Advances in upper airway diseases and allergen immunotherapy in 2007

Mast cell stabilisers

Mast cells play a critical role in type 1 hypersensitivity reactions. Indeed, mast cell mediators are implicated in many different conditions including allergic rhinitis, conjunctivitis, asthma, psoriasis, mastocytosis and the progression of many different cancers. Thus, there is intense interest in the development of agents which prevent mast cell mediator release or which inhibit the actions of such mediators once released into the environment of the cell. Much progress into the design of new agents has been made since the initial discovery of the mast cell stabilising properties of khellin from Ammi visnaga and the clinical approval of cromolyn sodium. This review critically examines the progress that has been made in the intervening years from the design of new agents that target a specific signalling event in the mast cell degranulation pathway to those agents which have been developed where the precise mechanism of action remains elusive. Particular emphasis is also placed on clinically used drugs for other indications that stabilise mast cells and how this additional action may be harnessed for their clinical use in disease processes where mast cells are implicated.

Allergen Immunotherapy in an HIV+ Patient with Allergic Fungal Rhinosinusitis

Patients with HIV/AIDS can present with multiple types of fungal rhinosinusitis, fungal balls, granulomatous invasive fungal rhinosinusitis, acute or chronic invasive fungal rhinosinusitis, or allergic fungal rhinosinusitis (AFRS). Given the variable spectrum of immune status and susceptibility to severe infection from opportunistic pathogens it is extremely important that clinicians distinguish aggressive fungal invasive fungal disease from the much milder forms such as AFRS. Here we describe a patient with HIV and AFRS to both remind providers of the importance of ruling out invasive fungal disease and outline the other unique features of fungal sinusitis treatment in the HIV-positive population. Additionally we discuss the evidence for and against use of allergen immunotherapy (AIT) for fungal disease in general, as well as the evidence for AIT in the HIV population.

Treatment of allergic asthma: modulation of Th2 cells and their responses

Atopic asthma is a chronic inflammatory pulmonary disease characterised by recurrent episodes of wheezy, laboured breathing with an underlying Th2 cell-mediated inflammatory response in the airways. It is currently treated and, more or less, controlled depending on severity, with bronchodilators e.g. long-acting beta agonists and long-acting muscarinic antagonists or anti-inflammatory drugs such as corticosteroids (inhaled or oral), leukotriene modifiers, theophyline and anti-IgE therapy. Unfortunately, none of these treatments are curative and some asthmatic patients do not respond to intense anti-inflammatory therapies. Additionally, the use of long-term oral steroids has many undesired side effects. For this reason, novel and more effective drugs are needed. In this review, we focus on the CD4+ Th2 cells and their products as targets for the development of new drugs to add to the current armamentarium as adjuncts or as potential stand-alone treatments for allergic asthma. We argue that in early disease, the reduction or elimination of allergen-specific Th2 cells will reduce the consequences of repeated allergic inflammatory responses such as lung remodelling without causing generalised immunosuppression.

Citrus/Cydonia Compositum Subcutaneous Injections versus Nasal Spray for Seasonal Allergic Rhinitis: A Randomized Controlled Trial on Efficacy and Safety

Background. Clinical experiences in vitro and clinical studies have demonstrated the curative potency and safety of Citrus/Cydonia compositum in seasonal allergic rhinitis treatment. Objectives. To compare the efficacy and safety of two routes of administration (nasal spray versus subcutaneous injections). Methodology: Design. a national, randomised, comparative clinical trial with two parallel groups. Participants. 23 patients fulfilled the study requirements. Intervention. after a one- or two-week wash-out period, 23 patients were randomized, to a 6-week treatment period. Outcomes. immunological and symptom severity changes and safety. Immunologic outcome assessments were blinded to group assignment. 23 patients were randomized and from 22/23 patients (11 in each group) blood samples were analyzed before and after treatment. Conclusion. Both routes of administration demonstrate immunological and clinical effects, with larger inflammatory and innate immunological effects of the nasal spray route and larger allergen-specific clinical effects of the subcutaneous route, and are safe.

Immunomodulatory properties of a lemon-quince preparation (Gencydo®) as an indicator of anti-allergic potency

INTRODUCTION

Gencydo®, a combination of lemon (Citrus limon) juice and aqueous quince (Cydonia oblonga) extract has been used traditionally in anthroposophical medicine for treating patients with allergic rhinitis or asthma. Because there are no reports about the mode of action, we investigated the anti-allergic effects of this preparation in vitro by using cell lines and primary cells in various biological and immunological endpoints.

MATERIALS AND METHODS

The release of soluble mediators from basophilic cells, mast cells and lung epithelial cells, which are essential for the initiation of early- and late-phase allergic reactions, was analyzed in relation to the synthetic anti-allergic drugs azelastine and dexamethasone. In addition, the impact of Gencydo® on the viability and activation of GM-CSF-activated eosinophil granulocytes was investigated.

RESULTS AND DISCUSSION

Gencydo® reduced the degranulation and histamine release of IgE-activated basophilic cells and mast cells and inhibited the IgE- and PMA/A23187-induced increases in IL-8, TNF-α and GM-CSF production in mast cells. The effects were comparable to that of the used concentration of azelastine and dexamethasone. Furthermore, Gencydo® partially blocked eotaxin release from human bronchial epithelial cells, but has no impact on the viability and activation of GM-CSF-activated eosinophil granulocytes. In conclusion, these results give a rational base for the topical use of Gencydo® in treatment of allergic disorders through the down regulation of soluble mediators, which are essential for the initiation and maintenance of allergic reactions.

Immunologic therapeutic approaches in the management of food allergy

Food allergy affects up to 6% of children and 3-4% of adults in Westernized countries, and is the most common cause of outpatient anaphylaxis in most studies. The mainstay of treatment is strict avoidance of the offending allergens and education regarding the use of emergency medication in cases of accidental ingestions or exposures. While these approaches are generally effective, there are no definitive treatments that cure or provide long-term remission from food allergy. However, with recent advances in characterizing food allergens and understanding humoral and cellular immune responses in food allergy, several therapeutic strategies are being investigated. Potential treatments include allergen-specific immunotherapy as well as allergen-nonspecific approaches to downregulate the overall allergic response in food-allergic individuals.

Effect of oral tolerance in a mouse model of allergic rhinitis

OBJECTIVE

Induction of oral tolerance (OT) is known to prevent allergic inflammation in models of asthma. This study investigated the preventive effect of OT and airway remodeling in a mouse model of allergic rhinitis (AR).

STUDY DESIGN

An in vivo study using an animal model.

SETTING

Catholic Research Institutes of Medical Science.

METHODS

Forty six-week-old, female BALB/c mice were divided into four groups: control, AR, low-dose OT, and high-dose OT. To induce OT, mice were fed ovalbumin (OVA) before sensitization with OVA/aluminum hydroxide, 1 mg for six days in the low-dose OT group and a 25 mg single dose in the high-dose OT group. Mice in the AR group were fed phosphate-buffered saline. After sensitization followed by challenges with OVA during six weeks, nasal behaviors, interleukin (IL)-13 and interferon gamma (IFN-gamma) levels in nasal lavage (NAL) fluids, as well as OVA-specific IgE levels in serum, were measured. The degree of goblet cell hyperplasia and thickness of lamina propria were observed in nasal tissues by periodic acid-Schiff and Masson's trichrome stain. A P value < 0.05 was accepted as statistically significant.

RESULTS

Both OT groups showed a significant decrease in inflammatory cells, IL-13 and IFN-gamma in NAL fluids, as well as OVA-specific IgE levels in serum compared with the AR group. In addition, the degree of goblet cell hyperplasia and thickness of lamina propria were attenuated in both OT groups compared with the AR group. Further, these alterations did not differ significantly between the two OT groups.

CONCLUSION

These results suggest that OT may effectively reduce allergic inflammation as well as airway remodeling in a mouse model of AR.

Food allergy: recent advances in pathophysiology and treatment

Food allergies are adverse immune reactions to food proteins that affect up to 6% of children and 3-4% of adults. A wide range of symptoms can occur depending on whether IgE or non-IgE mediated mechanism are involved. Many factors influence the development of oral tolerance, including route of exposure, genetics, age of the host, and allergen factors. Advances have been made in the understanding of how these factors interact in the pathophysiology of food allergy. Currently, the mainstay of treatment for food allergies is avoidance and ready access to emergency medications. However, with the improved understanding of tolerance and advances in characterization of food allergens, several therapeutic strategies have been developed and are currently being investigated as potential treatments and/or cures for food allergy.

Citrus/Cydonia comp. can restore the immunological balance in seasonal allergic rhinitis-related immunological parameters in vitro

In two in vitro studies, we examined the immunological (pathways of the) effects of Citrus/Cydonia comp. from, respectively, a healthy and an allergic donor; peripheral blood mononuclear cells (PBMCs) were isolated out of peripheral blood and analyzed in vitro after polyclonal stimulation of T-cells. The differentiation capacity and the influence with regard to Th1 (IFN-gamma) and Th2 (IL-5) cells were examined. Citrus/Cydonia comp. has a selective effect on the differentiation of T-cells by producing relatively more IL-10 than IL-12. By that, it also seems to have an effect on the induction of regulatory (IL-10 producing) T-cell subsets. It is in vitro capable of neutralizing (to some extent) the changes, characteristic to allergic rhinitis, with regard to the maturation, differentiation, and activity of the immune system. Thus, Citrus/Cydonia comp. can potentially restore the disturbed immune state of rhinitis patients, which essentially could be sufficient to make allergic symptoms disappear permanently.