Effect of IL-1β and TNF-α vs IL-13 on bronchial hyperresponsiveness, β2-adrenergic responses and cellularity of bronchial alveolar lavage fluid

1 Levels of IL-13, IL-1β and TNF-α are increased in bronchial lavage fluid of asthmatics and induce certain significant features of bronchial asthma including airway hyper-responsiveness (AHR). In this study, we have investigated the effect of these cytokines in naïve mice and those sensitized to ovalbumin (OVA) on bronchoconstrictions to methacholine (MCh) and the functional antagonism induced by β2 -adrenoceptor agonism. 2 Naïve or OVA-sensitized mice were treated for 3 days with IL-1β (250 U), TNF-α (150 ng), IL-13 (5 μg) or combinations of IL-1β with TNF-α or IL-1β with IL-13. MCh-induced bronchoconstriction and its sensitivity to albuterol, a β2-adrenoceptor agonist, was assessed 24 h after the last cytokine administration. 3 In naïve mice, responsiveness to MCh was significantly increased by the combination of IL-1β and TNF-α, IL-13 alone or in combination with IL-1β, but not by treatment with IL-1β or TNF-α alone. Similar results were obtained in OVA-sensitized mice except that treatment with IL-13 alone did not increase sensitivity to MCh. 4 In naïve mice, albuterol sensitivity was only significantly attenuated by treatment with IL-1β and TNF-α in combination. In mice sensitized to OVA, albuterol sensitivity was significantly attenuated by treatment with TNF-α, IL-13 or IL-13 in combination with IL-1β. 5 Inflammatory cell influx was increased by all cytokines and combinations except IL-13 in OVA-sensitized mice. 6 Our data do not support a link between inflammatory cell influx and AHR. In addition, the mechanism of IL-13-induced AHR might involve decreased β2-adrenoceptor responsiveness.

The effect of BCG vaccine at birth on the development of atopy or allergic disease in young children

BACKGROUND

Exposure to infectious diseases may reduce the development of asthma or allergy. In particular, the role of the BCG vaccine in modulating asthma or allergy has been a source of speculation.

OBJECTIVE

To study newborns from 3 international sites to evaluate the prospective effect of BCG vaccine on allergic diseases or atopic development.

METHODS

Infants were enrolled from newborn and well-infant clinics in Thailand, Argentina, and Turkey. The standard BCG vaccine for each country was given at birth. Parents who consented to have their infant included in the protocol completed an allergy family questionnaire. Infants underwent a standard purified protein derivative (PPD) test at 9 to 12 months of age, and the reaction size was measured. At the age of 2 years, the children returned to be studied. Allergy skin tests to common allergens appropriate to location and age were performed, and the parents completed the International Study of Allergy and Asthma in Childhood questionnaire. The PPD reaction size was compared with the presence of atopy and allergy questionnaire responses.

RESULTS

A total of 1,704 infants were studied. Statistical significance was found between a negative PPD response vs any positive PPD response and the risk of having an allergic history at the age of 2 years in Turkey (relative risk, 2.11; 95% confidence interval, 1.25-3.55; P = .005) and Thailand (relative risk, 2.16; 95% confidence interval, 1.18-3.94; P = .02) but not Argentina (relative risk, 1.09; 95% confidence interval, 0.70-1.68; P = .70).

CONCLUSIONS

This study further supports the role of infectious agents in modulating asthma and allergy development.

Modification of eosinophil function by suplatast tosilate (IPD), a novel anti-allergic drug

Suplatast tosilate (IPD), a new dimethylsulfonium agent, is used therapeutically in allergic diseases. Suplatast has been reported to attenuate airway hyperresponsiveness in guinea pigs, human IgE synthesis, and murine peritoneal eosinophilia. However, the effect of suplatast on human eosinophils is not known. In this study, we examined the effects of suplatast in human eosinophils on platelet activating factor (PAF, 1 microM)-induced chemotaxis by the blind well chamber technique, eosinophil adhesion to TNF-alpha (10 ng/ml) or IL-4 (10 ng/ml)-stimulated human umbilical vein endothelial cells (HUVECs), and expression of very late antigen-4 (VLA-4) on eosinophils and vascular cell adhesion molecule-1 (VCAM-1) on HUVECs by flow cytometry. Suplatast suppressed IL-4-induced eosinophil adhesion to HUVECs in a dose-dependent manner. Eosinophils from the normal subjects did not express VLA-4. However, there was a significant increase (P < 0.01) in the basal expression of VLA-4 in allergic patients. PAF or IL-4 did not enhance VLA-4 expression on eosinophils, and there was no significant effect of suplatast on VLA-4 expression in allergic patients. Suplatast did not affect TNF-alpha-induced VCAM-1 expression. Interestingly, suplatast significantly suppressed IL-4 induced VCAM-1 expression on HUVECs and PAF-induced eosinophil chemotaxis. These data suggest that suplatast may modify eosinophil participation in airway inflammation by attenuating inflammatory mediators-induced chemotaxis and adhesion to endothelial cells, and thus might be useful in the treatment of bronchial asthma.

Mycobacterial antigens attenuate late phase response, airway hyperresponsiveness, and bronchoalveolar lavage eosinophilia in a mouse model of bronchial asthma

Allergens, in combination with genetic predisposition, drive undifferentiated T cells towards the type 2 T cells. Some childhood infections may activate the production of a type 1 T cell profile. It is reasonable to speculate that a decrease in childhood infections may increase the incidence of allergy by allowing the immune balance to shift towards the type 2 T cells. We hypothesized that pre-exposure of mycobacterial antigens in sensitized mice would prevent the development of asthma-like conditions. Specifically, we examined the effect of mycobacterial antigens, Bacillus Calmette-Guerin (BCG) vaccine and Mycobacterium vaccae, on antigen-induced bronchoconstriction, airway hyperresponsiveness to methacholine, bronchoalveolar lavage eosinophilia, and plasma IL-4 and IL-12 levels in ovalbumin (OVA)-sensitized and challenged Balb/c mice. Challenge with OVA produced a 2-3-fold increase in bronchoconstriction within 3-5 min, followed by a delayed response after 60 min, the latter of which was significantly attenuated by both BCG and M. vaccae. Airway hyperresponsiveness to methacholine 24 h after OVA challenge was prevented by BCG and M. vaccae. Airway eosinophilia was also prevented by BCG and M. vaccae. The plasma IL-12 levels were significantly increased and plasma IL-4 levels were significantly decreased following BCG or M. vaccae administration in OVA-sensitized and challenged mice. Interestingly, a significant increase in plasma IL-12 was observed with BCG as compared to M. vaccae administration, suggesting a stronger type 1 response to BCG. These data support our hypothesis and suggest that BCG and M. vaccae may prevent the underlying pathophysiological changes in asthma.

Endogenous nitric oxide in allergic airway disease

There has been intense research into the role nitric oxide (NO) plays in physiologic and pathologic mechanisms. The presence of NO in exhaled breath and the high concentrations in nasal airways stimulated many studies examining exhaled and nasal NO as potential markers of airway inflammation, enabling repeated monitoring of airway inflammation not possible with invasive tests (eg, bronchoscopy). In airway inflammation, NO is not merely a marker but may have anti-inflammatory and proinflammatory effects. Nasal NO measurement may be used in the noninvasive diagnosis and monitoring of nasal disease. This review was compiled by speakers who gave presentations on NO at the annual meeting of the American Academy of Allergy, Asthma, and Immunology in 1999 on exhaled and nasal NO, in vitro studies of NO, the chemistry of airway NO formation, and standardized measurement of exhaled mediators.

Beclomethasone decreases elevations in phosphodiesterase activity in human T lymphocytes

BACKGROUND

We recently reported that CD4+ T cells that have been activated in vivo or in vitro contain elevated cyclic adenosine monophosphate (cAMP) phosphodiesterase (PDE) activity. Since both phosphodiesterase inhibitors and glucocorticoids have anti-inflammatory activity, we sought to investigate the effect of beclomethasone on PDE activity.

METHODS

PDE activity was measured in CD4+ T cells after 24 h of culture with beclomethasone. Cells were obtained from the peripheral blood of nonatopic persons (nCells), pre-seasonal (pCells), seasonal (within the first 2 weeks; sCells) and mid-seasonal (mCells) allergic rhinitics and asymptomatic allergic asthmatics (aCells). In addition, the effect of beclomethasone on Th2 cell lines and cells that had been activated in vitro with PHA or interleukin (IL)-2 was determined.

RESULTS

PDE activity was decreased in a concentration-dependent manner by incubation of mCells, Th2 lines and PHA or IL-2-activated CD4+ T cells with beclomethasone (p < 0.05). However, beclomethasone did not modulate PDE activity in nCells, pCells, sCells, or aCells.

CONCLUSIONS

Beclomethasone only decreases cAMP PDE activity in CD4+ T cells when it is increased by cell activation either in vitro or in vivo.

Therapeutic potential of phosphodiesterase 4 inhibitors in allergic diseases

Cyclic adenosine monophosphate (cAMP) is thought to be associated with inflammatory cell activity: high levels tend to decrease proliferation and cytokine secretion, whereas low concentrations have the opposite effect (1). Since many phosphodiesterases (PDEs) degrade cAMP, inhibitors of this enzyme decrease inflammatory cell activity. Theophylline, which has nonselective PDE inhibitor activity in addition to its other mechanisms of action, has been used in the treatment of asthma for many years. Unfortunately, because of the important role of PDEs in the cell, nonspecific inhibition of these enzymes causes many undesirable side effects. The discovery of PDE isoenzyme families (PDE1-PDE10), their subtypes (HPDE4 and LPDE4) and their differential distribution among the cell types, as well as their specific functions in controlling cell processes, has led to the development of new, specific PDE4 inhibitors. This review details the rationale for the use of PDE4 inhibitors in the treatment of allergic disease. In addition, the effects of PDE4 inhibitors in vitro, in preclinical animal models and in the clinic are covered. Finally, up-to-date information on the most recently developed inhibitors, such as SB-207499, CDP-840, AWD-12-281 and D-4418, is provided.

Phosphodiesterase type 4 inhibitors, but not glucocorticoids, are more potent in suppression of cytokine secretion by mononuclear cells from atopic than nonatopic donors

BACKGROUND

Both glucocorticosteroids and phosphodiesterase (PDE) type 4 inhibitors have modulatory effects on PBMC cytokine secretion. In this study we compared the effect of glucocorticoids and PDE inhibitors on IL-10 and TNF-alpha production by PBMCs from nonatopic versus atopic individuals.

METHODS

PBMCs were incubated with glucocorticoids (beclomethasone dipropionate and mometasone furoate) or media alone for 24 hours. PDE type 4 inhibitors (Ro20-1724 and rolipram) were then added to the cells preincubated with media. After stimulation with PHA, incubation was continued for 48 hours. The cytokine content of the cell supernatants was determined by ELISA.

RESULTS

PDE-4 inhibitors and glucocorticoids caused a concentration-dependent inhibition of the secretion of both TNF-alpha and IL-10. PDE-4 inhibitors were over 20 times more potent in suppressing cytokine secretion by PBMCs from atopic than nonatopic donors, and approximately 5 times more potent in preventing TNF-alpha than IL-10 secretion. In cells from nonatopic donors, glucocorticoids inhibited the production of TNF-alpha to a greater extent than IL-10, but these drugs were more potent in cells from nonatopic than atopic persons.

CONCLUSION

In conclusion, both PDE-4 inhibitors and glucocorticoids suppress secretion of TNF-alpha and IL-10. However, because PDE-4 inhibitors are more potent in suppressing cytokine secretion by PBMCs from atopic individuals but less potent in inhibiting production of IL-10, PDE-4 inhibitors may have greater therapeutic potential than glucocorticoids in allergic diseases.

An in vivo model of beta-adrenoceptor desensitization

Chronic use of beta2-agonists and increased production of inflammatory mediators during the late allergic reaction after antigen challenge results in the desensitization of beta-adrenoceptors in the airways and the accompanying rise in nonspecific airway hyperresponsiveness. In this study, we established an in vivo model of beta2-adrenoceptor desensitization in guinea pig airways by administration of IL-1beta intratracheally or chronic albuterol by inhalation. In the establishment of beta-adrenoceptor desensitization in response to both beta-agonist or inflammatory mediator, baseline pulmonary function responses were established to methacholine and isoproterenol-induced relaxation of methacholine bronchoconstriction. This was followed by the administration of IL-1beta (500 IU/d intratracheally for 2 days) or chronic albuterol (0.1 g/L by aerosol for 1 min three times a day for 10 days). After administration, the methacholine and isoproterenol-methacholine response was once again evaluated. Intratracheal administration of IL-1beta or chronic administration of albuterol significantly decreased (p < 0.05) the protective effect of isoproterenol on methacholine-induced bronchoconstriction, eliciting beta-adrenoceptor desensitization in vivo. The in vivo model will be very useful in monitoring the effect of other potential drugs on beta-adrenoceptor function in the airways.

Glucocorticoids inhibit proliferation and interleukin-4 and interleukin-5 secretion by aeroallergen-specific T-helper type 2 cell lines

BACKGROUND

Glucocorticoids play an important role in the treatment of allergic disease. The atopic process, itself, may reduce the response of peripheral blood mononuclear cells (PBMC) to these drugs.

OBJECTIVE

In this study we compared the effect of hydrocortisone (HC), beclomethasone (BDP), and mometasone (MF) on interleukin (IL)-4 and IL-5 secretion by aeroallergen-specific T-helper type 2 cells (Th2) and proliferation of PBMC from atopic donors.

METHODS

Cells were incubated with drug before stimulating with phytohemagglutinin and assessing proliferation (PBMC) and cytokine secretion (Th2).

RESULTS

The glucocorticoids concentration dependently inhibited proliferation and cytokine secretion, but had less effect on proliferation of cells from severe atopics than on cells from those whose symptoms required little treatment. The rank order of potency was MF (average IC50 0.01 nM) > BDP (4.0 nM) > HC (250 nM).

CONCLUSIONS

These experiments demonstrate glucocorticoid inhibition of IL-4 and IL-5 secretion by human Th2-like cells and proliferation of PBMC from severely and mildly allergic donors.

The profile of the cytokines secreted during the generation of T-helper cells from atopic asthmatic subjects

This study investigated cytokine release by T-cell lines from atopic and nonatopic individuals in the presence of specific aeroallergen. Cell lines from atopic and nonatopic individuals secreted IL-2 for less than 14 and more than 21 days, respectively. All of the atopic, but not the nonatopic, cell lines exhibited a biphasic peak in IL-4 and IL-5 secretion. Flow cytometry revealed that, after 35 days, 89.3% of the atopic cells were T helpers and 73.2% were activated. Only 7.4% of the nonatopic cells displayed activation markers. In conclusion, T-cell differentiation may be controlled by other factors in addition to stimulation by aeroallergens.

Budesonide delivered by Turbuhaler is effective in a dose-dependent fashion when used in the treatment of adult patients with chronic asthma

BACKGROUND

Airway inflammation is a hallmark of asthma, therefore current treatment recommendations include the use of inhaled glucocorticosteroids (GCS). However, there is little evidence that the effects of inhaled GCS are dose dependent.

OBJECTIVES

The objective of this study was to assess the efficacy and safety of a second-generation GCS, budesonide, delivered by Turbuhaler, in adults with chronic asthma.

METHODS

In a 12-week, randomized, double-blind, multicenter, parallel-group study, 473 subjects 18 to 70 years of age received either placebo or budesonide (200, 400, 800, or 1600 microg total daily dose) administered twice daily. Primary efficacy end points were mean change from baseline for FEV1 and morning peak expiratory flow. Safety was assessed by reported adverse events and by a cosyntropin-stimulation test.

RESULTS

The mean baseline FEV1 was 63% to 66% of predicted normal value between groups. All doses of budesonide were more effective than placebo (p < 0.001). The mean changes in morning peak expiratory flow were 12, 22, 27, and 30 L/min in the 200, 400, 800, and 1600 microg budesonide total daily dose groups, respectively, and -27 L/min for the placebo group. A statistically significant dose-response effect for the mean change from baseline over the 12-week study was seen for both morning peak expiratory flow and FEV1. Budesonide-treated subjects also demonstrated significant reduction in asthma symptoms and bronchodilator use compared with placebo. There were no clinically significant differences in treatment-related adverse experiences among groups.

CONCLUSIONS

Budesonide administered by Turbuhaler exhibited a dose response and was effective at low doses. It was well tolerated and significantly more effective than placebo.

Measurement of bronchoconstriction using whole-body plethysmograph: comparison of freely moving versus restrained guinea pigs

We have previously measured pulmonary function in guinea pigs using a double-chambered plethysmograph, however, the question remains regarding the accuracy of the double-chamber to gauge the long-term pulmonary function of late asthmatic response. This may be affected by confounding factors, such as stress on the animal and differences in size of the collar around the neck. Therefore, in this study we compared histamine-induced bronchoconstriction in the same guinea pigs using a single- versus a double-chambered body box. In the double-chambered body box, the specific airway resistance is proportional to time delay between thoracic and nasal flows and measured in cmH2O x s. Whereas, in the single-chambered body box, PenH units (Enhanced Pause) reflect "effort of breathing." This is measured as the pause between inspiration and expiration. Doubling concentrations of histamine (12.5-200 microg/ml dissolved in normal saline) were administered by DeVilbiss nebulizer for 1 min, followed by 1 min suction of residual drug in the chamber, and then the airway resistance was recorded by the computer for the following 3 min. There was a 15-min wash-out period between two doses of histamine. There was no statistically significant difference (p > 0.05) in the PC100 values for histamine between the two methods, however, it was much easier to work with the single-chambered body box in terms of handling the animal and eliminating the possible influence of collar placement on the bronchoconstriction. In conclusion, the data suggests histamine challenges produce equivalent PC100 data in both the double-chambered plethysmograph with sRAW units and single-chambered plethysmograph using the PenH units.

Glucocorticosteroids inhibit leukotriene production

BACKGROUND

The mode of action of corticosteroids, important drugs in the treatment of inflammatory disease, is not yet fully understood. Corticosteroids are known to inhibit phospholipase A2 in unprimed eosinophils and basophils, preventing leukotriene synthesis, but their effect on cells that are already primed is unknown.

OBJECTIVE

As inflammatory cells from atopic subjects are often primed in vivo, we studied the effects of two potent corticosteroids on basophil sulfidoleukotriene production in peripheral blood mixed leukocytes (PBML) from in-season and out-of-season atopic individuals.

METHODS

Cells were incubated for 24 hours with mometasone furoate or beclomethasone dipropionate, primed with IL-3, stimulated with calcium ionophore, buffer, allergen or anti-IgE, and leukotriene production was quantified.

RESULTS

Peripheral blood mononuclear leukocytes from five of ten donors (in season) produced elevated sulfidoleukotrienes without a stimulus; cells from seven donors responded to anti-IgE by increased sulfidoleukotrienes. Neither steroid consistently affected sulfidoleukotriene production in anti-IgE-stimulated cells which were releasing sulfidoleukotrienes in the absence of a stimulant. In comparison, sulfidoleukotriene production was significantly reduced by 0.01 to 10 nM beclomethasone dipropionate or mometasone furoate when the cells were primed with IL-3 after exposure to the drug and stimulated with calcium ionophore or allergen, but no dose-relationship was apparent. Leukotriene production by PBML in response to anti-IgE was potently inhibited by all concentrations of mometasone furoate (0.01 nM to 1 microM) with an inhibitory concentration50 of less than 0.01 nM. Beclomethasone dipropionate inhibited sulfidoleukotriene production in this group (inhibitory concentration50 6 nM) in a dose-dependent manner.

CONCLUSIONS

Sulfidoleukotriene production and, conceivably, priming may be more effectively inhibited by mometasone furoate than beclomethasone dipropionate.

Human lung mononuclear cells induce nitric oxide synthase in murine airway epithelial cells in vitro: role of TNFalpha and IL-1beta

Nitric oxide (NO) is a gas released by the airway epithelium, but the mechanism regulating NO release is unclear. We hypothesized that lung mononuclear cell release of tumor necrosis factor alpha (TNF) and interleukin-1beta (IL-1) would induce epithelial cells to release NO. Lung mononuclear cells were obtained from seven normal volunteers by bronchoalveolar lavage and cultured with Escherichia coli lipopolysaccharide for 24 h. The mononuclear cell culture-conditioned media (M-CM) were then applied to cultures of the murine lung epithelial cell line, LA-4. Nitrite and nitrite + nitrate concentrations were 0.9 +/- 0.1 and 11.8 +/- 2.4 microM in the M-CM. Culturing LA-4 cells line with the M-CM (1:10 dilution) resulted in a marked and time-dependent increase in nitrite or nitrite + nitrate compared with LA-4 cells cultured in media alone (2.4 +/- 0.5 versus 0.9 +/- 0.1 microm and 16.6 +/- 0.6 versus 11.8 +/- 2.4 microM after 24 h). Antibodies to TNF and/or IL-1 significantly reduced the nitrite or nitrite + nitrate concentrations and the concentrations of TNF and IL-1 in the M-CM correlated with nitrite concentrations in the LA-4 culture supernatant fluids (r2 = 0.848 and 0.956). Inducible nitric oxide synthase (iNOS) protein and mRNA examined by immunohistochemistry and Northern blot analysis revealed a marked elevation in the cells cultured with the M-CM which was significantly reduced by TNF and IL-1 antibodies. These data demonstrate that mononuclear cells can stimulate LA-4 cells to express iNOS by releasing TNF and IL-1.

Anti-interleukin-4 inhibits immunoglobulin E production in a murine model of atopic asthma

Immunoglobulin E (IgE) plays an important role in allergy, acting as an initiating factor and being involved in its persistence and exacerbations. As interleukin-4 (IL-4) is critical in IgE synthesis, we propose that treatment of mice with monoclonal anti-IL-4 (11B11) prior to active sensitization with ovalbumin will inhibit IgE synthesis, therefore arresting the allergic process at an early stage. Mice treated with 11B11 and sensitized with saline or ovalbumin had significantly less serum IgE than their respective control groups which were treated with saline (p < 0.05). This study suggests that anti-IL-4 may be a prophylactic agent in asthma and allergic disease.

Measurement of exhaled nitric oxide by three different techniques

The purpose of the study was to compare exhaled nitric oxide (NO) determined by three techniques. Ninety-one subjects performed a slow vital capacity maneuver: (1) through the mouth directly into a NO chemiluminescence analyzer (peak oral NO), (2) through the mouth into a collection bag (mean oral NO), and (3) through the nose into a collection bag (mean nasal NO). Peak oral NO was higher in patients with asthma (n = 18, 174.2 +/- 27.0 ppb), but lower in smokers (n = 36, 39.6 +/- 4.8 ppb) compared with nonsmoking control subjects (n = 23, 105.5 +/- 8.4 ppb, p < 0.05 both comparisons). Mean oral NO levels were significantly lower than peak oral NO levels (p < 0.05), but still higher in patients with asthma in comparison with nonsmoking healthy control subjects and asymptomatic smokers (27.2 +/- 3.5 versus 14.5 +/- 1.1 and 7.3 +/- 0.7 ppb, respectively, p < 0.05). In contrast, there was no significant difference in mean nasal NO levels between the three groups. Peak oral NO and mean oral NO levels correlated (r = 0.772, p < 0.0001). Determination of exhaled oral NO levels is qualitatively independent of the technique used, but nasal exhalation may affect NO determination in conditions associated with airway inflammation.

Phosphodiesterase inhibitors suppress proliferation of peripheral blood mononuclear cells and interleukin-4 and -5 secretion by human T-helper type 2 cells

It has been suggested that interleukin-4 and -5 (IL-4 and IL-5) are instrumental in the control of allergic disease. Elevated levels of IL-4 messenger RNA (mRNA) have been detected in numerous foci of atopic activity, including bronchoalveolar lavage (BAL) fluid from atopic asthmatics and skin of atopic dermatitis patients. IL-5 is important in eosinophil activation, which is a common feature of atopic disease. IL-5 mRNA has been detected in BAL fluid from both atopic and non-atopic asthmatics, indicating that IL-5 may be a common feature of the two disease states. Production of IL-4 and IL-5 by T cells appears to be associated with a high affinity cyclic AMP (cAMP) phosphodiesterase (PDE). This study was designed to compare the effects of PDE inhibitors Ro20-1724 and theophylline on (1) the mitogenic response of peripheral blood mononuclear cells from atopic and non-atopic individuals and (2) secretion of IL-4 and IL-5 by TH(2) cells after activation with PMA and anti-CD3. Both Ro20-1724 and theophylline inhibited proliferation of PBMC in a dose-dependent manner. There was no significant difference between proliferation of PBMC from atopic versus non-atopic donors, but Ro20-1724, a specific PDE IV inhibitor, was more potent at a concentration of 10(-5)M than theophylline in suppressing lymphocyte proliferation. Similarly, both PDE inhibitors suppressed secretion of IL-4 and IL-5 from TH(2)-like cell lines in a dose-dependent manner. In conclusion, as Ro20-1724 and theophylline inhibit proliferation of PBMC and secretion of IL-4 and IL-5 from human TH(2) cell lines, the development of a selective cyclic nucleotide PDE IV inhibitor may provide a promising new approach for asthma prophylaxis.

Tilarin in combination with astemizole

This multicentre double-blind, placebo controlled study had a practical objective, based on the expectation that many patients with seasonal allergic rhinitis will be prescribed oral antihistamine monotherapy by their primary care physician, whereas allergy specialists are more likely to prescribe combination therapy including antiinflammatories. The specific question was, "Will the addition of nedocromil sodium 1% nasal spray to astemizole tablets improve control of symptoms of seasonal allergic rhinitis induced by ragweed pollen, as compared to astemizole therapy alone?'. Following a one-week baseline, planned to coincide with the start of the local ragweed pollen season, patients (aged 12-64) were randomly assigned to four weeks' double-blind test treatment with either nedocromil sodium 1% nasal spray four times daily (QID) + astemizole (n = 146) or placebo nasal spray + astemizole (n = 148) or double-dummy (nasal spray + capsules) placebo (n = 71). Patient diary cards were kept throughout the five weeks, and clinic visits were made before and after baseline and after one and four weeks' treatment. During the 10-day peak pollen period, the diary card rhinitis symptom summary score (0-4 severity scale) was significantly reduced in patients receiving either astemizole alone (p < 0.001) or the combination therapy (p < 0.001) as compared with placebo. Direct comparison of the active treatments further showed that symptoms were significantly less severe (p < 0.01) with the combined therapy than with astemizole alone, and this despite significantly greater reliance on permitted rescue medications (p < 0.05 for pseudoephedrine usage) in the astemizole group. Clinical assessments of rhinitis made during the peak pollen visit, after the first week of test treatment, were also significantly (p < 0.05 - p < 0.01) in favour of combined therapy with nedocromil sodium 1% nasal spray + astemizole rather than astemizole alone, and at the same time this preference was confirmed by physician (p = 0.011) and patient (p = 0.003) opinions of symptom control. In conclusion, this antiinflammatory + antihistamine treatment proved superior to antihistamine alone for effective management of allergic rhinitis. The combined therapy worked quickly and was well-tolerated, with no serious adverse events or untoward effects on blood or urine variables.

Increased hypodense eosinophils after activation with PAF-acether and calcium ionophore in asthmatic subjects

Eosinophils play a major role in the pathogenesis of bronchial asthma. In this study, we examined the density characteristics of blood eosinophils from 9 normal healthy individuals and 9 allergic asthmatic patients. Furthermore, the effect of platelet-activating factor, a potent mediator of inflammation, and calcium ionophore, A23187, on the density of normodense eosinophils (density > 1.085 g/ml) has also been examined. Initially, asthmatic patients had 27.0 +/- 1.1% eosinophils of lighter density (density < or = 1.081 g/ml), significantly greater than that in the normal individuals (7.5 +/- 0.5%). After exposure to platelet-activating factor (1 microM) or calcium ionophore (A23187, 1 microgram/ml), the normodense eosinophils switched to hypodense in both groups: 16.7 +/- 2.1% and 54.2 +/- 3.7%, respectively, in normal individuals, and 30.6 +/- 5.7% and 77.4 +/- 2.3%, respectively, in asthmatic patients. These data demonstrated that a certain percentage of normodense eosinophils from asthmatics and normal subjects switched to hypodense after activation with platelet-activating factor or calcium ionophore. Furthermore, eosinophils from asthmatics switched to a greater degree than in normal subjects, suggesting that the normodense eosinophils in asthmatics become primed probably by endogenously released mediators.

The usefulness of questionnaire-derived information to predict the degree of nonspecific bronchial hyperresponsiveness

Nonspecific bronchial hyperresponsiveness (BHR) is a hallmark of clinical asthma, but can be present in nonasthmatics as well. The diagnosis of asthma is based on clinical grounds, and no laboratory procedure can definitely establish its presence. This poses a problem in studies of asthma. If epidemiological studies are to provide valid information, the tools used must have a relative degree of predictive or diagnostic ability. This report determined whether the American Thoracic Society-Division of Lung Disease (ATS-DLD) respiratory questionnaire has the ability to predict different degrees of non-specific BHR. In the years 1983-1990, when the ATS-DLD questionnaire was used in our Natural History of Asthma study, 192 subjects completed the ATS-DLD questionnaire and underwent a standardized methacholine challenge. A recursive partitioning analysis of the ATS-DLD questionnaire was able to predict which questions would likely be answered if the subject had nonspecific bronchial reactivity to inhaled methacholine of 100 and 200 breath units. Positive responses for questions concerning treatment for asthma, wheezing, or shortness of breath, and emergency treatment for asthma predicted the presence of increased bronchial reactivity.

Eosinophil accumulation and activation in antigen-induced late asthmatic response in guinea pigs

The purpose of this study was to investigate the participation of airway eosinophils in the antigen-induced late asthmatic response (LAR) and increased airway responsiveness in the guinea pig model of asthma. After antigen challenge, guinea pigs sensitized with aerosolized ovalbumin showed a late-phase decrease in specific airway conductance, which was accompanied by airway hyperresponsiveness to histamine, eosinophilia in the bronchoalveolar lavage fluid (BALF), decreased BALF eosinophil density, and increased generation of superoxide anions from purified BALF eosinophils. We demonstrated an association of the LAR with eosinophil accumulation and activation in the airway.

The effect of RP 59227, a platelet-activating factor antagonist, against antigen challenge and eosinophil and neutrophil chemotaxis in asthmatics

STUDY OBJECTIVES

Platelet-activating factor (PAF), an inflammatory mediator, induces microvascular leak, eosinophil chemotaxis, and possibly increases non-specific bronchial hyperresponsiveness in humans. PAF antagonists may have clinical benefits in asthma.

DESIGN

We determined the safety and efficacy of a 240 mg oral dose of RP-59227 in attenuating the early and late phase antigen challenge in eight asthmatics, using a double-blind, placebo-controlled, crossover design. Also determined was the effect of the ex vivo addition of PAF following placebo or drug and the level of neutrophil (NCA) and eosinophil chemotactic activity (ECA) in the serum immediately, and 4 h after antigen challenge with either drug or placebo.

RESULTS

There was not a significant difference in the maximum percent fall in FEV1 during the early and late phase on screening or placebo days or drug RP-59227 days. There was a significant inhibitory effect (p < 0.05) in peak ECA and NCA in blood after RP-59227. The addition of PAF to ex vivo serum was less effective in inducing chemotaxis to eosinophils following RP-59227 (p < 0.05).

CONCLUSIONS

RP-59227 attenuated the release of NCA and ECA after antigen challenge, and reduced the effect of exogenously added PAF in inducing eosinophil chemotaxis but did not protect against the antigen-induced early or late phase response.

Effect of terfenadine on human eosinophil and neutrophil chemotactic response and generation of superoxide

Second generation antihistamines have been reported to have anti-inflammatory properties in addition to their potency as H1 antagonists. In this in-vitro study, we evaluated the effect of terfenadine on platelet activating factor-(PAF)-induced or N-formyl-methionyl-leucyl-phenylamine-(FMLP)-induced human eosinophil and neutrophil chemotactic responses; and on superoxide anion generation from human eosinophils and neutrophils activated by either PAF, calcium ionophore (A23187) or phorbol myristate acetate. Since eosinophil degranulation is also associated with tissue inflammation, we further examined the effect of terfenadine on the PAF-induced release of eosinophil cationic protein. The peak concentration of terfenadine-related materials in serum of adult individuals after 60 mg of oral administration has been reported to be 351 +/- 0.4 ng/mL. We therefore used 100 to 1000 ng/mL concentrations of terfenadine. Purified normodense-eosinophils and neutrophils were obtained by discontinuous gradient from allergic subjects. We observed that terfenadine had greater inhibitory effects on eosinophils than neutrophils in both chemotactic response and superoxide generation. Terfenadine, at concentrations of 500 and 1000 ng/mL, significantly inhibited PAF-induced and FMLP-induced eosinophil chemotaxis, whereas 1000 ng/mL of terfenadine was necessary to suppress neutrophil chemotaxis. Terfenadine, at concentrations achievable at standard dosing regimens, has anti-inflammatory properties in vitro.

Longitudinal measurement of airway hyperresponsiveness in selected subjects with persisting pulmonary symptoms

The relationship between airway hyperresponsiveness and pulmonary symptoms was examined longitudinally in 52 subjects. Subjects were part of a larger study, the Natural History of Asthma, and had repeated measures of airway hyperresponsiveness using methacholine. Atopy was determined using skin tests and serum IgE levels. The subjects completed a standardized respiratory questionnaire. Each subject reported respiratory and pulmonary symptoms at either their initial or follow-up visit. The subjects did not, however, have a physician-confirmed diagnosis of asthma. Subjects were divided into groups according to the current status of their respiratory symptoms. The four groups included subjects who were initially normal but developed respiratory symptoms at follow-up; subjects who had symptoms at all visits; subjects with respiratory symptoms at their initial visit but who had no symptoms at follow-up; and subjects who had respiratory symptoms prior to their initial visit and who did not have a recurrence during follow-up. There was no statistical difference in airway hyperresponsiveness, IgE, or skin test scores at the initial visits. Subjects who had airway responsiveness were significantly more atopic than subjects who did not have airway responsiveness. Subjects were classified as "consistently positive," "variable," or "consistently negative" responders according to the pattern of methacholine-induced airway hyperresponsiveness. Overall, among the four groups, 33% were consistently positive at all visits, 43% were variable, and 22% were consistently negative. Airway hyperresponsiveness was statistically associated with atopy, but not necessarily associated with questionnaire-based respiratory symptomatology. These factors need to be considered in epidemiological studies of asthma utilizing respiratory questionnaires.

Effect of cetirizine on human eosinophil superoxide generation, eosinophil chemotaxis and eosinophil peroxidase in vitro

Cetirizine, a potent H1-antagonist, has been reported to inhibit eosinophil migration into human skin. We, therefore, further evaluated the effect of cetirizine on eosinophil function, including superoxide anion generation, chemotaxis, and eosinophil peroxidase (EP) release. In allergic subjects, superoxide anion generation 60 min after platelet-activating factor (PAF) activation was inhibited by concentrations of cetirizine ranging from 0.01 to 1 microgram/ml (2.612 x 10(-8) to 2.612 x 10(-6) M). No significant inhibition was observed in normal subjects. PAF (10(-6) M)-induced eosinophil chemotaxis was also inhibited by cetirizine. In allergic subjects, percent inhibitions were 47.5 +/- 6.1% at 0.01 microgram/ml, 50.8 +/- 5.1% at 0.1 microgram/ml and 58.9 +/- 6.4% at 1 microgram/ml of cetirizine. In allergic subjects, N-formyl-methionyl-lencyl-phenylalanine induced eosinophil chemotaxis was inhibited by cetirizine, although EP release was not. These results suggest cetirizine has effects on eosinophils which can not be explained by H1-blockade alone.

Effect of loratadine on human eosinophil function in vitro

We investigated the in vitro effect of loratadine, a new nonsedating H1 histamine antagonist, on the eosinophil functions of chemotaxis, superoxide anion (O2-) generation and eosinophil cationic protein (ECP) release, using purified eosinophils obtained from allergic patients. Loratadine significantly attenuated platelet-activating factor (PAF)-induced eosinophil chemotaxis and O2- generation at therapeutic concentrations (equivalent to serum concentrations after single oral administration of 20 mg or 40 mg). Loratadine, however, had no effect on PAF-induced ECP release. These findings suggest that loratadine has a direct inhibitory effect on eosinophil activation and may be beneficial in the therapy of allergic disorders with its anti-allergic properties.

Importance of interleukin-3 on histamine release from human basophils

We investigated the effects of interleukin-3 (IL-3) on histamine release (direct releasing and indirect enhancing effects) from basophils in allergic asthmatic subjects. Interleukin-3 caused direct histamine release (HR) in selected donors (IL-3 responders) and enhanced anti-IgE-induced HR in other IL-3 nonresponders, although both direct releasing and indirect enhancing activities of IL-3 on HR did not coexist with each other. There was a significant correlation between IL-3-induced HR and spontaneous histamine release (r = .8532, P < .0001).

Density change of neutrophils from allergic subjects by granulocyte-macrophage colony stimulating factor

We investigated neutrophil density change by platelet activating factor or granulocyte-macrophage colony-stimulating factor (GM-CSF). Although PAF significantly converted neutrophil density, there was no significant difference in density change between allergic subjects and normal subjects by platelet activating factor. Neutrophils from allergic subjects, however, were significantly converted by GM-CSF when compared with neutrophils from normals (P < .05). We conclude that neutrophils from allergic subjects are more sensitive to density change by GM-CSF than neutrophils from normal subjects. This might be due to preactivation or priming by biologic agents.

Effect of formoterol on superoxide anion generation from bronchoalveolar lavage cells after antigen challenge in guinea pigs

It is well known that antigen challenge of sensitized subjects can induce an immediate and late asthmatic response, airway eosinophilia, and hyperreactivity. Using our modified guinea pig asthma model, we investigated the superoxide anion generation from eosinophils and macrophages recovered from bronchoalveolar lavage (BAL) 24 h after antigen (ovalbumin) challenge. We also investigated the effect of formoterol, a new long-acting selective beta 2-agonist, on these functions. Antigen challenge increased the total cell counts and the ratio of eosinophils in BAL. Eosinophils and macrophages were collected using discontinuous density centrifugation. Antigen challenge enhanced superoxide anion generation from eosinophils, from 5.39 +/- 1.08 to 13.19 +/- 1.95 nmol 60 min after phorbol myristate acetate (PMA) (1 ng/ml) activation, and 0.22 +/- 0.49 to 3.34 +/- 1.67 nmol 40 min after platelet-activating factor (PAF) (10(-6) M) activation. Formoterol treatment before antigen challenge prevented these enhancements. Superoxide anion generation from macrophages was also enhanced by antigen challenge, from 6.57 +/- 0.76 to 10.66 +/- 0.88 nmol 60 min after PMA activation, and 4.20 +/- 1.17 to 6.63 +/- 0.64 nmol 60 min after PAF activation. Formoterol, however, failed to inhibit enhancement of superoxide anion generation from macrophages. These results show antigen challenge of sensitized guinea pigs induces an increase of eosinophils and macrophages in BAL and enhances the functional characteristics of both cells. Formoterol had inhibitory effects on the enhancement of superoxide anion generation from eosinophils but did not have this effect on macrophages.

Inhibitory effects of formoterol on platelet-activating factor induced eosinophil chemotaxis and degranulation

A new long-acting beta 2-agonist, formoterol, has been reported to have a greater efficacy and duration of action in asthmatic patients as compared to conventional beta 2-agonists. We recently demonstrated that formoterol inhibited antigen-induced late asthmatic response (LAR) and accompanying airway eosinophilia in guinea pigs. In this study, we investigated the direct effect of formoterol in vitro on human eosinophil function, focusing on platelet-activating factor (PAF)-induced eosinophil chemotaxis and eosinophil cationic protein (ECP) release. Purified normodense eosinophils were separated by discontinuous gradient from 12 mild asthmatic patients. Formoterol in concentrations of 1-100 microM significantly inhibited PAF-induced eosinophil chemotaxis in a dose-dependent manner with a concentration of drug required to produce 50% inhibition (IC50) of 10.16 microM; % inhibition: 22.9 +/- 13.0% (1 microM), 51.6 +/- 12.7% (10 microM), 75.0 +/- 11.3% (100 microM). When formyl-methionyl-leucyl-phenylamine (FMLP) was used as a chemoattractant, a similar inhibition of eosinophil chemotaxis by formoterol was observed; % inhibition: 13.1 +/- 5.0% (1 microM). 47.7 +/- 7.6% (10 microM), 65.5 +/- 16.5% (100 microM). A conventional beta 2-agonist, salbutamol, at doses to 100 microM did not show any inhibitory effects on PAF-induced eosinophil chemotaxis. Formoterol in concentrations of 1-100 microM also significantly inhibited PAF-induced ECP release from eosinophils; % inhibition: 21.7 +/- 9.0% (1 microM), 39.3 +/- 7.4% (10 microM), 39.6 +/- 8.4% (100 microM). In the presence of phosphodiesterase inhibitors, theophylline or isobutylmethyl xanthine (IBMX), the inhibition by formoterol on PAF-induced ECP release was enhanced.(ABSTRACT TRUNCATED AT 250 WORDS)

Antiallergic properties of the second-generation H1 antihistamines during the early and late reactions to antigen

Some of the second-generation H1 antihistamines reduce the bronchoconstrictor response after exercise and antigen challenge. For example, terfenadine causes a slight but significant increase in forced expiratory volume after 1 second. At doses of 120 and 240 mg, terfenadine has a protective effect against asthma induced by ultrasonic nebulized distilled water and cold air hyperventilation challenge. Certain other newer antihistamines, such as ketotifen, azelastine, and cetirizine, have additional antiallergy properties. These effects include inhibition of eosinophil, basophil, and neutrophil migration and platelet-activating factor-induced eosinophil accumulation in skin. The ability of cetirizine (and perhaps other antihistamines) to inhibit these responses at usual therapeutic doses may be useful in investigating the late allergic reaction.

Effects of platelet activating factor on cyclic AMP accumulation in human lymphocytes

The in vitro effects of platelet activating factor (PAF) on intracellular adenosine 3',5'-cyclic adenosine monophosphate (cAMP) accumulation were assessed in human lymphocytes in ten healthy volunteers and in eight asthmatic patients. Platelet activating factor to increased intracellular cAMP in both groups. In addition, PAF also enhanced the effects of isoproterenol and theophylline on intracellular cAMP production in these two groups.

The effect of formoterol on the late asthmatic phenomena in guinea pigs

We investigated the effects of formoterol, a new, long-acting, selective beta 2-adrenoceptor agonist, on the antigen-induced late asthmatic response (LAR) and airway inflammation in guinea pigs. Animals were sensitized by exposure to aerosolized ovalbumin (2% in saline). After antigen challenge, preceded by administration of an H1-receptor antagonist, specific airway conductance was measured with a two-chambered whole-body plethysmograph. An aerosolized solution of formoterol, isoproterenol, or saline was inhaled 15 minutes before challenge. Bronchoalveolar lavage (BAL) was performed 24 hours after challenge. The provocative concentrations of histamine required to decrease specific airway conductance by 50% were obtained before challenge, at 24 hours, and at 72 hours after challenge. The LAR (52.7% +/- 7.7% of the baseline; p less than 0.02) was observed 6 to 8 hours after antigen challenge. An increased cellular influx in BAL (mainly eosinophils and macrophages) and an increased bronchial responsiveness to histamine occurred 24 hours after antigen challenge. Formoterol completely inhibited the LAR and the cellular increase in BAL; however, isoproterenol failed to prevent either the cellular infiltration or the LAR. Formoterol also decreased the antigen-induced increase in bronchial reactivity. These findings suggest that formoterol has inhibitory effects on the underlying inflammatory processes in antigen-induced asthma in addition to prolonged bronchodilation.

The effect of a selective alpha 2-adrenergic receptor antagonist (midaglizole) on the cyclic 3',5'-adenosine monophosphate production in human mononuclear cells

A selective alpha 2-adrenergic antagonist, midaglizole, has been recently reported to have efficacy in patients with asthma. To understand the mechanisms, we investigated the effect of midaglizole on the cyclic 3', 5'-adenosine monophosphate (cAMP) production in human mononuclear cells (MNCs). MNCs were separated by a histopaque gradient from 10 normal subjects and 10 subjects with asthma. cAMP was measured by RIA kits. Midaglizole (10 mumol/L) significantly enhanced isoproterenol-induced cAMP production in both groups, although midaglizole (from 1 to 100 mumol/L) did not increase the cAMP production by itself. The percent increase in cAMP was more in subjects with asthma (183.8%) than in normal subjects (140.4%); however, the absolute increase was not different. Platelet-activating factor has been demonstrated to inhibit beta-agonist-induced cAMP production in several mammalian tissues, including human MNCs. Midaglizole also prevented platelet-activating factor-induced desensitization of the cAMP response to isoproterenol in MNCs. These findings suggest that midaglizole may be a useful additional agent for the therapy of bronchial asthma through an enhancement of the cAMP production.

Probability of asthma based on methacholine challenge

Methacholine inhalation challenge has become an accepted test to determine the presence of airway hyperresponsiveness, a hallmark of asthma. To help physicians interpret the results of a methacholine challenge test in a clinical setting, we analyzed the test data of 1,105 subjects, asthmatics and nonasthmatics. Applying Bayes' theorem, a nomogram was constructed incorporating the prechallenge clinical diagnosis with the response to methacholine to give a posttest probability of the diagnosis of asthma. The resulting curves represent different levels of cumulative breath units at which a methacholine challenge can be considered positive. The results of a methacholine challenge test, in association with a physician's clinical assessment, can be a valuable tool in the diagnosis of asthma in those patients with an atypical history and/or physical examination.

Longitudinal changes in bronchial hyperresponsiveness in asthmatic and previously asthmatic children

To determine if nonspecific bronchial hyperresponsiveness is present to the same degree in previously asthmatic children compared with currently asthmatic children, a longitudinal study was conducted. On the basis of a standardized respiratory questionnaire, 139 children from asthmatic families, between the ages of 6 and 21 years, were identified. Subjects had skin tests, a serum IgE level, and a methacholine challenge test. IgE and skin tests demonstrated atopy in both the previously and currently asthmatic children, which persisted over time. Bronchial hyperresponsiveness within the asthmatic children was not significantly different between visits. Previously asthmatic children did have significantly decreased airway hyperresponsiveness over time. Age did not affect the results of the bronchial hyperresponsiveness in the currently asthmatic children. Currently asthmatic children, however, were significantly more atopic when compared with previously asthmatic children at their initial evaluation. Currently asthmatic children were also more bronchial responsive and remained so over time. Bronchial hyperresponsiveness is persistent in children with current asthma symptoms.

Use of cetirizine to investigate non-H1 effects of second-generation antihistamines

In addition to their increased potency as H1 blockers and their nonsedating effects, the second-generation antihistamines have other unusual and potentially beneficial properties. Evidence is accumulating from several laboratories that at least one of these agents under investigation, cetirizine, may be effective in inhibiting the late reaction. The Johns Hopkins group showed that during the cutaneous late phase response (LPR), histamine release was not altered by cetirizine, 20 mg, pretreatment. The most dramatic effect of cetirizine was attenuation of inflammatory cell migration into the chamber. Eosinophils, neutrophils, and basophils were reduced by about 75% during hours 6 to 8. It can be concluded that cetirizine influences the LPR by causing a reduction in the inflammatory cell infiltrate. Cetirizine, 10 mg, orally once a day also induced a significant decrease in the wheal and flare skin reactions caused by pollen, histamine, and compound 48/80. Cetirizine inhibited eosinophil recruitment and platelet-activating factor (PAF) in skin chambers 24 hours after pollen challenge. We and others have studied the mechanisms of this effect. The release of eosinophil peroxidase induced by PAF and formyl-methionyleucyl/phenylalanine was not attenuated by cetirizine. At therapeutic concentrations, however, cetirizine has a potent inhibitory action in vitro on eosinophil chemotaxis induced either by formyl-methionyleucyl/phenylalanine or PAF and also on IgE-dependent stimulation of platelets. In a separate study in patients with chronic urticaria, cetirizine markedly reduced both the immediate wheal and flare induced by PAF and the delayed reaction at six hours. These results suggest that cetirizine acts on eosinophil migration to inhibit the late reaction.

Long-term cultured mouse mast cells: ultrastructure, histamine and leukotriene levels

Interleukin 3 (IL3), dependent cells were obtained from bone marrow (9/10 experiments) and spleen cells (4/5 experiments), but not from the thymus. These cells were similar to mucosal mast cell toluidine blue staining and electron microscopy. They had heterogenous metachromatic granules, and some had large scroll-like structures. They also contained histamine (200-800 ng/10(6) cells) for the first 2-5 weeks, whose level diminished to less than 30 ng/10(6) cells by 10 weeks of culture. They also generated leukotriene (LT) C4/D4 (10-40 ng/10(6) cells) and LTB4 (2-5 ng/10(6) cells) for over 100 days of culture. In one experiment, bone marrow-derived mast cells after 150 days of culture began to produce an IL3-like substance and proliferated exponentially without exogenous IL3.

Effect of terfenadine on neutrophil and eosinophil chemotactic activities after inhalation of platelet-activating factor in vivo and on neutrophil chemotaxis in vitro

In this double-blind crossover study we evaluated the effect of terfenadine on the rise in neutrophil chemotactic activity (NCA) and eosinophil chemotactic activity (ECA) in serum induced by platelet-activating factor (PAF) inhalation in 8 asthmatics. Additionally, we examined the direct effect of terfenadine on neutrophil chemotaxis in vitro in 7 allergic subjects. NCA and ECA in serum after PAF inhalation and neutrophil chemotaxis were measured using a modified Boyden chamber method. An initial elevation of NCA after PAF inhalation was inhibited by terfenadine, but the effect was diminished after subsequent PAF inhalations. Terfenadine showed no effect on ECA. In vitro PAF- and fMLP-induced neutrophil chemotaxis were significantly inhibited by terfenadine. These results suggest that terfenadine may have antiallergic properties in addition to its H1 receptor blockade.

Variations in chemotaxis and chemokinesis of neutrophils of different densities from patients with allergic rhinitis

We investigated chemotaxis and chemokinesis of neutrophils of different densities from normals and subjects with allergic rhinitis (AR). The chemotaxis of neutrophils with lower density was significantly increased compared with neutrophils with higher density in AR using fMLP (P less than .01) or PAF (P less than .05). In normal subjects, however, there was no significant difference in neutrophil chemotaxis of the two fractions. No significant difference was found in neutrophil chemokinesis of the two fractions from AR or normals. These results indicate that neutrophils with lower density from AR possess greater affinity to fMLP or PAF as compared with neutrophils with higher density and this may be relevant to the pathophysiology of AR.

Antagonism of airway reactivity induced by ovalbumin antigen in guinea pigs by 5-amino-4-imidazolecarboxamide riboside

The effect of 5-amino-4-imidazolecarboxamide riboside (AICA riboside), a modulator of purine metabolism, was studied on antigen-induced bronchospasm in ovalbumin (OA)-sensitized guinea pigs. In separate experiments, sodium cromoglycate (SCG) and terbutaline were used to compare their effectiveness with that of AICA riboside (wt/vol). AICA riboside and SCG were administered as an aerosol daily for a minimum of 2 weeks before OA aerosol challenge. Terbutaline, as an aerosol, was administered once 5 minutes before OA challenge. Airway reactivity was determined through the use of a whole-body plethysmography by monitoring specific airway resistance (SRaw). OA aerosol challenge of 0.05%, 0.1%, and 0.25% (wt/vol), administered for a period of 1 minute, increased SRaw. Each of the three agents attenuated the effect of OA on SRaw, although terbutaline demonstrated more consistency and potency as compared to either AICA riboside or SCG. However, at moderate degrees of OA challenge, AICA riboside appeared to be as effective as either agent. Although the mechanism of action of AICA riboside remains uncertain, it may have therapeutic benefit in the treatment of asthma or allergic diseases.

Cetirizine: a new H1 antagonist with antieosinophilic activity in chronic urticaria

Although the action of H1 antagonists in the early phase of IgE-mediated, allergic skin reactions is well established, the effect of these antihistamines on the ensuing late-phase reaction has only recently been investigated. The eosinophilic late-phase reaction, sometimes associated with the tissue damage that occurs in chronic idiopathic urticaria, is important in allergic responses. Cetirizine is a new H1 antagonist with potent inhibitory action against the infiltration of eosinophils into involved tissue, thereby affecting the late-phase reaction. No other antihistamine has yet been reported to possess this antieosinophilic property. The mechanisms by which cetirizine acts against eosinophils, although not thoroughly understood, seem to involve direct action against these cells.

Terfenadine effect on the bronchoconstriction, dermal response, and leukopenia induced by platelet-activating factor

We have investigated the protective effect of oral terfenadine, a H1 antagonist, on the dermal and pulmonary response, and changes of circulating WBCs to injected and inhaled platelet activating factor. Nine men with mild asthma participated in a double-blind, crossover study using terfenadine, 120 mg, or placebo. Three hours after administration of study drug, pulmonary function was measured, and a PAF challenge was performed. Skin test to histamine and PAF was performed prior to study drug, and 2.5 hours after drug. Circulating WBC count was determined prior to PAF inhalation and during the PAF challenge. There was a significant improvement in pulmonary function on terfenadine. Terfenadine significantly inhibited the wheal and flare response to histamine and the flare response to injected PAF. Terfenadine did not have an effect on the change in circulating WBC count or the change in pulmonary function to inhaled PAF. These results suggest a limited role for endogenous histamine for the effects of PAF.