Advances in upper airway diseases and allergen immunotherapy

Diagnostic Tools in Allergic Rhinitis

Allergic mechanisms account for most cases of chronic rhinitis. This condition is associated with significant impairment of quality of life and high indirect costs. The identification of the allergic triggers of rhinitis has been historically based on the performance of atopy test [skin prick test (SPT) and serum allergen-specific (s)IgE]. Nevertheless, these tests only denote sensitization, and atopy and allergy represent two different phenomena. It is now clear that allergic phenotypes of rhinitis can exist in both atopic (allergic rhinitis, AR) and non-atopic (local allergic rhinitis, LAR) individuals. Moreover, both allergic phenotypes can coexist in the same rhinitis patient (dual allergic rhinitis, DAR). Therefore, a diagnostic approach merely based on atopy tests is associated with a significant rate of misdiagnosis. The confirmation of the allergic etiology of rhinitis requires the performance of in vivo test like the nasal allergen challenge (NAC). NAC is mandatory for the diagnosis of LAR and DAR, and helps decide the best management approach in difficult cases of AR. Nevertheless, NAC is a laborious technique requiring human and technical resources. The basophil activation test (BAT) is a patient-friendly technique that has shown promising results for LAR and DAR diagnosis. In this review, the diagnostic usefulness for chronic rhinitis of SPT, NAC, olfactory tests, serum sIgE, BAT and the quantification of inflammatory mediators in nasal samples will be discussed. The accurate performance of an etiologic diagnosis of rhinitis patients will favor the prescription of specific therapies with disease-modifying potential like allergen immunotherapy.

Retracted: The role of HOTAIR-induced downregulation of microRNA-126 and interleukin-13 in the development of bronchial hyperresponsiveness in neonates

Long noncoding RNAs, including HOTAIR, are involved in the pathogenesis of a wide range of diseases. This study aimed to explore the mechanism underlying the involvement of HOTAIR in neonatal bronchial hyperresponsiveness (BHR). A total of 105 newborns were recruited in this study to collect their peripheral blood mononuclear cell and serum samples, which were then divided into different genotype groups based on the genotypes of rs4759314, rs874945, and rs7958904. The real-time polymerase chain reaction, western blot analysis, computational analyses, and luciferase assays were performed to establish the regulatory relationships between the HOTAIR, microRNA-126 (miR-126), and interleukin-13 (IL-13). The level of HOTAIR, miR-126, and IL-13 among rs4759314 AA, AG, and GG groups, as well as among rs874945 GG, AG, and AA groups was similar. However, the level of HOTAIR was increased in the rs7958904 GG group, accompanied by a decreased level of miR-126 and IL-13. In addition, the level of airway responsiveness was comparable among rs4759314 AA, AG, and GG groups, as well as among rs874945 GG, AG, and AA groups. However, the airway responsiveness in the groups rs7958904 CG and CC was much stronger than that of the GG group. We also demonstrated that, by directly binding to miR-126, HOTAIR reduced the expression of miR-126, which in turn decreased the expression of IL-13. In summary, we demonstrated the role of HOTAIR-induced downregulation of miR-126 and IL-13 in the development of BHR in neonates.

Eosinophilic gastroenteritis: A state-of-the-art review

Eosinophilic gastrointestinal disorders are a series of diseases that include eosinophilic esophagitis, eosinophilic gastritis, eosinophilic gastroenteritis, eosinophilic enteritis, and eosinophilic colitis. Among these disorders, eosinophilic gastroenteritis is an uncommon and heterogeneous disease characterized by eosinophilic infiltration of the gastrointestinal tract in the absence of secondary causes, presenting with a variety of gastrointestinal manifestations. Up to now, epidemiology and pathophysiology of eosinophilic gastroenteritis are still unclear. Based on clinical manifestations and depth of eosinophilic infiltration into the gastrointestinal tract wall, eosinophilic gastroenteritis is classified into three different patterns including predominantly mucosal pattern, predominantly muscular pattern, and predominantly serosal pattern. For diagnosing eosinophilic gastroenteritis, it is necessary for clinicians to have a high degree of clinical suspicion. In addition to the gastrointestinal symptoms, other evidences such as laboratory results, radiological findings and endoscopy can also provide important diagnostic evidences for eosinophilic gastroenteritis. And these indirect pieces of information together with histological results will lead to a definitive diagnosis of eosinophilic gastroenteritis. To avoid specific allergen, dietary treatments can be considered as initial treatment strategy before drug treatment. Corticosteroids are the main medication for eosinophilic gastroenteritis and have a dramatic therapeutic efficacy. Yet other medications need to further verify their effects in clinical practice, and surgery should be avoided as far as possible.

Genetic polymorphism of antioxidant enzymes in eosinophilic and non-eosinophilic nasal polyposis

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a chronic inflammatory disease of the paranasal sinuses, and its pathophysiology is not yet precisely known. It is suggested that oxygen free radicals play an important role in the pathogenesis of nasal polyposis. This study aimed to identify genetic polymorphisms of superoxide dismutase (SOD 2), catalase (CAT), and inducible nitric oxide synthase (iNOS) enzymes in eosinophilic CRSwNP and non-eosinophilic CRSwNP patients; the study also aimed to evaluate the effect of genetic polymorphism of antioxidant enzymes on CRSwNP etiopathogenesis. One hundred thirty patients, who received endoscopic sinus surgery due to CRSwNP, and 188 control individuals were included in this study. Nasal polyp tissues were divided into two groups histopathologically as eosinophilic CRSwNP and non-eosinophilic CRSwNP. Venous blood samples were taken from the patient and control groups. Polymorphisms in the Ala16Va1 gene, which is the most common variation of SOD-2 gene, and 21 A/T polymorphisms in catalase gene were evaluated with the restriction fragment length polymorphism method and -277 C/T polymorphism in the iNOS gene was evaluated with the DNA sequencing method. The GG genotype distribution for the (-277) A/G polymorphism in the iNOS gene was a statistically significant difference between eosinophilic CRSwNP and control groups (p < 0.05). The CC genotype distribution for the SOD2 A16V (C/T) polymorphism was not statistically significant in all groups (p > 0.05). The TT genotype distribution for the A/T polymorphism in catalase gene at position -21 was statistically significant differences in eosinophilic CRSwNP and control groups (p < 0.05). Increased free oxygen radical levels, which are considered effective factors in the pathogenesis of CRSwNP, can occur due to genetic polymorphism of enzymes in the antioxidant system and genetic polymorphism of antioxidant enzymes in eosinophilic CRSwNP patients might contribute to the pathophysiology.

Candidin and trichophytin stimulate the production of Th1 and regulatory cytokines by peripheral blood mononuclear cells: implication for their use as adjuvants in immunotherapy

Aim: This study's objective was to investigate whether candidin or trichophytin elicit recall immune responses that could potentially inhibit a Th2 response. Materials & methods: Peripheral blood mononuclear cells from nine allergic and seven nonallergic individuals were cultivated in vitro in the presence or absence of these fungal extracts. Results: Trichophytin or candidin, or both, stimulated the production of regulatory cytokines (TGF-β and/or IL-10), accompanied or not by stimulation of production of cytokines associated with the Th1 response (TNF-α, IL-12 and IFN-γ), but without stimulation of Th2 cytokines (IL-5 and IL-13) and IL-17, by peripheral blood mononuclear cells of most allergic and nonallergic individuals. Conclusion: These results indicate that these fungal extracts could be used as adjuvants in personalized therapeutic vaccines in a fair proportion of individuals. In addition, they justify the carrying out of investigations aimed at identifying molecules in these extracts that might exclusively induce Treg and/or Th1 immune responses.

IgE-mediated cow's milk allergy in children

The age at which the majority of children outgrow cow's milk allergy now appears to be later than previously reported. Recent studies have attempted to elucidate factors that may help prevent cow's milk allergy, assess markers of persistence, and evaluate the usefulness of new diagnostic methods. Strict avoidance of cow's milk has been the mainstay of treatment. However, given the potential nutritional, social, and immunologic ramifications of cow's milk elimination from a child's diet, there has been a focus on reevaluating this therapeutic approach.

Evaluation of ceruloplasmin levels in patients undergoing surgical interventions with nasal polyps

OBJECTIVE

Oxidative stress is believed to have a role in the development of nasal polyps (NPs). It is also known that ceruloplasmin (CP), an acute phase protein, limits oxidative stress. The purpose of this study was to evaluate the ceruloplasmin levels in patients with NPs.

METHODS

One hundred and twenty patients with NPs, septal deviations and concha hypertrophies were recruited to the study. Patients were divided in two groups; group 1 (n=60) consisted of patients with NPs, and group 2 (n=60) consisted of septal deviations and concha hypertrophies. Polyp specimens were taken from all patients who underwent endoscopic surgery due to NPs, as well as control specimens were acquired who underwent an operation due to septoplasty or concha hypertrophy. Blood and tissue samples were obtained to assess CP levels.

RESULTS

There were no statistical differences in gender, age and biochemical values between two groups (p>0.05 for all). Compared to group 2, group 1 had significantly higher CP levels both in serum and the tissue samples (both p<0.001).

CONCLUSION

As a result of our study; CP levels both in serum and the tissue in patients with NPs were higher, may be consequence of the inflammation, than in patients without NPs.

Fungal immunotherapy in patients with allergic fungal sinusitis

BACKGROUND

Allergic fungal sinusitis is a disease for which optimal treatment is unclear. Previous studies using fungal immunotherapy reported less recurrence after surgery. There has been concern that traditional high-dose immunotherapy could induce systemic hypersensitivity in patients with this condition.

OBJECTIVE

To determine the safety of high-dose subcutaneous fungal immunotherapy in patients with allergic fungal sinusitis.

METHODS

Safety of high-dose subcutaneous fungal immunotherapy was assessed in 14 patients from our clinic who met diagnostic criteria for allergic fungal sinusitis. Results were compared to a control group of 14 patients with chronic rhinosinusitis without allergic fungal sinusitis who received subcutaneous fungal immunotherapy. We also performed a literature search to identify all previous reports of subcutaneous fungal immunotherapy.

RESULTS

No differences between numbers of immediate local or large local reactions, delayed local reactions, or required dose adjustments were noted between patient and control groups. One patient from each group experienced a mild systemic urticarial reaction to immunotherapy. Similarly, there were no differences in complications in either group that also received immunotherapy with nonfungal allergens. No patient developed evidence of immune complex disease. Eight publications were identified for inclusion in our literature analysis, 7 of which used low-dose subcutaneous immunotherapy. None of these noted complications more serious than local reactions.

CONCLUSION

Our data demonstrate that subcutaneous fungal immunotherapy in patients with allergic fungal sinusitis is unlikely to cause adverse reactions other than those occurring with pollen immunotherapy. Clinical trials of high-dose, traditional immunotherapy with fungal allergens for efficacy may proceed in patients with allergic fungal sinusitis without undue concern.

Eosinophilic esophagitis: association with allergic disorders

Atopy has been linked to eosinophilic gastrointestinal disorders because of the role eosinophils play in atopic disorders. It has also been found that these disorders coexist. The goal of this article is to take a step back, and considering only eosinophilic esophagitis, attempt to determine from the available body of clinical and research literature: (1) Is the coexistence of these disorders attributable to a preconceived bias? If so, what is the source of the bias and how can it be removed? (2) Is there a cause and effect relationship? If so, can this relationship be harnessed for diagnostic and therapeutic modalities?

Immunoglobulins in nasal secretions of patients with allergic rhinitis and chronic rhinosinusitis

Allergic rhinitis and chronic rhinosinusitis are the most frequently encountered inflammatory reactions of the sinonasal mucosa. Nasal-associated lymphoid tissue has been suggested as an inductive site for humoral and cellular immune responses in the upper respiratory tract. Immunoglobulins are important elements in human adaptive immune responses and deficiencies of serum immunoglobulins may be associated with recurrent or refractory infections. However, the local humoral immune response to offending antigens in the nasal environment has not been well elucidated. To determine the levels of IgA and IgG subclasses antibodies in the nasal secretions of patients with allergic rhinitis and chronic rhinosinusitis, 25 patients with allergic rhinitis and 20 with chronic rhinosinusitis were included and their nasal secretions were collected to measure the levels of secretary IgA (sIgA), total IgA (tIgA), and IgG subclasses antibodies. There was a significant elevation of IgG(3) in the nasal secretions of patients with chronic rhinosinusitis. No difference was noted in the levels of sIgA, tIgA, IgG1, IgG2 and IgG4 among the three groups. The local defense mechanism of nose reacts to microorganisms and pathogenic antigens by inducing the adaptive humoral immune response to increase the amount of immunoglobulins, with IgG3 being the major up-regulated antibody.

BCR ligation antagonizes the IL-21 enhancement of anti-CD40/IL-4 plasma cell differentiation and IgE production found in low density human B cell cultures

We sought to discover the mechanisms explaining increased IgE production seen at low cell densities when IL-21 is added to human B cell cultures activated with anti-CD40 and IL-4. When cells were cultured in the absence of BCR ligation, qPCR demonstrated dramatic increases in mRNA for the plasma cell transcription factors BLIMP1 and XBP1. Furthermore, a majority of viable cells expressed high levels of CD38 while losing expression of surface IgD. In contrast, in the presence of BCR stimulation, both the XBP1 mRNA levels and CD38 cell surface expression were markedly reduced, and a large population of cells retained IgD expression, indicating reduced plasma cell differentiation. IgE levels were reduced in the BCR stimulated cultures by 90%, while IgG4 levels remained unchanged. In summary, IL-21 enhances IgE production at low densities through stimulating cell division and plasma cell differentiation and this activity is reduced upon BCR cross-linking.

Immunomodulation: the future cure for allergic diseases

Allergies are the result of aberrant immune reactivity against common innocuous environmental proteins (allergens). A pivotal component of allergic pathogenesis is the generation of allergen-specific Th cells with an effector phenotype. These Th cells activate a complex immune cascade that triggers the release of potent mediators and enhances the mobilization of several inflammatory cells types, which in turn elicit the acute allergic reactions and promote the development of chronic inflammation. The current therapies for allergic diseases focus primarily on pharmacological control of symptoms and suppression of inflammation. This approach is beneficial, but not curative, since the underlying immune pathology is not inhibited. In an attempt to develop more effective therapeutic strategies, the scientific interest has been directed toward methods down-modulating the immune mechanisms that initiate and maintain the allergic cascade. Today, the only widely used disease-modifying form of allergy treatment is the specific immunotherapy with allergen extracts. More recently the use of anti-IgE has been approved for patients with allergic asthma. Other immunomodulatory methods being currently explored are the administration of microbial adjuvants that inhibit Th2 reactivity and the design of molecules that interrupt the activity of key allergic cytokines, chemokines, or other Th2 effector mediators.

Advances in upper airway diseases and allergen immunotherapy

The purpose of this review is to highlight important articles on upper airway diseases and immunotherapy that appeared during 2006. Studies from Europe continue to examine the usefulness of the Allergic Rhinitis and its Impact on Asthma classification of allergic rhinitis as intermittent or persistent and its levels of severity as mild or moderate/severe. A number of physical agents were shown to effect nasal inflammation: sudden temperature changes in patients with allergic rhinitis increased eosinophilic inflammation; in children with allergic asthma, the personal exposure to particles <2.5 microm air pollution correlated with percent of nasal eosinophils and levels of markers of nasal exudation; and in patients who developed rhinorrhea on exposure to cold and windy weather, nasal challenge with cold dry air caused sloughing of nasal epithelial cells. A 3-month double-blind, placebo-controlled study of nasal washes with amphoteracin B showed no benefit in patients with chronic rhinosinusitis. Studies of immunotherapy with grass and dog dander extracts confirmed the need for doses containing 15 to 20 microg of the major allergen for optimal effectiveness. The protective effect of immunotherapy on the development of asthma in children with allergic rhinitis was shown to still be present 2 years after completion of a 3-year course of treatment. Injection immunotherapy with a moderate dose of house dust mite extract in house dust-sensitive adults with atopic dermatitis reduced symptoms and use of corticosteroids and antihistamines compared with treatment with about 1/1000 of that dose of the same extract. Pretreatment for 9 weeks with the monoclonal anti-IgE antibody omalizumab reduced systemic reactions during rush immunotherapy 5-fold and allowed further build-up at weekly intervals without systemic reactions. A review of sublingual immunotherapy confirmed both efficacy and safety, but evidence for appropriate dosing and for the effectiveness of sublingual immunotherapy employing multiple allergen mixes was still lacking. Two studies with a sublingual grass pollen extract tablet showed a clear dose response and the ability to initiate sublingual immunotherapy without an up-dosing phase. A pilot study with cytosine phosphorothionate quanosine DNA conjugated to the major allergen of ragweed reported impressive improvement in symptoms the first pollen season that persisted during the second pollen season without any further administration of the conjugate. In conclusion, studies on rhinitis and sinusitis explored the pathophysiology of the disease more than offering new therapeutic approaches. Studies on immunotherapy addressed optimal dosing, but also a variety of safer and more convenient approaches such as reduction of IgE with omalizumab, conjugating allergen to immunostimulatory DNA sequences, or administration by the sublingual route.

Treating allergic rhinitis in pregnancy

Numerous pregnant women suffer from allergic rhinitis, and particular attention is required when prescribing drugs to these patients. In addition, physiologic changes associated with pregnancy could affect the upper airways. Evidence-based guidelines on the management of allergic rhinitis have been published. Medication can be prescribed during pregnancy when the apparent benefit of the drug is greater than the apparent risk. Usually, there is at least one "safe" drug from each major class used to control symptoms. All glucocorticosteroids are teratogenic in animals but, when the indication is clear (for diseases possibly associated, such as severe asthma exacerbation), the benefit of the drug is far greater than the risk. Inhaled glucocorticosteroids (eg, beclomethasone or budesonide) have not been incriminated as teratogens in humans and are used by pregnant women who have asthma. A few H1-antihistamines can safely be used as well. Most oral decongestants (except pseudoephedrine) are teratogenic in animals. There are no such data available for intranasal decongestants. Finally, pregnancy is not considered to be a contraindication for the continuation of immunotherapy.

Oxidative stress in nonallergic nasal polyps associated with bronchial hyperresponsiveness

BACKGROUND

Nasal polyposis (NP) is a chronic inflammatory disease of upper airway with unknown etiology. NP is frequently associated with asthma; the interaction between these comorbidities remains interesting. Oxidative stress has been implicated in the pathophysiology of NP and asthma. The aim of this study is to investigate the significance of oxidative stress in sinonasal microenvironments by evaluating its association with clinopathological parameters and its impacts on the pathogenesis of bronchial hyperresponsiveness (BHR) in NP.

METHODS

Polyp biopsy specimens were obtained from 20 nonallergic patients; control mucosas were obtained from 20 volunteers. The levels of free radicals in the tissues and in blood were determined by a sensitive chemiluminescence (CL) method. NP patients were substratified into three subgroups, NP without BHR, NP with asymptomatic BHR, and NP with BHR and asthma by the results of provocative testing. Four histological characteristics of NP, inflammatory cells, eosinophil infiltration, edema and fibrosis were estimated and applied to correlate with the tissue-CL.

RESULTS

The mean CL level in polyp-tissues, but not in blood, was higher than in the control specimens. In NP patients, tissue-CL was associated with endoscopy score; high tissue-CL levels were positively correlated with the abundance of inflammatory cells and eosinophils. Tissue-CL and endoscopy score were associated with BHR/asthma phenotype.

CONCLUSION

These results suggest an important role for oxidative stress in the pathophysiology of NP and a causal relation between oxidative stress and inflammatory cells, especially the eosinophils. Free radical levels in polyp-tissues associated with NP severity and with BHR/asthma phenotype in nonallergic NP patients.

Seasonal dynamics of chemokine receptors and CD62L in subjects with asymptomatic skin sensitization to birch and grass pollen

BACKGROUND

Asymptomatic skin sensitization (AS) has been shown to be a risk factor for respiratory allergic disease. CCR4, CXCR1 and CD62L have all been assigned a role in the immunopathogenesis of allergy. Memory T-cell expression of CCR4, CXCR1 and CD62L has not hitherto been investigated in subjects with AS.

METHODS

We investigated seasonal CD4 memory T-cell expression of the chemokine receptors CCR4, CXCR1 as well as L-selectin (CD62L) in fresh cultures derived from symptomatic atopics (SAs), subjects with AS and healthy controls (HCs). Peripheral blood mononuclear cells from all three groups were isolated during birch and grass pollination as well as in the following winter. CD4 memory T-cell expression of CCR4, CXCR1 and CD62L was determined by flow-cytometry.

RESULTS

During spring and summer, a significantly increased proportion of memory T cells expressed CCR4, CXCR1 and CD62L in SAs when compared with subjects with AS and HCs. Only SAs exhibited seasonal fluctuations in numbers of CCR4, CXCR1 and CD62L positive memory T cells.

CONCLUSION

Although clearly IgE sensitized, subjects with AS have significant diminished numbers of CCR4, CXCR1 and CD62L positive memory T cells, during pollination, when compared with SAs. In contrast to SAs, cultures derived from subjects with AS did not display seasonal variation. Our findings explain the lack of clinical symptoms, during pollination, in subjects with AS.

In contrast to specific B cells, human basophils are unaffected by the toxic activity of an allergen toxin due to lack of internalization of immunoglobulin E-bound allergen

BACKGROUND

Specific immunotherapy is the only curative therapy for type I allergies and the alarming increase in allergy prevalence emphasizes the need for additional/alternative strategies for curative treatment. Allergen toxins (AT), fusion products of an allergen with an apoptosis inducing cytotoxin, are a new kind of immunotoxin.

OBJECTIVE

AT should allow allergen-specific targeting and elimination of allergy-relevant cells, with B cells being the primary target. An important question is the fate of the effector cells, e.g. mast cells and basophils, which carry allergen-specific IgE: the immunotoxin might even prove to be harmful.

METHODS

We established a reliable in vitro B cell model (using two mouse hybridoma cell lines) for testing specificity and toxicity of P5-ETA', a fusion protein of the major timothy grass pollen allergen Phl p 5b and truncated Pseudomonas Exotoxin A. In a second step, we investigated the impact of the AT on human basophils.

RESULTS

P5-ETA' reliably eliminated Phl p 5-specific cells in the in vitro B cell model, leaving unspecific B cells unharmed. Human basophils of grass pollen allergic donors specifically bound P5-ETA', released IL-4 and up-regulated the activation marker CD203c, but were not subject to the toxic effect because of lack of internalization of IgE-bound allergen.

CONCLUSION

According to our data, basophils are pure effector cells in the context of IgE-bound allergen and not involved in classical antigen presentation.

Advances in upper airway diseases and allergen immunotherapy

The purpose of this review is to highlight important articles on upper airway disease and immunotherapy that appeared in the Journal of Allergy and Clinical Immunology and elsewhere during 2005. In recent studies of tissue from patients with chronic hypertrophic eosinophilic sinusitis, increased leukotriene C4 synthase and 5-lipoxygenase activity and increased levels of cysteinyl leukotriene production were demonstrated that correlated with disease severity but not with whether the patient was aspirin sensitive. However, the cysteinyl leukotriene 1 receptor was increased in leukocytes in the sinus tissue only in those patients with aspirin sensitivity. Major basic protein, released by eosinophils into the mucus in the paranasal sinus lumen, was found to reach concentrations capable of damaging the sinus epithelium, predisposing to bacterial infections. Testing the hypothesis that chronic hypertrophic eosinophilic sinusitis represents a reaction to common fungi, a double-blind trial of intranasal instillation of amphotericin B was conducted. There were marginal but significant differences in favor of amphotericin B treatment for sinus mucosal thickening on the basis of computed tomography and the evidence of eosinophilic inflammation in the sinus mucus. The effectiveness of topical nasal corticosteroids for treatment of nasal polyps was confirmed in 2 large studies. Improvement in sleep quality and daytime drowsiness in patients with allergic rhinitis treated with nasal corticosteroids was reported to correlate with reduction in nasal obstruction. The statistical analysis behind studies that reported a decrease in asthma exacerbations with nasal corticosteroids or oral antihistamines has been questioned. It appears that the results of at least one of these studies are indeed too good to be true. Although caution is still indicated in administering immunotherapy to patients receiving beta-adrenergic blocking agents, the prohibition might not be absolute. A study in patients with Hymenoptera sensitivity given venom immunotherapy revealed no increase in serious adverse reactions to venom injections and no greater incidence of reactions to insect stings in those taking beta-blocking agents. Sublingual immunotherapy for 8 to 12 weeks in patients with hazelnut sensitivity significantly increased their tolerance to hazelnut in double-blind, placebo-controlled challenges while inducing increased IgG4 and IL-10 levels, indicating induction of regulatory T cells. There were a number of articles in the Journal of Allergy and Clinical Immunology in 2005 that addressed the entity of chronic hypertrophic eosinophilic sinusitis. In addition, an update of the "Practice parameters on sinusitis" was published. The major focus in allergen immunotherapy continues to be sublingual administration.

Factors that regulate naturally occurring T regulatory cell–mediated suppression

T regulatory (Treg) cells play a key role in the modulation of allergic and autoimmune responses. This review will discuss the factors that regulate naturally occurring Treg (nTreg) cell-mediated suppression. The involvement of cytokines, costimulatory molecules, and ligands on antigen-presenting cells in the inhibition of nTreg cell-mediated suppression in vitro is summarized. Understanding the events that control suppressive function of nTreg cells will allow manipulation of these cells to inhibit or enhance their functions in the development of novel therapies for autoimmune and allergic diseases.

Antigen-specific targeting and elimination of EBV-transformed B cells by allergen toxins

BACKGROUND

With the exception of antigen-specific immunotherapy, current treatments for atopic diseases provide only symptomatic relief. Because of the increasing incidence of such diseases, the development of novel strategies and concepts for the treatment of allergies is urgently needed.

OBJECTIVE

Here we present a new approach for the treatment of atopic diseases. The strategy is comparable to the application of immunotoxins in cancer therapy, in which a cytotoxic peptide is coupled to a cancer cell-specific antibody fragment or ligand. In the case of so-called allergen toxins (ATs), the target cell-specific moiety is an allergen or allergen-derived fragment, which should be bound only by allergen-reactive cells. After receptor-mediated internalization, allergen-specific cells are killed, and the allergic pathogenesis is interrupted.

METHODS

Proof of the AT principle was shown by using a human ex vivo system in which EBV was used to transform human B cells specific for the timothy grass pollen allergen Phl p 5b. The AT is composed of the major B-cell and T-cell epitopes of the Phl p 5b (P5) allergen fused to a truncated form of the highly toxic Pseudomonas aeruginosa exotoxin A (ETA').

RESULTS

Allergen-specific and nonspecific B cells were challenged with P5-ETA', but only the Phl p 5b-reactive B cells showed selective binding and cytotoxicity.

CONCLUSION

This approach represents an initial step toward a novel therapeutic strategy in the treatment of atopic diseases.

The role of leukotrienes in allergic rhinitis

OBJECTIVE

To review the role of cysteinyl leukotrienes (cysLTs) in allergic rhinitis and the scientific rationale for therapy with leukotriene receptor antagonists (LTRAs).

DATA SOURCES

Relevant basic science and clinical articles were identified by a search of the PubMed database for articles published from 1984 to 2004 using the following keywords: allergic rhinitis; nose; immune response; allergen challenge; leukotrienes C, D, and E; cysteinyl leukotriene; cysteinyl leukotriene receptor; cytokine; leukocyte; montelukast; zafirlukast; and pranlukast.

STUDY SELECTION

The authors' expert opinion was used to select studies for inclusion in this review.

RESULTS

CysLTs are synthesized via 5-lipoxygenase metabolism of arachidonic acid by mast cells and basophils during the early-phase response to antigen and by eosinophils and macrophages during the late phase. The cysLT levels in nasal secretions are elevated after short-term allergen instillation and in allergy season in patients with allergic rhinitis. These lipid mediators act locally and systemically by interacting with receptors, particularly the cysLT1 receptor, on target cells. Evidence derived from topical application of cysLTs in the nose and from the effects of LTRAs indicates that cysLTs contribute to nasal mucous secretion, congestion, and inflammation. CysLTs promote allergic inflammation by enhancing immune responses and the production, adhesion, migration, and survival of inflammatory cells such as eosinophils. They also increase the generation of an array of other proinflammatory mediators, such as cytokines, which in turn increase the production of and receptors for cysLTs. Clinical trials have demonstrated that LTRAs have significant but modest efficacy as single agents but additive efficacy when used with other classes of agents.

CONCLUSIONS

CysLTs fulfill the criteria for relevant mediators of allergic rhinitis via their diverse effects on immune, inflammatory, and local structural components of disease. By blocking the cysLT1 receptor responsible for most of these effects, LTRAs represent a useful approach to treatment of this important and prevalent disorder.

Interleukin-13-dependent bronchial hyper-responsiveness following isolated upper-airway allergen challenge in a murine model of allergic rhinitis and asthma

BACKGROUND

We have previously shown that isolated allergic sensitization and challenge of the upper airway results in lower-airway inflammation, which supports the concept of the united airways.

OBJECTIVE

This study investigates the hypothesis that isolated upper-airway allergic sensitization is sufficient to induce bronchial hyper-responsiveness (BHR), characteristic of asthma, and that IL-13 is an essential mediator in both the upper and lower airways.

METHODS

BALB/c mice were sensitized and challenged by intranasal instillation of allergen ovalbumin (OVA) using our standard protocol. BHR to methacholine was determined and inflammation in nares and lung was assessed.

RESULTS

Isolated intranasal application of allergen in awake animals resulted in almost exclusive deposition in the upper airways while in anaesthetized mice there was almost equal distribution in the upper and lower airways. We have demonstrated significant BHR to methacholine challenge in animals receiving OVA only in the upper airway. Also noted was concomitant increase in eosinophilic infiltrates in lung and nares as well as increased granulocytes and IL-13 levels in bronchoalveolar lavage (BAL) fluid. Using a polyclonal anti-IL-13 antibody we have shown inhibition of airways inflammation, both in nares and in lung with significant reduction of granulocytes in BAL from anti-IL-13 treated mice (P<0.0001). Anti-IL-13 treatment also abrogates allergen-induced BHR (P<0.01).

CONCLUSION

These data suggest that isolated upper-airway allergen deposition initiates allergic responses along the entire airway. IL-13 mediates both airway inflammation and BHR and may play a role in the communication between the upper and lower airways.

A Review of the Evidence from Comparative Studies of Levocetirizine and Desloratadine for the Symptoms of Allergic Rhinitis

BACKGROUND

Levocetirizine and desloratadine are newer antihistamines indicated for the treatment of allergic rhinitis and chronic idiopathic urticaria.

OBJECTIVE

This article discusses the pharmacokinetics and pharmacodynamics of levocetirizine and desloratadine and reviews studies that have directly compared the effects of these 2 drugs in allergic rhinitis and urticaria.

METHODS

Relevant articles were identified through a search of MEDLINE from 1999 through 2004 using the main search terms levocetirizine and desloratadine.

RESULTS

Levocetirizine is absorbed rapidly and reaches a steady-state plasma concentration more quickly than does desloratadine. It is also metabolized to a lesser extent than desloratadine, has a lower V(d), and has higher specificity for histamine(1) receptors. Eight well-controlled trials were identified that directly compared the effects of levocetirizine and desloratadine in the skin and nose of healthy individuals and patients with allergic rhinitis. Drug activity was measured in terms of wheal, flare, and itch reactions; nasal symptoms or symptom scores; increases in concentrations of inflammatory markers; or facial thermography. In most of these trials, levocetirizine had a faster onset and greater consistency of effect than desloratadine. The differences in the pharmacokinetic and pharmacodynamic profiles of the 2 drugs may partially explain these clinical findings.

CONCLUSIONS

Levocetirizine may be preferred to desloratadine as a treatment option for allergic rhinitis because of its faster onset of action and greater consistency of effect. Although comparative studies in chronic idiopathic urticaria are not available, data from histamine-induced wheal and flare studies in healthy volunteers suggest that levocetirizine may be more effective in preventing itching than desloratadine.

Eosinophilic gastroenteritis

Eosinophilic gastroenteritis despite its uncommon occurrence is one of the most important primary eosinophilic gastrointestinal disorders, and most commonly presents with abdominal pain. The terminology is, however, misleading because all levels of the gastrointestinal tract from the esophagus to the rectum may be affected. A history of atopy and allergies is present in 25-75% cases. The heterogeneity in the clinical presentations of EG is determined by the site and depth of eosinophilic infiltration. Eosinophilic intestinal inflammation also occurs secondarily in the gastrointestinal tract in inflammatory bowel disease, autoimmune diseases, as reactions to medications, infections, hypereosinophilia syndrome, and after solid organ transplantation. Recent investigations providing an insight into the pathogenesis of eosinophilic gastroenteritis support a critical role for allergens, eosinophils, Th-2 type cytokines, and eotaxin in mediating eosinophilic inflammation. The diagnosis is confirmed by demonstrating prominent tissue eosinophilia on histopathology. Treatment recommendations based on data extrapolated from retrospective, uncontrolled studies, and expert opinion support the use of restricted diets, corticosteroids, leukotriene receptor antagonists, and mast cell stabilizers. Many unanswered questions remain with regard to the natural history, optimal duration of therapy, safer steroid-sparing long-term treatment agents, and the means of reliable and non-invasive follow-up.

Dose dependence and time course of the immunologic response to administration of standardized cat allergen extract

BACKGROUND

The immunologic response to allergen immunotherapy with 3 serial 5-fold doses of cat extract has been studied after approximately 5 weeks of immunotherapy. The highest dose containing 15 mug of Fel d 1 produced the most consistent and favorable response. It is unknown whether the comparative response on reaching a maintenance dose is maintained with long-term maintenance therapy.

OBJECTIVE

The purpose of this investigation was to evaluate the immunologic responses with these 3 serial doses of cat hair and dander extract at baseline, after reaching the maintenance dose (approximately 5 weeks), and after 1 year of maintenance immunotherapy.

METHODS

Twenty-eight patients with cat allergy randomized in a double-blind study were assigned to one of 4 treatment groups: placebo or cat hair and dander extract containing 0.6 mug of Fel d 1, 3 mug of Fel d 1, and 15 mug of Fel d 1 at maintenance. Studies included skin prick tests and late cutaneous reactions with cat hair and dander extract, titrated nasal challenges with the extract, serum cat allergen-specific IgG4 and IgE measurement, and flow cytometric and ELISA analysis of whole blood and intranasal cytokines (TGF-beta, IL-10, IFN-gamma, IL-4, and IL-5).

RESULTS

Twenty-six subjects completed the study. After both 5 weeks and 1 year, significant and dose-dependent differences were seen with total symptom scores on nasal challenge ( P < .0001), with titrated skin prick testing with cat dander extract at 5 weeks ( P = .014) and 1 year ( P < .0001), and with cat-specific IgG4 measurement at 5 weeks ( P = .004) and 1 year ( P = .003). At 1 year, neither flow cytometry of whole blood nor ELISA evaluation of nasal cytokines demonstrated any significant differences among the treatment groups.

CONCLUSION

The response to titrated nasal allergen challenge, titrated skin prick testing, and allergen-specific IgG4 measurement to cat immunotherapy at 5 weeks is predictive of the response at 1 year.