Inhibition of cytokine production from human peripheral blood leukocytes by anti-allergic agents in vitro

The role of antihistamines in the treatment of vasomotor rhinitis

Background

The pathogenesis of vasomotor rhinitis is not understood. It is unlikely that antihistamines, based on their H1 antagonist activity alone, would be effective in this disorder.

Methods

Nonetheless, at least one double-blind, placebo-controlled multicenter trial has found that intranasal azelastine relieves symptoms of this disorder better than placebo. The mechanism responsible for its beneficial effect in nonallergic rhinitis is unclear but probably relates to "anti-inflammatory/antiallergic" activities.

Results

Such mechanisms have been demonstrated for a number of different oral antihistamines, but often the concentrations required in vitro are higher than those that are normally achieved in vivo using recommended dosing. It has been postulated that intranasal administration, which can achieve high local levels, might be a factor responsible for enhancing the "anti-inflammatory/antiallergic" properties.

Conclusions

Interpreting this information allows one to conclude that antihistamines may be potentially effective agents in vasomotor rhinitis, and are more likely to be so when administered intranasally, despite the fact that data documenting this beneficial effect are sparse.

Vasomotor (perennial chronic) conjunctivitis

PURPOSE OF REVIEW

To increase the awareness of nonimmunoglobulin E-mediated conjunctival disorders similar to those recognized to affect other organs that are targets in immunoglobulin E-mediated disorders. Such conditions may include 'vasomotor' instability, that is vasomotor conjunctivitis, which leads to a more common perennial chronic conjunctivitis. These conditions are not commonly included in the differential diagnosis of allergic conjunctivitis.

RECENT FINDINGS

Although there have not been specific recent findings regarding the eye, it appears that evidence for such disorders in the rhinitis literature suggests that they can be involved in more than 25% of chronic conjunctivitis cases. The extrapolation of such conditions to the conjunctival surface clearly reflects these syndromes which have clearly been underappreciated and underdiagnosed.

SUMMARY

A significant amount of work remains to be performed to understand perennial chronic conjunctivitis (vasomotor conjunctivitis or nonallergic noninfectious conjunctivitis) as well as other forms of chronic conjunctivitis that can mimic or exist in a comorbid state with ocular allergy. These disorders need to be better defined, categorized and classified to determine the best treatment modalities. Management guidelines and parameters of chronic noninfectious conjunctivitis need to be set on a national and international basis that will advance clinically applicable research results, pharmaceutical development and relief for patients.

Role of histamine and platelet-activating factor in allergic rhinitis

This review is focused on the effects of histamine and platelet-activating factor (PAF) in allergic rhinitis and the plausible implications for therapy. Rhinitis is defined as a heterogeneous disorder resulting from an IgE-mediated reaction associated with nasal inflammation of variable intensity. Two phases of response are triggered by an IgE/allergen cross-linking event: the first is the release of preformed mediators such as histamine or interleukins from mast cells and basophils; the second begins when cells start producing lipid-derived mediators. One of these mediators is PAF. Apart from leukotrienes, PAF is perhaps the most potent inflammatory mediator in allergic rhinitis for inducing vascular leakage, a response that may contribute to the appearance of rhinorrhea and nasal congestion.

Allergic rhinitis in children : diagnosis and management strategies

The incidence of allergic rhinitis has been increasing for the last few decades, in keeping with the rising incidence of atopy worldwide. Allergic rhinitis has a prevalence of up to 40% in children, although it frequently goes unrecognized and untreated. This can have enormous negative consequences, particularly in children, since it is associated with numerous complications and comorbidities that have a significant health impact on quality of life. In fact, allergic rhinitis is considered to be a risk factor for asthma. There are numerous signs of allergic rhinitis, particularly in children, that can alert an observant clinician to its presence. Children with severe allergic rhinitis often have facial manifestations of itching and obstructed breathing, including a gaping mouth, chapped lips, evidence of sleep deprivation, a long face, dental malloclusions, and the allergic shiner, allergic salute, or allergic crease. The medical history is extremely important as it can reveal information regarding a family history of atopy and the progression of atopy in the child. It is also important to identify the specific triggers of allergic rhinitis, because one of the keys to successful management is the avoidance of triggers. A tripartite treatment strategy that embraces environmental control, immunotherapy, and pharmacologic treatment is the most comprehensive approach. Immunotherapy has come to be viewed as potentially prophylactic, capable of altering the course of allergic rhinitis. The most recent guidelines for the management of allergic rhinitis issued by the WHO recommend a tiered approach that integrates diagnosis and treatment, in which allergic rhinitis is subclassified both by frequency, as either intermittent or persistent, and by severity, as either mild or moderate to severe. Oral or topical antihistamines and intranasal corticosteroids are the mainstay of pharmacologic therapy for allergic rhinitis, depending upon its severity, and several agents have been approved for use in children aged 5 years old and younger.

Differential regulation of IL-4 expression and degranulation by anti-allergic olopatadine in rat basophilic leukemia (RBL-2H3) cells

Olopatadine hydrochloride (olopatadine) is an anti-allergic drug that functions as a histamine H(1) antagonist and inhibits both mast cell degranulation and the release of arachidonic acid metabolites in various types of cells. In this study, we examined the ability of olopatadine to inhibit the expression of cytokine genes in vitro via high-affinity receptors for immunoglobulin E in mast cells, using a rat basophilic leukemia (RBL-2H3) cell line and an in vivo mouse model. Levels of gene expression in RBL-2H3 cells were determined by semi-quantitative RT-PCR, and serum interleukin-4 (IL-4) level in mice was quantified by ELISA. Olopatadine inhibited significantly the induction of IL-4 expression by mast cells both in vivo and in vitro. Olopatadine inhibited Ca(2+) influx through receptor-operated channels (ROC) without affecting Ca(2+) release from intracellular stores. Comparative analysis of olopatadine with other anti-allergic drugs and the ROC blocker SKF-96365 demonstrated that the potency of inhibition of Ca(2+) influx correlated with the degree of suppression of degranulation and arachidonic acid release. Inhibition of Ca(2+) influx decreased phosphorylation of p38 mitogen-activated protein kinase and c-Jun NH(2)-terminal kinase, which participate in regulation of cytokine (e.g. IL-4) gene expression. However, the rank order of inhibition of Ca(2+) influx did not correspond to reduction of IL-4 expression, suggesting that an unknown mechanism(s) of action, in addition to inhibition of Ca(2+) influx, is involved in the expression of cytokines in mast cells.

Anti-inflammatory potential of the selective phosphodiesterase 4 inhibitor N-(3,5-dichloro-pyrid-4-yl)-[1-(4-fluorobenzyl)-5-hydroxy-indole-3-yl]-glyoxylic acid amide (AWD 12-281), in human cell preparations

AWD 12-281 is a potent (IC(50) = 9.7 nM) and highly selective inhibitor of the phosphodiesterase 4 (PDE4) isoenzyme with low affinity to the high-affinity rolipram-binding site. The compound was optimized for topical treatment of asthma, chronic obstructive pulmonary disease (COPD), and allergic rhinitis. The aim of the present study was to assess the effect of AWD 12-281 in human inflammatory cells. Peripheral blood mononuclear cells (PBMCs), diluted whole blood, and human nasal polyp cells derived from surgically resected nasal polyps from patients with polyposis comprise sources of target tissue cells that can be used to predict anti-inflammatory effects in patients. AWD 12-281 was capable of suppressing the production of cytokines in stimulated PBMCs: interleukin-2 (IL-2, phytohemagglutinin stimulation), IL-5 (concanavalin A stimulation), IL-5 and IL-4 (anti-CD3/anti-CD28 costimulation), and lipopolysaccharide-stimulated release of tumor necrosis factor alpha (TNF alpha). The corresponding values for half-maximum inhibition, EC(50), for AWD 12-281 were within a narrow range (46-121 nM). Comparing the effect of AWD 12-281 with roflumilast, cilomilast (SB 207499), rolipram (RPR-73401), and 1-(3-nitrophenyl)-3-(4-pyridylmethyl)pyrido[2,3-d]pyrimidin-2,4(1H,3H)-dione (RS-25344-000), it could be shown that the PDE4 inhibitory activity was closely correlated with inhibitory potential as measured by the above-described assays. AWD 12-281 was also shown to suppress TNF alpha release in dispersed nasal polyps (EC(50) = 111 nM) and in diluted whole blood (EC(50) = 934 nM). The reduced activity in human blood may be related to high plasma protein binding. Currently, phase II clinical studies are under way to evaluate the therapeutic potential of AWD 12-281 in asthma, COPD, and allergic rhinitis.

Ocular allergy guidelines: a practical treatment algorithm

The treatment of ocular allergy requires a better understanding of the spectrum of clinical disorders involving various components of the immune system, and of interactions at the conjunctival surface. The immune response focuses primarily on the different levels of activity of Th2 lymphocytes and various other immune cells associated with allergic disorders, including mast cells, eosinophils, fibroblasts, and epithelial and endothelial cells. Ocular allergic disorders include seasonal allergic conjunctivitis (SAC), perennial allergic conjunctivitis (PAC), vernal keratoconjunctivitis (VKC), giant papillary conjunctivitis (GPC) and atopic keratoconjunctivitis (AKC), which, through immunopathological and molecular immunological techniques, can all be better appreciated as being part of a larger spectrum of an atopic disease state. In SAC, pathological changes, such as increased mast-cell activation, the presence of migratory inflammatory cells, and early signs of cellular activation at the molecular level, are minimal. In PAC, these changes are more pronounced in line with the increased duration of allergenic stimulation. In more chronic forms of allergic conjunctivitis, such as VKC in children and AKC in adults, the following changes are evident: a persistent state of mast cell, eosinophil and lymphocyte activation; noted switching from connective-tissue to mucosal-type mast cells; increased involvement of corneal pathology; and follicular development and fibrosis. The treatment of acute and more chronic forms of allergic conjunctivitis has focused in the past on symptomatic relief of symptoms, but with a better understanding of the mechanisms involved we can now provide interventional therapeutic strategies and symptomatic relief. Our advances in the basic understanding of these conditions are providing the foundation for guidelines that improve the ocular health of patients with ocular allergies.

Therapeutic options in allergic disease: antihistamines as systemic antiallergic agents

As has been reported throughout this supplement, the pathophysiologic factors of allergic diseases involve many elements of systemic disease-effector-cell recruitment from circulation, stimulation of bone marrow progenitors, systemic effector-cell priming, anaphylactic reactions, and others. With this understanding, allergic inflammation can be thought of as a reflection of systemic immunologic responses with compartmentalized manifestations in various organ systems, including the upper respiratory tract, lungs, gastrointestinal tract, and skin. Thus, any therapeutic approach to the treatment of allergic disease should address, in addition to the localized disease manifestations, the systemic immunologic dysregulation. Second-generation antihistamines (cetirizine, fexofenadine, loratadine) have been used since the 1980s to treat localized allergy symptoms in upper airways, skin, and, in some cases, the lungs; however, the efficacy of these agents in controlling systemic immune dysregulation and chronic allergic inflammation (eg, nasal congestion) has not been proved. The potential role of newer antihistamines in the amelioration of both localized and systemic aspects of allergic disease represents an active area of interest. Desloratadine, a new selective histamine H(1)-receptor antagonist with potent antihistaminic and anti-inflammatory activity, is introduced and its potential for treating the systemic aspects of allergic disease is discussed.

Effect of a novel anti-allergic agent, HSR-609, on antigen-induced airway hyperresponsiveness in mice

The effects of a newly synthesized anti-allergic agent, HSR-609, on allergic airway hyperresponsiveness and airway inflammation have been studied in sensitized mice. The effects were compared with those of two histamine H(1) receptor antagonists, cetirizine and terfenadine, and prednisolone. Three inhalations of antigen caused an increase in leukocytes (including eosinophils) with increases in IL-5 in BALF and airway hyperresponsiveness to acetylcholine in BALB/c mice. All drugs were orally administered once a day for 10 days from the day before the first inhalation of antigen. HSR-609 (10 mg/kg) and prednisolone (5 mg/kg) significantly inhibited the antigen-induced airway hyperresponsiveness, whereas cetirizine (10 mg/kg) or terfenadine (100 mg/kg) did not affect this airway response. At the same time HSR-609 inhibited the antigen-induced eosinophilia and IL-5 production in BALF. Prednisolone also showed an inhibitory effect on the airway eosinophilia and IL-5 production but not cetirizine and terfenadine in the same experiments. In addition, HSR-609 (p.o.) dose-dependently suppressed the accumulation of eosinophils elicited by antigen-stimulated D10G4.1 cells, a murine Th2 clone, in peritoneal cavity lavage fluid in AKR/J mice. These results suggest that HSR-609 inhibits allergic airway hyperresponsiveness to acetylcholine probably because of the inhibition of Th2-dependent eosinophilia caused by IL-5. In addition, effects of HSR-609 were different from those of cetirizine and terfenadine concerning the inhibition of antigen-induced airway hyperresponsiveness in mice.

Effect of topical nasal azelastine on the symptoms of rhinitis, sleep, and daytime somnolence in perennial allergic rhinitis

BACKGROUND

Recent data suggested that daytime somnolence in patients with allergic rhinitis was secondary to disrupted sleep caused by nasal congestion. Medications, which decreased congestion, would be expected to improve sleep and daytime somnolence. Previously, we demonstrated that nasal steroids improved all three symptoms. The effect of topical nasal antihistamines on these symptoms has yet to be studied.

OBJECTIVE

The objective of this 8-week, double-blind, placebo-controlled study was to determine whether topical nasal azelastine was effective at decreasing congestion, daytime somnolence, and improving sleep.

METHODS

We recruited 24 subjects with perennial allergic rhinitis and randomized them in a double-blinded, crossover fashion, to receive placebo or azelastine two sprays BID, using Balaam's design. Questionnaires, daily diary, and Epworth Sleepiness Scale were used as tools. The last 2 weeks of each 4-week treatment period were summarized, scored, and compared by PROC MIXED in SAS.

RESULTS

The analysis of the Rhinitis Severity Score showed significant improvement only of rhinorrhea in the azelastine group (P = .03). The symptom severity of nasal congestion and daytime somnolence was not significantly different between placebo and azelastine. Subjects considered azelastine effective at improving their sleep (P = .04), but daytime somnolence (P = .06) and congestion (P = .09) were not statistically improved.

CONCLUSION

Azelastine is effective in reducing rhinorrhea and improving sleep quality. We were unable to demonstrate that azelastine can significantly reduce the severity of congestion or daytime somnolence.

Specific inhibition of TH2-type cytokine production from human peripheral T cells by terfenadine in vitro

BACKGROUND

Cytokine imbalance is thought to be one of the causes for allergic diseases. The effect of anti-allergic drugs on cytokine production from T cells should be examined in a convenient way.

OBJECTIVES

To study the in vitro effect of terfenadine, a prototype non-sedating H1 receptor antagonist, on cytokine production from activated T cells.

METHODS

T cells were cultured in the presence of terfenadine on anti-CD3 mAb and anti-CD26 mAb-coated wells, anti-CD3 mAb and anti-CD28 mAb-coated wells, and anti-CD3 mAb wells with PMA. T-cell proliferation, along with the concentrations of interleukin (IL) -2, interferon (IFN) -gamma, IL-4, and IL-5 were measured.

RESULTS

Terfenadine inhibited T-cell proliferation and IL-4 and IL-5 production under each costimulatory condition tested, whereas it had no effect on IL-2 and IFN-gamma production.

CONCLUSIONS

These results indicate that terfenadine has a specific inhibitory effect on TH2-type cytokine production induced by several ways of costimulatory activation.

Inhibitory effects of azelastine hydrochloride in alcohol-induced asthma

BACKGROUND

Alcohol-induced bronchoconstriction is due to high blood concentrations of acetaldehyde, a metabolic product of ethanol, which lead to the release of histamine from basophils and mast cells.

OBJECTIVE

We examined the inhibitory effects of azelastine hydrochloride, which inhibits histamine release and blocks H1 receptors, in alcohol-induced asthma.

METHODS

Subjects were 13 Japanese asthmatic patients. We measured the change in FEV1 after ingestion of 30 g of pure ethanol. Blood ethanol, acetaldehyde, histamine, leukotriene C4 (LTC4), and thromboxane B2 (TXB2) concentrations were also measured. Alcohol challenge test was repeated in responders after administration of azelastine for 1 week at 4 mg/day.

RESULTS

Of 13 asthmatic patients, five (38.5%) tested positive during an ethanol challenge test, represented by a fall more than 20% in FEV1. The responders had a high blood ethanol, and showed a rise in blood acetaldehyde and histamine concentrations, but not in LTC4 or TXB2. After azelastine treatment, there was no significant fall in FEV1 among responders. Neither the rise in blood ethanol nor blood acetaldehyde levels were blunted by treatment with azelastine, but the rise in blood histamine was blunted by this treatment.

CONCLUSION

Our results suggest that antihistamine agents may be effective against alcohol-induced asthma by both blocking H1 receptors and inhibiting histamine release.

Azelastine suppresses the release of arachidonic acid metabolites from cultured human umbilical vein endothelial cells

We investigated the effects of azelastine, an anti-allergic agent, on the release of arachidonic acid metabolites from cultured human umbilical vein endothelial cells (HUVEC). High performance liquid chromatography (HPLC) revealed that HUVEC treated with 10(-5) M azelastine released smaller amounts of arachidonic acid metabolites into the medium than control HUVEC. Azelastine significantly reduced the release of prostaglandin F2 alpha (PGF2 alpha), leukotriene B4 (LTB4) and 5-hydroxy-eicosatetraenoic acid (5-HETE) by HUVEC. These results suggest that azelastine may inhibit contraction of bronchial smooth muscle cells and reduce bronchial inflammation by suppressing the release of arachidonic acid metabolites from vascular endothelial cells.