from the ethmoid sinuses, maxillary sinuses, and inferior nasal turbinates of 14 allergic subjects with chronic sinusitis. The composition of the inflammatory infiltrate in the three tissue sites was examined by immunocytochemistry with anti-CD3 (total T cells), anti-CD4 (helper T cells), anti-CD8 (suppressor T cells), anti-MBP (eosinophils), antitryptase (mast cells), and antichymase (mast cells) antibodies. These revealed a significant increase in the T-cell helper/suppressor ratio and eosinophils in the ethmoid sinus mucosa compared with those in the maxillary sinus mucosa and the inferior turbinate. Eosinophil numbers were also higher in the maxillary sinus than in the inferior turbinate. Mast cells were present in significantly higher numbers in the ethmoid sinus and inferior turbinate biopsy sections than in the maxillary sinus. With antisense, radiolabeled riboprobes, we used in situ hybridization to examine the expression of interleukin-4 and interleukin-5 transcripts. The density of cells expressing interleukin-4 transcripts was significantly higher in the inferior turbinate biopsy sections than in those from the ethmoid and maxillary sinuses. In addition, the number of interleukin-4 mRNA-positive cells was higher in the ethmoid than in the maxillary sinus mucosa. The density of interleukin-5 mRNA-positive cells was significantly higher in the ethmoid and maxillary sinuses than in the inferior turbinate. The results of this study indicate (1) a more intense inflammatory response in the ethmoid sinus than in the maxillary sinus and inferior turbinate in allergic chronic sinusitis and (2) different inflammatory responses in the upper airways that are dependent on the anatomic site. These findings have potential implications in the design of new therapeutic interventions for allergic chronic sinusitis.

Adolescent↗

PubMed1998

GM-CSF, IL-5 and RANTES immunoreactivity and mRNA expression in chronic hyperplastic sinusitis with nasal polyposis (NP).

BACKGROUND: Eosinophils are a prominent feature of chronic hyperplastic sinusitis with nasal polyposis (CHS/NP). Our previous studies showed that their presence was associated with the expression of GM-CSF and RANTES mRNA. In allergic NP, increased expression of IL-5 was also found. OBJECTIVE: We wished to examine cytokine immunoreactivity for IL-5, GM-CSF and RANTES mRNA in allergic and non-allergic NP and compare immunoreactivity with expression of cytokine mRNA by in situ hybridization. Methods NP were obtained from five allergic and eight non-allergic subjects with CHS/ NP. Middle turbinate tissue from eight normal subjects were used as controls. Cell-associated cytokine mRNA was detected by in situ hybridization (ISH). Cytokine immunoreactive cells were enumerated by immunostaining. Colocalization immunostaining was also performed to identify specific cell types producing IL-5. RESULTS: Immunostaining for GM-CSF, IL-5 and RANTES protein was increased in both allergic and non-allergic NP compared with control middle turbinates. Allergic polyps contained greater numbers of IL-5 immunoreactive cells (P = 0.01), whereas non-allergic polyps contained greater numbers of GM-CSF immunoreactive cells (P = 0.04). Immunostaining was primarily associated with inflammatory cells, but immunostaining for RANTES and, to a lesser extent GM-CSF, was also seen in the epithelium. The density of immunoreactive cells was variably correlated with cytokine mRNA+ cells (GM-CSF: R=0.56, P=0.05; IL-5: R=0.76, P=0.003; and RANTES: R=0.89, P=0.0005). Colocalization immunostaining revealed that the majority of IL-5 immunoreactive cells in both allergic and non-allergic NP were T lymphocytes. However, allergic NP contained greater numbers of IL-5+/CD3+ T lymphocytes and IL-5+ mast cells, whereas non-allergic NP contained greater numbers of IL-5+ eosinophils. CONCLUSION: We conclude that GM-CSF, IL-5 and RANTES are produced in increased amounts in both allergic and non-allergic NP. Distinguishing features of non-allergic NP include fewer numbers of CD3 T lymphocytes, fewer IL-5+/CD3+ T lymphocytes and greater numbers of IL-5+ eosinophils. These differences may suggest different mechanisms of eosinophil accumulation and activation in allergic vs non-allergic NP.

Asthma↗

PubMed1998

Th-2 type cytokine receptors in allergic rhinitis and in response to topical steroids.

OBJECTIVES: Th-2 type cytokine production (interleukin-4 [IL-4] and interleukin-5 [IL-5]) has been demonstrated to play a significant role in the pathophysiology of allergic rhinitis (AR), and the treatment of AR with topical corticosteroids has been shown to reduce the expression of Th-2 type cytokines in vivo. However, the contribution and expression of Th-2 type cytokine receptors in AR and their response to corticosteroid treatment remain to be clarified. Objectives of the current study are 1. To examine the expression of the cytokine IL-4 and IL-5 receptors (IL-4R and IL-5R) in a nasal allergen challenge model and to contrast this with the expression of the receptor for the Th-1 type cytokine, interferon-gamma receptor (IFN-gammaR), and 2. to examine the effects of pretreatment with topical corticosteroid before allergen challenge on the expression of these same receptors. STUDY DESIGN: Randomized prospective study involving 14 ragweed-allergic subjects evenly divided between placebo and corticosteroid pretreatment. METHODS: Immunocytochemistry (alkaline phosphatase-antialkaline phosphatase labeling [APAAP] technique) was used to stain nasal biopsy specimens before and after allergen challenge. Antibodies used included anti-CD3, CD4, CD8, MBP, IL-4R, IL-5R, and IFN-gammaR. RESULTS: Following allergen challenge, we observed a significant increase in the Th-2 type cytokine receptors (IL-4R and IL-5R; P < .05), as well as a significant decrease in the expression of the Th-1 type cytokine receptor (IFN-gammaR; P < .05). Pretreatment with topical corticosteroids before nasal allergen challenge resulted in decreased expression of IL-4R (P < .05) and IL-5R (P < .05) and increased expression of IFN-gammaR (P <.05). Further, IL-4R and IL-5R expression correlated with eosinophil infiltration in the tissues. CONCLUSIONS: We have demonstrated that in AR, cytokine receptors for IL-4, IL-5, and IFN-gamma follow a similar pattern to their ligands. In addition, pretreatment with topical corticosteroids was shown to alter the cytokine receptor expression pattern from a Th-2 profile more toward a Th-1 profile.

Administration, Topical↗

PubMed1998

Molecular concepts of IgE-initiated inflammation in atopic and nonatopic asthma.

Atopic and nonatopic (intrinsic) asthmatics were characterized by a broadly conserved bronchial mucosal proeosinophilic cytokine network in which IL-5 appears to play a key role. Inappropriate IgE-mediated mechanisms may occur in asthma, irrespective of its atopic status, as suggested by elevated serum IgE concentrations and bronchial mucosal expression of FcepsilonRI, IL-4, IL-13, Iepsilon, and Cepsilon. In general, these observations support the concept that these subtypes of asthma, despite showing distinct clinical and biologic features, share many common immunopathologic mechanisms. The most promising future directions of research regarding intrinsic asthma concern the possible identification of novel allergens or antigens, the detailed description of local bronchial mucosal IgE production, and the understanding of a possible macrophage dysfunction. Furthermore, a role for infectious (viral?) or autoimmune processes has yet to be firmly identified in intrinsic asthma. Animal models may also help us to understand the role of IgE and atopy in asthma. Although these are largely IgE-mediated mechanisms, allergen-induced bronchial hyperresponsiveness and eosinophilic inflammation can also occur in the absence of IgE (null mutation of the Cepsilon locus), as shown in a mouse model of hypersensitivity to Aspergillus fumigatus (57). Thus, despite the absence of atopy, IgE-mediated mechanisms may operate in intrinsic asthma (Fig. 1).

Animals↗

PubMed1998

Glucocorticoid receptor mRNA and protein in fetal rat lung in vivo: modulation by glucocorticoid and androgen.

Pulmonary glucocorticoid receptor (GR) is essential to timely preparation for the onset of breathing air at birth. We have previously used primary culture of late-gestation fetal rat lung cells to demonstrate differential regulation of GR by glucocorticoid depending on cell type. In this study, we hypothesized that the action of glucocorticoid on GR mRNA expression and protein elaboration in lung cells might be modulated by interactions present in vivo but not in primary culture. Given that male sex hormone (androgen) has an inhibitory effect on antenatal lung development, we also postulated that androgen would decrease antenatal lung GR. We report that antenatal maternal injection of the glucocorticoid dexamethasone (1 mg/kg) enhanced fetal lung cellular levels of GR mRNA and protein as assessed by in situ hybridization and immunocytochemistry (ICC), respectively. ICC was performed using polyclonal rabbit anti-human antibody that reacts with rat GR whether bound to ligand or not and does not interfere with GR binding to DNA. Levels of GR mRNA and protein were enhanced in cells throughout all areas of the lung tissue, suggesting that interactions occurring in intact tissue may override the previously reported direct inhibition by glucocorticoid of GR protein elaboration in isolated fetal rat lung epithelial cells. Furthermore, antenatal administration of the androgen 5alpha-dihydrotestosterone (0.2 mg/kg) reduced tissue levels of GR mRNA and protein, consistent with androgenic inhibition of antenatal lung development by decreasing GR. We conclude that glucocorticoids and androgens exert opposite effects on fetal lung GR.

Animals↗

PubMed1998

Granulocyte/macrophage-colony stimulating factor in allergen-induced rhinitis: cellular localization, relation to tissue eosinophilia and influence of topical corticosteroid.

BACKGROUND: Allergen-induced late nasal responses are associated with recruitment of T lymphocytes and eosinophils, and preferential messenger RNA (mRNA) expression of 'TH2-type' cytokines. We previously showed that topical steroid inhibited the late response and associated tissue eosinophilia. In this study we tested the hypothesis that granulocyte/macrophage-colony stimulating factor (GM-CSF) may contribute to late-responses and tissue eosinophilia and is inhibitable by topical corticosteroid. METHODS: Nasal biopsies were taken before and 24 h after nasal allergen provocation following 6 weeks of treatment with either a nasal corticosteroid spray (fluticasone propionate) or a matched placebo nasal spray twice daily. Cryostat sections were processed by immunohistochemistry and in situ hybridization to assess cytokine mRNA expression for GM-CSF. RESULTS: Increases in T lymphocytes and eosinophils were seen in the nasal mucosa after allergen challenge (p = 0.01) which were accompanied by a 5-fold increase in cells expressing mRNA for GM-CSF (p = 0.01). Double immunohistochemistry/in situ hybridization demonstrated that the majority of GM-CSF mRNA+ cells were co-localized to CD68+ (40%), or T cells (40%) with a lesser contribution from eosinophils (<20%). Topical steroid treatment was accompanied by a decrease in both the CD3+ and major basic protein (MBP+) cells expressing GM-CSF mRNA (p = 0.01) with a corresponding proportionate increase in the % of macrophages expressing GM-CSF. CONCLUSIONS: The results indicate that after allergen provocation, eosinophils are recruited to the nasal mucosa and that, at least in part, this may be due to GM-CSF. Topical nasal corticosteroid inhibits late responses and the associated eosinophilia, possibly indirectly by decreasing GM-CSF from T lymphocytes or reducing autocrine production of GM-CSF from eosinophils.

Administration, Intranasal↗

PubMed1998

Interleukin-5 expression in the bone marrow of sensitized Balb/c mice after allergen challenge.

Interleukin-5 (IL-5) is a potent eosinophilopoietic factor implicated in the chronic inflammatory cell accumulation accompanying bronchial asthma. However, its role in stimulating eosinophil differentiation within the bone marrow following allergen exposure remains to be elucidated. The aims of our study were to determine the expression of IL-5 within the bone marrow of sensitized and control mice after allergen exposure, and to investigate the cellular phenotype of IL-5-producing cells. Sensitized Balb/c mice were challenged with either ovalbumin (OVA) or sterile saline. After 6 h, the mice were exsanguinated and the bone marrow prepared for cytospins. Bone marrow-derived cells from OVA-sensitized mice exhibited an increase in IL-5 immunoreactivity and mRNA compared with those from nonsensitized control mice (p < 0. 05). After allergen challenge, there was a further increase in IL-5 expression (p < 0.05) within the bone marrow. Both sensitization and allergen challenge resulted in an increase in the number of cells expressing major basic protein (MBP) (p < 0.05). In nonsensitized mice, the IL-5 mRNA was expressed predominantly by CD34-positive (CD34+) progenitor cells. Following sensitization and allergen challenge, CD3-positive (CD3+) T lymphocytes were the major source of this cytokine. These results demonstrate the presence of IL-5 within the bone marrow of normal Balb/c mice. After sensitization and allergen challenge, the increase in IL-5-producing cells within the bone marrow is attributed by T lymphocytes.

Allergens↗

PubMed1998

Expression of IgE heavy chain transcripts in the sinus mucosa of atopic and nonatopic patients with chronic sinusitis.

We have recently shown the increased mRNA expression of interleukin (IL)-4 and IL-13 in sinus biopsies from allergic subjects with chronic sinusitis (ACS), whereas only IL-13 mRNA was elevated in biopsies obtained from nonallergic subjects with chronic sinusitis (NCS). In the lymph nodes and spleen, these cytokines may promote IgE production through transcriptional activation of the germline IgE heavy chain promoter, an event which precedes immunoglobulin isotype switching to IgE in B cells. We hypothesized that local expression of IL-4 and/or IL-13 might act by inducing germline IgE heavy chain transcript expression locally in the sinus mucosa of chronic sinusitis patients. Mucosal sinus biopsies were obtained from 13 patients with ACS, 12 subjects with NCS, and 11 normal control individuals. The numbers of B cells in the sinus mucosa were studied by immunocytochemistry with anti-CD20 monoclonal antibodies. In situ hybridization was performed using antisense radiolabeled riboprobes complementary to the IgE epsilon -heavy chain germline (Iepsilon) and heavy chain constant region (Cepsilon) gene transcripts. Riboprobes specific for the IgG gamma-heavy chain constant region (Cgamma) were used as an isotype control. Immunocytochemical analysis indicated augmented numbers of CD20-positive B cells in the biopsies obtained from ACS patients compared with NCS subjects (P < 0.05) and normal control subjects (P < 0.01). Statistically significant increases were observed in the numbers of cells expressing Iepsilon and Cepsilon transcripts in the sinus mucosa of ACS patients compared with those with NCS (P < 0. 001) and normal controls (P < 0.001), while Cgamma RNA expression did not differ significantly between the groups. In three randomly selected ACS biopsies, 92-100% of cells expressing Cepsilon transcripts and 100% of Iepsilon RNA-positive cells coexpressed CD20 immunoreactivity. Cells expressing Cepsilon transcripts were also significantly increased in NCS compared with normal controls (P < 0. 05). The results of this study suggest that local IgE class switching occurs in the pathogenesis of ACS and that ACS and NCS are both associated with increased expression of Cepsilon transcripts.

Adult↗

PubMed1998

Interleukin-4, interleukin-5, and granulocyte-macrophage colony-stimulating factor receptor expression in chronic sinusitis and response to topical steroids.

Chronic sinusitis and its associated eosinophilic infiltrate are believed to be mediated, at least in part, by the upregulation of Th-2 cytokines, including interleukin-4, interleukin-5, and granulocyte-macrophage colony-stimulating factor (GM-CSF). Interleukin-4 is involved in IgE production and in eosinophil recruitment through upregulation of vascular cell adhesion molecule-1. Interleukin-5 and GM-CSF are involved in eosinophil growth and survival. The aim of this study was to investigate the expression of receptors for these cytokines in the sinus mucosa of subjects with chronic sinusitis. Using the technique of in situ hybridization to detect specific cytokine receptor messenger RNA, we studied the sinus mucosa of subjects with nonallergic chronic sinusitis, subjects with allergic chronic sinusitis, subjects with allergic chronic sinusitis treated with topical steroids, and normal controls. Our data demonstrate higher expression of interleukin-4 receptor in subjects with allergic chronic sinusitis than in controls (p < 0.001) and higher expression of interleukin-5 receptor in both subjects with nonallergic chronic sinusitis and subjects with allergic chronic sinusitis than in controls (p < 0.001, p < 0.001). The expression of interleukin-4 receptor and interleukin-5 receptor was higher in subjects with allergic chronic sinusitis than in subjects with nonallergic chronic sinusitis (p < 0.001). GM-CSF receptor expression was also found to be higher in subjects with allergic chronic sinusitis and subjects with nonallergic chronic sinusitis than in controls (p < 0.001, p < 0.001). In contrast to interleukin-4 receptor and interleukin-5 receptor, however, expression of GM-CSF receptor was higher in subjects with nonallergic chronic sinusitis than in subjects with allergic chronic sinusitis (p < 0.001). In subjects with allergic chronic sinusitis treated with topical corticosteroids, the expression of interleukin-4 receptor and interleukin-5 receptor messenger RNA levels was significantly lower than levels in patients with allergic chronic sinusitis who were not taking topical steroids (p < 0.001, p < 0.001). Steroid treatment had no effect on GM-CSF receptor messenger RNA expression. In conclusion, our data support a role for Th-2 cytokine receptors in the pathophysiology of chronic sinusitis. Further, our data lend support to the theory that differential activation of distinct cytokine pathways mediates inflammation in chronic sinusitis depending on whether there is associated allergy. Finally, treatment with topical corticosteroids has been demonstrated in chronic sinusitis to downregulate receptors for interleukin-4 and interleukin-5.

Administration, Topical↗

PubMed1998

Assessment by nasal biopsy of long-term use of mometasone furoate aqueous nasal spray (Nasonex) in the treatment of perennial rhinitis.

Allergic rhinitis is associated with specific histopathologic changes in the nasal mucosa including squamous metaplasia and local eosinophilia. Previous studies have shown that mometasone furoate aqueous nasal spray is effective and well tolerated in reducing perennial rhinitis and seasonal allergic rhinitis symptoms. We undertook a multicenter, open-label study to evaluate, by nasal biopsy, the tissue changes associated with mometasone furoate use (200 microg/day) during a 12-month treatment period in patients with perennial rhinitis. Of the 69 patients enrolled in the study, 52 completed all 12 months of treatment. Nasal biopsy specimens obtained from patients at baseline and after treatment were evaluated in a blinded fashion by computerized image analysis, qualitative histologic examination, and immunocytochemistry. Morphologic examination of nasal biopsy specimens showed a decrease in focal metaplasia, no change in epithelial thickness, and no sign of atrophy after treatment with mometasone furoate. Immunocytochemical analyses of nasal biopsy specimens obtained before and after treatment revealed a significant decrease in major basic protein-positive eosinophils and tryptase-positive mast cells in the epithelium and lamina propria after treatment. Mometasone furoate appeared to attenuate the inflammatory process by reducing the extent of inflammatory cell infiltration, particularly of eosinophils. This study demonstrated that long-term administration of mometasone furoate is not associated with adverse tissue changes in the nasal mucosa of patients with perennial rhinitis.

Administration, Intranasal↗

PubMed1998

Local cytokine messenger ribonucleic acid expression and in vitro allergic late phase responses in Brown-Norway rats.

The events subsequent to antigen challenge in allergic asthmatics involve the synthesis of pro-inflammatory cytokines. However, little is known how cytokine gene activation prior to allergen challenge may influence this series of events, nor how cytokine gene expression is related to antigen-induced alterations in lung function. Using a novel in vitro explant technique, we hypothesized that the local expression of cytokines influenced the development of antigen-induced late-onset airway responses, and that alterations in cytokine messenger ribonucleic acid (mRNA) expression were associated with antigen-induced changes in airway luminal area. Explants were prepared from excised lungs of ovalbumin-sensitized Brown-Norway rats. Airways were challenged by direct application of ovalbumin or an irrelevant control antigen. Cryostat sections of explants were used for in situ hybridization and mRNA for interleukin (IL)-2, IL-4 and interferon (IFN)-gamma were detected using radiolabelled probes. We found that the presence of high numbers of cells expressing IFN-gamma and IL-2 mRNA within the airways attenuated the development of antigen-induced late airway responses in sensitized rat lung explants. Furthermore, we observed that cytokine mRNA for IL-4 was significantly increased following allergen exposure in sensitized lung explants exhibiting late airway responses. This study implicates the local expression of interferon-gamma and interleukin-2 messenger ribonucleic acid in the failure of sensitized rat lung explants to exhibit late airway responses, and provides evidence linking local interleukin-4 messenger ribonucleic acid expression to the sequelae of events occurring as a result of antigen exposure within the airways.

Animals↗

PubMed1998

Tuberculin-induced delayed-type hypersensitivity reaction in a model of hu-PBMC-SCID mice grafted with autologous skin.

We have developed an animal model to study human delayed-type hypersensitivity reactions. Previous studies in humans have shown after tuberculin injection the presence of a mononuclear cell infiltration, with almost no eosinophils, associated with a preferential Th-1-type cytokine profile. Human skin graft obtained from tuberculin-reactive donors was grafted onto the back of severe combined immunodeficient mice. After healing, mice were reconstituted intraperitoneally with peripheral mononuclear cells. Tuberculin and diluent were injected intradermally, and skin biopsies were performed 72 hours later. Skin grafts were divided into two parts, one for immunohistochemistry and one for in situ hybridization studies. Immunohistochemistry was performed on cryostat sections using the alkaline phosphatase anti-alkaline phosphatase technique. In the tuberculin-injected sites as compared with the diluent-injected sites, there were significant increases in the number of CD45+ pan leukocytes and CD4+, CD8+, CD45RO+ T cells but not in CD68+ monocytes/macrophages and EG2 or MBP+ eosinophils. The activation markers CD25 and HLA-DR were up-regulated in the tuberculin-injected sites. In situ hybridization was performed using 35S-labeled riboprobes for interleukin (IL)-2, interferon (IFN)-gamma, IL-4, and IL-5. After tuberculin injection, a preferential Th-1-type cytokine profile was observed with significant increases in the numbers of IL-2 and IFN-gamma mRNA-expressing cells. These results are similar to those reported after tuberculin-induced delayed-type hypersensitivity in humans, suggesting that this model might be useful to study cutaneous inflammatory reaction.

Animals↗

PubMed1998

Monocyte chemotactic protein expression in allergy and non-allergy-associated chronic sinusitis.

OBJECTIVE: Chronic sinusitis (CS) is characterized by inflammatory mucosal thickening and polyp formation with a predominantly eosinophilic infiltrate. Chemokines are a novel group of inflammatory mediators capable of attracting specific inflammatory cell populations. Monocyte chemotactic proteins (MCP) are a subfamily of chemokines (MCP-1, MCP-2, MCP-3, and MCP-4) that share a number of functional properties including chemotactic activity for eosinophils. The purpose of this study was to investigate the expression of the MCP family of chemokines in allergy and non-allergy-associated chronic sinusitis using the technique of immunocytochemistry. METHOD: We examined the expression of MCP-1, MCP-3, and MCP-4 in biopsies from the ethmoid sinuses of patients with CS and normal controls. RESULTS: MCPs were localized to the epithelial cells and a subset of inflammatory cells within the mucosa. The expression of both MCP-3 and MCP-4 immunoreactivity were significantly increased in patients with both allergy and non-allergy-associated CS compared to normal controls (p < .001). There was no significant difference in the expression of MCP-1 in nasal biopsies from individuals with CS and normals. The level of expression of MCP-3 and MCP-4 correlated with eosinophil (p < .001) and CD4-positive T-cell infiltrate (p < .001) but not with CD8-positive T-cell infiltration. CONCLUSIONS: Our data suggest biologic redundancy in the expression of eosinophil chemoattractants in CS and a potential role for MCP-3 and MCP-4, but not MCP-1, in the pathophysiology of this disorder. Further, chemokines may be a common link between the eosinophilia of allergy-associated and non-allergy-associated CS, a finding that may have therapeutic implications.

Adult↗

PubMed1997

Allergen-induced increases in IL-5 receptor alpha-subunit expression on bone marrow-derived CD34+ cells from asthmatic subjects. A novel marker of progenitor cell commitment towards eosinophilic differentiation.

We have proposed previously that hemopoietic myeloid progenitors contribute to the ongoing recruitment of proinflammatory cells, namely eosinophils, to sites of allergen challenge in allergic diseases such as asthma. In this study, we investigated the involvement of bone marrow-derived progenitors in the development of allergen-induced pulmonary inflammation in mild asthmatic subjects. By flow cytometry, we enumerated the level of expression of CD34, a hemopoietic progenitor cell marker, on bone marrow aspirates taken before and 24 h after allergen challenge. In addition, the coexpression of the alpha-subunits of IL-3 receptor (IL-3R) and IL-5 receptor (IL-5R) on CD34+ cells was investigated. After allergen-challenge, although no significant change in total BM CD34+ cell numbers was observed, a significant increase in the proportion of CD34+ cells expressing IL-5R alpha, but not IL-3R alpha, was detected in the 24-h post-allergen, compared with the pre-allergen bone marrow. This was associated with a significant blood and sputum eosinophilia and increased methacholine airway responsiveness, 24 h post-allergen. Using simultaneous in situ hybridization and immunocytochemistry, we colocalized the expression of messenger RNA for membrane-bound IL-5R alpha to CD34+ cells. In summary, our data suggest that increased expression of IL-5R alpha on CD34+ cells favors eosinophilopoiesis and may thus contribute to the subsequent development of blood and tissue eosinophilia, a hallmark of allergic inflammation.

Adult↗

PubMed1997

Association of glucocorticoid insensitivity with increased expression of glucocorticoid receptor beta.

In many chronic inflammatory disorders, glucocorticoid (GC) insensitivity is a challenging clinical problem associated with life-threatening disease progression. The molecular basis of GC insensitivity, however, is unknown. Alternative splicing of the GC receptor (R) pre-messenger RNA generates a second GCR, termed GCR-beta, which does not bind GCs but antagonizes the transactivating activity of the classic GCR, termed GCR-alpha. In the current study, we demonstrate that GC-insensitive asthma is associated with a significantly higher number of GCR-beta-immunoreactive cells in peripheral blood than GC-sensitive asthmatics or normal controls. Furthermore, we show that patients with GC-insensitive asthma have cytokine-induced abnormalities in the DNA binding capability of the GCR. These abnormalities can be reproduced by transfection of cell lines with the GCR-beta gene resulting in significant reduction of their GCR-alpha DNA binding capacity. We conclude that increased expression of GCR-beta is cytokine inducible and may account for GC insensitivity in this common inflammatory condition.

Asthma↗

PubMed1997

Increased expression of eotaxin in bronchoalveolar lavage and airways of asthmatics contributes to the chemotaxis of eosinophils to the site of inflammation.

Presently, there is considerable evidence for the participation of eosinophils in the pathophysiology of human bronchial asthma. Although increased numbers of eosinophils are present in the airways and bronchoalveolar lavage (BAL) fluid of atopic asthmatics, the mechanisms responsible for their preferential accumulation are still largely unknown. Eotaxin is a chemokine that promotes the selective recruitment of eosinophils. We report that atopic asthmatic patients have high concentrations of eotaxin in BAL fluid and an increased expression of eotaxin mRNA and protein in the epithelium and submucosa of their airways when compared with normal controls. In the BAL cells from asthmatic patients, eotaxin immunoreactivity colocalized predominantly to macrophages (62.2%), with a lesser contribution from T cells (16.3%) and eosinophils (8.9%). BAL fluid from asthmatics contained chemotactic activity for eosinophils that was attributable in part to the presence of eotaxin. Moreover, eotaxin was more effective at inducing in vitro eosinophil chemotaxis when eosinophils were stimulated with IL-5 (a cytokine that enhances the effector capacity of mature eosinophils). These observations suggest that eotaxin contributes to the pathogenesis of asthma by the specific recruitment of eosinophils into the airways.

Adult↗