In allergic asthma experimental exposure to allergens is associated with depletion of blood eosinophils overexpressing LFA-1.

BACKGROUND: In atopic individuals, exposure to allergens is followed by recruitment of blood eosinophils in the target tissue. We investigated whether allergen inhalation challenge could result in depletion of blood eosinophils overexpressing adhesion molecules involved in eosinophil migration. METHODS: Blood eosinophils were isolated from seven atopic asthmatic patients and seven control subjects and the "at baseline" expression of lymphocyte function-associated antigen-1 (LFA-1), macrophage antigen-1 (Mac-1) and very late antigen-4 (VLA-4) was assessed by monoclonal antibody staining and flow cytometry analysis. Asthmatic patients underwent allergen challenge and the expression of LFA-1, Mac-1 and VLA-4 by blood eosinophils was again evaluated 3 h and 24 h after allergen challenge. RESULTS: As compared to controls, eosinophils from atopics showed at baseline enhanced LFA-1 expression (P=0.0012), but similar Mac-1 or VLA-4 expression (P > 0.1, each comparison). In atopics, the percentage and absolute number of blood eosinophils were significantly decreased 3 h after allergen challenge (P=0.001 and P=0.022, respectively) but returned to similar values to prechallenge values after an additional 21 h (P > 0.1). Allergen challenge was also followed by a significant decrease in LFA-1 expression by eosinophils, at 3 h (P=0.002) and at 24 h (P=0.038), while no changes in Mac-1 and VLA-4 were observed. A significant correlation between postchallenge decrease in LFA-1 expression and in blood eosinophilia, both expressed as percentage (r=0.88; P < 0.01) or absolute number (r=0.87; P < 0.01) was demonstrated at 3 h (r=0.88; P < 0.01) but not at 24 h (r=0.64, P > 0.05 and r=0.11; P > 0.05, respectively). CONCLUSION: In allergic asthma, an early recruitment of blood eosinophils overexpressing LFA-1 occurs in the first hours after allergen challenge.

Natural analogue peptides of an HIV-1 GP120 T-helper epitope antagonize response of GP120-specific human CD4 T-cell clones.

Neutralizing antibodies and specific cytotoxic T lymphocytes (CTL) may contribute to controlling viral spread, and ideally, to virus clearance in HIV infection. Both effector mechanisms depend on specific CD4 T-helper (Th) cells. Nevertheless, HIV hypervariability facilitates appearance of escape mutants for antibodies and for CTL responses. Here we also show that natural mutations (i.e., from sequences of different HIV strains) in an immunodominant Th epitope recognized by human CD4 clones specific for the envelope glycoprotein gp120 escape CD4 T-cell recognition. Furthermore, several natural analogue peptides exert an antagonistic function by inhibiting proliferative response of T cells specific to gp120 with a wild-type sequence. If similar events occur in vivo, they may represent an additional escape mechanism for HIV. In fact, antagonism for CD4 Th response may occur during superinfection with a different strain, or with the appearance of a variant carrying a mutated antagonistic sequence. In both cases, impaired Th cell function could lead to reduced immune control of HIV infection by interfering with CTL and antibody response.

Stimulation of eosinophil IgE low-affinity receptor leads to increased adhesion molecule expression and cell migration.

Immunoglobulin binding on eosinophil surface receptors results in activation of these cells. Evaluating blood eosinophils from atopic subjects, it was investigated whether ligation of immunoglobulin E low-affinity receptor (FcepsilonRII/ CD23) with specific monoclonal antibodies (Mabs) resulted in enhanced eosinophil migration and adhesion molecule expression. Eosinophils from 20 subjects with allergic asthma (atopic individuals) and nine nonatopic normal individuals (controls) were purified using Percoll gradients. The effect of antihuman CD23 Mabs on: 1) eosinophil migration through human umbilical vein endothelial cells (HUVECs); and 2) eosinophil expression of the adhesion molecules leukocyte function-associated antigen-1 (LFA-1, CD11a/CD18), macrophage antigen-1 (Mac-1, CD11b/CD18) and very late activation antigen-1 (VLA-4, CD49d/CD29) was evaluated by specific Mab staining and flow cytometric analysis. As compared to controls, freshly isolated eosinophils from atopic individuals showed enhanced migration through HUVECs (p<0.05) and increased LFA-1 expression (p<0.01), but similar Mac-1 and VLA-4 expression (p>0.1 for both). In both controls and atopic individuals, eosinophil incubation with antihuman CD23 Mabs induced a dose-dependent increase in cell migration through HUVECs, significant at antihuman CD23 Mab concentrations of 5 microg x mL(-1) (p>0.05 for all). Similarly, incubation of the cells with antihuman CD23 Mabs induced dose-dependent upregulation of LFA-1 and Mac-1 expression, whereas no changes in VLA-4 expression were observed (p>0.1). Finally, the enhanced eosinophil migration induced by antihuman CD23 Mab stimulation was significantly inhibited by antihuman LFA-1 (84+/-14% (mean+/-SEM); p<0.01) and VLA-4 Mabs (47+/-15%; p<0.05) but not by antihuman Mac-1 Mabs (p>0.1). In both atopic and control subjects, immunoglobulin E, low-affinity receptor stimulation induces functional changes in eosinophils characterized by increased eosinophil migration associated with enhanced late function antigen-1 and Mac-1 expression.

Nasal brushing: a clinically useful procedure in pediatric patients with rhinosinusitis?

Sinusitis is a common complication of non-allergic and allergic rhinitis, and can trigger lower respiratory diseases, such as bronchitis and asthma. Standard radiography is unable to give any data about the underlying pathological mechanisms (infectious or allergic) involved and infectious rhinosinusitis is very common in pediatric age, even in allergic patients. We investigated the possibility of obtaining more useful diagnostic information, performing nasal brushing (NB) on 117 children with recurrent respiratory symptoms. The following hypothesis were evaluated: (1) whether NB neutrophil/eosinophil percentages and/or NB culture could predict the radiological evidence of maxillary sinusitis; and (2) whether differences between nonallergic and allergic patients could be detected. In the total patient group and in the nonallergic group, the comparison of NB neutrophil percentages in patients with and without maxillary sinusitis showed a statistically significant difference (median 2 and 18%, respectively; P < 0.001). In the nonallergic group, a NB neutrophil rate > or = 5% was chosen as a cut-off between positive and negative NB diagnosis of rhinosinusitis and NB data were compared with radiological investigations. The results obtained showed that NB was fairly sensitive (91%) and predictive (84%). In allergic patients, neither neutrophil nor eosinophil percentages significantly correlated with the presence of sinusitis. Microbiological studies showed that, even if the presence of bacteria in NB resulted associated with sinusitis, a negative culture was not predictive of the absence of the disease. We therefore suggest that NB describes the present inflammatory status of the upper airways, hence, it is more suitable to describe the inflammation related to ongoing upper respiratory tract infections rather than chronic inflammation due to allergic rhinitis, characterized by relapsing episodes of acute inflammation. In conclusion, we propose to consider NB a reliable tool in the diagnosis of rhinosinusitis, particularly in nonallergic pediatric patients. Compared to standard radiological techniques, NB makes it possible to avoid radiation exposure and gives information about the pathological mechanisms involved in the single patient.

Modulation of HLA-DR antigen and ICAM-1 molecule expression on airway epithelial cells by sodium nedocromil.

OBJECTIVE: To test in vitro and in vivo the hypothesis that sodium nedocromil could modulate the expression of surface molecules on airway epithelial cells. METHODS: Human bronchial epithelial cells, obtained from surgically resected bronchi, were cultured and stimulated with recombinant IFN-gamma in the presence of sodium nedocromil. The intensity of the expression of surface molecules HLA-DR and ICAM-1 molecules on bronchial epithelial cells in vitro, was quantified by specific antibody staining and flow-cytometry analysis. Furthermore, we studied the effect of the drug on airway inflammation in vivo and on allergic rhinitis patients sensitized to house dust mites. Nasal epithelial cells were collected by brushing, at baseline and 2 to 3 weeks after treatment with sodium nedocromil. The expression of HLA-DR and ICAM-1 molecules was measured by flow-cytometry, and the proportions of neutrophils and eosinophils "contaminating" the epithelial cells evaluated by light microscopy examination of nasal brushings. RESULTS: The enhanced HLA-DR and ICAM-1 expression, induced by IFN-gamma, was effectively downregulated, in a dose-dependent manner, by sodium nedocromil. At all the concentrations tested (10(-9) to 10(-4) M), the inhibitory activity of the drug was stronger on HLA-DR than on ICAM-1 expression (P<.05, all comparisons). As compared with healthy subjects, patients with allergic rhinitis had a higher expression of HLA-DR (P<.05) but not of ICAM-1 molecules (P>.05) on nasal epithelial cells, and higher proportions of nasal eosinophils (P<.05). Treatment with sodium nedocromil downregulated the expression of HLA-DR (P<.05), but not of ICAM-1 (P>.05), and induced a mild, but not statistically significant, decrease of nasal eosinophilia (P>.05). CONCLUSION: These data demonstrate that the antiinflammatory activity of sodium nedocromil may include modulation of surface molecule expression on airway epithelial cells.

beta 2-agonist-induced inhibition of neutrophil chemotaxis is not associated with modification of LFA-1 and Mac-1 expression or with impairment of polymorphonuclear leukocyte antibacterial activity.

Patients with chronic obstructive lung disorders often show increased susceptibility to airway infections. As beta 2-adrenoceptor agonists, in addition to reversing the contractile response of bronchial smooth muscles, may inhibit a variety of inflammatory and immuno-effector cell functions, it is possible that these drugs interfere with host defence mechanisms. The present study was designed to test in vitro whether fenoterol, a short-acting beta 2-adrenoceptor agonist, could modify human blood neutrophil recruitment and antimicrobial activity. Pre-exposure to fenoterol significantly reduced neutrophil migration towards the complement component C5a, at concentrations ranging from 10(-7) M to 10(-5) M, or towards lipopolysaccharide, at a concentration of 10(-5) M (P < 0.05, each comparison). In contrast, the drug (10(-8)-10(-5) M) did not significantly modify the increased expression of lymphocyte function-associated antigen (LFA-1, i.e. CD11a/CD18) the macrophage antigen-1 (Mac-1, i.e. CD11b/CD18) induced by N-formylmethionylleucylphenylalanine (fMLP) (P > 0.05, each comparison). Finally, incubation of neutrophils with fenoterol (10(-8)-10(-5) M) did not significantly influence phagocytosis or intracellular killing of bacteria (Staphylococcus aureus) or H2O2 release induced by tetradecanoyl-phorbol-acetate (P > 0.1 for each comparison). These results suggest that short-acting beta 2-adrenoceptor agonists, such as fenoterol, are able partially to reduce neutrophil recruitment in the airways without interfering with the processes involved in phagocytic activity against bacteria.

Budesonide down-regulates eosinophil locomotion but has no effects on ECP release or on H2O2 production.

Treatment of allergic asthma with inhaled corticosteroids results in local down-regulation of proinflammatory cytokine synthesis and in marked decrease in tissue eosinophilia. Blood concentrations of inhaled corticosteroids, although significantly lower than those measured in the lung, may still have antiinflammatory effects on circulating eosinophils, reducing their ability to migrate. The aim of our study was to evaluate in vitro the activity of budesonide on blood eosinophils by measuring their chemotactic response, eosinophil cationic protein (ECP) release, and hydrogen peroxide (H2O2) production in the presence of different drug concentrations similar to those obtained at airway level (10(-8) and 10(-7) M) and at blood level (10(-10) and 10(-9) M). Partially purified blood eosinophils, isolated from 23 asthmatic subjects, were used to evaluate the activity of budesonide on: (1) chemotaxis toward the activated fifth component of complement (C5a, 0.1 microg/ml) or recombinant human (rh) interleukin (IL)-5 (200 pg/ml), (2) ECP release by cells stimulated with tetradecanoylphorbol acetate (TPA) and (3) H2O2 production by TPA-activated cells. The chemotactic response to C5a was down-regulated significantly by budesonide only by the highest concentrations tested (10(-8) and 10(-7) M); differently, budesonide was effective in inhibiting eosinophil migration toward rhIL-5, at all concentrations tested (p < 0.01, each comparison). By contrast, no drug-induced modifications were observed in ECP release or in H2O2 production (p > 0.05, each comparison). We conclude that concentrations of budesonide similar to those obtained in vivo are effective in inhibiting eosinophil locomotion but not in down-regulating the release of reactive oxygen species and granule-associated proteins.

Insensitivity of volume-sensitive chloride currents to chromones in human airway epithelial cells.

Chromones (sodium cromoglycate and sodium nedocromil) block cell swelling-activated Cl- channels in NIH-3T3 fibroblasts and endothelial cells. This has led to hypothesize that cell volume regulation might be involved in asthma pathogenesis. Using whole-cell patch-clamp experiments, we studied the effect of chromones on volume-sensitive Cl- currents in transformed human tracheal epithelial cells (9HTEo-) and in primary cultures of human bronchial epithelial cells (BE). Cl- currents activated by hypotonic shock were poorly blocked by extracellular nedocromil or cromoglycate. The block was voltage-dependent since it was observed only at positive membrane potentials. At the concentration of 5 mM, the current inhibition by both chromones at +80 mV was about 40% for 9HTEo- and only 20% for BE. Intracellular application of chromones elicited a voltage-independent inhibition in 9HTEo- cells. Under this condition, volume-sensitive Cl- currents were reduced at all membrane potentials (60 and 45% inhibition by 2 mM nedocromil and cromoglycate respectively). In contrast intracellular chromones were ineffective in BE cells. The relative refractoriness to chromones, in contrast with the high sensitivity shown by other Cl- channels, suggests that the epithelial volume-sensitive Cl- channel is not involved in asthma.

LFA-1 expression by blood eosinophils is increased in atopic asthmatic children and is involved in eosinophil locomotion.

Allergic asthma is characterized by eosinophil migration in the airways, which is strictly dependent on the expression of adhesion molecules. This study investigated whether the expression of adhesion molecules on eosinophils is increased and associated with disease activity in allergic asthma. Twenty atopic asthmatic (AA) subjects and nine controls were studied and the expression of lymphocyte function-associated antigen-1 (LFA-1; CD11a/CD18), Mac-1 (CD11b/CD18) and very late antigen-4 (VLA-4; CD49d/CD29) on blood eosinophils was evaluated by specific monoclonal antibody (Mab) staining and flow-cytometric analysis. Compared with controls, eosinophils from AA showed increased expression of LFA-1 (p<0.005), but not of Mac-1 or VLA-4 (p>0.1). In addition, LFA-1 expression correlated positively with blood eosinophil number (r=0.792, p<0.05), while no correlations were observed between Mac-1 or VLA-4 expression and blood eosinophil number. The migration of eosinophils through human umbilical vein endothelial cells with or without anti-LFA-1, Mac-1 and VLA-4-blocking Mab was studied. Compared with controls, eosinophils from AA showed increased migration toward C5a (p<0.01). Cell migration was totally inhibited by preincubating eosinophils with anti-LFA-1 (p<0.05), while anti-Mac-1 had no effect (p>0.1). Thus, the expression of lymphocyte function-associated antigen-1 by blood eosinophils is increased in atopic asthmatics and seems to modulate the enhanced eosinophil migration observed in allergic asthma.

Downregulation of the expression of intercellular adhesion molecule (ICAM)-1 on bronchial epithelial cells by fenoterol, a beta2-adrenoceptor agonist.

Inflammatory airway disorders, such as asthma and chronic bronchitis, are characterized by overexpression of adhesion molecules on airway epithelial and endothelial cells. This phenomenon is associated with increased adherence and activation of polymorphonuclear leukocytes (PMNs). With the knowledge that beta2-adrenoceptor agonists demonstrate some anti-inflammatory activity in vitro, the present study was designed to evaluate whether fenoterol could interfere with adhesion molecule expression on airway epithelium. Human bronchial epithelial cells (HBECs), obtained by protease digestion from surgically resected bronchi, were stimulated with human recombinant interferon-gamma (rh IFN-gamma) in the presence of (a) fenoterol (10(-12)-10(-5) M); (b) dexamethasone (10(-12)-10(-5) M); and (c) fenoterol and dexamethasone. Because desensitization after high-dose exposure to agonists has been described for many membrane-associated receptors, in additional sets of experiments HBECs were preexposed to fenoterol and, as control, to dexamethasone for 8 hr, then washed and stimulated with rh IFN-gamma in the presence of fresh drugs. The cells were harvested after 24-hr culture and stained by specific monoclonal antibodies. The intensity of intercellular adhesion molecule-1 (ICAM-1) expression was then measured by flow cytometry analysis and expressed as mean fluorescence channel (mfc). The significant increase in ICAM-1 expression on HBECs induced by rh IFN-gamma was inhibited, in a dose-dependent manner, by the two drugs, but fenoterol was more efficient than dexamethasone at all of the concentrations tested (p < 0.05, all comparisons). In addition, the inhibitory activity of fenoterol was not enhanced by the simultaneous presence of dexamethasone in rh IFN-gamma-stimulated HBEC cultures (p > 0.05, all comparisons). Finally, preexposure to fenoterol or to dexamethasone did not induce any modification of the inhibitory effect of the two drugs on ICAM-1 expression (p > 0.05, all comparisons). These results suggest that clinical efficacy of fenoterol in patients with obstructive lung disease may include downregulation of adhesion molecule expression on airway epithelial cells.

An improved method to obtain highly differentiated monolayers of human bronchial epithelial cells.

Electrophysiological studies of human bronchial epithelial cells in vitro are limited by the scarcity of biological material available for primary culture. To overcome this problem, we set up a protocol in which the cell number is first enlarged in LHC9/RPMI 1640 serum-free medium for up to six passages, each passage giving a four- to eightfold amplification. The cells are then plated at high density on permeable supports. Cell differentiation, monitored by measuring transepithelial potential difference (PD) and electrical resistance (R), is induced with a medium containing serum and a cocktail of different supplements and hormones. Maximal values of PD and R, obtained after 4-7 d of culture on permeable supports, are around -50 mV and 3000-4000 omega/cm2, respectively. Ussing chamber experiments show that basal short-circuit current (Isc) is partially inhibited by the epithelial Na+ channel blocker amiloride. Stimulation with a cAMP-elevating agent induces a Isc increase that is inhibited by the cystic fibrosis transmembrane conductance regulator (CFTR) blocker glibenclamide. Our culture protocol provides a large number of differentiated bronchial epithelial cell monolayers starting from a low amount of material. This characteristic is useful for in vitro studies of ion transport in airway epithelium.

Requirement for different presenting cells and for different processing mechanisms by human CD4 T helper clones specific for M. tuberculosis antigens.

Human T helper cells specific for mycobacterial antigens have been extensively investigated. Differences have been detected according to antigen specificity and to fine epitope specificity. In this work we have analyzed two additional parameters that allow discrimination among antigen specific T helper cells: requirement for certain types of antigen presenting cells (APC) and requirement for protease-sensitive antigen processing pathways. We used T cell clones from peripheral blood or from pleural exudates, and specific for different antigenic fractions of M. tuberculosis. APC were autologous peripheral blood mononuclear cells, adherent monocytes, adherent pleural monocytes, EBV transformed B lymphocytes and dendritic cells. Seven clones out of twelve were stimulated by all APC irrespective of their specificity, whereas other clones had more selective requirements. When protease inhibitors were used during antigen pulsing of APC, the production of certain epitopes, and thus T cell activation, was impaired with six clones out of sixteen. These results demonstrate that the human T helper repertoire specific for mycobacterial antigens is highly diverse also according to APC populations needed for presentation and to processing mechanisms required for production of the relevant T epitopes.

Stimulation of blood mononuclear cells of atopic children with the relevant allergen induces the release of eosinophil chemotaxins such as IL-3, IL-5, and GM-CSF.

Peripheral blood mononuclear cells (PBMC) from 10 atopic asthmatic children (atopics), sensitized to Dermatophagoides pteronyssinus (Dp), and from 5 nonatopic healthy children (controls) were stimulated with Dp extract or with birch extract (Be). After 6 days we tested the supernatant's (Sn) chemotactic activity toward purified blood eosinbnophils and T-lymphocyte proliferation. Dp induced a statistically significant T-cell proliferation from atopics as compared to controls (p < 0.05), which correlated with the levels of eosinophil chemotactic activity in the Sn (r = 0.713; p < 0.05). Measurable levels of IL-3, IL-5, and GM-CSF were demonstrated in the Sn of Dp-stimulated PBMC from atopics, while eosinophil locomotion toward different concentrations of recombinant human (rh) IL-3, rhIL-5, and rhGM-CSF confirmed that these cytokines were able to stimulate eosinophil chemotaxis in a close concentration range. Preincubation of different concentrations of the same Sn with blocking antisera demonstrated that anti-human (ah) IL-3, ahIL-5, and ahGM-CSF effectively decreased eosinophil chemotaxis (p < 0.05; each comparison). Thus PBMC activation with the relevant allergen induces the release by T cells with a Th2 phenotype of chemotactic factors for eosinophils.

Eosinophil locomotion and the release of IL-3 and IL-5 by allergen-stimulated mononuclear cells are effectively downregulated in vitro by budesonide.

BACKGROUND: Treatment of allergic asthma with inhaled corticosteroids, such as budesonide (BDN), results in downregulation of T-cell activation and of eosinophil recruitment. OBJECTIVE: Since blood concentrations of BDN, although significantly lower than those measured in the lung, may still have anti-inflammatory effects, we evaluated the activity of BDN in vitro on: allergen-induced release of lymphokines involved in eosinophil chemotaxis (i.e. IL-3 and IL-5), at drug concentrations similar to those obtained in vivo in the lung (10-8 M), and eosinophil locomotion, at "systemic concentrations' of the drug (10(-10)M and 10(-9)M). METHODS: Twenty-three atopic asthmatic subjects (atopics) sensitized to Dermatophagoides pteronyssinus (Dp) and seven non-atopic healthy subjects (controls) were studied. Purified blood mononuclear cells (BMC) were stimulated with Dp, with or without BDN 10(-8) M and, after 6 days, the supernatants were collected and frozen to test their chemotactic activity toward purified blood eosinophils and their levels of interleukin (IL)-3 and IL-5 by immunoassay. BMC were then pulsed for additional 18 h with [3H]thymidine to evaluate allergen-induced T-cell proliferation. In addition, to test possible direct effects of 'systemic concentrations' of the drug on eosinophil locomotion, blood eosinophils were incubated for 1 h with BDN (10(-10) M and 10(-9) M) prior to test their chemotactic response toward recombinant human IL-3 and IL-5. RESULTS: Stimulation of BMC from atopics with Dp induced a statistically significant increase in [3H]thymidine incorporation (P < 0.05); secretion of chemotactic factors for eosinophils (P < 0.001) and the release of IL-3 and IL-5 (P < 0.005 and P < 0.05 respectively). BDN, at the concentration of 10(-8) M, was able to significantly down-regulate T-cell proliferation (P < 0.05), the secretion of chemotactic factors for eosinophils (P < 0.001) and the release of IL-3 and IL-5 (P < 0.01 and P < 0.05 respectively). Similarly, "systemic concentrations' of BDN (10(-10) M and 10(-9) M) totally inhibited the chemotactic response of blood eosinophils toward recombinant human IL-3 and IL-5 (P < 0.005). CONCLUSIONS: Concentrations of BDN similar to those obtained in vivo are effective in inhibiting both the release of eosinophils chemotaxins by allergen-activated mononuclear cells and eosinophil locomotion.

Evaluation of the inhibitory effects of budesonide on the mitogen-induced or the allergen-induced activation of blood mononuclear cells isolated from asthmatic patients.

BACKGROUND: Corticosteroids are thought to be effective in the treatment of allergic reactions including bronchial asthma because they not only have anti-inflammatory effects, but also downregulate the processes of T-cell activation. OBJECTIVE: To evaluate in vitro the inhibitory activity of budesonide, a widely used inhaled corticosteroid, on allergen-induced mononuclear cell activation. METHODS: Thirty-one atopic asthmatic patients, sensitized to Dermatophagoides pteronyssinus (Der p) were studied. Peripheral blood mononuclear cells isolated from these patients were used to determine the ability of budesonide to inhibit (1) the proliferative response of blood T-lymphocytes to Der p allergen extract and to phytohemoagglutinin (PHA) and (2) the release of different cytokines known to modulate the interaction between T-lymphocytes and monocytes in the allergic processes. RESULTS: A significant T-cell proliferation was observed both in the presence of PHA (P < .001) and that of Der p allergen extract (P < .05), and was associated with increased release of interleukin-2 [IL-2 (respectively P < .001 and P < .01)], gamma-interferon [gamma-IFN (respectively P < .001 and P < .01)], granulocyte-macrophage colony-stimulating factor [GM-CSF (respectively P < .01 and P < .001)], interleukin-1 beta [IL-1 beta (respectively P < .05 and P < .01)], and tumor necrosis factor-alpha [TNF-alpha (P < .05 each comparison)]. The addition at the beginning of the cell cultures of different concentrations (from 10(-10) M to 10(-7) M) of budesonide, and as control of dexamethasone, induced a dose-dependent inhibition of T-cell proliferation, in response to PHA and Der p. Budesonide at the lowest concentrations tested (10(-10) M and 10(-9) M) was more effective than dexamethasone. Budesonide was also more active than dexamethasone in inhibiting the release of IL-2, gamma-IFN, IL-1 beta and GM-CSF (in both PHA-stimulated and Der p-stimulated blood mononuclear cell cultures) and TNF-alpha (in Der p-stimulated blood mononuclear cell cultures). CONCLUSIONS: Budesonide is equally or more effective than dexamethasone in inhibiting the allergen-induced T-cell proliferation and in reducing the release of cytokines by allergen-stimulated blood mononuclear cells.

Effects of "systemic" budesonide concentrations on in vitro allergen-induced activation of blood mononuclear cells isolated from asthmatic patients.

Blood levels of inhaled corticosteroids are significantly lower than those measured in the lung, but their concentration could still have anti-inflammatory effects. To determine whether budesonide, at concentrations similar to those obtained in blood after drug inhalation (10(-9) M), could downregulate the allergen-induced activation of mononuclear cells, we studied 21 atopic patients, sensitized to Dermatophagoides pteronyssinus (Der p). On blood mononuclear cells, isolated from these patients, incubated with Der p allergen extract and with or without budesonide, we evaluated: 1) the proliferative response of T cells; 2) the expression of two surface activation markers, the HLA-DR antigens and the interleukin (IL)-2 receptors; and 3) the release of cytokines known to modulate the allergic processes. Allergen-induced T-cell proliferation was associated with increased HLA-DR antigen and IL-2 receptor expression (P < 0.001), and with increased release of IL-2, interferon-gamma (IFN-gamma), IL-1 beta, tumor necrosis factor-alpha (TNF-alpha), and granulocyte/macrophage colony-stimulating factor (GM-CSF). The addition of budesonide at the beginning of the cell cultures induced a dose-dependent inhibition of T-cell proliferation, still significant (P < 0.05) at the lowest concentrations tested (10(-9) and 10(-10) M). A significant inhibitory effect on T-cell proliferation was also present when budesonide (10(-9) M) was added to the cell cultures 3 or 5 days after the beginning of the cell cultures.(ABSTRACT TRUNCATED AT 250 WORDS)

The Increased Expression of HLA-DR and ICAM-1 Molecules by Human Bronchial Epithelial Cells, Induced by Activated Mononuclear Cells, is Downregulated by Nedocromil Sodium.

To test the hypothesis that mononuclear cell products could increase the expression of HLA-DR and ICAM-1 molecules in bronchial epithelial cells (BECs), subconfluent cultures of human BECs, obtained from surgically resected bronchi, were incubated with PHA-activated blood mononuclear cell conditioned media (BCM-CM) or recombinant IFN-gamma. The presence of HLA-DR and ICAM-1 molecules on BECs was then evaluated by specific antibody staining and flow-cytometry analysis. The addition to BEC cultures of different concentrations of PHA-stimulated BMC-CM, or of IFN-gamma induced a dosedependent increase of HIA-DR and ICAM-1 expression, while no effect was observed with unstimulated BMC-CM. The ability of nedocromil sodium and, as control, of dexamethasone, to prevent the upregulation of HLA-DR and ICAM-1 expression on BECs was then tested. Increasing concentrations (10(-7) to 10(-4) M) of nedocromil significandy inhibited HLA-DR and ICAM-1 expression by BECs in a dose-dependent fashion. A similarly dose-dependent inhibitory effect was also observed with dexamethasone, which, however, was less active than nedocromil on HL-ADR expression and more active on ICAM-1 expression. Finally, nedocromil and dexamethasone showed a significant synergistic effect on the expression of both cell surface molecules at the lowest concentrations tested.

Thymomodulin enhances phagocytic and intracellular killing activities of polymorphonuclear leucocytes without increasing release of chemotactic factors.

Thymomodulin, a calf thymus derivative, is able to stimulate T-lymphocytes and monocytes, and to activate phagocytes and their precursors. However, it is not fully understood whether the effect of thymomodulin on phagocytic cells is a direct stimulation, or a phenomenon mediated by cytokines released by mononuclear cells. To answer this question, we first evaluated the effects of thymomodulin on the phagocytosis and intracellular killing of Staphylococcus aureus by blood polymorphonuclear cells (PMNs), cultured with or without autologous mononuclear cells. Secondly, during the processes of phagocytosis and intracellular killing, we evaluated the release by PMNs of chemotactic factors for PMNs, lymphocytes and monocytes. No difference was found in the phagocytosis and killing processes when PMNs were incubated alone or with autologous mononuclear cells (p > 0.05, each comparison). Thymomodulin was able to increase the phagocytosis process when PMNs were incubated with lymphocytes and monocytes (p = 0.05), and to enhance the killing by PMNs cultured alone (p = 0.05), or cultured with autologous mononuclear cells (p < 0.05). The release of chemotactic factors for PMNs, lymphocytes and monocytes in the supernatants of the phagocytosis experiments, was higher when PMNs were incubated with mononuclear cells, compared to cultures of PMNs alone (p < 0.05, each comparison); and thymomodulin did not increase their release without the presence of autologous mononuclear cells in the cultures (p > 0.05 each comparison). These data suggest that thymomodulin acts upon PMNs, inducing mononuclear cells to release factors able to stimulate the phagocytosis and the intracellular killing of exogenous organisms, but does not amplify the immune reaction enhancing further leucocytes recruitment.

Bronchial and bronchoalveolar lavage after allergen challenge in atopic patients.

Twenty patients with allergic rhinitis and/or asthma sensitised to Dermatophagoides pteronyssinus were studied. On two consecutive days they underwent methacholine challenge and allergen bronchial challenge. 72 h after allergen challenge, fibreoptic bronchoscopy with bronchial (BL) and bronchoalveolar (BAL) lavage was performed. Specific IgE antibodies were measured both in serum and in BL from 14 patients. Both BAL and BL cell differentials were similar in patients with isolated early response to allergen and in patients with dual response. Patients with dual response to allergen showed higher levels of antigen specific IgE antibodies in BL than patients with isolated early response, while IgE levels in serum were similar in the two groups.

Late-phase asthmatic reaction to inhaled allergen is associated with early recruitment of eosinophils in the airways.

To determine whether a link exists between the recruitment of inflammatory cells in the airways and the development of the late-phase asthmatic reaction, we studied with bronchoalveolar lavage 54 asthmatic patients either at baseline (10 patients) or 4 h (11 patients), 24 h (13 patients), and 72 h (20 patients) after allergen inhalation challenge. Among the patients studied 4 h after allergen challenge, five were known to have a late-phase asthmatic response and showed a significant increase in the number and percentage of eosinophils in bronchoalveolar lavage compared with either patients without late-phase response (p less than 0.05) or unchallenged patients (p less than 0.01). Both the number and the percentage of eosinophils in bronchoalveolar lavage were also increased (p less than 0.05) in patients without a late-phase asthmatic reaction studied 24 h but not in those studied 4 h after allergen challenge. The numbers and the percentages of macrophages, neutrophils, or lymphocytes did not differ significantly among the different groups of patients. Of the patients studied 4 and 24 h after allergen challenge, only those with a late-phase asthmatic response showed an increased airway responsiveness to methacholine 1 h before bronchoalveolar lavage. We conclude that the development of the late-phase asthmatic response to allergen inhalation challenge and the allergen-induced increase in airway responsiveness are associated with an early recruitment of eosinophils in the airways.