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Biomedical subjects

A B Kay

Publications and source records attributed to A B Kay.

At least 19 recordsLinked to original sources
PubMed1992

Human eosinophils synthesize and secrete interleukin-6, in vitro.

Using the technique of in situ hybridization, we have shown that resting, unstimulated, human peripheral blood eosinophils, obtained from subjects with greater than 8% eosinophilia, transcribe and translate messenger RNA (mRNA) for interleukin-6 (IL-6). After incubation for 24 hours in culture medium alone, approximately 19% of eosinophils were positive for IL-6 mRNA. This may be a reflection of their in vivo activation, but also may suggest that the gene for this cytokine is constitutively expressed in eosinophils. After stimulation with interferon gamma (IFN gamma) (500 U/mL), the percentage of IL-6-mRNA+ cells increased to 51.3%. This was accompanied by an enhancement of intensity of the hybridization signals. The specificity of the IL-6 probe and the hybridization signals was confirmed by the use of an IL-6 sense probe and RNase pretreatment of cell preparations. Evidence for the translation of IL-6 mRNA was obtained by immunocytochemical staining. Normal and activated eosinophils gave IL-6-specific immunoreactivity with a polyclonal antihuman IL-6 antibody. A higher percentage of positive cells was detected among activated eosinophils than those treated with medium alone. Using a specific immunoenzymetric assay, we detected 190.15 +/- 18.1 and 403.32 +/- 213.6 pg/mL of IL-6 in supernatants of unstimulated and IFN gamma-treated (24 and 48 hours) eosinophils, respectively. These data indicate that eosinophils are an important cellular source of IL-6.

Antibodies↗
PubMed1992

Interleukin-5 selectively enhances the chemotactic response of eosinophils obtained from normal but not eosinophilic subjects.

We have attempted to determine whether interleukin-5 (IL-5), a cytokine that selectively affects eosinophil (as opposed to neutrophil) differentiation and activation, also modulates eosinophil migrational responses. Using a modified Boyden chemotaxis assay, IL-5, IL-3, and granulocyte-macrophage colony-stimulating factor (GM-CSF) gave a weak locomotory response for eosinophils from normal nonatopic subjects (optimal at 10(-11), 10(-8), and 10(-9) mol/L, respectively), but not for eosinophils from subjects with an eosinophilia associated with asthma and/or allergic rhinitis. In contrast, IL-5 and IL-3 had no effect on neutrophils, while GM-CSF was chemotactic for neutrophils over a limited concentration range, optimal at 10(-8) mol/L. When eosinophils from normal subjects were incubated with IL-5 (10(-9) mol/L), the locomotory response to platelet-activating factor (PAF; 10(-8) mol/L, P less than .05), leukotriene B4 (LTB4; 10(-6) mol/L, P less than .01), and N-formyl-methionyl-leucyl-phenylalanine (FMLP; 10(-8) mol/L, P less than .01) was significantly enhanced. The percentage enhancement of eosinophil locomotion by IL-5 was greater for eosinophils from normal as compared with subjects with an eosinophilia associated with asthma (P less than .05 for PAF and LTB4; P less than .01 for FMLP). Preincubation of eosinophils from normal subjects with IL-5 (10(-9) mol/L) attenuated the subsequent locomotory response to IL-5 (10(-12) and 10(-11) mol/L, P less than .05). Therefore, the observed refractoriness of eosinophils from eosinophilic subjects to both directional migratory and priming effects of IL-5 in vitro, may reflect a deactivation process resulting from prior exposure in vivo. The selective priming of eosinophil but not neutrophil locomotion by IL-5 suggests that this cytokine may play a significant role in the preferential accumulation of eosinophils at sites of allergic inflammation.

Asthma↗
PubMed1992

Cytokine messenger RNA expression for IL-3, IL-4, IL-5, and granulocyte/macrophage-colony-stimulating factor in the nasal mucosa after local allergen provocation: relationship to tissue eosinophilia.

Tissue eosinophilia is characteristic of human atopic allergic inflammation, although the mechanism is largely unknown. In this study we test the hypothesis that eosinophil infiltration during allergen-provoked rhinitis in hayfever sufferers may occur as a consequence of activation of a population of cells having a characteristic cytokine profile equivalent to the murine Th lymphocyte Th2 subset. Biopsies of the nasal inferior turbinate were obtained from 10 grass pollen-sensitive patients 24 h after local nasal provocation with allergen and after a control challenge with the allergen diluent. Biopsies were divided into two and subsequently processed for in situ hybridization using 35S-labeled RNA probes for selected cytokines and for immunohistology using an eosinophil granule mAb (EG2) which recognizes secreting eosinophils. At allergen-challenged sites compared with control sites there were significant increases in mRNA+ cells for IL-3 (p less than 0.04), IL-4 (p = 0.01), IL-5 (p = 0.02) and granulocyte/macrophage-CSF (p = 0.03). In contrast, only occasional hybridization signals were observed for IL-2 and IFN-gamma at both allergen and control sites. After allergen there was an increase (p = 0.01) in EG2+ eosinophils and significant correlations were observed between EG2+ cells and mRNA expression for "Th2-type" cytokines, particularly IL-5 (r = 0.90, p less than 0.0001). These results demonstrate that recruitment of eosinophils during human allergen-induced rhinitis is associated with cells expressing mRNA for IL-3, IL-4, IL-5, and granulocyte/macrophage-CSF.

Adult↗
PubMed1992

Preferential messenger RNA expression of Th1-type cells (IFN-gamma+, IL-2+) in classical delayed-type (tuberculin) hypersensitivity reactions in human skin.

We recently established that the allergen-induced late-phase cutaneous reaction in atopic subjects was associated with high mRNA expression for the cytokine gene cluster IL-3, IL-4, IL-5, and granulocyte/macrophage-CSF (GM-CSF), compared with IFN-gamma and IL-2, suggesting that allergic skin reactions contained the equivalent of murine Th2 cells. We now show that, in humans, classical delayed-type hypersensitivity is associated with cells preferentially expressing a Th1-type cytokine profile. Cryostat sections from skin biopsies from 24-h tuberculin reactions in 10 nonatopic subjects were hybridized with 35S-labeled RNA probes and processed by using in situ hybridization. On the whole, tuberculin biopsies showed preferential expression of mRNA encoding IFN-gamma and IL-2, although in some cases mRNA expression for IL-3, IL-4, IL-5, and GM-CSF was also observed. Biopsies from diluent control sites gave only occasional signals. The difference in the number of cells expressing mRNA in the diluent compared with tuberculin sites was statistically significant for IL-2 and IFN-gamma (p less than 0.01) but not for IL-3, IL-4, IL-5, and GM-CSF. These results suggest that cells infiltrating the site of the 24-h tuberculin reaction preferentially transcribe mRNA encoding IFN-gamma and IL-2, supporting the hypothesis that delayed-type hypersensitivity is associated with preferential activation of cells having a cytokine profile similar to the murine Th1 subset.

Adult↗
PubMed1992

IFN-gamma induces expression of Fc gamma RIII (CD16) on human eosinophils.

The extent to which eosinophils constitutively express FcRIII (CD16) is controversial. We were unable to detect this receptor on freshly isolated, peripheral blood eosinophils. The capacity of eosinophils to change their Fc gamma R expression in vitro has not been previously demonstrated. Culture with IFN-gamma for 1 to 2 days induced FcRIII expression on eosinophils. This effect was dose-dependent and significant at concentrations of 100 U/ml IFN-gamma and above. Expression of FcRI (CD64) and FcRII (CDw32) was also upregulated. These increases were inhibited by cycloheximide (10(-6) M), suggesting a requirement for protein synthesis, and dexamethasone (10(-6) M). Northern blot analysis demonstrated the presence of FcRIII mRNA in eosinophils cultured with IFN-gamma for 2 days but not in unstimulated eosinophils. By contrast, culture with IL-3 caused an up-regulation of eosinophil FcRII expression but did not induce expression of FcRI or FcRIII. The FcRIII expressed by eosinophils after IFN-gamma stimulation was functionally active, as shown by the triggering of eosinophil membrane depolarization and LTC4 generation by an anti-CD16 mAb. Treatment of IFN-gamma-stimulated eosinophils with phosphatidylinositol-specific phospholipase C reduced FcRIII expression, suggesting that, like neutrophils, eosinophils express the phosphatidylinositol glycan-linked form of this receptor. Therefore, this study demonstrates that IFN-gamma-treated eosinophils express a functionally active, phosphatidylinositol glycan-anchored form of FcRIII.

Antigens, Differentiation↗
PubMed1992

Trial of cyclosporin in corticosteroid-dependent chronic severe asthma.

The treatment of chronic severe asthma is unsatisfactory for many patients. In a randomised, double-blind, placebo-controlled, crossover trial we have tested whether cyclosporin, which is thought to act primarily by inhibition of T lymphocyte activation, improves lung function in corticosteroid-dependent asthmatics. After a 4-week run-in period, 33 patients with longstanding asthma (mean duration 27 years), and who had required continuous oral corticosteroids for a mean of 9.3 years, were randomised to receive either cyclosporin (initial dose 5 mg/kg per day) or placebo for 12 weeks, crossing over after a 2-week washout period. Mean baseline forced expiratory volume in 1 s (FEV1) was 60.1% of the predicted value. 2 patients failed to complete the protocol and 1 withdrew because of hypertrichosis. Cyclosporin therapy resulted in a mean increase above placebo of 12.0% in morning peak expiratory flow rate (PEFR; p less than 0.004) and 17.6% in FEV1 (p less than 0.001). The frequency of disease exacerbations requiring an increased prednisolone dose was reduced by 48% in patients on cyclosporin compared with placebo (p less than 0.02). Diurnal variation in PEFR decreased by a mean of 27.6% (p = 0.04). Cyclosporin for 12 weeks was well tolerated by this group of chronic asthmatics, in whom the mean whole-blood trough concentration was 152 micrograms/l. These findings provide further evidence of a role for activated T lymphocytes in the pathogenesis of asthma. Specific pharmacological targeting of this cell could form the basis of a novel approach to the treatment of asthma.

Adult↗
PubMed1992

Predominant TH2-like bronchoalveolar T-lymphocyte population in atopic asthma.

BACKGROUND: In atopic asthma, activated T helper lymphocytes are present in bronchial-biopsy specimens and bronchoalveolar-lavage (BAL) fluid, and their production of cytokines may be important in the pathogenesis of this disorder. Different patterns of cytokine release are characteristic of certain subgroups of T helper cells, termed TH1 and TH2, the former mediating delayed-type hypersensitivity and the latter mediating IgE synthesis and eosinophilia. The pattern of cytokine production in atopic asthma is unknown. METHODS: We assessed cells obtained by BAL in subjects with mild atopic asthma and in normal control subjects for the expression of messenger RNA (mRNA) for interleukin-2, 3, 4, and 5, granulocyte-macrophage colony-stimulating factor (GM-CSF), and interferon gamma by in situ hybridization with 32P-labeled complementary RNA. Localization of mRNA to BAL T cells was assessed by simultaneous in situ hybridization and immunofluorescence and by in situ hybridization after immunomagnetic enrichment or depletion of T cells. RESULTS: As compared with the control subjects, the subjects with asthma had more BAL cells per 1000 cell that were positive for mRNA for interleukin-2 (P less than 0.05), 3 (P less than 0.01), 4 (P less than 0.001), and 5 (P less than 0.001) and GM-CSF (P less than 0.001). There was no significant difference between the two groups in the number of cells expressing mRNA for interferon gamma. In the subjects with asthma, mRNA for interleukin-4 and 5 was expressed predominantly by T lymphocytes. CONCLUSIONS: Atopic asthma is associated with activation in the bronchi of the interleukin-3, 4, and 5 and GM-CSF gene cluster, a pattern compatible with predominant activation of the TH2-like T-cell population.

Adult↗
PubMed1992

Activated T-lymphocytes and eosinophils in the bronchial mucosa in isocyanate-induced asthma.

We have studied the phenotype and activation status of leukocytes in the bronchial mucosa in patients with isocyanate-induced asthma. Fiberoptic bronchial biopsy specimens were obtained from nine subjects with occupational (five toluene- and four methylene diisocyanate-sensitive) asthma, 10 subjects with extrinsic asthma, and 12 nonatopic healthy control subjects. Bronchial biopsy specimens were examined by immunohistology with a panel of monoclonal antibodies and the alkaline phosphatase-antialkaline phosphatase method. There was a significant increase in the number of CD25+ cells (interleukin-2 receptor-bearing cells, presumed "activated" T-lymphocytes; p less than 0.01) in isocyanate-induced asthma compared with that of control subjects. There were also significant increases in major basic protein (BMK-13)-positive (p less than 0.02) and EG2-positive (p less than 0.01) cells that represent total and "activated" eosinophil cationic protein-secreting eosinophils, respectively. In agreement with our previous findings, CD25+ (p less than 0.01), BMK-13 (p less than 0.03), and EG2+ (p less than 0.01) cells were also elevated in extrinsic asthma. No significant differences were observed in the numbers of T-lymphocyte phenotypic markers (CD3, CD4, and CD8) between subjects with asthma (isocyanate-induced and extrinsic) and control subjects. Similarly, no significant differences in immunostaining for neutrophil elastase (neutrophils) or CD68 (macrophages) were observed. The results suggest that isocyanate-induced occupational asthma and atopic (extrinsic) asthma have a similar pattern of inflammatory cell infiltrate. The results support the view that T-lymphocyte activation and eosinophil recruitment may be important in asthma of diverse etiology.

Adult↗
PubMed1992

Immunohistology of the nasal mucosa in seasonal allergic rhinitis: increases in activated eosinophils and epithelial mast cells.

The immunohistology of the nasal mucosa was examined in 13 grass pollen-sensitive patients and in seven normal nonatopic control subjects before and during the pollen season. Cryostat sections (6 microns) of biopsy specimens from the inferior turbinate were immunostained with the alkaline-phosphatase antialkaline-phosphatase method and a panel of monoclonal antibodies. Mast cell subtypes were measured with a double sequential immunostaining method. Within the submucosa, seasonal increases in total (MBP+, p less than 0.01) and "activated" (EG2+, p less than 0.01) eosinophils were observed for the patients, which were significant when these counts were compared with counts for those of control subjects (MBP+ p less than 0.01; EG2+ p less than 0.001). Within the nasal epithelium, seasonal increases in total (p less than 0.05) and "activated" (p less than 0.02) eosinophils were also observed. Mast cell counts revealed seasonal increases in tryptase-only positive mast cell (MCT) (p less than 0.02) but not chymase plus tryptase-positive mast cells (MCTC) within the epithelium that were significant when counts were compared with those of control subjects (p less than 0.03). No significant changes were observed within the submucosa or epithelium for total leukocytes (CD45+ cells) or T-lymphocytes (CD3+, CD4+, CD8+, and CD 25+ cells) for either group. Similarly, no significant changes were observed for neutrophils (antielastase), macrophages (CD68+), nor HLA-DR+ cells. In the subjects with rhinitis, seasonal submucosal CD3+ counts correlated with MBP+ eosinophils (r = 0.56; p less than 0.05) and MCTS (r = 0.65; p less than 0.02). Similarly, seasonal epithelial EG2+ eosinophil counts correlated with MCTs (r = 0.56; p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

T cells and eosinophils in the pathogenesis of asthma.

Persistent asthma is characterized by chronic inflammation of the bronchial mucosa, where T cells and eosinophils are prominent. This article summarizes the evidence that asthmatic bronchial inflammation is initiated and propagated by cytokines secreted by activated T cells and other cells, and describes how the release of specific cytokines could result in local preferential accumulation and activation of eosinophils.

Asthma↗
PubMed1992

Eosinophils 1992.

This report from a recent meeting* highlights some of the key developments in eosinophil research and assesses their impact on current views of the role of eosinophils in inflammation. Considerable progress has been made in defining the structure, constituents and properties of eosinophils in vitro and these new insights into eosinophil biology are summarized. A new era is beginning in which the roles of eosinophils can be assessed and defined in vivo.

Animals↗
PubMed1992

Asthma. Eosinophils and neutrophils.

Eosinophils are strongly implicated as a major proinflammatory cell in the pathogenesis of asthma. Basic proteins from the crystalloid granule may be responsible for damage to mucosal epithelium whereas membrane-derived lipid mediators (particularly platelet activating factor and leukotriene C4) might directly influence bronchial smooth muscle contraction, microvascular permeability and mucus hypersecretion. The numbers of eosinophils and their products correlated with the severity of disease whereas successful treatment is usually associated with a resolution of local eosinophilia. Neutrophils may also be implicated in the pathogenesis of asthma but the evidence that this cell per se plays an important role remains controversial. Neutrophil products have the potential for altering airway function. More research is required to define the precise role of this cell type in asthma. It needs to be emphasised that the inflammation associated with bronchial asthma is complex and involves several cell types (i.e. T lymphocytes, mast cells and macrophages) in addition to the eosinophil and neutrophil.

Asthma↗
PubMed1992

Asthma. Role of T-lymphocytes and lymphokines.

It is now widely accepted that bronchial mucosal inflammation is an important feature of the pathogenesis of asthma. Lymphocytes probably play a role in all inflammatory responses which are antigen driven, since they are the only cells which, through the CD3/antigen receptor complex, directly recognise and respond to processed antigens. Activated T-lymphocytes, through the release of lymphokines, have the capacity to control the amount and nature of inflammatory responses. Increasing evidence is accumulating that activated CD4 T-lymphocytes participate in the inflammatory reaction observed in the asthmatic bronchial mucosa, by secreting lymphokines which attract and activate eosinophils and mast cells. CD4 T-lymphocytes may be a potentially important target for glucocorticoid therapy in asthma. Further characterisation of the functional properties of these cells might allow a definition of asthma in terms of functional abnormalities at the cellular level, and may uncover variability in asthma pathogenesis according to its aetiology.

Asthma↗
PubMed1992

The effect of a single oral dose of prednisolone or cetirizine on inflammatory cells infiltrating allergen-induced cutaneous late-phase reactions in atopic subjects.

The effect of a single dose of prednisolone (20 mg) or cetirizine (10 mg) on the immunohistology of the cutaneous late-phase reaction was determined in a double-blind, placebo-controlled, cross-over study in 12 atopic allergic individuals. The subjects were challenged with intradermal allergen (30 BU) 2 hr after ingestion of the drugs or placebo. The magnitude of the cutaneous reactions were determined at 15 min, 6 and 24 hr, and skin biopsies performed at 24 hr. Cetirizine produced a 50% average inhibition of the immediate weal and flare response (P = 0.001) and a 27% average inhibition of the 6 hr late-phase induration (NS). Prednisolone reduced the immediate (27%, P = 0.03) and significantly inhibited the late-phase reaction (53%, P = 0.02). Prednisolone significantly inhibited infiltration of CD45+ (total leucocytes), neutrophil elastase+, EG2+ (activated eosinophils) and CD25+ (IL-2R) cells (P = 0.017, 0.005, 0.005 and 0.032 respectively). CD3, CD4, CD8 and HLA-DR expression was also inhibited but this was not significant. Cetirizine also reduced the numbers of EG2+ cells, particularly those with high counts before treatment but the overall results were not significant. No other changes in the cellular infiltrate were demonstrated when cetirizine was compared with placebo. These findings indicate a single dose of prednisolone significantly reduces leucocyte infiltration and activation as well as the magnitude of the cutaneous late-phase reaction.

Administration, Oral↗
PubMed1992

Application of monoclonal antibodies against major basic protein (BMK-13) and eosinophil cationic protein (EG1 and EG2) for quantifying eosinophils in bronchial biopsies from atopic asthma.

A monoclonal antibody prepared against the eosinophil major basis protein (MBP) was compared with the anti-eosinophil cationic protein (ECP) antibodies (EG1 and EG2) in immunostaining of bronchial biopsies from atopic asthma and controls. Anti-MBP (designated BMK-13) did not cross-react with other eosinophil basic proteins (i.e. ECP, eosinophil peroxidase [EPO] or eosinophil-derived neurotoxin [EDN]) and stained more than 98% of peripheral blood eosinophils irrespective of their degree of activation. EG2 stained 15% of resting and 75% of activated eosinophils; EG1 recognized 74% and 78% of resting and activated cells, respectively. The numbers of BMK-13, EG1 or EG2-positive staining cells in bronchial biopsies from asthma were significantly greater than atopic non-asthmatics (P less than 0.02, P less than 0.01 and P less than 0.05, respectively) and normal non-atopic controls (P less than 0.001). For each of the various groups studied, the rank order for the number of eosinophils stained was BMK-13 greater than EG1 greater than EG2. BMK-13 stained significantly more cells from bronchial biopsies of atopic asthma and atopic non asthma when compared to EG2 (P less than 0.001 and P less than 0.05, respectively). Since only a proportion of BMK-13+ cells were EG2+, these results suggest that not all tissue eosinophils are actively secreting. Thus, BMK-13 can serve as a useful pan-eosinophil marker in tissue sections since it appears to stain most eosinophils.

Antibodies, Monoclonal↗
PubMed1992

Allergy. Conventional and alternative concepts. A report of the Royal College of Physicians Committee on Clinical Immunology and Allergy.

Allergy is an exaggerated response of the immune system to external substances. It plays a role in a wide range of diseases. In some, such as summer hayfever, the symptoms are due entirely to allergy. In other conditions, particularly asthma, eczema and urticaria, allergy plays a part in some patients but not all. In these situations, allergy may have either a major role or provide just one of many triggers. In an individual patient's illness, the importance of allergy may change with time. The most common allergens (substances causing allergy) are grass and tree pollens, the house dust mite, products from pets and other animals, agents encountered in industry, wasp and bee venom, drugs, and certain foods. Food allergy presents a particularly difficult problem. Some individuals who react to food suffer from food allergy in its strict sense but in others there is no evidence of an alteration in the immune system. Here the term 'food intolerance' is preferable. Conventional doctors treat allergy by allergen avoidance--where this is possible--and drugs that relieve symptoms. In a few selected cases, in which other methods have failed, immunotherapy (desensitisation or hyposensitisation) is recommended. Although patients who consult practitioners of alternative allergy may do so by preference, it is often also because they are dissatisfied with the conventional approach to diagnosis and treatment, or because they have conditions which conventional doctors do not accept as having an allergic basis. There is a very wide range of alternative approaches to allergy, including the methods used by clinical ecologists and other treatments such as acupuncture and homoeopathy. Hypnosis may have a small role to play in helping the asthmatic and similar effects have been suggested for acupuncture. Furthermore, it is likely that there are still many active ingredients in medicinal plants used by herbalists but these need to be clearly identified and purified before their usefulness can be evaluated properly. Apart from these situations, we have yet to be convinced by substantial evidence that any of the other alternative methods of diagnosing or treating allergic disease are of proven value. There have, however, been many false and misleading claims and serious harm may be caused by misdiagnosis or delays in appropriate treatment. The public should be warned against costly methods of diagnosis and treatment which have not been validated.(ABSTRACT TRUNCATED AT 400 WORDS)

Allergens↗