Asthma and inflammation

Inhalation of steaming seafood aroma: suddent death in an asthmatic

A 29-year-old asthmatic with a family history of atopy inhaled a large dose of fumes from sizzling, steaming seafood being served to another client in a restaurant. She immediately developed respiratory distress, loss of consciousness and cyanosis; she also vomited profusely, aspirated and died with 58 min of the onset of symptoms. Autopsy revealed epiglottitis and tracheobronchitis associated with an infiltration by mast cells. The blood IgE was marginally elevated. Death was attributed to upper respiratory airway obstruction due to aspiration of gastric contents, and to bronchospasm following the inhalation of steaming vapour from the seafood dish. The practice of transporting a platter of sizzling, steaming seafood across dining rooms and restaurants with its aroma permeating the entire premises could prove fatal for atopic customers.

Effect of a novel leukotoriene synthesis inhibitor, BAY x1005, on the antigen-and LPS-induced airway hyperresponsiveness in guinea pigs

Due to the inhibition of 5-lipoxygenase-activating protein (FLAP), BAY x1005 is a new selective inhibitor of leukotriene synthesis. The effects of BAY x1005 on the antigen- and bacterial lipopolysaccharide (LPS)-induced airway hyperresponsiveness in guinea pigs were investigated. Six times provocation of aeroantigen caused biphasic increases in airway resistance which peaked at 1 hr (immediate phase reaction) and 4 hrs (late phase reaction). It also caused airway hyperreactivity to acetylcholine. BAY x1005 at doses of 10 mg/kg and 30 mg/kg significantly inhibited antigen-induced increase in respiratory resistance (Rrs) at 1 and 4 hrs after the last antigen challenge. Simultaneously, BAY x1005 inhibited the antigen-induced airway hyperresponsiveness at doses of 10 and 30 mg/kg and airway eosinophilia (bronchoalveolar lavage study) at a dose of 30 mg/kg. In addition, BAY x1005 at a dose of 30 mg/kg inhibited bacterial LPS-induced airway hyperreactivity to acetylcholine. In this model, BAY x1005 did not affect the increase of the number of leukocytes in bronchoalveolar lavage fluid. These results suggest that BAY x1005 is a potent anti-asthmatic agent with an inhibitory action to airway hyperreactivity.

Airway eosinophilic inflammation, epithelial damage, and bronchial hyperresponsiveness in patients with mild-moderate, stable asthma

Allergic asthma is characterized by chronic recruitment of eosinophils in the airways. Once activated, eosinophils release toxic products, including eosinophil cationic protein (ECP), able to damage airway epithelial cells. To test the hypothesis that also in mild-moderate stable asthma, a significant eosinophil activation could occur, we studied 25 asthmatic patients (34 +/- 19 years old), of whom 18 were allergic (27 +/- 12 years) and seven nonallergic (42 +/- 10 years), with FEV1 values > or = 70% of predicted, and eight normal volunteers (controls, 33 +/- 11 years). All subjects underwent methacholine (MCh) challenge on the first visit, and bronchoalveolar lavage (BAL) on the second visit (approximately 3-4 days later). BAL cells were counted and albumin (Alb) (as index of protein dilution in BAL fluid) and ECP levels (as index of eosinophil activation) in BAL fluid were measured. As compared to controls, a significant increase in BAL eosinophil and in BAL epithelial cell numbers was observed in asthmatic patients (P > 0.05, each comparison), with no differences between the two asthmatic patient subgroups. Detectable ECP levels (> 2 micrograms/1) were found in BAL of 18 asthmatic patients (14 allergic and four nonallergic asthmatic patients), while Alb levels were measurable in 25 BAL fluids and found to be similar in controls and asthmatic patients, and in the two asthmatic patient subgroups (P > 0.05, each comparison). In BAL of asthmatic patients, positive correlations were found between eosinophil numbers and 1) ECP/Alb levels (r = 0.50, P = 0.020); 2) epithelial cell numbers (r = 0.50, P = 0.014). In asthmatic patients, a significant negative correlation was found between bronchial reactivity to MCh (log Pd15) and ECP/Alb levels in BAL fluid (r = -0.6, P = 0.005), whereas no correlation was found between log Pd15 MCh and BAL eosinophil or epithelial cell number (P > 0.1, each correlation). These data suggest that bronchial eosinophil recruitment and activation may occur also in mild-moderate stable asthma and that bronchial epithelium damage and airway responsiveness may be partially associated with the eosinophilic inflammatory reaction.

Pathophysiology of reactive airway disease and sinusitis

The association between asthma and sinusitis was recognized more than a century ago. Since 1980, several studies have documented that severe asthma improved after coexisting sinusitis was effectively treated either medically or surgically. Because the mechanism relating sinusitis to asthma is not known, several theories have been proposed: 1) aspiration of infected sinus secretions into the lungs during sleep, 2) enhanced vagal stimulation in the infected sinus producing direct bronchospasm, 3) bronchospasm from excessive airway drying from mouth breathing, 4) production of bacterial toxins that induce partial beta blockade, and 5) production in the infected sinus of cytokines and bronchoconstrictive mediators. There are data to support each of these hypotheses, and any or all of them may be operative. In view of recent demonstrations of activated lymphocytes and eosinophils in asthmatic airways, it is intriguing that biopsies of chronic hypertrophic sinusitis have revealed increased numbers of eosinophils and increased levels of granulocyte-macrophage colony stimulating factor, interleukin-3, and interleukin-5 compared to control tissue. These findings suggest that sinusitis might induce asthma by stimulating eosinophil production and activation and thereby supplying peptidoleukotrienes (LTC4 and LTD4) and other asthmagenic eosinophil products.

Leukotriene C(4) biosynthesis in isolated August rat peritoneal leukocytes

The mixed leukocyte population obtained from the peritoneum of the August rat is a potentially important experimental model of inherent eosinophilia that has not been well characterized. In the present study, isolated cell preparations generated a concentration-dependent release of leukotriene (LT) C(4) when exposed to the Ca(2+) ionophore A23187, reaching maximal stimulation at 5.0 muM. This response was inhibited by the 5-lipoxygenase activating protein antagonist MK-886 (0.1 muM), nominally Ca(2+) and Mg(2+)-free incubation media and by activation of protein kinase C via phorbol 12-myristate 13-acetate (50 nM). These findings establish a model system for investigating LTC(4) profiles contingent with innate peritoneal eosinophilia and are consistent with the hypothesis that cellular LTC(4) biosynthesis is phosphoregulated.

Increased spontaneous production and generation of superoxide anion by blood neutrophils in patients with asthma

Spontaneous production and PMA- and opsonized zymosan- stimulated generation of superoxide anion by blood cells in asthmatic patients were compared with those in normal volunteers and chronic obstructive pulmonary disease (COPD) patients using a lucigenin-dependent chemiluminescence method. Superoxide anion generation by 100 microl of blood in patients with asthma and/or COPD was significantly greater than that in normal subjects [asthma: 5684 +/- 253 chemiluminescence (CL); COPD: 4994 +/- 240 CL; normal: 2543 +/- 213CL]. This is consistent with the increased superoxide generation per leukocyte (PMN) in these patients (Asthma: 1.56 +/- 0.08 CL/PMN; COPD: 1.31 +/- 0.08 CL/PMN; normal: 0.83 +/- 0.07 CL/PMN. However, spontaneous production of superoxide by individual PMNs was increased only in asthmatic patients, compared with that in normal subjects (Asthma: 0.14 +/- 0.02 CL/PMN; COPD: 0.07 +/- 0.01 CL/PMN; normal: 0.07 +/- 0.01 CL/PMN. These results indicate that the respiratory burst is enhanced in both asthmatic patients and COPD patients, and that superoxide production by resting neutrophils is also increased in asthmatic patients, but not in COPD patients, compared with normal subjects.

Minimal persistent inflammation is present at mucosal level in patients with asymptomatic rhinitis and mite allergy

The natural exposure to house dust mites causes sensitization in genetically susceptible patients. Persistent exposure of sensitized patients causes chronic inflammation, and consequently, hyperreactivity, thus promoting the development of clinical features. Recently, intercellular adhesion molecule-1 (ICAM-1)/CD54 expression on epithelial cells triggered by allergen has been demonstrated and related to the inflammation caused by the allergic reaction. Therefore we evaluated the possible presence of inflammation (i.e., inflammatory cell infiltrate and ICAM-1/CD54 expression on epithelium) at conjunctival and nasal levels in patients with asymptomatic allergic rhinitis caused by mites, in their relatives living in the same environment, and in healthy volunteers. In addition, the possible relationship between inflammation and house dust mite allergen exposure was evaluated. Conjunctival and nasal scrapings of allergic subjects enrolled in the study showed many inflammatory cells. A mild ICAM-1/CD54 expression on conjunctival and nasal epithelium was detectable in allergic subjects, whereas relatives and healthy volunteers showed few inflammatory cells and no ICAM-1/CD54 expression on epithelial cells. A detectable level of house dust mite, sufficient to cause sensitization, was found in all houses. This study demonstrates a minimal persistent inflammation at conjunctival and nasal levels constantly detectable in patients without symptoms who are sensitized to mites and continuously exposed to the natural allergens.

Bronchial responsiveness, eosinophilia, and short term exposure to air pollution

The number of capillary blood eosinophils and the prevalence of bronchial hyperresponsiveness (BHR) were compared between schoolchildren living in a polluted area (Ardal) and unpolluted area (Laerdal). In Ardal there is an aluminium smelter emitting sulphur dioxide and fluoride to the environment. Daily measurements of these pollutants in ambient air were available. The mean number of eosinophils in Ardal was 220 x 10(6)/l compared with 106 x 10(6)/l in Laerdal. The prevalence of BHR was 15.9% in Ardal and 11.8% in Laerdal. The odds ratio of having BHR in relation to these pollutants during the last 24 hours were: 1.12 (95% confidence interval (CI) 1.01 to 1.24) by increasing sulphur dioxide with 10 micrograms/m3, and 1.31 (95% CI 1.07 to 1.60) when fluoride exposure increased with 1 micrograms/m3. Similarly, these exposures were associated with a decrease in eosinophils of -21 x 10(6)/l (95% CI -36 to -6) and -52 x 10(6)/l (95% CI -98 to -8), respectively, in atopics. It is hypothesised that recent exposure to irritants induces changes in the airways leading to BHR in addition to recruitment of eosinophils to the airways in atopic subjects.

Genetic susceptibility to asthma--bronchial hyperresponsiveness coinherited with a major gene for atopy

BACKGROUND

Bronchial hyperresponsiveness, a risk factor for asthma, consists of a heightened bronchoconstrictor response to a variety of stimuli. The condition has a heritable component and is closely related to serum IgE levels and airway inflammation. The basis for these relations is unknown, as is the mechanism of genetic susceptibility to bronchial hyperresponsiveness. We attempted to define the interrelation between atopy and bronchial hyperresponsiveness and to investigate the chromosomal location of this component of asthma.

METHODS

We studied 303 children and grandchildren of 84 probands with asthma selected from a homogeneous population in the Netherlands. Ventilatory function, bronchial responsiveness to histamine, and serum total IgE were measured. The association between the last two variables was evaluated. Using analyses involving pairs of siblings, we tested for linkage between bronchial hyperresponsiveness and genetic markers on chromosome 5q31-q33, previously shown to be linked to a genetic locus regulating serum total IgE levels.

RESULTS

Serum total IgE levels were strongly correlated (r = 0.65, P < 0.01) in pairs of siblings concordant for bronchial hyperresponsiveness (defined as a > or = 20 percent decrease in the forced expiratory volume in one second produced by histamine [threshold dose, < or = 16 mg per milliliter]), suggesting that these traits are coinherited. However, bronchial hyperresponsiveness was not correlated with serum IgE levels (r = 0.04, P > 0.10). Analyses of pairs of siblings showed linkage of bronchial hyperresponsiveness with several genetic markers on chromosome 5q, including D5S436 (P < 0.001 for a histamine threshold value of < or = 16 mg per milliliter).

CONCLUSIONS

This study demonstrates that a trait for an elevated level of serum total IgE is coinherited with a trait for bronchial hyperresponsiveness and that a gene governing bronchial hyperresponsiveness is located near a major locus that regulates serum IgE levels on chromosome 5q. These findings are consistent with the existence of one or more genes on chromosome 5q31-q33 causing susceptibility to asthma.

Inhibition of tumour necrosis factor-alpha (TNF-alpha) release from mast cells by the anti-inflammatory drugs, sodium cromoglycate and nedocromil sodium

TNF-alpha is a cytokine thought to be involved in the pathogenesis of asthma and in several other inflammatory conditions. Given recent evidence that mast cells (MC) are an important source of TNF-alpha, we investigated the effects of two anti-inflammatory drugs, nedocromil sodium (NED) and sodium cromoglycate (SCG), on rat MC-derived TNF-alpha. We established that at least 2 h pretreatment with NED or SCG followed by washing was required to inhibit TNF-alpha-dependent cytotoxicity by rat peritoneal MC (PMC). A maximum inhibition of TNF-alpha occurred after 6 h treatment. The inhibitory effect of NED and SCG (10(-5)-10(-3)M) was concentration-dependent (20-37% for NED and 16-37% for SCG). The time-course analysis and the use of cycloheximide, an inhibitor of protein synthesis, provided strong evidence that new protein synthesis by the MC is required for this inhibitory effect. Furthermore, 24 h treatment with 1 mM NED inhibited the levels of mRNA for TNF-alpha by 59-83%. In addition to the effect on TNF-alpha-dependent cytotoxicity by MC, 20 min pretreatment with 10(-4) M NED and SCG inhibited antigen-stimulated TNF-alpha release (6h) by 42% and 48%, respectively. Interestingly, the functionally distinct intestinal mucosal MC (IMMC) is unresponsive to these drugs with regard to histamine secretion. However, as with PMC, 2h pretreatment with NED or SCG inhibited TNF-alpha-dependent cytotoxicity by IMMC. These effects may be important in the action of these drugs in vivo in the late phase reaction in asthma or other inflammatory conditions.

Cross-sectional study of bone density in asthmatic children

The emphasis in treatment of asthma in children has shifted from bronchodilators to inhaled anti-inflammatory medications, including inhaled corticosteroids (ICS). Children with chronic asthma and moderate to severe symptoms have been targeted as particularly deserving of maintenance therapy with ICS. We have previously reported a cross-sectional study of bone density in children treated with ICS. There was no significant difference between the total bone density of asthmatic patients and controls. We sought to extend the information available on bone density in asthmatic children by evaluating 15 asthmatic subjects taking daily ICS (beclomethasone dipropionate) and comparing them with age- and sex-matched controls. We compared total and regional bone density, bone age, and calcium intakes in these subjects. Asthmatic subjects were on ICS for 4-60 months, with doses ranging from 200 to 450 micrograms/day. There was no significant difference between asthmatics and matched controls for height, weight, % RDA Ca2+, or bone age. The asthmatic subjects had bone density (total and regional measurements) equivalent to their controls. These results provide additional support for the safety of low-dose ICS on bone density in asthmatic children.

Elevation of serum soluble vascular cell adhesion molecule-1 (sVCAM-1) levels in bronchial asthma

We have previously shown the elevation of serum soluble intercellular adhesion molecule-1 (sICAM-1) and soluble E-selectin (sE-selectin) in patients with bronchial asthma during asthma attacks. In the present study, we extended our earlier study by measuring serum sVCAM-1 levels by ELISA in 45 patients with bronchial asthma (23 atopic and 22 non-atopic) during asthma attacks and in stable conditions in order to assess further the state of adhesion molecules in allergic inflammation of bronchial asthma. The levels of sVCAM-1 in sera obtained during bronchial asthma attacks were higher than those in sera obtained in stable conditions. These findings were observed regardless of atopic status. To examine the regulatory mechanism in the elevation of serum sVCAM-1 levels, serum tumor necrosis factor-alpha (TNF-alpha) levels were measured by ELISA. TNF-alpha levels in sera obtained during bronchial asthma attacks were higher than those in sera obtained in stable conditions. The nature of change in serum TNF-alpha levels correlated with the nature of change in serum sVCAM-1 levels, but serum TNF-alpha levels did not correlate with serum sVCAM-1 levels. These results suggest that higher levels of sVCAM-1 during asthma attacks may reflect the up-regulation of VCAM-1 expression in allergic inflammation, and that a soluble form of VCAM-1 molecules may be useful markers for the presence of allergic inflammation. TNF-alpha is shown to enhance the expression and release of VCAM-1 in vitro, however; the regulatory mechanism in the elevation of serum sVCAM-1 levels remains to be clarified.

Murine pulmonary Ca(2+)-transport system activated by allergic immune response retains sensitivity to oxidative stress

Exaggerated oxygen radical production by airway cells may contribute to increased airway responsiveness and heightened smooth muscle constriction in asthmatic lungs. Smooth muscle cell contractility in the lung is regulated by Ca2+ homeostasis. The contribution of inflammatory cells to these events is unclear. A murine model of allergic pulmonary hypersensitivity was developed to study the role of Ca2+ transport in allergic pulmonary reactions. Sensitization of mice was accomplished by injection with ovalbumin (OA) (1 or 50 micrograms) or OA (1 microgram) plus Al(OH)3. Pulmonary responses were elicited by inhalation provocation challenge with OA aerosol and quantified by the extent of inflammatory cell infiltrate at 24 h. Increased Ca2+ transport was found in microsomes and homogenates of the lung after antigen challenge. Activation of Ca2+ transport was correlated with the severity of the allergic pulmonary response as evidenced from specific antibody production and inflammatory cell infiltrate. The greatest increase in Ca2+ transport was noted in microsomes from mice sensitized with OA plus adjuvant. Ca2+ transport in sensitized, but not in control mice, was responsive to oxidative stress induced by addition of phenol and hydrogen peroxide. Lung homogenates from both groups of animals responded similarly to phenoxyl radical-induced oxidative stress induced by phenol plus exogenous tyrosinase. These results are the first to indicate heightened Ca2+ transport in pulmonary microsomes following an allergic lung response and emphasize the role of aluminum hydroxide in enhancing allergic reactions in the lung. The responsiveness of the system to oxidative stress suggests that oxidative mechanisms may contribute to the physiologic and pathologic manifestations, such as airway hyperreactivity, associated with allergic pulmonary disease.

T cell receptor genetics, autoimmunity and asthma

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Pharmacologic modulation by cetirizine of some adhesion molecules expression in psoriatic skin lesions

BACKGROUND

Adhesion molecules play a major role in the pathogenesis of inflammatory skin diseases by regulating lymphocyte trafficking and homing in an inflamed area.

METHODS

The expression of the lymphocyte function-associated antigen-1 (LFA-1) and of its ligand, the intercellular adhesion molecule-1 (ICAM-1) has been studied in psoriatic skin lesions of 10 patients with guttate, nummular, and palmoplantar psoriasis. In addition, the peculiar immunophenotype of infiltrating cells (CD3, CD4, CD8, CD25) and their correlation with HLA-DR expression before and after treatment with oral cetirizine, a highly selective, third generation H1-receptor antagonist has been examined using the labeled avidin biotin (LAB) system.

RESULTS

Cetirizine treatment modulated in vivo the expression of adhesion molecules LFA-1/CAM-1 as shown in all cases by decreased levels of their expression on keratinocytes and on dermal endothelial cells (P < 0.001). The expression of HLA-DR on keratinocytes and endothelial cells was also inhibited after treatment. The numbers of infiltrating CD3-, CD4-, CD8-positive cells were reduced, whereas there was no significant modification of CD25-positive cells within the epidermis and the dermis.

CONCLUSION

This open clinical trial suggests that cetirizine could be effective in treating psoriasis: (1) for its symptomatic control on itching; (2) for its immunopharmacologic modulation of leukocyte integrins and on the immunophenotype pattern of infiltrating and resident cells, and (3) for contributing to the clearing of the lesions clinically.

Prevention of asthma with ketotifen in preasthmatic children: a three-year follow-up study

Growing morbidity and mortality rates call for research towards more effective methods of preventing asthma. During the last decade several groups have reported the results of natural history and asthma prevention studies. However, the attempt to prevent development of asthma in genetically predisposed children, has not resulted in a generally accepted management scheme. The aim of this study was to evaluate the effectiveness of ketotifen in preventing the onset of asthma in infants considered to be at high risk of developing the disease, but who had no history of respiratory obstruction. These children have been described as preasthmatic. In this double-blind, placebo-controlled, parallel study, 100 infants with a family history of major allergy and elevated serum IgE levels, but with no history of bronchial obstruction, were treated with either ketotifen (n = 50) or placebo (n = 50) over a 3-year period. There were no statistically significant differences between the two groups with regard to age, sex, degree of hereditary allergy, levels of serum IgE upon joining the study, and family smoking habits. At the end of 3 years, only four of the 45 infants who had received ketotifen had developed asthma (9%). Of the 40 children given placebo, 14 had developed asthma (35%) (P = 0.003). These results suggest that ketotifen is effective in preventing the onset of asthma in preasthmatic children.

Effects of NIP-502 on antigen-induced bronchial responses and allergic reactions in animal models

We examined the effect of a newly synthesized pyridazinone derivative, NIP-502 [4-chloro-5-(3-ethoxy)-4-phenoxybenzamine)-3(2H)-pyridazinone], on antigen-induced bronchial responses and allergic reactions in several animal models. NIP-502 (10 mg/kg, p.o.) inhibited the antigen-induced immediate asthmatic response in passively sensitized guinea pigs. The inhibitory effect was also observed in metyrapone (an inhibitor of 11 beta-hydroxylase)-pretreated guinea pigs. NIP-502 improved ovalbumin (OA)-induced airway hyperresponsiveness to acetylcholine and inhibited the OA-induced increase in the number of inflammatory leukocytes in the bronchoalveolar lavage fluid. These inhibitory effects on OA-induced responses were similar to those of prednisolone. NIP-502 also showed an inhibitory effect on the passive cutaneous anaphylactic reaction in rats but did not inhibit the reversed cutaneous anaphylactic reaction, reversed Arthus reaction or delayed type hypersensitivity reaction. On the other hand, prednisolone showed broad inhibitory effects except for the reversed cutaneous anaphylactic reaction. In the in vitro study, NIP-502 (30 microM) significantly inhibited Formyl-Met-Leu-Phe-induced superoxide anion production by the guinea pig alveolar macrophages. These results indicate that the inhibitory effects of NIP-502 on bronchial responses are similar to those of prednisolone, but this compound seemed to act more selectively on the respiratory tract than prednisolone. Because of its effectiveness against a variety of bronchial responses, NIP-502 may be useful in the treatment of bronchial asthma.

Antibody against interleukin-5 prevents antigen-induced eosinophil infiltration and bronchial hyperreactivity in the guinea pig airways

Interleukin-5 (IL-5) induces proliferation, differentiation and activation of eosinophils. An animal model of local allergen (airways) sensitization was employed to study the effects of anti-IL-5 monoclonal antibody (mAb) on infiltration of eosinophils into inflammatory region, the development of antigen-induced late asthmatic response (LAR) and the increased bronchial responsiveness following LAR. Guinea pigs exposed to aerosolized ovalbumin (OVA) daily for 10 days developed an increase in the number of eosinophils in the tracheal wall 24 h after aerosolized OVA challenge. Furthermore, all animals developed an apparent LAR determined by the response with a 2-fold increase in respiratory resistance and showed an increase in bronchial responsiveness to acetylcholine 24 h after OVA challenge. In animals treated with anti-IL-5 mAb, however, eosinophil number in the tracheal wall dramatically decreased compared with animals treated with control antibody. The development of LAR was also remarkably suppressed by anti-IL-5 mAb treatment, although a similar magnitude of immediate bronchoconstriction was observed. Moreover, in anti-IL-5 antibody-treated guinea pigs, an increase in bronchial responsiveness to acetylcholine significantly decreased. Data demonstrate that IL-5 is involved in airway eosinophilia, development of LAR and an increase in bronchial responsiveness induced by allergen sensitization via the airways. Development of IL-5 synthesis inhibitors and/or receptor antagonists could provide another therapeutic class of anti-asthmatic drugs.

Inhibition of mediator release in RBL-2H3 cells by some H1-antagonist derived anti-allergic drugs: relation to lipophilicity and membrane effects

In a model for mucosal mast cells (RBL-2H3 cells) a set H1-antagonist derived anti-allergic drugs containing a diphenylmethyl piperazinyl moiety was examined for their ability to inhibit release of the mediator beta-hexosaminidase. Cells were activated with antigen or the calcium ionophore A23187, whether or not in combination with the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA). Oxatomide, hydroxyzine and cetirizine inhibit the antigen induced beta-hexosaminidase release. The release triggered by A23187, whether or not in combination with TPA is hardly influenced by the compounds. A biphasic dependence of the inhibition of exocytosis in RBL cells on lipophilicity is observed with the optimum at log P is 5-6. The extremely lipophilic compounds meclozine and buclizine are not active in this model. pH dependence of the effect of the drugs shows that especially the uncharged species are active in inhibiting exocytosis. The investigated compounds show an effect on phase transitions in L-alpha-phosphatidylcholine dipalmitoyl liposomes as assayed with differential scanning calorimetry (DSC). For the less extremely lipophilic compounds the induced changes in the phospholipid membranes increased with lipophilicity. The relation between structural features of the drug and the interaction with phospholipids is discussed in view of the DSC results. We conclude that location of the active drugs at the membrane or the membrane/protein interface is important for the inhibiting activity on exocytosis. This could affect several membrane related processes, which are abundant in the early phases of the IgE-mediated signal transduction process.

The effect of MK-0591, a novel 5-lipoxygenase activating protein inhibitor, on leukotriene biosynthesis and allergen-induced airway responses in asthmatic subjects in vivo

BACKGROUND

The 5-lipoxygenase metabolites of arachidonic acid are likely to be involved in the pathophysiology of atopic asthma. We investigated the effect of pretreatment with MK-0591, a novel 5-lipoxygenase activating protein inhibitor, on allergen-induced early asthmatic reactions (EARs) and late asthmatic reactions (LARs), and subsequent airway hyperresponsiveness to histamine.

METHODS

Eight atopic men with mild to moderate asthma aged 19 to 31 years, (forced expiratory volume in 1 second [FEV1] > or = 67% of predicted value, histamine provocative concentration causing a 20% fall in FEV1 [PC20] < 4 mg/ml) and documented EAR and LAR to house dust mite extract participated in a two-period, double-blind, placebo-controlled, crossover study. During each study period histamine PC20 was measured 2 days before and 1 day after a standardized allergen inhalation challenge test. MK-0591 was administered in 3 oral doses of 250 mg each at 24, 12, and 1.5 hours before inhalation of allergen. Biochemical activity of MK-0591 was determined by calcium ionophore A-23187-stimulated leukotriene (LT)B4 biosynthesis in whole blood ex vivo and by urinary LTE4 excretion. Airway response to allergen was measured by FEV1 (percent fall from baseline). The EAR (0 to 3 hours) and the LAR (3 to 8 hours) were expressed as corresponding areas under the time-response curves.

RESULTS

MK-0591 and placebo did not differ in their effects on prechallenge FEV1 (p = 0.10). As compared with the value before pretreatment, MK-0591 blocked LTB4 biosynthesis and LTE4 excretion by a mean of 98% (range, 96% to 99%; p < 0.002) and 87% (range, 84% to 96%; p < 0.046), respectively, from 0 to 24 hours after allergen challenge. Both the EAR and the LAR were significantly reduced after administration of MK-0591 as compared with placebo, with a mean inhibition of 79% (p = 0.011) and 39% (p = 0.040), respectively. Allergen-induced airway hyperresponsiveness was not significantly different between the two pretreatment periods (p = 0.37).

CONCLUSIONS

In this study oral MK-0591 prevented leukotriene biosynthesis after allergen challenge in patients with mild to moderate asthma. The results of our study indicate that 5-lipoxygenase products play an important role during the EAR, whereas their contribution to the pathophysiology of the LAR seems to be of less importance.

Cellular and mediator profile in bronchoalveolar lavage of guinea pigs after toluene diisocyanate (TDI) exposure

Toluene diisocyanate (TDI) is a volatile, highly reactive chemical widely used as a polymerizing agent in the production of polyurethane foams, lacquers, adhesives, and other items. Repeated airway exposures in the workplace to TDI may cause a concentration-dependent risk of developing chronic airway disorders. Different pathomechanisms are involved. IgE-mediated sensitization and irritative effects were clearly demonstrated in exposed subjects as well as in animals. In this study we examined the cellular and mediator composition in bronchoalveolar lavage fluid (BALF) of guinea pigs (eight in each group) exposed to TDI (10, 20, or 30 ppb) on 5 consecutive days for 2 hours each. Increased numbers of eosinophils and significantly elevated levels of LTB4 and LTC4/LTD4/LTE4 were obtained in BALF of all exposed animals when compared to nonexposed control animals. PGD2 and TXB2 remained unaltered in BALF. Stimulation of BALF cells of exposed and control animals with Ca-ionophore A23187 and arachidonic acid induced an increased generation of LTB4. Furthermore, BALF cells of the exposed animal groups generated immunoreactive LTC4/LTD4/LTE4, whereas controls did not show peptido-leukotriene formation in the presence and absence of stimuli. Our data clearly demonstrate an influx of eosinophils into the airways associated with mediator release and higher cellular responsiveness after TDI exposure.

Serum interleukin 5 concentrations in atopic and non-atopic patients with glucocorticoid-dependent chronic severe asthma

BACKGROUND

Interleukin (IL)-5 is thought to play a part in asthmatic bronchial mucosal inflammation and is a potential therapeutic target. Detectable serum IL-5 concentrations have been found previously in a proportion of patients with acute severe asthma, but not in the same patients following oral glucocorticoid therapy or in normal controls. A study was undertaken to investigate whether or not IL-5 is detectable in the serum of patients with glucocorticoid-dependent chronic severe asthma.

METHODS

Serum concentrations of IL-5 were measured in 29 patients with stable oral glucocorticoid-dependent chronic severe asthma (mean PEFR 59.7% predicted) and seven normal controls using a specific enzyme-linked immunoassay calibrated with recombinant human IL-5 standards (lower limit of sensitivity 40 pg/ml).

RESULTS

Interleukin 5 was detectable in the serum of 15 of the 29 patients at a median concentration of 150 pg/ml (range 40-690), but was undetectable in the serum of all the control subjects. The patients with detectable serum IL-5 concentrations did not differ from those with undetectable concentrations in terms of atopic status, disease severity (percentage predicted PEFR or FEV1), prednisolone dosage, serum IgE concentrations, or peripheral eosinophil count.

CONCLUSIONS

Interleukin 5 is detectable in the serum of a proportion of both atopic and non-atopic patients with chronic severe asthma, and concentrations in these patients were higher than in normal controls. These observations are compatible with the hypothesis that IL-5 release occurs in these patients during a period of stable asthma despite systemic glucocorticoid therapy.

Effects of ZCR-2060 on allergic airway inflammation and cell activation in guinea-pigs

The effects of 2-(2-(4-(diphenylmethyl)-1-piperadinyl) ethoxy) benzoic acid malate (ZCR-2060) on allergic airway inflammation and inflammatory cell activation in guinea-pigs were studied. Allergic airway inflammation was induced by inhalation of antigen into actively-sensitized animals and the increase in inflammatory cells into bronchoalveolar lavage fluid (BALF) was measured. Aeroantigen-induced infiltration of inflammatory cells, especially eosinophils and neutrophils, in BALF gradually increased, and reached a peak at 6 or 9 h after the challenge. ZCR-2060 (1 mg kg-1 p.o.) clearly inhibited the increase of eosinophil numbers in BALF. Moreover, the effect of ZCR-2060 on inflammatory cell activation in terms of chemotaxis and superoxide generation in-vitro was studied. ZCR-2060 (10(-6)-10(-4) M) inhibited the platelet-activating factor (PAF)-induced chemotaxis of eosinophils and neutrophils, but did not inhibit the leukotriene B4-induced chemotaxis of eosinophils and the formyl-Met-Leu-Phe-induced chemotaxis of neutrophils. PAF-induced superoxide anion generation by eosinophils, neutrophils and alveolar macrophages was inhibited by ZCR-2060 (10(-6)-10(-4) M). However, ZCR-2060 did not affect phorbol myristate acetate-induced superoxide anion generation by eosinophils, neutrophils and alveolar macrophages. These results indicate that ZCR-2060 inhibits allergic airway inflammation, and PAF-induced inflammatory cell activation in guinea-pigs. ZCR-2060 may prove useful for the treatment of allergic airway inflammation or allergic disorders, especially inflammatory cell infiltration and activation.

Eosinophil cationic protein in nasal secretion and in serum and myeloperoxidase in serum in respiratory syncytial virus bronchiolitis: relation to asthma and atopy

Eosinophil cationic protein (ECP) in nasal secretions was determined in 34 infants with respiratory syncytial virus (RSV) bronchiolitis during the acute infection stage and one and six months later. ECP in serum was determined in 19 of these children at the same time. Myeloperoxidase (MPO) was determined in the same 19 children at the acute infection stage and after one month. All children were followed prospectively for two years after the infection with regard to the development of bronchial obstructive symptoms. Asthma, defined as three or more episodes of bronchial obstruction verified by a physician, developed in 18% of children and less severe obstructive symptoms in 29%. A screening test for food IgE antibodies in serum was performed six months and a skin prick test two years after the acute infection. Nasal ECP/albumin ratios after six months were significantly higher than during the acute RSV infection. MPO, but not ECP, levels in serum were significantly elevated at the time of acute infection compared with levels after one month. Nasal ECP/albumin ratios at the acute infection were compared to a control group of 27 infants with non-RSV upper respiratory tract infections and did not differ. It was not possible to predict, either from ECP/albumin ratios in nasal secretion or from ECP and MPO in serum, which children would develop asthma, other bronchial obstructive symptoms or positive IgE tests.

Comparative morphology of the airways in asthma and chronic obstructive pulmonary disease

Asthma and chronic obstructive pulmonary disease (COPD) are complex conditions with imprecise definitions that make definitive morphological comparisons difficult. Asthma may be divided into extrinsic (allergic), intrinsic (late onset), and occupational forms. The airways in fatal asthma are occluded by markedly tenacious plugs of exudate and mucus; there is fragility of airway surface epithelium, thickening of the reticular basement membrane, and bronchial vessel dilatation, congestion, and edema. There is enlargement of bronchial smooth muscle and also of submucosal gland mass, particularly in medium-sized bronchi. There is increased inflammatory infiltrate comprising activated lymphocytes and eosinophils with release of granular content in the latter; the allergic inflammation is associated with gene expression for interleukins IL-4 and IL-5 (ie, TH2 phenotype) and also GMCSF and TNF alpha. Many of these changes are already present in mild forms of asthma. In comparison, three conditions contribute to COPD: (1) In chronic bronchitis there is inflammation associated with mucous hypersecretion, enlargement of tracheo-bronchial submucosal glands, and a disproportionate increase of acidic mucus. The reticular basement membrane is not consistently thickened. (2) In small (peripheral) airways disease there is a macrophage bronchiolitis, mucous metaplasia and hyperplasia, increased intraluminal mucus, increased wall muscle, fibrosis, and airway stenoses. Respiratory bronchiolitis and loss of alveolar wall attachments are important lesions. (3) Emphysema involves elastolytic destruction of the alveolar wall; its overall severity, rather than type, appears to be an important determinant of chronic irreversible deterioration of airflow in COPD.

Dextran sedimentation induces a difference in the percentage of hypodense eosinophils in peripheral blood between children with allergic asthma and healthy controls

Considerable differences in the percentage of hypodense eosinophils in the peripheral blood of asthmatics have been reported by different investigators. In these previous studies dextran sedimentation was used for removal of erythrocytes prior to density centrifugation. We hypothesized that the sedimentation procedure might induce the presence of hypodense eosinophils in the peripheral blood of asthmatic patients. In order to test this hypothesis, we compared eosinophil density profiles from peripheral blood of children with asthma and of age-matched healthy controls, using different procedures. In the first method (direct method) blood samples were directly layered on a discontinuous Percoll gradient. Erythrocytes were removed by isotonic lysis. In the second method (dextran sedimentation) erythrocytes were removed by sedimentation with dextran prior to gradient centrifugation. Results of the direct method show no significant difference in percentage of hypodense eosinophils between children with asthma and healthy controls (9.19% and 6.84% respectively). However, after dextran sedimentation, children with asthma had a significantly higher percentage of hypodense eosinophils than healthy controls (15.40% and 8.84% respectively; P < 0.05). The percentage of hypodense eosinophils was correlated with the number of eosinophils and with the lung function, measured as the Tiffeneau index (FEV1/VC), in the whole group of subjects when the direct method was used. We conclude that an increased percentage of hypodense eosinophils is not present in the circulation of children with asthma, but can be induced in vitro by dextran sedimentation. Therefore, in vitro generation of hypodense eosinophils in the blood of patients with asthma seems to be related with the primed state of eosinophils.

Evidence of intercellular adhesion molecule-1 expression on nasal epithelial cells in acute rhinoconjunctivitis caused by pollen exposure

Rhinoconjunctivitis caused by pollen allergy is characterized by typical signs and symptoms and mucosal infiltration by inflammatory cells during pollen season. It has been recently demonstrated that the adhesion molecule system is deeply involved in cell-to-cell interaction during inflammatory response consequent to allergic reactions. The aim of this study was to evaluate the expression of intercellular adhesion molecule-1 (ICAM-1 or CD54) on nasal epithelial cells, before and during natural seasonal exposure, in 10 allergic patients (Parietaria judaica-sensitized) and in 10 healthy volunteers, correlating this parameter with clinical and cytologic involvement. Nasal epithelial cells of allergic subjects showed a significant expression of CD54 during pollen season (p < 0.001). On the contrary, no CD54 expression was observed out of pollen season. In healthy volunteers no CD54 expression was observed both before and during pollen season. Cytologic evaluation demonstrated an infiltration by eosinophils (mainly activated [EG2+]), (p < 0.001), neutrophils (p < 0.001), and metachromatic cells (p < 0.001) during pollen season only in allergic subjects. Therefore results indicate that seasonal allergic rhinitis is characterized by an infiltration of inflammatory cells correlated with CD54 expression on nasal epithelial cells. This phenomenon is specific, being restricted only to allergic patients during pollen season.

Detection of interleukin-5 messenger RNA and interleukin-5 protein in bronchial biopsies from asthma by nonradioactive in situ hybridization and immunohistochemistry

Recently direct evidence for the role of interleukin-5 (IL-5) in eosinophilic inflammation in the airways of persons with asthma has been provided by an in situ hybridization study that used radioisotope-labeled IL-5 complementary RNA probes. Radioisotope-labeled probes, although sensitive, require autoradiographic detection, which is time-consuming. In the most recent study we attempted to detect IL-5 messenger RNA in the bronchial biopsy specimens from patients with asthma using nonradioactive in situ hybridization, which gives rapid results. Bronchial biopsy specimens were obtained from eight patients with asthma and seven diseased control subjects. IL-5 complementary DNA probes were labeled with digoxigenin-deoxyuridine triphosphate and hybridized to permeabilized sections. Hybridization signals were visualized by an immunohistochemistry technique. Positive hybridization signals were observed in six of the eight biopsy specimens from patients with asthma. Pretreatment with ribonuclease or hybridization with an unrelated probe produced negative results. Immunohistochemical staining of serial sections with a monoclonal antibody to IL-5 revealed that a few cells within the mucosa positively stained, suggesting active synthesis of IL-5. Biopsy results from the seven diseased control subjects did not show any hybridization signal. These results confirm and extend previous observations of IL-5 messenger RNA expression in the airways of patients with asthma, and suggest that digoxigenin-labeled IL-5 complementary DNA probes would be a powerful research tool.

Serum eosinophil cationic protein (ECP) in chronic asthma. Relationship to spirometry, flow-volume curves, PC20, and exacerbations

Serum ECP was measured in a double-blind study in relation to spirometry, flow-volume curves, and histamine PC20 (30-s tidal breathing method, normal value > 32 mg ml-1) in 20 chronic asthmatic patients (five male), mean age 48.9 yr (SD 11.0), once a month and at additional visits due to acute exacerbations over a 6-month period. All patients were on maintenance inhaled corticosteroid therapy. Serum ECP was considered elevated at > or = 20 micrograms l-1. ECP showed significant negative correlations with lung function, especially when ECP was elevated (45/143 observations): r = -0.48, -0.48, and -0.49 for respectively FEV1, PEF, and MMEF (all at baseline and as % predicted, P = 0.001), the best correlation being with FEV1/FVC ratio (r = -0.61, P < 0.001). PC20 only had a weak overall correlation with ECP (r = -0.21, P = 0.015). Eosinophilia at > or = 0.400 x 10(9) cells l-1 (38/143 observations) did not show any significant correlations with the lung function variables. The patients were subdivided into three groups according to exacerbations. Group A consisted of seven patients with suspected infectious exacerbations (mean 1.4), group B of six patients with suspected inflammatory exacerbations (mean 3.2), and group C of seven patients who did not experience any symptomatic exacerbations. A significant difference in mean ECP was found between group B and A (33.1 vs. 10.2, P = 0.003). Group B also differed significantly from group A with respect to lung function and PC20, but not to atopy, lung function and PC20 being lower and variability higher in group B. The findings of this study suggest that serum ECP is a sensitive marker of inflammatory airflow obstruction in chronic asthma. Elevated ECP seems to denote patients at risk from inflammatory exacerbations, resulting in practical implications for the therapeutic management of chronic asthma.

Polymerase chain reaction quantification of cytokine messenger RNA expression in peripheral blood mononuclear cells of patients with acute exacerbations of asthma: effect of glucocorticoid therapy

We have measured the expression of messenger ribonucleic acid (RNA) (mRNA) encoding interleukin-5 (IL-5), IL-4, IL-2 and interferon-gamma (IFN gamma) in peripheral blood mononuclear cells (PBMC) from 10 patients with acute exacerbations of asthma and nine non-asthmatic controls. Measurements were repeated in seven of the asthmatics following 7 days of oral glucocorticoid therapy. Total RNA was extracted from the PBMC, reverse transcribed using oligo-(dT) primers and aliquots of the resulting complementary DNA (cDNA) amplified using the polymerase chain reaction (PCR) in the presence of cytokine-specific primers under non-saturating conditions. PCR products were quantified on a relative basis after Southern blotting and probing with radiolabelled internal oligonucleotide probes by computer assisted densitometry of blot autoradiographs. The relative amounts of IL-5 mRNA in PBMC from the asthmatic patients prior to glucocorticoid therapy were greater (P < 0.01) than those in PBMC from non-asthmatic controls. In contrast, there were no differences in the relative amounts of IL-4, IL-2 and IFN gamma mRNA. In the asthmatics, the relative amounts of IL-5 mRNA correlated with the peripheral blood eosinophil counts (P = 0.02). After oral glucocorticoid therapy of the asthmatics, lung function improved and the relative amounts of PBMC IL-5 mRNA were reduced (P = 0.04) and no longer differed from those in PBMC from non-asthmatic controls. Glucocorticoid therapy was not associated with significant changes in the relative amounts of PBMC IL-4, IL-2 and IFN gamma mRNA. PBMC from atopic subjects contained significantly greater quantities of IL-4 mRNA (P = 0.04) but not IL-5, IL-2 and IFN gamma mRNA compared with non-atopic subjects regardless of their asthmatic status. We conclude that PBMC of patients with acute exacerbations of asthma demonstrate elevated expression of mRNA encoding IL-5, but not IL-2, IL-4 and IFN gamma and that the clinical improvement associated with glucocorticoid therapy is associated with a reduction of IL-5 mRNA expression. We further conclude that elevated expression in PBMC of mRNA encoding IL-4 is a feature of atopy but not of asthma. These observations suggest that IL-5 synthesis by activated T-lymphocytes may be relevant to the pathogenesis of asthma, and that inhibition of this release by glucocorticoids may at least partly explain their therapeutic effect in this disease.

Bone mineral density in normal and asthmatic children

BACKGROUND

The largest increase in bone mass occurs during childhood and adolescence. A subnormal bone mass is associated with increased risk of fracture. Bone mass is influenced by height, age, race, exercise, and stage of puberty. It is adversely affected by chronic disease states and corticosteroid use. We performed a cross-sectional study of bone density in children with moderate to severe asthma who were treated with inhaled corticosteroids, inhaled cromolyn, oral corticosteroids, or a combination of these, and we compared them with normal children.

METHODS

A cross-sectional study of bone density, measured either by dual-photon or dual-energy absorptiometry, was performed on 97 normal white and 30 asthmatic white children, aged 5 to 18. Average daily calcium intake, height, weight, and Tanner stage were determined. The total daily and lifetime doses of inhaled corticosteroids in children with asthma were calculated. T tests, multiple regression, chi square analysis, and analysis of covariance were performed.

RESULTS

No significant difference in bone density was demonstrated between children with asthma and normal control subjects. No measure (including calcium intake, Tanner stage, daily or lifetime inhaled corticosteroid dose, or duration of illness), except for height and age, provided a significant contribution to the explanation of bone density in children with asthma.

CONCLUSION

Children and adolescents with moderate to severe asthma, including those treated with inhaled corticosteroids, do not appear to have adversely affected bone mass. There was, however, the possibility of a type II error in this study because of the sample size.

Pharmacological studies of platelet-activating factor (PAF)-induced augmentation of response to histamine in guinea-pigs

An acute increase in airway response to histamine produced by platelet activating factor (PAF) was investigated pharmacologically in guinea-pigs. (1) The airway response to histamine (3 micrograms/kg) measured as pulmonary pressure was increased 8 min after injection of PAF at a dose of 25 ng/kg without affecting the numbers of leukocytes (macrophages, eosinophils, neutrophils and lymphocytes) in bronchoalveolar lavage fluid and airway capillary permeability. (2) To investigate the mechanism responsible for the PAF (25 ng/kg)-induced airway hyperresponsiveness to histamine, the effects of CV-3988 (a PAF-antagonist), ONO-1078 (a leukotriene (LT) antagonist), AA-861 (a 5-lipoxygenase inhibitor), indomethacin (a cyclooxygenase inhibitor), OKY-046 (a thromboxane A2 (TXA2) synthetase inhibitor) and S-1452 (a TXA2 receptor antagonist) were examined. Simultaneously, to investigate the direct antagonistic effects of these drugs on PAF-induced response, the effects of above agents on PAF (150 ng/kg) induced bronchoconstriction were examined. CV-3988 completely inhibited both reactions, while ONO-1078 and AA-861 had no effect on both reactions. OKY-046, S-1452 and indomethacin inhibited PAF-induced bronchoconstriction more potently than PAF-induced airway hyperresponsiveness. These results indicate that inflammatory response is not involved in the onset of PAF-induced acute airway hyperreactivity. Results also suggest that TXA2 but not LT may play a role in the onset of this airway hyperreactivity and the role of TXA2 in hyperreactivity is less important than in PAF-induced bronchoconstriction.

Activated peripheral blood CD4 and CD8 T-lymphocytes in child asthma: correlation with eosinophilia and disease severity

There now exists compelling evidence of a role for cell-mediated immunity in the pathogenesis of adult asthma, but little information is available as to what extent this process participates in the pathogenesis of childhood asthma. We hypothesised that asthma in children is associated with the activation of T-lymphocytes whose products regulate, at least in part, the mobilisation and recruitment of eosinophils and thereby disease severity. Our aims, therefore, were to compare the expression of activation markers, including CD45 isoforms, on peripheral blood T-lymphocytes from asthmatic and non-asthmatic, allergic control children matched for age and atopic status, and to attempt to correlate the percentages of activated T-lymphocytes in the asthmatics with the numbers of peripheral blood eosinophils and with disease severity. Seventeen children with moderate to severe chronic asthma were compared with 8 non-asthmatic, allergic children matched for age and atopic status. Expression of the activation markers CD25, HLA-DR and VLA-1 and the CD45 isoforms CD45RA and CD45RO on peripheral blood CD4 and CD8 T-lymphocytes was measured using dual fluorescence flow cytometry. Peripheral blood eosinophils were measured using an automated laser cytometer. Asthma severity was assessed by a symptom score, spirometry and measurement of histamine PC20. The absolute numbers of eosinophils in the peripheral blood of the asthmatics were elevated as compared to the non-asthmatic, allergic controls (p < 0.01), whereas the absolute numbers of both CD4+ and CD8+ T-lymphocytes were not significantly different.(ABSTRACT TRUNCATED AT 250 WORDS)

Assessment of inflammation in noninfectious chronic maxillary sinusitis

BACKGROUND AND AIM

Pathologic examination of the sinus mucosa and titration of inflammatory mediators in the sinus fluid were carried out to characterize inflammation in chronic sinusitis and determine whether patients with chronic allergic rhinitis (CAR) and sinusitis differ from patients with chronic nonallergic rhinitis (CNAR) and sinusitis.

METHODS

Nine control subjects (patients requiring ear, nose, and throat surgery not related to sinusitis), 12 patients with CAR and sinusitis, and 13 patients with CNAR and sinusitis were investigated. Eosinophil cationic protein, tryptase, myeloperoxidase, histamine, and prostaglandin D2 were measured in the sinus lavage fluids, and cells were enumerated. The cellular infiltrate was studied by immunohistochemistry with monoclonal antibodies against eosinophil cationic protein (eosinophils), tryptase (mast cells), neutrophil elastase (neutrophils), CD3 (lymphocytes), CD68 (macrophages), and proliferating cell nuclear antigens.

RESULTS

Neutrophils were not increased in sinusitis. In comparison with control subjects, patients with CAR and CNAR with sinusitis showed significant increases in eosinophils and macrophages in biopsy specimens and in eosinophil cationic protein in sinus lavage fluids. In comparison with patients with CNAR, patients with CAR had an increased number of intraepithelial mast cells and lymphocytes.

CONCLUSIONS

These findings suggest that patients with CNAR and sinusitis can be distinguished from patients with CAR and sinusitis, which resembles nonallergic rhinitis with eosinophilia syndrome.

Cobalt-related asthma: clinical and immunological aspects

Several clinical and experimental findings point to cobalt as the only sensitizer and causal agent of hard metal asthma. The clinical features have been clearly defined by bronchial provocation tests, with a prevalence of late phase responses. Epidemiology is still insufficient to configure prevalence and incidence rates for cobalt asthma. IgE and IgG antibodies with cobalt specificity have been demonstrated, but T-lymphocytes and eosinophils involvement seem to be important in the mechanism of an allergic inflammation in the airways. Such an immunological pathogenesis links cobalt asthma with other manifestation of hard metal disease.

[Eosinophil and its pathology]

Hypercosinophilia was previously considered as a biological marker, particularly useful for diagnostic investigation. However, it can also appear as a marker of disease activity since fundamental studies have revealed the potent pathogenic role of human eosinophils. This new appreciation is related to a better definition of the molecular and cellular basis of eosinophil functions. Thus, eosinophils were identified as inflammatory and/or cytotoxic cells after the characterization of the role of surface molecules (adhesion molecules, Fc receptor of immunoglobulins) and mediators. The molecular components which endow the eosinophil with certain of its functional characteristics are primarily the cationic proteins of the specific granules and the phospholipid mediators that are newly formed during cellular activation. Some of these effector molecules are also directly involved in the induction of deleterious effects.