Late cutaneous allergic responses in isolated IgE-dependent reactions

Topical corticosteroids for hives and itch (urticaria): Systematic review and Bayesian meta-analysis of randomized trials

BACKGROUND

Topical corticosteroids are widely used as a treatment for itch and wheals (urticaria), but their benefits and harms are unclear.

OBJECTIVE

To systematically synthesize the benefits and harms of topical corticosteroids for the treatment of urticaria.

METHODS

We searched MEDLINE, EMBASE, and CENTRAL from database inception to March 23, 2024, for randomized trials comparing topical corticosteroids with placebo for patients with urticaria (either chronic spontaneous or inducible urticaria or acute urticaria elicited from skin/intradermal allergy testing). Paired reviewers independently screened records, extracted data, and assessed risk of bias. Random-effects meta-analyses addressed urticaria severity, itch severity (numeric rating scale; range 0-10; higher is worse), and adverse events. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach informed certainty of evidence ratings. PROSPERO registration: CRD42023455182.

RESULTS

A total of 19 randomized controlled trials enrolled 379 participants with a median of mean age of 30.1 (range 21.1-44.0) years. Compared with placebo, topical corticosteroids may reduce wheal size (ratio of means 0.47, 95% CI 0.38-0.59; low certainty) and itch severity (mean difference -1.30, 95% CI -5.07 to 2.46; very low certainty). Topical corticosteroids result in little to no difference in overall adverse events (94 fewer patients per 1000, 95% credible intervals 172 fewer to 12 more; high certainty).

CONCLUSION

Compared with placebo, topical corticosteroids may result in a reduction of wheal size and little to no difference in overall adverse events. Topical corticosteroids may reduce itch severity, but the evidence is very uncertain. Future large, randomized trials addressing the use of topical corticosteroids would further support optimal urticaria management.

Identification of true chemical respiratory allergens: Current status, limitations and recommendations

Asthma in the workplace is an important occupational health issue. It comprises various subtypes: occupational asthma (OA; both allergic asthma and irritant-induced asthma) and work-exacerbated asthma (WEA). Current regulatory paradigms for the management of OA are not fit for purpose. There is therefore an important unmet need, for the purposes of both effective human health protection and appropriate and proportionate regulation, that sub-types of work-related asthma can be accurately identified and classified, and that chemical respiratory allergens that drive allergic asthma can be differentiated according to potency. In this article presently available strategies for the diagnosis and characterisation of asthma in the workplace are described and critically evaluated. These include human health studies, clinical investigations and experimental approaches (structure-activity relationships, assessments of chemical reactivity, experimental animal studies and in vitro methods). Each of these approaches has limitations with respect to providing a clear discrimination between OA and WEA, and between allergen-induced and irritant-induced asthma. Against this background the needs for improved characterisation of work-related asthma, in the context of more appropriate regulation is discussed.

Biphasic anaphylaxis: A review of the literature and implications for emergency management

BACKGROUND

The biphasic reaction is a feared complication of anaphylaxis management in the emergency department (ED). The traditional recommended ED observation time is 4-6 h after complete resolution of symptoms for every anaphylaxis patient. However, there has been great controversy regarding whether this standard of care is evidence-based.

METHODS

Articles were selected using a PubMed, MEDLINE search for the keywords "biphasic anaphylaxis", yielding 155 articles. Articles were filtered by English language, and the keyword biphasic in the title. Case reports and case series were excluded, narrowing to 33 articles. Then, articles were filtered by relevance to the ED setting, and studies conducted in outpatient clinic settings were excluded, narrowing the search to 16 articles. All remaining articles were reviewed and findings were discussed.

RESULTS

The reported mean time to onset between the resolution of initial anaphylaxis and biphasic reaction ranges widely by study from 1 to 72 h with the majority of studies reporting the mean time to onset >8 h. A delay between anaphylaxis symptom onset and administration of epinephrine of 60-190 min was reported to correlate with biphasic anaphylaxis in three studies. Anaphylaxis requiring >1 dose of epinephrine to achieve symptom resolution was also reported to correlate with biphasic reactions in two studies. No definitive conclusions about the role of corticosteroids in preventing biphasic reactions can be made at this time however; a couple small studies have shown that they may decrease the incidence of biphasic reactions. Additional risk factors correlated with biphasic reaction vary widely between studies and the generalizability of these risk factors is questionable.

CONCLUSIONS

There is a need for further research to identify true risk factors associated with biphasic anaphylaxis and to clearly define the role of corticosteroids in biphasic reactions. However, given the low incidence and rare mortality of biphasic reactions, patients who receive epinephrine within one hour of symptom onset and who respond to epinephrine with rapid and complete symptom resolution can probably be discharged from the ED with careful return precautions and education without the need for prolonged observation.

Allergic and Nonallergic Rhinitis: Classification and Pathogenesis Part I. Allergic Rhinitis

Chronic rhinitis, although not life-threatening, substantially interferes with one's quality of life. Associated symptoms of nasal obstruction, sneezing, rhinorrhea, and anosmia afflict an estimated 40 million Americans. Directed clinical history and physical examination combined with noninvasive and routine procedures permit physicians to diagnose the myriad conditions causing rhinitis. Although the precise etiology of many of these conditions is only partially known, a practical diagnostic classification can be formulated based on clinical and laboratory findings. An understanding of the pathophysiology of allergic rhinitis as well as the other less understood entities provides the clinician with a integral foundation to implement preventative and therapeutic measures. This comprehensive review should provide the reader an opportunity to better understand and appreciate the causes and pathophysiology of chronic rhinitis. Part I of this article concentrates on IgE-mediated reactions, mediators, and drugs involved in allergic rhinitis. Part II focuses on the recent advances gained in understanding the nonallergic (non-IgE) causes of chronic rhinitis.

The Role of Soluble Interleukin-4 Receptor and Interleukin-5 Antibody in Preventing Late-Phase Allergy-Induced Eustachian Tube Dysfunction

OBJECTIVES: We investigated the role of soluble interleukin (IL)-4 receptors (sIL-4R) and IL-5 antibodies (IL-5Ab) in preventing allergic eustachian tube dysfunction (ETD) and middle ear effusion (MEE).

STUDY DESIGN: Brown-Norway rats were sensitized to ovalbumin (OVA) and challenged transtympanically. Two groups of rats received either IL-4R or IL-5Ab transtympanically 1 hour before challenge. Three additional groups were used as controls. Following the second transtympanic challenge, the ventilatory and clearance functions of the eustachian tube (ET) were assessed at 0, 2, and 8 hours. Histology was prepared using cut paraffin sections stained with hematoxylin and eosin.

RESULTS: sIL-4R-pretreated rats showed no significant changes in ventilatory or clearance functions of the ET or inflammatory changes in ET mucosa, whereas IL-5Ab pretreatment showed significant late ventilatory and clearance dysfunction as well as inflammatory mucosal changes.

CONCLUSION: These data demonstrate that the late-phase allergic inflammatory response that leads to subsequent formation of ETD and MEE is prevented by pretreatment with sIL-4R and, more modestly, with IL-5Ab.

Otitis media with effusion (OME) remains a significant problem in the pediatric population today. Despite advances in screening and treatment, the incidence has steadily risen over the past 20 years. It is now estimated that more than 80% of all children with have at least 1 episode of OME by age 3 and 40% will have 3 or more episodes. 1 Furthermore, earaches/ear infections represent the single greatest reason for a visit to the pediatrician after well-child visits. 2 Numerous studies have investigated the sequelae for children exposed to multiple episodes of OME, with conclusions ranging from no significant permanent deficits to impairments in receptive language skills, 1 balance and coordination, 3 and school readiness measures. 4

There remain several important controversies with regards to the pathogenesis and treatment of OME. One of these is the relationship between OME and allergy. A link between OME and allergy has existed for some time, 5 and one of the older empiric observations on the relationship between children with recurrent OME and allergy has resurfaced in recent years to explain the large number of patients with no other causative factor for fluid in the middle ear space. Bernstein 6 has demonstrated in a study of 100 patients with recurrent OME that almost a third can be attributed directly to allergy. Indeed, some consider this number a very conservative estimate. It is the intent of this study to examine the role of newer therapies such as antagonists to interleukin (IL)-4 and IL-5 for preventing the late-phase allergic reaction and their effect of preventing eustachian tube dysfunction and formation of middle ear effusion.

IL−4 and −5 are 2 of a host of mediators that comprise the late-phase allergic response. Produced by a variety of cell types, their principal functions are to control subsequent cascades that are a response to antigenic challenge. Tissue inflammation, edema formation, mucus production, and eosinophilia are controlled by these cytokines. Our hypothesis is that administration of antagonists of both IL−4 and IL−5, in the form of sIL-4R and IL−5Ab, respectively, will result in a decreased allergic response to challenged tissue.

The Inhibitory Effects of Low-Dose Ionizing Radiation in IgE-Mediated Allergic Responses

Ionizing radiation has different biological effects according to dose and dose rate. In particular, the biological effect of low-dose radiation is unclear. Low-dose whole-body gamma irradiation activates immune responses in several ways. However, the effects and mechanism of low-dose radiation on allergic responses remain poorly understood. Previously, we reported that low-dose ionizing radiation inhibits mediator release in IgE-mediated RBL-2H3 mast cell activation. In this study, to have any physiological relevance, we investigated whether low-dose radiation inhibits allergic responses in activated human mast cells (HMC-1(5C6) and LAD2 cells), mouse models of passive cutaneous anaphylaxis and the late-phase cutaneous response. High-dose radiation induced cell death, but low-dose ionizing radiation of <0.5 Gy did not induce mast cell death. Low-dose ionizing radiation that did not induce cell death significantly suppressed mediator release from human mast cells (HMC-1(5C6) and LAD2 cells) that were activated by antigen-antibody reaction. To determine the inhibitory mechanism of mediator released by low-dose ionizing radiation, we examined the phosphorylation of intracellular signaling molecules such as Lyn, Syk, phospholipase Cγ, and protein kinase C, as well as the intracellular free Ca²⁺ concentration ([Ca²⁺]_i). The phosphorylation of signaling molecules and [Ca²⁺]_i following stimulation of FcεRI receptors was inhibited by low dose ionizing radiation. In agreement with its in vitro effect, ionizing radiation also significantly inhibited inflammatory cells infiltration, cytokine mRNA expression (TNF-α, IL-4, IL-13), and symptoms of passive cutaneous anaphylaxis reaction and the late-phase cutaneous response in anti-dinitrophenyl IgE-sensitized mice. These results indicate that ionizing radiation inhibits both mast cell-mediated immediate- and delayed-type allergic reactions in vivo and in vitro.

Delayed-type hypersensitivity: activation of mast cells by antigen-specific T-cell factors initiates the cascade of cellular interactions

In delayed-type hypersensitivity reactions sensitized T cells orchestrate a cascade of cellular interactions. Initiation of these responses depends on a newly recognized event, namely the release of vasoactive mediators fiom mast cells that are activated by antigen-specific T-cell-derivedfactors. Here Philip Askenase and Henk Van Loveren discuss how this event initiates a sequence of steps that lead to T-cell recruitment of effector cells; and how this event differs from activation of mast cells by IgE antibody. They also suggest that the conventional time-based separation of immediate and delayed hypersensitivity should be replaced by a classcation based on the type of antigen-specific lymphocyte - B or T-responsible for the effects of hypersensitivity.

Local reactions from subcutaneous allergen immunotherapy

Local reactions from subcutaneous allergen immunotherapy are very common during the course of immunotherapy. These local reactions are not bothersome to patients. Local reactions from immunotherapy also do not predict future local or systemic reactions. This review discusses the studies that show that local reactions are not predictive of future reactions and that dose adjustments for local reactions from allergen immunotherapy are unnecessary. The article also focuses on factors that lead to patient noncompliance with immunotherapy and evaluates methods to prevent local reactions from subcutaneous allergen immunotherapy.

Deciphering the structure and function of FcεRI/mast cell axis in the regulation of allergy and anaphylaxis: a functional genomics paradigm

Allergy and anaphylaxis are inflammatory disorders caused by immune reactions mainly induced by immunoglobulin-E that signal through the high-affinity FcεRI receptor to release the inflammatory mediators from innate immune cells. The FcεRI/mast cell axis is potently involved in triggering various intracellular signaling molecules to induce calcium release from the internal stores, induction of transcription factors such as NF-kB, secretion of various cytokines as well as lipid mediators, and degranulation, resulting in the induction of allergy and anaphylaxis. In this review, we discuss various cellular and molecular mechanisms triggered through FcεRI/mast cell axis in allergy and anaphylaxis with a special emphasis on the functional genomics paradigm.

Parthenium the terminator: An update

Parthenium dermatitis is a distressing dermatitis caused by the air borne allergen of the Compositae weed Parthenium hysterophorus. Uncommon presentations, newer insights in pathogenesis and management of this "scourge" are discussed in this article.

High-affinity IgE receptors on dendritic cells exacerbate Th2-dependent inflammation

The IgE-mediated and Th2-dependent late-phase reaction remains a mechanistically enigmatic and daunting element of human allergic inflammation. In this study, we uncover the FcεRI on dendritic cells (DCs) as a key in vivo component of this form of allergy. Because rodent, unlike human, DCs lack FcεRI, this mechanism could be revealed only by using a new transgenic mouse model with human-like FcεRI expression on DCs. In the presence of IgE and allergen, FcεRI(+) DCs instructed naive T cells to differentiate into Th2 cells in vitro and boosted allergen-specific Th2 responses and Th2-dependent eosinophilia at the site of allergen exposure in vivo. Thus, FcεRI on DCs drives the cascade of pathogenic reactions linking the initial allergen capture by IgE with subsequent Th2-dominated T cell responses and the development of late-phase allergic tissue inflammation.

Subcutaneous late phase responses are augmented during local inhalational tolerance in a murine asthma model

Acute exposure of sensitized mice to antigen elicits allergic airway disease (AAD) characterized by Th2 cytokine-dependent pulmonary eosinophilia, methacholine hyperresponsiveness and antigen-specific IgE elevation. However, chronic exposure induces a local inhalational tolerance (LIT), with resolution of the airway responses but persistent systemic IgE production. To further determine if systemic immunologic responses were maintained during LIT, we assessed subcutaneous late phase responses to ovalbumin in this model. Sensitized and AAD mice developed small subcutaneous responses to ovalbumin, with footpad thickness increasing to 113.7 and 113.6% of baseline, respectively. In comparison, LIT mice developed marked foot swelling (141.6%). Histologic examination confirmed increased inflammation in the chronic animals, with a significant contribution by eosinophils. Thus, the resolution of airway inflammatory responses with chronic antigen inhalation is a localized response, not associated with loss of systemic responses to antigen.

Understanding allergic asthma from allergen inhalation tests

The allergen challenge has evolved, in less than 150 years, from a crude tool used to document the etiology of allergen-induced disease to a well-controlled tool used today to investigate the pathophysiology and pharmacotherapy of asthma. Highlights of the authors' involvement with the allergen challenge include confirmation of the immunoglobulin E-dependence of the late asthmatic response, importance of (nonallergic) airway hyper-responsiveness as a determinant of the airway response to allergen, identification of allergen-induced increase in airway hyper-responsiveness, documentation of beta(2)-agonist-induced increase in airway response to allergen (including eosinophilic inflammation), advances in understanding the pathophysiology and kinetics of allergen-induced airway responses, and development of a multicentre clinical trial group devoted to using the allergen challenge for investigating promising new therapeutic strategies for asthma.

Anti-IgE and other antibody targets in asthma

Asthma is a heterogeneous disorder of unknown etiology that manifests as recurrent episodes of coughing, wheezing, and breathlessness. These symptoms are often debilitating and exacerbations usually are unexpected, resulting in work or school absences, limitations in activity, reduced quality of life, and personal and economic hardships. Over the past several decades, a great deal has been learned about asthma pathophysiology, and currently available therapies have revolutionized asthma treatment. However, asthma remains a global public health problem, and the hope is that newer therapies targeting specific biological mediators of asthma, particularly antibody-mediated therapies, offer exciting new modes to the control of this disease. We will review some of these therapies, with the majority of attention devoted to anti-IgE therapy which has been approved for treatment of adult and childhood asthma by the US Food and Drug Administration (FDA) since 2003.

IgEb immune complexes activate macrophages through FcgammaRIV binding

Because functional analysis of Fc receptors (FcRs) relies heavily on mouse models, the identification of another Fcgamma receptor is particularly noteworthy. We demonstrate that FcgammaRIV, identified here as the mouse ortholog of primate FcgammaRIII, required association of the FcR gamma-chain for optimal expression and function on myeloid cells; its signaling potential was also enhanced by a cytoplasmic 'YEEP' motif that was able to recruit the adaptor molecule Crk-L and phosphatidylinositol-3-OH kinase. Unexpectedly, FcgammaRIV 'preferentially' bound immunoglobulin E antibodies of the 'b' allotype (IgE(b)) as well as IgG2a and IgG2b antibodies. Ligation of FcgammaRIV by antigen-IgE(b) immune complexes promoted macrophage-mediated phagocytosis, presentation of antigen to T cells, production of proinflammatory cytokines and the late phase of cutaneous allergic reactions. IgE(b) antibody-mediated modification of macrophage responses may therefore influence mouse asthma models and strain-dependent differences in parasite susceptibility.

Biphasic anaphylaxis: review of incidence, clinical predictors, and observation recommendations

Biphasic anaphylactic reactions have been found to develop in as many as 20% of anaphylactic reactions. The biphasic reaction can be less severe, equally severe, or more severe than the initial reaction, ranging in degree from mild symptoms to fatal reactions. In this review, retrospective and prospective studies as well as case studies and case series are discussed in an attempt to gain insight on the incidence of biphasic reactions, the potential clinical characteristics suggestive of a uniphasic reaction developing into a biphasic reaction, and the recommendations for observation periods after an anaphylactic reaction.

Biphasic anaphylactic reactions

OBJECTIVE

To examine the impact of the second phase of a biphasic response on the required observation time after resolution of symptoms that occurred during the initial phase.

DATA SOURCES

We performed a MEDLINE search of the literature for studies published between January 1970 and January 2005 on biphasic response using the keywords anaphylaxis, biphasic anaphylaxis, late phase reaction, and early phase reaction.

STUDY SELECTION

Prospective studies, retrospective studies, and case reports were selected for inclusion in this review.

RESULTS

The incidence of biphasic anaphylactic reactions as described in the literature is highly variable, ranging from a low of 1% to a high of 20% of episodes. There is no clear consensus regarding distinguishing features of the primary response that predicts the occurrence of a secondary response. However, the severity of the reaction, the time of onset after administration of antigen before the occurrence of symptoms of the primary response, the presence of hypotension or laryngeal edema during the primary response, and the history of a previous biphasic reaction have all been mentioned as risk factors in various studies. The severity of the late-phase reaction is highly variable, and events have ranged from mild to severe with rare fatalities. Most late-phase reactions, however, are mild to moderate in severity. A delay in the administration of epinephrine and too small a dose of epinephrine given for the primary response have also been mentioned as risk factors. It is unclear whether corticosteroids given for the primary event can prevent or ameliorate the second reaction.

CONCLUSIONS

Biphasic responses occur with significant frequency and therefore should be taken into consideration when one considers the observation period after the initial event. An observation period of 8 hours is sufficient for most reactions, but since reactions can occur as long as 72 hours after resolution of the primary event, some authors have recommended a 24-hour waiting period.

Evaluation of the precision of intradermal injection of control substances for intradermal testing in clinically normal horses

OBJECTIVE

To evaluate the precision of intradermal testing (IDT) in horses.

ANIMALS

12 healthy adult horses.

PROCEDURE

IDT was performed on the neck of each horse by use of 2 positive control substances (histamine and phytohemagglutinin [PHA]) and a negative control substance. An equal volume (0.1 mL) for each injection was prepared to yield a total of 20 syringes ([4 concentrations of each positive control substance plus 1 negative control substance] times 2 positive control substances times 2 duplicative tests) for each side of the neck. Both sides of the neck were used for IDT; therefore, 40 syringes were prepared for each horse. Hair was clipped on both sides of the neck, and ID injections were performed. Diameter of the skin wheals was recorded 0.5, 4, and 24 hours after ID injection.

RESULTS

Intra- and interhorse skin reactions to ID injection of histamine and PHA resulted in wheals of uniform size at 0.5 and 4 hours, respectively. Significant intra- and interhorse variation was detected in wheals caused by PHA at 24 hours.

CONCLUSIONS AND CLINICAL RELEVANCE

ID injection of histamine and PHA caused repeatable and precise results at 0.5 and 4 hours, respectively. Concentrations of 0.005 mg of histamine/mL and 0.1 mg of PHA/mL are recommended for use as positive control substances for IDT in horses. This information suggests that consistent wheal size is evident for ID injection of control substances, and variation in wheals in response to ID injection of test antigens results from a horse's immune response to specific antigens.

Anti-IgE antibodies for the treatment of asthma

PURPOSE OF REVIEW

Allergic asthma is a hypersensitivity reaction initiated by immunologic mechanisms mediated by IgE antibodies. IgE plays a central role in the initiation and propagation of the inflammatory cascade and thus the allergic response. Targeting factors involved in the allergic response, such as IgE, is a novel strategy for new therapies. Attenuating allergic disease by specifically inhibiting IgE and the development of the monoclonal anti-IgE antibody, omalizumab, were major breakthroughs in asthma management.

RECENT FINDINGS

Several studies have shown that omalizumab has significant anti-inflammatory effects and that it may act on multiple components of the inflammatory cascade. Specific binding of IgE by omalizumab reduces both the early allergic response and the late allergic response and symptoms of IgE-mediated allergy. The long-term clinical efficacy of omalizumab has been demonstrated along with improvements in quality of life. As add-on therapy in severe asthma, omalizumab reduces the requirement for inhaled corticosteroids and improves disease control. Clinical studies have shown that the patients who benefit most from omalizumab therapy are those at high risk of exacerbations, those with poorly controlled and/or severe asthma, and those with IgE-mediated comorbidities.

SUMMARY

Omalizumab is a significant addition to current asthma treatments and shows great promise as a therapy for allergic asthma and for patients with concomitant allergic rhinitis. This is particularly true for difficult-to-treat patients with moderate to severe allergic asthma who have poorly controlled disease on conventional therapies, experience severe adverse effects secondary to high-dose or prolonged corticosteroid treatment, have frequent exacerbations, and/or are at high risk of hospitalization. Future studies will continue to investigate the anti-inflammatory mechanisms of anti-IgE therapy. Because many of these mechanisms are common to all IgE-mediated allergic diseases, the efficacy of omalizumab in other allergic diseases should be further explored.

Reassessing the Th2 cytokine basis of asthma

T helper (Th) 2 cytokines, particularly interleukin 4 (IL-4), IL-5 and IL-13, might be important in the development of allergic asthma. Humanized monoclonal antibodies (hMAbs) against IL-5, and a recombinant soluble human IL-4 receptor have been developed as possible treatments for this disorder. However, these approaches have not yet proven to be successful in the treatment of persistent asthma, suggesting that neither IL-4 nor IL-5 is important in asthma pathogenesis. Indeed, there is insufficient information about the efficacy of soluble IL-4 receptor and the anti-IL-5 hMAbs in the treatment of asthma to draw firm conclusions about the importance of these Th2 cytokines. Nevertheless, because IL-4 is required for IgE production and IL-5 is required for eosinophilopoesis, these Th2 cytokines must remain important candidates for a role in the pathogenesis of allergic asthma.

Cutaneous hypersensitivity reactions to Psoroptes ovis and Der p 1 in sheep previously infested with P. ovis--the sheep scab mite

We have previously shown that infestation with Psoroptes ovis induces an IgE response and intense tissue eosinophilia, typical of a Type I hypersensitivity response [Parasite Immunol. 22 (2000) 407]. Intradermal tests (IDSTs) suggest that there are also delayed and Arthus-type responses to this parasite. In order to study the nature of ovine cutaneous reactions to P. ovis, naïve controls and experimentally infested sheep (n = 5) were challenged intradermally with mite antigen. Challenge elicited immediate (P < 0.001) and delayed (P < 0.005) wheal reactions in sensitised sheep. At 6 (P < 0.02) and 30 h (P < 0.001) the predominant infiltrating cells were eosinophils. To explore the role of circulating antibodies, naïve sheep (n = 5) were subjected to Prausnitz-Kustner (PK) tests. These elicited immediate (P < 0.02) but not delayed wheal reactions. At 6 h eosinophils (P < 0.001) dominated the infiltrate. These results suggest that P. ovis allergens provoke an IgE-dependent immediate and late phase response and a cell-mediated eosinophil-rich delayed-type hypersensitivity response (ER-DTH).

The combined effect of topical CX-659S, a novel diaminouracil derivative, with topical corticosteroid on the three types of allergic responses in mice or guinea pigs

CX-659S ((S)-6-amino-5-(6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxamido)-3-methyl-1-phenyl-2,4(1H,3H)-pyrimidinedione), a newly discovered anti-inflammatory compound, exerts inhibitory effects against picryl chloride-, oxazolone-, and dinitrochlorobenzene-induced acute contact hypersensitivity responses (CHRs) characterized by Th1-type reactions. Furthermore, this compound suppressed chronic CHRs characterized by Th2-type reactions, which is well known to mimic many, if not all, events occurring within the lesional skin of patients with atopic dermatitis (AD). The present study was conducted to determine the combined effect of topical CX-659S with topical corticosteroid on immediate type (ITR), late type (LTR), and delayed type hypersensitivity (DTHR) allergic reactions that are involved in AD. An ineffective dose of CX-659S (0.03 mg/ear) combined with betamethasone valerate (BV) significantly potentiated inhibitory activity of BV alone (0.1 micro g/ear and 0.3Shizuokag/ear) on both the ITR and the LTR in mice with the ovalbumin (OVA)-induced biphasic cutaneous reaction. Furthermore, the combined effect of CX-659S with BV was also observed on dinitrochlorobenzene (DNCB)-induced DTHR in guinea pigs. These results indicate that CX-659S has a combined effect with corticosteroids on every ITR, LTR, and DTHR. Proper treatment with corticosteroids for a safe and effective treatment of AD is needed. Thus, the combination therapy of topical CX-659S with topical corticosteroid would be one of the potential approaches for devising a proper treatment with corticosteroids.

Inhibition of allergic dermal inflammation by the novel imidazopyridazine derivative TAK-427 in a guinea pig experimental model of eczema

Antigen challenge by patch ovalbumin emulsion induced an eczema-like skin lesion in epicutaneously sensitized guinea pigs. Diseased skin sites were macroscopically characterized by manifestations of dermatitis, such as erythema, edema, and papules, and microscopically characterized by acanthosis, spongiosis, and dermal infiltration by eosinophils. Using such lesions as a model of eczema, we evaluated the potential value of TAK-427 [2-[6-[[3-[4-(diphenylmethoxy)piperidino]propyl]amino] imidazo[1,2-b]pyridazin-2-yl]-2-methylpropionic acid dihydrate] as a therapeutic agent for atopic dermatitis by comparing it with dexamethasone and antihistamines. TAK-427 (0.3-30 mg/kg, p.o.) and dexamethasone (3 and 10 mg/kg, p.o.) inhibited eosinophil infiltration into the skin and ameliorated the dermatitis manifestations and epidermal damage. By contrast, none of the antihistamines tested (azelastine, ketotifen, terfenadine, and cetirizine) suppressed the eosinophil infiltration or dermatitis manifestations. To elucidate the mechanism by which TAK-427 inhibited the development of eczema, we investigated cytokine expression in the affected skin. Both TAK-427 and dexamethasone suppressed the increased mRNA expression of interleukin (IL)-13, granulocyte-macrophage colony-stimulating factor, IL-1alpha, tumor necrosis factor-alpha, interferon-gamma, and IL-8, but not IL-10, suggesting that TAK-427 inhibits allergic inflammation of the skin leading to the development of eczema by inhibiting the expression of proinflammatory cytokines after antigen challenge.

[Role of aeroallergens in the etiopathogenesis of atopic dermatitis]

Atopic dermatitis is a chronic relapsing inflammatory skin disease. It is most frequent in childhood and its clinical manifestations vary with age. The etiopathogenic mechanisms that explain this process are still poorly understood; several studies performed in adults speculate on the possible role of aeroallergens through direct contact with the skin but, because the etiology of this disease varies with age, studies in children of different ages are required.

AIMS

(i) To determine whether children with atopic dermatitis are sensitized to inhalant allergens. (ii) To determine whether these inhalant allergens cause dermatitis or whether they provoke allergic respiratory disease (asthma, rhinitis) concomitant with atopic dermatitis. (iii) To evaluate whether sensitization to a particular allergen takes place at any age or whether there are differences according to age.

MATERIAL AND METHODS

This study was performed in the following groups: (i) 64 children with atopic dermatitis, divided into two subgroups, one consisting of 37 children who also presented allergic respiratory disease (asthma, rhinitis) (AR) and another subgroup of 27 patients who presented atopic dermatitis only. (ii)

CONTROL GROUP

eight children who presented AR only, to determine whether this group reacted to patch testing with inhalant allergens. (iii)

CONTROL GROUP

seven healthy children to rule out non-specific positive tests in the non-atopic population. All groups were divided by age according to the phases of atopic dermatitis: early childhood phase (< 2 years): 21, childhood phase (2-10 years): 37, adolescent phase (> 10 years): 21. In all children total serum IgE determination (RIA), allergen-specific IgE determination (RAST), prick- and patch test were performed. In the three tests the same allergens were used, consisting of the usual components of standardized inhalant and food allergens. When the results of patch testing were positive, biopsy and histopathological analysis were performed and monoclonal antibodies were used to determine reproducibility of the eczematous lesion.

RESULTS

Sensitization was found to differ among patients with atopic dermatitis according to whether they presented respiratory symptoms and according to age with a clear predominance of food sensitization in the group aged less than 2 years. In the group aged 2-10 years, mixed sensitization predominated, mainly because of simultaneous respiratory involvement, but it is highly probably that inhalant allergens participate in the etiopathogenesis of atopic dermatitis. In children aged more than 10 years sensitization to inhalant allergens predominated as most presented respiratory symptoms. Patch testing was positive in 34.3 % of patients with atopic dermatitis and approximately half were positive to dust mites. The patch test is of great diagnostic value in atopic dermatitis and none of the tests were positive in the control group. All the biopsies of patch tests with inhalant allergens reproduced the lesions typical of eczema, demonstrating their involvement in the etiopathogenesis of dermatitis.

Late-phase reactions to intradermal testing with Dermatophagoides farinae in healthy dogs and dogs with house dust mite-induced atopic dermatitis

OBJECTIVE

To determine the prevalence of late-phase reactions to intradermal testing with Dermatophagoides farinae in healthy dogs and dogs with atopic dermatitis and an immediate reaction to D farinae.

ANIMALS

6 healthy dogs and 20 dogs with atopic dermatitis and immediate reactions to D farinae.

PROCEDURE

ntradermal tests were performed with D farinae at 1:1,000 wt/vol and 1:50,000 wt/vol concentrations, and skin reactivity was evaluated after 0.25, 6, and 24 hours. Serum D farinae-specific IgE antibodies were assayed. Extent of lesions (atopy index) and pruritus (visual analogue scale) were evaluated in dogs with atopic dermatitis.

RESULTS

Late-phase reactions were observed in healthy dogs at 6 hours (n = 2 dogs) and 24 hours (1) with the 1:1,000 wt/vol concentration, and at 6 hours (1) and 24 hours (1) with the 1:50,000 wt/vol concentration of allergen. Late-phase reactions in healthy dogs were only observed in dogs with an immediate reaction to D farinae. Late-phase reactions were observed in 11 of 20 dogs with atopic dermatitis at 6 and 24 hours with the 1:1,000 wt/vol concentration and in 10 of 20 at 6 and 24 hours with the 1:50,000 wt/vol concentration of allergen. There was no difference in mean atopy index, mean visual analogue scale of pruritus, or mean serum D farinae-specific IgE concentration of dogs with a late-phase reaction, compared to dogs without a late-phase reaction.

CONCLUSIONS AND CLINICAL RELEVANCE

Late-phase reactions may be observed after an immediate reaction to intradermal skin testing in healthy and allergic dogs but are more commonly observed in dogs with atopic dermatitis.

Desensitization to urine-derived gonadotropins in a woman with secondary infertility

BACKGROUND

Urine-derived gonadotropins have been used to treat infertility but may cause allergic reactions. IgE-mediated hypersensitivity reactions can be treated with desensitization, especially when new therapies such as recombinant human gonadotropins are unavailable.

OBJECTIVE

This case is described to highlight a successful intervention with desensitization in a woman with a complicated history of secondary infertility. She had been treated with ovulation-induction regimens, such as IVF-M (in vitro fertilization-human menopausal gonadotropin [hMG]) and IVF-C (human chorionic gonadotropin [hCG]), for intrauterine insemination. During treatment, however, she experienced reactions to IVF-M and IVF-C. Because she strongly wanted a baby and no alternative preparation was available, desensitization was attempted.

METHODS

Intradermal tests with IVF-M and IVF-C using both negative and positive controls were performed on the patient and four normal control subjects. Immediate wheal-and-flare reactions occurred only in the patient. ELISA and ELISA inhibition tests showed positive responses to IVF-M and IVF-C, but not to highly purified hMG, hCG, or D-mannitol, a preservative in IVF-M and IVF-C. Desensitization to IVF-M and IVF-C was done with a protocol used for parenteral desensitization to penicillin.

RESULTS

During the IVF-M desensitization, the intramuscular injections were well tolerated. For the next 2 days, daily administration of IVF-M was uneventful. Thirty-six hours later, desensitization to IVF-C was performed successfully. The patient had two intrauterine inseminations and became pregnant.

CONCLUSIONS

Nongonadotropin proteins in urine-derived gonadotropins cause IgE-mediated hypersensitivity reactions. Acute desensitization to urine-derived gonadotropins can be performed effectively, as shown in our current case.

A comparison of allergen and polycation induced cutaneous responses in the rabbit

Allergic inflammatory responses contribute to the symptoms of a number of diseases including atopic dermatitis, asthma and rhinitis. Cationic proteins are released from inflammatory cells and levels are known to be raised in disease states. Using an in vivo model of acute inflammation, we investigated the characteristics of cutaneous responses to antigen (Alternaria tenuis, AT) and poly-L-lysine (PLL, used as a paradigm for cationic proteins). We aimed to compare the inflammatory profile of cationic polypeptides and the allergic response and to identify similarities and differences between these responses. Responses to intradermal injection of the polycation, PLL and antigen were compared using radiolabelled protein ((125)I-bovine serum albumin, BSA) and cells ((111)In-neutrophils, PMN) to study plasma exudation (PE) and PMN accumulation (PMNA) in the skin of AT sensitized rabbits. Both PLL and antigen caused dose-related increases in PE and PMNA. PE (and PMNA) responses to PLL were prolonged (up to 3 h), as were those to antigen. This is in contrast to PE responses to fMLP which were maximal at 45 min. In immunized animals, treated with colchicine (1 mg kg(-1) i.v.), PE responses to the directly acting mediator, bradykinin (BK), were not affected, whereas PE responses to the neutrophil dependent mediator, f-met-leu-phe (fMLP), were significantly (P<0.01) reduced. Antigen-induced PE responses were significantly (50, 500 (P<0.05); 200 (P<0.01) p.n.u. site(-1)) inhibited by colchicine, but PLL-induced responses were not significantly affected. We conclude that although PLL-induced responses had a similar time course to those of antigen, some differences were observed between responses, which indicate that although polycations may contribute to allergic responses, these two responses are produced by distinct mechanisms.

A Kampo formulation: Byakko-ka-ninjin-to (Bai-Hu-Jia-Ren-Sheng-Tang) inhibits IgE-mediated triphasic skin reaction in mice: the role of its constituents in expression of the efficacy

We have demonstrated that oral administration of a Kampo formulation, Byakko-ka-ninjin-to (Bai-Hu-Jia-Ren-Sheng-Tang), inhibited IgE-mediated triphasic skin reaction, including immediate phase response (IPR), late phase response (LPR) and very late phase response (vLPR), in passively sensitized mice with anti-DNP IgE antibody. Variant formulations of Byakko-ka-ninjin-to without Gypsum Fibrosum (Sekko), Glycyrrhizae Radix (Kanzo) or Oryzae Semen (Kobei) attenuated the inhibitory effect as compared with that of Byakko-ka-ninjin-to. The decreased effect of Byakko-ka-ninjin-to without Kanzo was restored by the addition of Kanzo to the variant formulations before oral administration, while the decreased effect of Byakko-ka-ninjin-to without Sekko could not be recovered by the addition of Sekko. Comparison of HPLC profiles of variant formulations without one crude drug with that of original Byakko-ka-ninjin-to revealed that some peaks could be detected only when five constituent crude drugs were simultaneously present during the preparation of Byakko-ka-ninjin-to formulation. Since elimination of Sekko from the Byakko-ka-ninjin-to constituents attenuated the efficacy although it did not show any activity per se, mutual interaction of Sekko with other constituents during the preparation may result in the production of new components. These findings suggest that the effect of Byakko-ka-ninjin-to formulation on cutaneous inflammatory disease can differ from the sum of the effect of the individual constituents.

Antigen-specific IgE and IgA antibodies in bronchoalveolar lavage fluid are associated with stronger antigen-induced late phase reactions

The mechanism(s) leading to the development of late phase allergic reactions is (are) unknown. Previous studies have indicated that a relationship between serum IgE and the late phase exists. To explore the relationships between allergen-specific immunoglobulins in bronchoalveolar lavage (BAL) fluids and the magnitude of airflow limitation during the late phase response to inhaled allergen. Ragweed-specific IgE, IgA, secretory IgA (sIgA) and IgG were measured in BAL fluid and in the serum 1-5 weeks before whole lung antigen challenge with ragweed extract, in 16 ragweed allergic asthmatics. In addition, BAL and serum eosinophil cationic protein (ECP) and BAL fibrinogen levels were determined and BAL cells counted and differentiated. The latter procedures were repeated in a second BAL performed 24 h after the end of the ragweed challenge. After the challenge, lung function was monitored hourly for 8 h, to record the magnitude of airflow limitation. Ragweed-specific immunoglobulins were detected in 25% to 37.5% of BAL samples. Compared to the subjects with undetectable BAL fluid ragweed-specific IgE levels at baseline, those with detectable antibodies had stronger late phase reactions as determined by the nadir of FEV1 between hours 4 and 8 after the ragweed inhalation challenge (P = 0.0007). Allergen-induced changes in BAL ECP and fibrinogen levels were also higher in those subjects with detectable ragweed-specific IgE in baseline fluids (P = 0.03 and P = 0.005, respectively). Significant relationships between BAL antigen-specific IgA, serum ragweed-specific IgE and IgA and the late phase reaction were also found. The results of this study point towards the possibility that allergen-specific IgE and IgA may be independently involved in the pathogenesis of the late phase reaction. This notion merits further exploration.

Role of selectins on IgE-mediated skin reaction

Selectins play an important role on leukocytes infiltration into inflammatory tissues. To understand the role of selectins, we investigated the effects of selectin-IgG chimeras and anti selectin antibodies on the murine IgE-mediated skin inflammation model. Biphasic skin reactions were induced by intradermal challenge with ovalbumin (OA) to ears of actively sensitized mice. This reaction was characterized by immediate and late phase responses observed as which were induced via a rapid increase in capillary permeability and leukocyte infiltration, respectively. The expression of E-selectin mRNA was significantly increased to reach its highest level at 2 h after OA challenge. E-, P-, and L-selectin-IgG chimeras inhibited the late phase responses, i.e. ear swelling, neutrophil infiltration and eosinophil infiltration at 24 h after OA challenge in a dose-dependent manner at dose range of 0.1 - 10 mg kg(-1), i.v. Antiselectin antibodies did not inhibit the increase of ear swelling. But anti E- and P-selectin antibodies significantly inhibited neutrophil infiltration and eosinophil infiltration. These results indicate that selectins play an important role on the late phase response of the murine IgE-mediated skin inflammation model by mediating inflammatory cell adhesion to endothelium.

Tear and conjunctival changes during the allergen-induced early- and late-phase responses

BACKGROUND

Allergic eye disease is common, but little is known about the underlying disease mechanisms. Conjunctival allergen challenge causes symptoms similar to those of seasonal allergic conjunctivitis and is a useful model to study.

OBJECTIVE

We have used allergen challenge to investigate the course of the ocular response, tear inflammatory mediators, tissue adhesion protein expression, and cellular infiltration.

METHODS

Eighteen atopic patients and 4 nonatopic control subjects were challenged with extracted mixed grass or Dermatophagoides pteronyssinus in one eye and control vehicle in the other. The clinical response was recorded, and tears were collected over a 6-hour period. Conjunctival biopsy specimens were taken from the challenged eye at 6 or 24 hours.

RESULTS

An early-phase response (maximal at 20 minutes) showed a significant increase in tear histamine and tryptase levels, reducing to control levels again by 40 minutes. At 6 hours, a late-phase response occurred with increased symptoms, a second peak of tear histamine and eosinophil cationic protein but not tryptase, upregulation of the adhesion molecules E-selectin and intercellular adhesion molecule, and a cellular infiltrate of mast cells, neutrophils, eosinophils, macrophages, and basophils, with T cells increased only in bulbar biopsy specimens.

CONCLUSIONS

The early peaks of tear histamine plus tryptase indicate that the mast cell is responsible for the early-phase response, but basophils may be involved in the late-phase response. Both tear and biopsy findings underline the significance of the late-phase response as the transition between a type I response and clinical disease.

Ligation of IgE receptors causes an anaphylactic response and neutrophil infiltration but does not induce eosinophilic inflammation in mice

BACKGROUND

Eosinophils are selectively recruited into the tissues during chronic allergic inflammation. IgE is considered an initiator of the allergic reaction; however, the roles of IgE in allergic inflammation are not fully understood.

OBJECTIVE

We tested the hypothesis that antigen interaction with specific IgE antibody provokes eosinophilic inflammation.

METHODS

BALB/c mice were actively sensitized with ragweed extract and passively sensitized with anti-dinitrophenyl (anti-DNP) mouse IgE and challenged intraperitoneally by injecting either ragweed extract or DNP-ovalbumin (OVA). Immediate anaphylactic responses were examined by monitoring vascular permeability and by measuring histamine content in peritoneal lavage fluids. Late-phase allergic responses were examined by total cell counts and cell differentials.

RESULTS

Mice sensitized and challenged with ragweed showed immediate anaphylactic responses followed by temporal increases in neutrophils at 3 to 12 hours and sustained increases in eosinophils in their peritoneal cavities after 24 hours. Double-sensitized mice (ie, sensitized actively for ragweed and passively for DNP-OVA) challenged with ragweed showed immediate anaphylactic responses and peritoneal eosinophilia at 48 hours. Double-sensitized mice challenged with DNP-OVA showed comparable immediate anaphylactic responses but no peritoneal eosinophilia. Furthermore, at 8 hours, ragweed-challenged animals recruited both eosinophils and neutrophils, but DNP-OVA-challenged animals recruited only neutrophils. Finally, after active sensitization and challenge with ragweed, mast cell-deficient mice (WBB6F1-W/W(v)) lacked the immediate response but showed comparable eosinophil accumulation as their litter mate controls (WBB6F1-+/+).

CONCLUSION

Interaction of antigen with IgE antibody is insufficient to provoke eosinophilic inflammation in mice.

Sequential patterns of inflammatory events during developing and expressed skin late-phase reactions

BACKGROUND

Although there has been much study of the histologic features of the late-phase reactions (LPR) seen 6 to 24 hours after intradermal injection of allergens, much less is known about the events occurring during development of such LPR.

OBJECTIVE

Our purpose was to compare sequential gross and histologic inflammatory responses during developing skin LPR within 6 hours after challenge.

METHODS

Gross reactions were measured and biopsy specimens obtained at 20 minutes and 1, 2, and 6 hours after intradermal allergen (Ag) and buffer diluent control (B) injections in 7 atopic subjects with known immediate and LPR. Inflammatory cell responses were compared, as detected by immunohistochemistry in Ag and B sites. These findings were then compared with those at 24 hours.

RESULTS

Gross LPR evolved without a hiatus from the immediate wheal responses over the next 6 hours (P =.04 vs that in B sites) and then decreased by 24 hours. Prominent PMN accumulation started by 20 minutes, peaking at 1 hour (P <.01). Eosinophil accumulation was significant, starting at 1 hour (P <.001) and peaking at 6 hours (P < .001). Many eosinophils were activated (EG(2)(+)). T-cell accumulation started at 2 hours (P =.01) and was most prominent at 24 hours. The frequency of vessels expressing E-selectin increased at 1 hour (P <.005), correlating with the degree of local PMN accumulation. The frequency of vessels expressing vascular cell adhesion molecules started increasing at 6 hours (P = .02), well after eosinophil accumulation was prominent.

CONCLUSIONS

Skin LPR is characterized by evolution of a gross indurated reaction from the immediate whealing response over the first 6 hours after intradermal Ag challenge, with an early accumulation of PMN and eosinophils, not directly attributable to lymphocyte entry or vascular cell adhesion molecule expression. Likely, multiple other factors may also play roles in the complex pathogenesis of LPR.

Isolated late cutaneous reactions to allergen skin testing in children

BACKGROUND

Occasionally parents report a reaction developing at the site of an allergen skin test several hours after application of the test, despite there having been no immediate reaction. The medical literature contains little information regarding isolated late reactions (ILRs) to allergen skin testing.

OBJECTIVE

The goal of this project was to determine the incidence of ILRs in children undergoing allergen skin testing.

METHODS

Prick and intradermal (ID) skin testing was performed for routine clinical indications in an allergy clinic. Children with a positive histamine control, and at least one negative immediate reaction to allergen skin testing were enrolled in the study. The parents were given detailed instructions to examine the skin test sites 6 hours later, and to record the size of any erythematous indurated sites. Circles of various diameters were included on the report form to assist the parents' size estimates.

RESULTS

Fifty-seven children enrolled in the study and 50 returned the forms. No patients reported ILRs to prick skin tests. Eighteen of the 50 respondents reported 40 ILRs to ID tests, of > or = 5 mm diameter; 7 of these were > or = 10 mm. The most common allergen causing ILR was cockroach, accounting for 20% of the ILRs. Each of the other allergens also caused ILRs. The clinical history did not show a definite correlation of symptoms with exposure to the allergens causing ILRs, although all 14 patients with ILRs to indoor allergens had year-round symptoms. There was no correlation between the incidence of ILRs and age, gender, or diagnosis of asthma.

CONCLUSION

ILRs to allergen skin testing occurred in 36% of pediatric allergy clinic patients. The clinical significance of such reactions is unknown.

Effect of Shimotsu-to (a Kampo medicine, Si-Wu-Tang) and its constituents on triphasic skin reaction in passively sensitized mice

Previous studies have reported that mice passively sensitized with anti-DNP (dinitrophenol) IgE antibody exhibited IgE-mediated skin reaction with an immediate phase response (IPR) at 1 h and a late phase response (LPR) at 24 h after the challenge of DNFB (dinitrofluorobenzene). We recently found that a third phase inflammatory reaction with intense and persisting infiltration of eosinophils, named very late phase response (vLPR), was induced by DNFB challenge peaking at 8 days. In this study, we examined the effects of a Kampo medicine, Shimotsu-to (Si-Wu-Tang), and its constituent crude drugs on triphasic skin reaction in passively sensitized mice. Shimotsu-to inhibited ear swelling in LPR and vLPR after DNFB challenge in a dose-dependent manner, and slightly diminished the scratching behavior considered to be associated with pruritus in IPR. The inhibitory effect on LPR and vLPR was partly due to Cnidii Rhizoma (Senkyu) in Shimotsu-to formulation, especially its fraction 5 containing cnidilide. On the other hand, Angelicae Radix (Toki) rather than Cnidii Rhizoma (Senkyu) in Shimotsu-to, inhibited the scratching behavior, although it did not inhibit the ear swelling in IPR. These findings indicate that the Shimotsu-to formulation is useful for the inhibition of cutaneous inflammatory diseases.