Eosinophils isolated by magnetic cell sorting respond poorly to lipid chemoattractants

BACKGROUND

Eosinophils play an important role in allergic inflammation. In vitro methods to isolate human eosinophils for the study of chemotactic responses are essential in understanding the mechanisms involved in tissue eosinophilia.

OBJECTIVE

We compared LTB4 and PAF-induced chemotactic responses of eosinophils isolated by the standard Percoll (positive selection) versus the magnetic cell separation systems (MACS) (negative selection) technique.

METHODS

Discontinuous Percoll gradients were preceded by dextran and Ficoll-Paque steps, and followed by gelatin wash and red blood cell (RBC) lysis. MACS isolation included Percoll 1.090 g/mL layering and RBC lysis; incubation with CD16 antibody conjugated to magnetic beads (to bind neutrophils); and isolation of eluate from column positioned in magnet.

RESULTS

Percoll-isolated eosinophils migrated to the lipid mediators, LTB4 and PAF, in a dose-responsive fashion. Although MACS isolation provided a greater number and higher purity of eosinophils, these eosinophils migrated less to LTB4 and PAF. Neither dextran sedimentation, dextran and Ficoll-Paque, nor dextran Ficoll-Paque and Percoll prior to MACS isolation reversed the decreased chemotactic responses observed with MACS isolated eosinophils. Further, Percoll-isolated eosinophils further purified with CD16 MicroBeads did not respond as well to LTB4 or PAF.

CONCLUSIONS

The technique used to isolate eosinophils clearly affects the chemotactic responsiveness of this cell to LTB4 and PAF. Since several in vivo studies suggest that LTB4 and PAF are eosinophil chemoattractants, Percoll isolation of these cells might be more appropriate for studies involving eosinophil chemotactic responses to these lipid mediators.

Administration of budesonide once daily by means of turbuhaler to subjects with stable asthma

BACKGROUND

Optimal management of chronic, mild-to-moderate asthma with inhaled steroids may include use of the lowest possible doses, as recommended in guidelines, and a reduction in the frequency of daily administration for greater convenience. Lower doses and once daily treatment with inhaled steroids must be rigorously evaluated in controlled clinical trials.

OBJECTIVES

The objective of this study was to assess the efficacy and safety of once daily treatment with budesonide in subjects with stable asthma.

METHODS

Once daily budesonide was assessed in 309 adult subjects, including those who were and were not using an inhaled steroid at baseline. The subjects were stratified by inhaled steroid use and randomly assigned to one of 3 treatments: 200 microgram budesonide, 400 microgram budesonide, or placebo administered by means of Turbuhaler once daily in the morning for 6 weeks. Beyond this point, treatment was continued unchanged for another 12 weeks (maintenance) in those receiving 200 microgram budesonide once daily and placebo. In those who received 400 microgram budesonide once daily, the dose was reduced to 200 microgram once daily at week 6 and held constant for the remaining 12 weeks (400/200 microgram group). Primary efficacy endpoints were mean change from baseline in FEV1 and morning peak expiratory flow.

RESULTS

Once daily budesonide was well tolerated and resulted in significant improvements in all efficacy endpoints, even though baselines were well stabilized. Baseline lung function was elevated with little room for improvement; however, mean increases in FEV1 during the maintenance period were 0.10 L and 0.11 L in the 200 microgram and 400/200 microgram groups, respectively, versus a decrease of -0.09 L in the placebo arm (P <.001). Results for peak expiratory flow were similar. Significant improvements in secondary endpoints, including symptoms, beta-agonist use, and quality of life, also developed with budesonide 200 and 400 microgram once daily.

CONCLUSION

Inhaled budesonide, in doses as low as 200 microgram, may be an appropriate introductory or maintenance dose in subjects with stable, mild-to-moderate asthma.

Demonstration of therapeutic equivalence of generic and innovator beclomethasone in seasonal allergic rhinitis. SAR Study Group

BACKGROUND

Although generic formulations of drugs are chemically equivalent, they may not be bioequivalent to the innovator. Since bioequivalence of intranasal corticosteroids has been difficult to demonstrate by pharmacokinetic methods, clinical trials have been necessary to compare generic and innovator agents.

OBJECTIVE

We therefore designed a multicenter, randomized double-blind, parallel-group placebo-controlled study to examine the therapeutic equivalence of generic beclomethasone diproprionate to the innovator.

METHODS

A total of 518 patients, ages 12 to 60, with ragweed-induced seasonal allergic rhinitis from eight centers were randomized to receive intranasal generic or innovator beclomethasone 42 microg, 84 microg or placebo twice daily for 6 weeks. Efficacy was assessed by means of rhinitis symptom scores as recorded in patient diaries. Adverse events were recorded throughout the study to assess safety.

RESULTS

Mean rhinitis composite symptom scores (congestion, postnasal drip, runny nose, and sneezing) were significantly lower in patients receiving 42 microg (P = .0003) or 84 microg (P = .0001) beclomethasone twice daily compared with placebo. Generic beclomethasone was equivalent therapeutically to the innovator in alleviating nasal congestion (42 microg and 84 microg doses), postnasal drip (84 microg dose), runny nose (84 microg dose), sneezing (42 microg and 84 microg doses) and mean composite (42 microg and 84 microg doses) symptom scores during the 6-week study period. Similar and equivalent efficacy was also demonstrated during the 5-day period of peak pollen counts at each site. The type and incidence of drug-related adverse events were similar for both beclomethasone treatment groups and did not differ significantly from placebo in severity and frequency.

CONCLUSIONS

Generic beclomethasone was therapeutically equivalent to the innovator in regards to both efficacy and side effect profile in the treatment of ragweed-induced allergic rhinitis.

Safety and efficacy of once-daily fexofenadine HCl in the treatment of autumn seasonal allergic rhinitis

Fexofenadine HCl (Allegra, Telfast) is approved in the US for twice-daily dosing in the treatment of seasonal allergic rhinitis (SAR). A once-daily dose (already available in some countries outside the US) can improve patient compliance and health outcomes. This multicenter, placebo-controlled, 14-day US study was conducted to compare the safety and effectiveness of once-daily fexofenadine HCl with placebo in the treatment of patients with moderate to severe autumnal SAR symptoms. After a 1-week placebo lead-in, patients received 120 or 180 mg fexofenadine HCl or placebo at 8 A.M. Patients recorded SAR symptom severity scores instantaneously (for the 1 hour before medication; i.e., trough blood levels), and reflectively (for the previous 12 hours) at 8 A.M. and 8 P.M. The primary efficacy measure was change from baseline in average instantaneous 8 A.M. total symptom score (TSS, the sum of individual symptom scores excluding nasal congestion). In 861 intent-to-treat patients, both fexofenadine HCl doses provided significant (p < or = 0.05) improvement in 8 A.M. instantaneous TSS compared with placebo. Similarly, both fexofenadine doses were superior to placebo for reflective TSS assessments (p < or = 0.0012). There were no statistical differences in efficacy between the two fexofenadine doses, though the 180 mg dose showed a trend toward greater symptom relief. Incidence of adverse events was similar between fexofenadine and placebo groups (30.2% and 30.0%, respectively), with headache the most frequently reported adverse event (8.9% and 7.5%, respectively). In conclusion, once-daily fexofenadine HCl, 120 or 180 mg, is safe and effective in the treatment of autumnal SAR.

Cytokine-induced sequential migration of neutrophils through endothelium and epithelium

OBJECTIVE AND DESIGN

To better understand the mechanisms by which cytokines induced neutrophils to migrate into the airways, we constructed a novel in vitro model system.

MATERIALS

Human umbilical vein endothelial cell (HUVE) monolayers were grown on top of permeable filters and human lung type II-like alveolar epithelial cell (A549) monolayers were grown on the undersurface of the filters.

METHODS

The sequential migration of human neutrophils through the endothelium (apical to basal movement) and subsequently through the epithelium (basal to apical movement) in response to IL-1 beta or TNF alpha located basally to the epithelium was measured.

RESULTS

We found that IL-1 beta and TNF alpha induced dose-responsive and time-dependent migration through the double monolayers-filter complex. The pattern of migration was similar, and the amount greater than or equal to that observed through either single monolayer/filter complex. Neutrophil migration through naked filters was generally less than that observed through the cellular barriers. The contribution of the monolayer orientation was also examined and found to favor the more physiologic directional migration of neutrophils through an endothelial and epithelial barrier, apical to basal and basal to apical, respectively. In contrast, FMLP-induced neutrophil migration was not dependent upon either the orientation or presence of the monolayer(s).

CONCLUSIONS

Thus, we have established an in vitro model system to examine cytokine-induced sequential migration of neutrophils through endothelium and the respiratory epithelium in a manner analogous to that occurring with an in vivo airway stimulus causing neutrophil-rich airway inflammatory responses.

The sequential migration of neutrophils through endothelium and epithelium: a new model system

To better understand the mechanisms by which neutrophils migrate into the airways, we constructed a novel in vitro model system with human umbilical vein endothelial cell (HUVE) monolayers grown on top of permeable filters and human lung Type II-like alveolar epithelial cell (A549) monolayers grown on the undersurface of the filters. The sequential migration of human neutrophils through the endothelium (apical to basal movement) and subsequently through the epithelium (basal to apical movement) in response to a stimulus located basally to the epithelium was measured. We found that the neutrophil chemoattractants, formylmethionylleucylphenylalanine (FMLP), leukotriene B4 (LTB4), and interleukin-8 (IL-8), induced dose-responsive migration through the double monolayer-filter complex. The pattern of migration was similar to that observed through either a naked filter or single monolayer-filter complex. Maximal chemotaxis through the double monolayer-filter complex was observed by 3 hours. Thus, we have established an in vitro model system to examine the sequential migration of neutrophils through endothelium and the respiratory epithelium in a manner analogous to that occurring with an in vivo airway stimulus causing neutrophil-rich airway inflammatory responses.

Efficacy, safety, and impact on quality of life of salmeterol in patients with moderate persistent asthma

OBJECTIVE

To evaluate the efficacy, safety, and impact on asthma-specific quality of life of salmeterol, a highly selective, long-acting beta 2-agonist, compared with that of placebo (i.e., "as-needed" albuterol).

STUDY DESIGN

Randomized, double-blind, placebo-controlled, parallel-group, multicenter study.

PATIENTS AND METHODS

Five hundred thirty-eight nonsmoking symptomatic patients 12 years of age and older meeting American Thoracic Society asthma criteria were enrolled at 55 outpatient clinics; 443 patients completed the study. Patients were randomly assigned to treatment with either salmeterol aerosol 42 micrograms twice daily or placebo (as-needed albuterol) for 12 weeks. We assessed changes in quality of life using the Asthma Quality of Life Questionnaire (AQLQ). Efficacy measurements included daily peak expiratory flow (PEF) rate, daytime and nighttime asthma symptoms, results of pulmonary function tests, and supplemental albuterol use. Patients recorded their PEF rate, supplemental albuterol use, and asthma-related symptoms daily. Pulmonary function tests and AQLQ assessments were performed at baseline and after 4, 8, and 12 weeks of treatment. Safety measurements included vital signs, physical examination, and reports of clinical adverse events at baseline and after 4, 8, and 12 weeks of treatment.

RESULTS

Mean changes from baseline in AQLQ global and domain scores were significantly greater in the salmeterol group compared with the placebo group (P < 0.001). Patients treated with salmeterol also had significant improvements in mean PEF rates, supplemental albuterol use, asthma symptom scores, and forced expiratory volume in 1 second compared with those given placebo. Both salmeterol and placebo were well tolerated and were not associated with any clinically significant changes in vital signs or physical examination findings.

CONCLUSIONS

Salmeterol 42 micrograms twice daily resulted in significantly greater improvements in asthma-specific quality of life, pulmonary function, and asthma symptoms compared with placebo (as-needed albuterol) in patients with moderate persistent asthma.

Orientation and presence of epithelium are key to endotoxin-induced neutrophil migration

The mechanisms by which endotoxins mediate neutrophil transepithelial migration and lung inflammation are unclear. It was hypothesized that both the presence and orientation of epithelial cells are critical to endotoxin-induced neutrophil migration. Neutrophil migration was compared through naked filters and filters with A549 lung epithelial monolayers grown on the upper and lower surface of permeable filters to simulate the apical and basal directional movement of neutrophils, respectively. The endotoxin, Pseudomonas aeruginosa lipopolysaccharide, was placed below the filter, acting as either a basal or an apical stimulus. Endotoxin without serum failed to stimulate neutrophil migration. In the presence of 1% human serum, endotoxin-induced neutrophil migration through naked filters was dose dependent. Endotoxin-induced neutrophil migration across A549 monolayers was minimal when the monolayers were cultured on the upper surface of the filters (basal stimulus). In contrast, neutrophil transepithelial migration was much greater and dependent on both dose and time when the monolayer was cultured on the lower surface of the filter (basal to apical neutrophil directional movement). Furthermore, enhanced neutrophil transepithelial migration was greater with an apical than with a basal stimulus. Endotoxin-induced neutrophil transepithelial migration was markedly inhibited (>95%) by actinomycin D pretreatment of the monolayers, suggesting the necessity for intact protein synthesis capacity of the A549 cells. Thus, both the presence and orientation of airway epithelium are key in supporting endotoxin-mediated lung neutrophilic responses.

Interleukin-8 plays a significant role in IgE-mediated lung inflammation

Interleukin (IL)-8 is a potentially important cytokine in allergic respiratory responses since it is released by many resident lung cells, and it is a potent granulocyte chemoattractant. Therefore, we induced an immunoglobulin (Ig)E-mediated response in human lung samples and studied whether IL-8 was produced in sufficient quantities to promote human neutrophil and eosinophil migration across naked filters and endothelial and pulmonary epithelial monolayers cultured on these filters. Fresh human lung fragments from 16 thoracotomy specimens were treated with either a 1:100 dilution of anti-IgE or buffer (control) for 30 min. All anti-IgE treated lung samples had significant release of histamine and neutrophil and eosinophil chemotactic activity. Fourteen of the 16 lung samples had a significant increase in IL-8 subsequent to anti-IgE treatment (p<0.01). Anti-IL-8 antibody (4 microg x mL[-1]) inhibited 42% and 53% of neutrophil and eosinophil chemotactic activity respectively, contained in supernatants from anti-IgE-treated lung samples. Finally, we found that IL-8 at a concentration near that measured after anti-IgE treatment of lung samples (2,000 pg x mL[-1]) induced neutrophil and eosinophil migration through naked filters and endothelial and pulmonary epithelial cell monolayers. Thus, human lung IgE-mediated responses in vitro results in the rapid release of interleukin-8 in amounts sufficient to affect a biological response, granulocyte transcellular migration, indicating that interleukin-8 may play a significant role in allergic respiratory diseases.

Tumor necrosis factor alpha is necessary for granulocyte-macrophage-colony-stimulating-factor-induced eosinophil transendothelial migration

BACKGROUND

We have previously shown that granulocyte macrophage-colony stimulating factor (GM-CSF) was capable of inducing eosinophil migration across naked filters but not endothelial monolayers. Tumor necrosis factor alpha (TNF-alpha) has been shown to be a key factor in granulocyte adhesion and transendothelial migration.

METHODS

We, therefore, pretreated human umbilical vein endothelial cell (HUVEC) monolayers with TNF-alpha and studied whether TNF-alpha could support GM-CSF-induced eosinophil transendothelial migration.

RESULTS

We found that TNF-alpha supported GM-CSF-induced eosinophil transendothelial migration and that this process was: (1) dependent upon GM-CSF and TNF-alpha dose; (2) time-dependent; (3) not due to TNF-alpha having a chemotactic effect itself; (4) not due to TNF-alpha-induced soluble factor production by endothelium, and (5) inhibitable by actinomycin D. We next studied the specificity of this response. Neutrophils did not migrate across TNF-alpha-pretreated endothelium in response to GM-CSF. TNF-alpha pretreatment of A549 human type-II-like epithelial lung cells (A549) did not support GM-CSF-induced transepithelial migration. Neither interleukin (IL)-1 nor GM-CSF pretreatment of the HUVEC supported GM-CSF-induced transendothelial migration. However, IL-5 induced eosinophil migration through naked filters as well as TNF-alpha-pretreated HUVEC in a manner analogous to GM-CSF. Antibodies to ICAM-1, but not VCAM-1 significantly inhibited this response. Although IL-1 did not support GM-CSF-induced eosinophil transendothelial migration, IL-1 and TNF-alpha induced equivalent expression of ICAM-1 on HUVEC.

CONCLUSION

Thus, TNF-alpha-supported eosinophil transendothelial migration in response to GM-CSF (and IL-5) is dependent upon ICAM-1, and is both specific and complex.

Evaluation of a non-chlorofluorocarbon formulation of cromolyn sodium (Intal) metered-dose inhaler versus the chlorofluorocarbon formulation in the treatment of adult patients with asthma: a controlled trial

BACKGROUND

Cromolyn sodium is a nonsteroidal inhaled antiinflammatory agent for the treatment of asthma. As with other pressurized aerosol medications, the metered-dose inhaler (MDI) formulation currently contains chlorofluorocarbon (CFC) propellants. Because of their harmful effects on the environment CFCs are now generally banned from production and use. Alternative propellants under production for MDIs include derivatives of hydrofluoroalkane (HFA). This study uses HFA-227 in an MDI formulation of cromolyn sodium.

OBJECTIVES

The objectives of the study were (1) to examine the efficacy and safety of an HFA formulation of cromolyn sodium (Intal) MDI and (2) to compare the HFA formulation with the CFC formulation.

METHODS

A multicenter, randomized, double-blind, placebo-controlled, parallel study with two active groups (HFA-cromolyn sodium [n = 113] and CFC-cromolyn sodium [n = 107]) and a placebo-treated group (n = 105).

RESULTS

Patients treated with either formulation of cromolyn sodium MDI showed a statistically significant (p < 0.05) improvement of 12% to 18% compared with placebo in symptom summary score, daytime asthma symptoms, and albuterol use. No statistically significant differences were observed in pulmonary function. Patient and physician opinions of overall effectiveness favored HFA-cromolyn sodium over placebo (p = 0.01), with no other significant between-treatment differences. No statistically significant differences existed among groups in the incidence of treatment-related adverse events.

CONCLUSION

The HFA formulation of cromolyn sodium MDI is a well- tolerated and active alternative treatment for asthma patients aged 12 years and more.

Cytokine-induced neutrophil transepithelial migration is dependent upon epithelial orientation

The mechanisms by which mediators and cytokines stimulate neutrophils to migrate across the lung epithelium are still unclear. We hypothesized that neutrophil transepithelial migration depends upon polarity of the epithelium. We therefore compared neutrophil migration through human lung Type II-like alveolar epithelial cell line (A549) monolayers grown on the upper versus lower surface of permeable filters to simulate apical-to-basal and basal-to-apical movement of neutrophils, respectively. The classic chemoattractants formyl-methionylleucylphenylalanine (FMLP), leukotriene B4 (LTB4), and interleukin-8 (IL-8) induced equivalent neutrophil transepithelial migration in the apical-to-basal and basal-to-apical directions. However, the degree of neutrophil transepithelial migration was significantly greater in the basal-to-apical direction in response to either IL-1beta or tumor necrosis factor-alpha (TNF-alpha). Enhanced TNF-alpha-induced neutrophil migration through A549 monolayers in the basal-to-apical direction occurred regardless of whether the TNF-alpha was above or below the filter/monolayer complex. Actinomycin D pretreatment of A549 monolayers had no effect on FMLP-induced neutrophil transepithelial migration, but markedly (about 75%) inhibited both TNF-alpha- and IL-1beta-induced neutrophil transepithelial migration, regardless of monolayer orientation. Thus, in contrast to classic chemoattractants, IL-1beta and TNF-alpha induced greater neutrophil transepithelial migration in a basal-to-apical direction, and this occurred independently of the cytokine location, but depended upon intact metabolic capacity of the A549 cells. These data suggest that the mechanisms important for neutrophil transepithelial migration in response to classic chemoattractants differ from those important for migration in response to inflammatory cytokines.

Use of an anti-IgE humanized monoclonal antibody in ragweed-induced allergic rhinitis

BACKGROUND

Increased serum levels of antigen-specific IgE are often associated with allergic respiratory disorders. RhuMAb-E25, a recombinant humanized monoclonal antibody, decreases free serum IgE by forming biologically inactive immune complexes with free IgE.

OBJECTIVE

We hypothesized that rhuMAb-E25 would decrease total serum IgE and reduce symptoms.

METHODS

Two hundred forty subjects were enrolled into five groups to determine the safety, tolerance, and efficacy of repeated administration of rhuMAb-E25 in adults with ragweed-induced allergic rhinitis and to explore the pharmacodynamic relationship of rhuMAb-E25 and IgE. One hundred eighty-one subjects received an initial intravenous loading dose (day 0, 1 month before ragweed season), followed by administration of rhuMAb-E25 (in mg/kg body weight) of 0.15 mg/kg subcutaneously, 0.15 mg/kg intravenously, or 0.5 mg/kg intravenously on days 7, 14, 28, 42, 56, 70, and 84. A subcutaneous placebo group and an intravenous placebo group were included. The total evaluation time included the 84-day treatment period, followed by a 42-day observation period.

RESULTS

Adverse events were mild, and no differences were observed in the rates between the three active and two placebo treatment groups. Ragweed-specific IgE levels correlated with symptom scores. RhuMAb-E25 decreased serum free IgE levels in a dose- and baseline IgE-dependent fashion. However, only 11 subjects had IgE levels that were suppressed to undetectable levels (< or = 24 ng/ml), a sample too small to demonstrate significant differences and clinical efficacy. Thus the case for efficacy was not proven. Nonetheless, the study confirms that it is safe to repeatedly administer rhuMAb-E25 over a period of months.

CONCLUSIONS

Because rhuMAb-E25 decreased serum free IgE in a dose-dependent fashion and because symptom scores correlated with antigen-specific IgE levels, the results suggest that if given in adequate doses, rhuMAb-E25 should be an effective therapy for allergic diseases.

Human lung anaphylaxis results in rapid release of interleukin-4

BACKGROUND

Interleukin-4 has been implicated as having numerous roles in the inflammatory responses characteristic of allergic asthma. Interleukin-4 has been shown to be involved in IgE synthesis, upregulation of BCAM-1 on endothelium, and promotion of inflammatory cell infiltration into the airways.

OBJECTIVE

We therefore examined whether IL-4 was produced after an IgE-mediated response in human lung samples.

RESULTS

Anti-IgE treatment of 12 human lungs resulted in the significant release of IL-4 within 30 minutes.

CONCLUSIONS

Although the source of released IL-4 is unknown, the rapid release of IL-4 suggests that cells with performed stores, such as mast cells and eosinophils, are involved. Once released, IL-4 may play an important role in the pathogenesis of asthma.

Speed of onset of action of Tilarin

Two studies have been carried out specifically to examine the speed of onset of action of intranasal nedocromil sodium 1% (Tilarin) for the relief of symptoms due to ragweed allergic rhinitis. One, a multicentre placebo-controlled comparative study using a QID regimen, 1 spray per nostril, was designed to assess the speed of onset of action of nedocromil sodium during the first week of treatment in patients with rhinitis symptoms, and to evaluate the efficacy and safety of nedocromil sodium during 6 weeks of treatment (1). A 1-week baseline, the start of which was timed to coincide with the start of the ragweed season, was followed by 6 weeks double-blind trial treatment; only patients (n = 166) who were symptomatic at the end of baseline were included in the double-blind phase. Non-parametric analyses of all variables including a summary score (stuffy nose, runny nose, itchy nose and sneezing) showed that the onset of action of nedocromil sodium occurred on the first day of treatment. Further, patients using nedocromil sodium had less symptoms during the 10 days of peak pollen, at which time physician assessment showed reduced mucosal oedema and nasal discharge, and both patient and clinician opinions favoured nedocromil sodium. No significant adverse events were reported during this 6-week study. In the second study (2), 104 patients were randomly allocated to receive either nedocromil sodium or placebo, QID. They then spent 10 hours per day for 2 consecutive days in Iowa City Park during the peak of the ragweed season. Only patients showing significant symptoms of seasonal allergic rhinitis (SAR) during 3 hourly baseline assessments were included. Over the 2-day period, symptom scores for stuffy nose, runny nose, itchy nose and sneezing, and global symptom summary scores, were recorded at 19 hourly time points. At home in the evening, patients recorded symptom scores for the post-exposure period. In comparison with placebo, nedocromil sodium significantly improved rhinitis symptoms within 2 hours, and this reduction in SAR symptoms was maintained throughout the 2-day exposure period. Post exposure symptom summary scores were also significantly lower in patients treated with nedocromil sodium than in those patients treated with placebo. Overall, very few adverse events were reported, none of them serious. In conclusion, nedocromil sodium 1% nasal spray acts rapidly, within 2 hours on the first day of treatment, to reduce ongoing symptoms of SAR. Relief of rhinitis symptoms is maintained throughout the peak pollen period with nedocromil sodium QID, which appears to be a safe and well tolerated treatment for ragweed SAR.

Isolation technique alters eosinophil migration response to IL-8

Disparate reports exist on the eosinophil chemotactic capacity of interleukin-8 (IL-8). We hypothesized that the difference is due to the methods used to purify eosinophils. We therefore compared the eosinophilotactic capacity of IL-8 on human cells isolated by Percoll (positive selection) vs. magnetic cell separation system (MACS) (negative selection). Discontinuous Percoll gradients were preceded by dextran and Ficoll-Paque steps, and followed by gelatin wash and red blood cell (RBC) lysis. MACS isolation included: Percoll 1.090 g/ml layering and RBC lysis; incubation with CD16 antibody conjugated to magnetic beads (to bind neutrophils); and isolation of eluate from column positioned in magnet. Percoll isolated eosinophils migrated to IL-8 in a dose-responsive fashion. Although MACS isolation provided a greater number and higher purity of eosinophils, these eosinophils did not migrate to IL-8. Neither dextran sedimentation, Ficoll-Paque and Percoll prior to, nor Percoll discontinuous gradients subsequent to, MACS isolation reversed the negative chemotactic response. Moreover, Percoll-isolated eosinophils further purified with CD16 MicroBeads no longer chemotactically responded to IL-8. This inhibition was not due to change in eosinophil purity, a loss of eosinophil adhesion molecules or activation markers, the presence of a soluble neutrophil or eosinophil inhibitor or the effect of the magnet. Thus, the technique used to isolate eosinophils clearly affects the chemotactic responsiveness of this cell to IL-8. Since several in vivo studies suggest that IL-8 is an eosinophil chemoattractant, Percoll isolation of these cells might be more appropriate for studies involving eosinophil chemotactic responses to IL-8.

Neutrophil transepithelial migration is dependent upon epithelial characteristics

To better understand the mechanisms by which neutrophils migrate to the airway lumen during an inflammatory response, we constructed an in vitro model system to examine the interactions of human neutrophils, human lung epithelial cells, mediators, and proinflammatory cytokines. We directly compared neutrophil movement through three lung epithelial cell lines, A549, H441, and 16-HBE-14o, in response to three chemoattractants, FMLP, LTB4, and IL-8, and the proinflammatory cytokines IL-1 alpha and beta and TNF alpha. While there was variation in the responses to the chemotaxins, there was no correlation between the transmonolayer electrical resistance and the ability of the neutrophils to migrate across the epithelia in response to the agents used. FMLP, IL-8, and LTB4 induced dose- and time-dependent neutrophil migration across all three epithelia. However, TNF alpha- and IL-1-induced neutrophil migration occurred only through monolayers that produced soluble chemoattractants in response to these cytokines. Although all three epithelia produced low amounts of IL-8 constitutively, the capacity of IL-1 and TNF alpha to induce transepithelial migration was directly associated with the ability of the epithelia to produce large amounts of IL-8 in response to IL-1 and TNF alpha. We conclude that the phenotype of the epithelial cell (e.g., capacity to produce IL-8) affects stimulated neutrophil transepithelial migration.

Effects of in vitro mast cell degranulation on human lung beta-receptor binding parameters

BACKGROUND

Numerous studies have demonstrated that subjects with allergic asthma have beta-adrenergic hyporesponsiveness, predisposing these individuals toward bronchospasm, mucous production, and mast cell degranulation. Since sympathetic innervation of the human respiratory tract is sparse, reduced beta-responsiveness probably results from alterations at or beyond the receptor level.

OBJECTIVE

We therefore examined whether anaphylaxis of human lung tissue acutely modulated the human lung beta-receptor system in ways that might lead to decreased beta-adrenergic responsiveness.

METHODS

Fresh thoracotomy peripheral lung samples from 26 patients were incubated with (anaphylaxis) or without (control) anti-IgE (1:100) for up to 90 minutes and histamine release was documented. Lung fragments were quick frozen at various times after anti-IgE for analyses of beta-receptor binding parameters. Antagonist Kd (dissociation constant) and receptor concentration values were determined using (-)[125I]pindolol and agonist IC50 values were determined using isoproterenol.

RESULTS

In comparison with time O, neither anaphylaxis nor control samples had differences in receptor binding parameters with time. There were also no differences between anaphylaxis and control lung samples at any time point, and ratios of log control binding parameter/log anaphylaxis binding parameter ranged from 0.96 to 1.01.

CONCLUSIONS

Anaphylaxis of lung does not lead to acute changes in antagonist or agonist affinity for beta-receptors or changes in receptor concentration. Under the conditions studied, lung mast cell degranulation does not acutely alter the human lung beta-receptor system in ways that might account for the beta-adrenergic hyporesponsiveness found in allergic asthma.

TNF alpha is important in human lung allergic reactions

Tumor necrosis factor alpha (TNF alpha) is a potentially important cytokine in allergic respiratory reactions since it is released by mast cells and eosinophils, and it can promote mediator and cytokine release, adhesion molecule expression, and granulocyte migration. Therefore, we induced an IgE-mediated response in human lung samples and studied: (1) whether TNF alpha was produced in sufficient quantities to promote granulocyte migration; and (2) which cells expressed mRNA for TNF alpha using in situ hybridization. Lung fragments (from thoracotomy) were treated for 30 min with either anti-IgE, 1:100 dilution, or buffer (control). Anti-IgE treatment of 16 lungs resulted in greater than 4-fold increase in histamine release and the significant production of chemotactic activity. The chemotactic activity generated induced dose-responsive neutrophil and eosinophil migration through naked filters and endothelial and pulmonary epithelial monolayers. Fourteen of 16 samples had a significant increase in TNF alpha subsequent to anti-IgE treatment (P < 0.05). Anti-TNF alpha antibody (4 micrograms/ml) inhibited about 25% of the neutrophil chemotactic activity in supernatants from anti-IgE treated lungs. TNF alpha at a concentration measured after anti-IgE treatment of lung samples (50 pg/ml) induced neutrophil transendothelial migration. Finally, we found that anti-IgE treatment led to an increase in TNF alpha mRNA-positive cells by in situ hybridization (1.6/ mm2 experimental versus 0.5/mm2 control), some of which were eosinophils. Thus, human lung IgE-mediated responses in vitro results in: (1) release of TNF alpha in amounts sufficient to effect a biologic response, granulocyte chemotaxis: and (2) upregulation of mRNA for TNF alpha in eosinophils and other cells. These findings suggest that TNF alpha is an important effector molecule in the pathogenesis of allergic respiratory reactions.

Eosinophil migration in response to three molecular species of platelet activating factor

Multiple molecular species of the eosinophil chemoattractant platelet activating factor (PAF) are produced as a result of inflammatory processes. We therefore compared the ability of three naturally occurring PAF species (C16:0, C18:0, and C18:1), which only varied at carbon 1, to induce eosinophil chemotaxis through naked 3-microns pore polycarbonate filters. Timecourse experiments indicated that all species of PAF tested induced significant and equivalent eosinophil migration at 1 h which peaked at 2 h. Overall, the rank order of chemotactic potency for the PAF species was relatively equivalent. The specific PAF antagonist WEB 2086 inhibited eosinophil migration induced by all three PAF species equally. We conclude that the degree of PAF-induced eosinophil migration is not dependent upon the molecular species of PAF.

Cytokines induce selective granulocyte chemotactic responses

Neutrophils, eosinophils and cytokines are important in allergic airway inflammatory responses. However, it is unclear how cytokines selectively influence neutrophils versus eosinophils to migrate to an inflammatory site. The cytokines, transforming growth factor-beta1 (TGF-beta1), interleukin (IL)-1alpha, IL-5, IL-8, granulocyte macrophage-colony stimulating factor (GM-CSF) and tumor necrosis factor-alpha (TNF-alpha), are released subsequent to allergic reactions and affect both neutrophil and eosinophil functions. We studied whether these cytokines differed in capacity to induce human neutrophil versus eosinophil migration through naked filters and human umbilical vein endothelial cell (HUVEC) and human pulmonary type II-like epithelial (A549) cell monolayers grown on filters. Dose-response experiments using all barriers were performed for each granulocyte and cytokine. TGF-beta1 did not induce granulocyte migration. IL-5 induced eosinophil migration only through naked filters. IL-1alpha stimulated neutrophil migration through cellular barriers, but not through naked filters. TNF-alpha and GM-CSF induced neutrophil and eosinophil migration through filters, but only neutrophil migration through cellular monolayers. Only IL-8 induced significant neutrophil and eosinophil migration; however, there were clear-cut differences between the neutrophilotactic and eosinophilotactic responses through all barriers employed. Thus, our data show that these cytokines induce distinct chemotactic responses for neutrophils versus eosinophils. Moreover, by using relevant cellular barriers versus naked filters, our data better examines the capability of these cytokines to induce selective granulocyte migration to an inflammatory site in lung diseases such as asthma.

Interleukin-8 mediates interleukin-1 alpha-induced neutrophil transcellular migration

Interleukin-1 alpha (IL-1 alpha) is a cytokine with a myriad of potent proinflammatory effects. Neutrophils are important immune effector cells in allergic and inflammatory lung diseases. We examined the effects of IL-1 alpha on human neutrophil migration across naked filters and human umbilical vein endothelial (HUVE) cell and type II-like pulmonary epithelial cell (A549) monolayers cultured on these filters. IL-1 alpha from 10(-13) to 10(-9) M induced dose-dependent neutrophil migration through both HUVE and A549 cellular monolayers but not through naked filters. Neutrophil migration was consistently greater through A549 monolayers compared with HUVE monolayers. IL-1 alpha-induced neutrophil migration was also time dependent, and the kinetics of neutrophil migration through HUVE and A549 monolayers were similar. Significant migration through either monolayer was not observed until 2 h, and maximal migration occurred at 3 h through A549 and 5 h though HUVE cellular monolayers. Supernatants of IL-1 alpha (10(-11) M)-stimulated HUVE and A549 monolayers induced significantly more migration of neutrophils across naked filters than 10(-11) M IL-1 alpha itself, suggesting the release of soluble secondary chemotactic factor(s). Pretreatment of HUVE and A549 monolayers with actinomycin D inhibited both IL-1 alpha-induced production of soluble chemotactic factor(s) and transcellular migration by > 90%. Supernatants from IL-1 alpha-treated HUVE and A549 cells contained significant concentrations of interleukin 8 (IL-8), and coincubation of these supernatants with anti-IL-8 inhibited approximately 50% of supernatant-induced chemotaxis.(ABSTRACT TRUNCATED AT 250 WORDS)

The leukotriene D4-receptor antagonist, ICI 204,219, relieves symptoms of acute seasonal allergic rhinitis

The efficacy and safety of single oral doses of the leukotriene D4-receptor antagonist, ICI 204,219, were tested in subjects with acute seasonal allergic rhinitis. Subjects who were enrolled in the double-blind, placebo-controlled trial spent 8 h/d for two consecutive days in a park at the peak of ragweed season (counts > 1,000 grains/m3). Subjects (n = 164) who had sufficient symptoms during a 3-h baseline period on Day 1 were randomized to treatment with 10 (n = 33), 20 (n = 33), 40 (n = 33), or 100 mg (n = 32) of ICI 204,219 or placebo (n = 33). Rhinitis symptoms (nasal congestion, sneezing, rhinorrhea, itchy nose, throat and palate, and eye symptoms) were recorded hourly in the park and three times each evening at home. Blood samples were collected twice daily to determine plasma levels of ICI 204,219. Nasal congestion improved (p < 0.01) most consistently from the evening of Day 1 through Day 2 after treatment with 20- and 40-mg doses of ICI 204,219 versus placebo. Sneezing and rhinorrhea (p < or = 0.05) also improved on Day 2 for subjects who received 20- and 40-mg doses of ICI 204,219 compared with placebo. Mean symptoms scores for the entire day showed that 20 mg of ICI 204,219 was the minimally effective dose in this trial. The onset of action for all treatment groups, including placebo, was within the first 2 h of dosing. No serious adverse events were reported during the trial. ICI 204,219 was well tolerated and relieved symptoms of acute seasonal allergic rhinitis.

5-Hydroxyeicosatetraenoic acid (HETE)-induced neutrophil transcellular migration is dependent upon enantiomeric structure

The 5(R) and 5(S) hydroxyeicosatetraenoic acids (5[R]-HETE, 5[S]-HETE) are important inflammatory mediators in lung diseases: they increase mucus, induce airway contraction, and potentiate neutrophil chemotaxis. Neutrophils are important cells in allergic and inflammatory lung diseases. Therefore, we examined the effects of both 5(R)-HETE and 5(S)-HETE on human neutrophil migration across naked filters and human umbilical vein endothelial (HUVE) cell and human type II-like pulmonary epithelial cell (A549) monolayers cultured on these filters. Time courses for both 5(R)-HETE and 5(S)-HETE show significant neutrophil migration at 40 min and maximal migration at 60 to 90 min through all three barriers. Checkerboard analysis showed that migration was chemotactic. Dose-response curves for both isomers through cellular monolayers had the same shapes, but 5(R)-HETE was more potent than 5(S)-HETE. There was greater migration through cellular barriers than through naked filters. Actinomycin D pretreatment of the cellular monolayers slightly inhibited the neutrophil transcellular chemotactic response to both 5-HETEs equally. Enhanced transcellular migration was not due to the production of a soluble chemotactic factor. Thus, although both isomers of 5-HETE were potent chemotactic agents, 5(R)-HETE was slightly more potent. Moreover, relevant endothelial and epithelial monolayers enhance both dose- and time-dependent neutrophil migration stimulated by 5(R)-HETE and 5(S)-HETE. These data indicate that (1) both 5(R)-HETE and 5(S)-HETE are important in mediating lung inflammatory processes, and (2) 5(R)-HETE may play a more important role in neutrophil-rich lung inflammatory responses than 5(S)-HETE because it is a more potent inducer of neutrophil migration through endothelial and epithelial barriers.