Selection of patients for aspirin desensitization treatment

Nanosized aspirin-Arg-Gly-Asp-Val: delivery of aspirin to thrombus by the target carrier Arg-Gly-Asp-Val tetrapeptide

Resistance and nonresponse to aspirin dramatically decreases its therapeutic efficacy. To overcome this issue, a small-molecule thrombus-targeting drug delivery system, aspirin-Arg-Gly-Asp-Val (A-RGDV), is developed by covalently linking Arg-Gly-Asp-Val tetrapeptide with aspirin. The 2D ROESY NMR and ESI-MS spectra support a molecular model of an A-RGDV tetramer. Transmission electron microscopy images suggest that the tetramer spontaneously assembles to nanoparticles (ranging from 5 to 50 nm in diameter) in water. Scanning electron microscopy images and atomic force microscopy images indicate that the smaller nanoparticles of A-RGDV further assemble to bigger particles that are stable in rat blood. The delivery investigation implies that in rat blood A-RGDV is able to keep its molecular integrity, while in a thrombus it releases aspirin. The in vitro antiplatelet aggregation assay suggests that A-RGDV selectively inhibits arachidonic acid induced platelet aggregation. The mechanisms of action probably include releasing aspirin, modifying cyclic oxidase, and decreasing the expression of GPIIb/IIIa. The in vivo assay demonstrates that the effective antithrombotic dose of A-RGDV is 16700-fold lower than the nonresponsive dose of aspirin.

Use of nasal inspiratory flow rates in the measurement of aspirin-induced respiratory reactions

BACKGROUND

Nasal ketorolac challenge with modified oral aspirin challenge is a safe and effective alternative for desensitizing patients with aspirin-exacerbated respiratory disease. In addition to clinical judgment, objective tests assessing nasal flow may help in diagnosing nasal reactions.

OBJECTIVE

To evaluate the feasibility of peak nasal inspiratory flow (PNIF) as an objective measurement in the assessment of a reaction to nasal ketorolac and to determine changes in PNIF that have adequate sensitivity and specificity.

METHODS

One hundred fifty-one patients referred to the Scripps Clinic for aspirin challenge and desensitization and 14 healthy controls participated in the study. Percentages of decrease in PNIF during reactions were compared with the nonreactors' measurements. A receiver operating characteristic curve was constructed to assess the diagnostic performance of PNIF measurement during a clinically positive nasal challenge.

RESULTS

A total of 165 subjects participated in the study. One hundred fourteen patients (69.1%) clinically reacted to the nasal ketorolac challenge. There was no statistical difference between nasal reactors and nonreactors regarding sex, baseline forced expiratory volume in 1 second, and use of systemic steroid before challenge. The mean percentage of decrease in PNIF was significantly higher in the reactor group (-0.30 ± 0.29 vs -0.07 ± 0.16, P < .001). A cutoff value of 25% decrease in PNIF had the maximum sensitivity and specificity (56.1% and 94.1%).

CONCLUSION

The high specificity of a 25% decrease in PNIF found in receiver operating characteristic curve analysis indicated that PNIF measurements can be useful for assessing nasal reactions during nasal ketorolac challenges in the diagnosis of aspirin-exacerbated respiratory disease.

Aspirin sensitivity syndrome (Samter's Triad): an unrecognized disorder in children with nasal polyposis

Aspirin sensitivity syndrome is an underdiagnosed entity in pediatric otolaryngology. The diagnosis must be considered in a pediatric non-cystic fibrosis patient with florid nasal polyposis. In this small case series, we will describe 2 patient's presentation, work up, allergic and surgical therapies and their postoperative course. In doing so, we hope to increase awareness and to illustrate the details that are involved in its diagnosis and treatment.

Clinical Management of Nonsteroidal Anti-inflammatory Drug Hypersensitivity

Hypersensitivity diseases caused by nonsteroidal anti-inflammatory agents are relatively common in the population. This article summarizes the present understanding on the various allergic and nonallergic clinical pictures produced through hypersensitivity to these drugs using the pathogenic classification of hypersensitivity reactions recently proposed by the Nomenclature Committee of the World Allergy Organization to guide clinicians in the diagnosis and management of patients with these conditions.

Cardiovascular prophylaxis and aspirin "allergy"

Aspirin is an important antiplatelet agent in the treatment of cardiovascular disease. Aspirin "allergy" often directs the physician away from this potentially life-saving modality. The majority of patients with a history of "reactions to aspirin" have aspirin/nonsteroidal anti-inflammatory drug (NSAID)-induced gastritis, easy bruisability, or other side effects. The minority of these patients has a "true allergy," referred to as a hypersensitivity reaction. The former group can be started on aspirin without the need for special challenge. Adding a proton-pump inhibitor can often mitigate the gastrointestinal side effects. Patients with aspirin hypersensitivity can be safely challenged with aspirin.

Aspirin sensitivity and coronary artery disease: implications for the practicing cardiologist

Aspirin is the most commonly used antiplatelet agent in patients with coronary artery disease (CAD). It continues to play a key role as an antiplatelet agent given its long-term safety, efficacy and low cost. Aspirin or NSAID hypersensitivity is not an uncommon occurrence and can vary from generalized urticaria and angioedema to exacerbation of upper and lower respiratory tract reactions. It is not uncommon for clinicians to avoid using aspirin and alternative agents when encountering aspirin hypersensitivity among CAD patients. However, given the critical role of aspirin in CAD patients, particularly among those who receive the drug-eluting stents, aspirin desensitization can be useful. This article highlights the importance of aspirin desensitization, the mechanism and the process involved. We draw attention to recently described rapid desensitization protocols and how they can be more useful than the old procedure.

[Aspirin desensitization: therapy options in patients with aspirin-exacerbated respiratory disease]

Aspirin desensitization has established itself as an additional therapy option in the treatment of aspirin- exacerbated respiratory disease, recurrent chronic rhinosinusitis and nasal polyps. Inpatient treatment is strongly recommended due to the risk of life-threatening side effects. In addition, the necessary requirements, indications and contraindications should be carefully considered from a medicolegal perspective. A maintenance dose of 300 (-500) mg ASS is currently recommended. Indications include persisting symptoms despite intensive medical care and/or recurrent nasal polyps, leading to recurrent sinus operations and/or the need to take systemic corticosteroids in order to control nasal symptoms or asthma. If ASS intake is interrupted for more than 48 h, aspirin desensitization should be resumed to prevent renewed intolerance reactions.

Nonallergic drug hypersensitivity reactions

BACKGROUND

Nonallergic drug hypersensitivities, also referred to as pseudoallergic or anaphylactoid reactions, have clinical manifestations that are often indistinguishable from allergic reactions.

METHODS

We performed a PubMed search using the terms 'drug allergy, drug hypersensitivity, pseudoallergies, anaphylaxis and nonallergic drug reactions' and reviewed 511 publications dated between 1970 and 2012. A total of 160 papers that were relevant to the most common nonallergic drug hypersensitivity reactions were selected for discussion.

RESULTS

Nonallergic drug hypersensitivities do not involve either IgE-mediated (type 1) or delayed (type 4) hypersensitivity. Nonallergic hypersensitivities are commonly referred to as pseudoallergic or idiosyncratic reactions. The common nonallergic drug hypersensitivities are secondary to chemotherapeutic drugs, radiocontrast agents, vancomycin, nonsteroidal anti-inflammatory agents, local anesthetic reactions and opiates. Protocols for skin testing of radiocontrast, nonsteroidal anti-inflammatory agents, local anesthetics and chemotherapeutic agents have been developed, though most have not been validated or standardized. Other diagnostic tests include in vitro-specific IgE tests, and the current 'gold' standard is usually an oral challenge or bronchoprovocation test. In the case of aspirin, even though it is not believed to be IgE-mediated, a 'desensitization' protocol has been developed and utilized successfully, although the mechanism of this desensitization is unclear.

CONCLUSIONS

Diagnostic methods exist to distinguish allergic from nonallergic drug hypersensitivity reactions. The best option in nonallergic drug hypersensitivity is avoidance. If that is not possible, premedication protocols have been developed, although the success of premedication varies amongst drugs and patients.

Interleukin-4 in the Generation of the AERD Phenotype: Implications for Molecular Mechanisms Driving Therapeutic Benefit of Aspirin Desensitization

Aspirin-exacerbated respiratory disease (AERD) is explained in part by over-expression of 5-lipoxygenase, leukotriene C4 synthase (LTC₄S) and the cysteinyl leukotriene (CysLT) receptors (CysLT1 and 2), resulting in constitutive over-production of CysLTs and the hyperresponsiveness to CysLTs that occurs with aspirin ingestion. Increased levels of IL-4 have been found in the sinus mucosa and nasal polyps of AERD subjects. Previous studies demonstrated that IL-4 is primarily responsible for the upregulation of LTC4S by mast cells and the upregulation of CysLT1 and 2 receptors on many immune cell types. Prostaglandin E₂ (PGE₂) acts to prevent CysLT secretion by inhibiting mast cell and eosinophil activation. PGE₂ concentrations are reduced in AERD reflecting diminished expression of cyclooxygenase (COX)-2. IL-4 can inhibit basal and stimulated expression of COX-2 and microsomal PGE synthase 1 leading to decreased capacity for PGE₂ secretion. Thus, IL-4 plays an important pathogenic role in generating the phenotype of AERD. This review will examine the evidence supporting this hypothesis and describe a model of how aspirin desensitization provides therapeutic benefit for AERD patients.

Smoking, environmental tobacco smoke, and aspirin-exacerbated respiratory disease

BACKGROUND

Tobacco smoke is a widely recognized environmental pollutant and is a major public health hazard worldwide. Although environmental tobacco smoke (ETS) has a clear link with many conditions, including asthma, ear infections, and sinus cancer, evidence related to aspirin-exacerbated respiratory disease (AERD) requires further investigation.

OBJECTIVE

To investigate whether active smoke or ETS exposures are associated with an increased risk of developing AERD.

METHODS

A total of 260 patients with AERD were enrolled in a case-control study with their respective asymptomatic spouses serving as matched controls. Multiple logistic regression analysis was used to examine the association of AERD with active smoking and ETS, adjusted for age, sex, and location of childhood residence.

RESULTS

The AERD case patients were more likely to have ever smoked actively when compared with controls (odds ratio [OR], 1.54; 95% confidence interval [CI], 1.04-2.28). A significant association (OR, 3.46; 95% CI, 2.22-5.39) was found between childhood ETS exposure and AERD. If a patient was exposed to ETS during both childhood and adulthood, results showed an OR of 5.09 for developing AERD (95% CI, 2.75-9.43). However, no statistically significant association between AERD and ETS only during adulthood was found (OR, 1.60; 95% CI, 0.75-3.40), suggesting that the combined effect of childhood and adulthood ETS may be augmented by the prior childhood exposure.

CONCLUSIONS

Active smoking and childhood ETS exposure are associated with increased odds of developing AERD. In particular, combined childhood and adulthood exposure had major effects. This study suggests that ETS is at least one contributor to the syndrome of AERD.

Role of aspirin desensitization in the management of chronic rhinosinusitis

PURPOSE OF REVIEW

This review is set to revisit the pathogenesis of aspirin-exacerbated respiratory disease (AERD), the diagnostic method used, and finally the real impact of aspirin desensitization on chronic sinusitis with nasal polyposis (CRSwNP) in aspirin intolerant patients.

RECENT FINDINGS

In AERD, increased baseline production of cysteinyl-leukotriene (Cys-LT) is associated with upregulation of Cys-LT receptors on nasal inflammatory cells. This is further aggravated by inhibition of cyclooxygenase-1 by aspirin and other NSAIDs. New-found genetic markers need further study. Oral aspirin challenge is still the gold standard of diagnosis and can be safely conducted in a specialized outpatient clinic. Oral and endonasal aspirin desensitization show positive impact on CRSwNP course with decreased polyp recurrence, decreased number of hospitalizations, and decreased need for corticosteroids. Modulation of arachidonic acid metabolism and inhibition of intracellular biochemical pathways in key inflammatory cells involving anti-inflammatory cytokines interleukin (IL)-4 and IL-13 explain the clinical outcomes.

SUMMARY

Future studies should focus on establishing the lowest possible dose to maintain disease under check, allowing more widespread use of this underutilized and underrecognized treatment modality.

Drug allergy: an updated practice parameter

Adverse drug reactions (ADRs) result in major health problems in the United States in both the inpatient and outpatient setting. ADRs are broadly categorized into predictable (type A and unpredictable (type B) reactions. Predictable reactions are usually dose dependent, are related to the known pharmacologic actions of the drug, and occur in otherwise healthy individuals, They are estimated to comprise approximately 80% of all ADRs. Unpredictable are generally dose independent, are unrelated to the pharmacologic actions of the drug, and occur only in susceptible individuals. Unpredictable reactions are subdivided into drug intolerance, drug idiosyncrasy, drug allergy, and pseudoallergic reactions. Both type A and B reactions may be influenced by genetic predisposition of the patient

Clinical immunology review series: an approach to desensitization

Allergen immunotherapy describes the treatment of allergic disease through administration of gradually increasing doses of allergen. This form of immune tolerance induction is now safer, more reliably efficacious and better understood than when it was first formally described in 1911. In this paper the authors aim to summarize the current state of the art in immunotherapy in the treatment of inhalant, venom and drug allergies, with specific reference to its practice in the United Kingdom. A practical approach has been taken, with reference to current evidence and guidelines, including illustrative protocols and vaccine schedules. A number of novel approaches and techniques are likely to change considerably the way in which we select and treat allergy patients in the coming decade, and these advances are previewed.

Aspirin-exacerbated respiratory disease: evaluation and management

The clinical syndrome of aspirin-exacerbated respiratory disease (AERD) is a condition where inhibition of cyclooxygenase-1 (COX-1) induces attacks of upper and lower airway reactions, including rhinorrhea and varying degrees of bronchospasm and laryngospasm. Although the reaction is not IgE-mediated, patients can also present with anaphylactic hypersensitivity reactions, including hypotension, after exposure to COX-1 inhibiting drugs. All patients with AERD have underlying nasal polyps and intractable sinus disease which may be difficult to treat with standard medical and surgical interventions. This review article focuses on the management of AERD patients with a particular emphasis on aspirin desensitization and continuous treatment with aspirin.

Modulation by aspirin of nuclear phospho-signal transducer and activator of transcription 6 expression: Possible role in therapeutic benefit associated with aspirin desensitization

BACKGROUND

Aspirin-exacerbated respiratory disease is characterized by asthma, nasal polyps, and intolerance to aspirin with overexpression of leukotriene (LT) C(4) synthase and cysteinyl leukotriene receptors. Through an unknown mechanism, aspirin desensitization is an effective treatment.

OBJECTIVE

We hypothesized that aspirin desensitization blocks IL-4-induced expression of these LT activities through inhibition of signal transducer and activator of transcription 6 (STAT6)-mediated transcription.

METHODS

Nuclear extracts were derived from THP-1 and normal human monocytes resting and cocultured with aspirin before IL-4 stimulation. Quantitative PCRs were conducted. Electrophoretic mobility shift assays were performed by using oligomers for STAT6 sites within the LT receptor and synthase promoters. Western blots of nuclear extracts were probed by using anti-phospho-STAT6 antibodies.

RESULTS

Upregulation of LT receptor mRNA by IL-4 was negated by aspirin and ketorolac but not by sodium salicylate. The STAT6 site in the LT receptor and synthase promoters was confirmed by using mobility shift assays by competing with unlabeled STAT6 consensus probes and supershifts with anti-STAT6 antibodies. Aspirin and ketorolac decreased the IL-4-inducible expression of nuclear STAT6 observed in mobility shift assays and Western hybridization.

CONCLUSION

The LT receptor and synthase promoters have STAT6-binding sites that are engaged by IL-4-induced nuclear extracts and inhibited by aspirin. Assuming that normal monocytes behave like monocytes from patients with aspirin-exacerbated respiratory disease, inhibition of IL-4-STAT6 might explain a mechanism in aspirin desensitization daily treatment, resulting in downregulation of production and responsiveness to cysteinyl leukotrienes. This biologic activity of aspirin likely reflects COX inhibition because it was shared with ketorolac but not sodium salicylate.

Aspirin sensitivity and desensitization for asthma and sinusitis

NSAIDs-including aspirin (ASA)-that inhibit cyclooxygenase (COX)-1 induce nonallergic hypersensitivity reactions consisting of attacks of rhinitis and asthma. Such reactions occur exclusively in a subset of asthmatic patients who also have underlying nasal polyps and chronic hyperplastic eosinophilic sinusitis. We now refer to their underlying inflammatory disease of the entire respiratory tract as aspirin-exacerbated respiratory disease. This review focuses on descriptions of these patients; methods available to diagnose ASA-exacerbated respiratory disease; the unique ability of all NSAIDs that inhibit COX-1 to cross-react with ASA; lack of cross-reactivity with selective COX-2 inhibitors; an update on pathogenesis; and current thoughts about treatment, including ASA desensitization and daily ingestion of ASA itself.

The clinical effectiveness of aspirin desensitization in chronic rhinosinusitis

Aspirin-exacerbated respiratory disease (AERD) is a chronic inflammatory disease characterized by chronic rhinosinusitis, nasal polyposis, asthma, and airway reactivity to aspirin and other nonsteroidal antiinflammatory drugs (NSAIDs). For patients who have inadequately controlled rhinosinusitis and/or asthma despite treatment with topical corticosteroids and leukotriene-modifying drugs, aspirin desensitization is an important therapeutic option. This review examines the evidence supporting the effectiveness of aspirin desensitization for the treatment of chronic rhinosinusitis in patients with AERD. Practical aspects of conducting safe aspirin desensitization procedures and optimizing therapeutic benefits are also reviewed. When conducted in accordance with current guidelines, aspirin desensitization is a safe procedure that allows patients with AERD who have an indication for aspirin or other NSAIDs to safely ingest these medications. There is now strong evidence that aspirin desensitization and daily aspirin therapy is effective for treatment of the chronic inflammatory disease of the upper airway and lower airways in AERD.

An economic analysis of aspirin desensitization in aspirin-exacerbated respiratory disease

BACKGROUND

Aspirin desensitization is an effective therapy for moderate-to-severe aspirin-exacerbated respiratory disease (AERD). Desensitization also allows the use of aspirin for secondary cardiovascular prevention.

OBJECTIVE

We sought to investigate the cost-effectiveness of aspirin desensitization with subsequent aspirin therapy in patients with AERD.

METHODS

The Healthcare Cost and Utilization Project was used, together with average reimbursements from a large Midwestern health care plan, to model the costs of aspirin desensitization for therapeutic and prophylactic use in patients with AERD. Event probabilities were based on the published literature.

RESULTS

Ambulatory desensitization for AERD cost $6768 per quality-adjusted life year (QALY) saved ($18.54 per additional symptom-free day). Aspirin desensitization for AERD remained cost-effective (<$50,000 per QALY saved) across a wide range of assumptions. When secondary cardiovascular prophylaxis was considered, ambulatory aspirin desensitization was less expensive than an alternative antiplatelet agent, clopidogrel. Clopidogrel cost $106,453 per incremental QALY saved when compared with desensitization.

CONCLUSIONS

Aspirin desensitization is a cost-effective therapeutic intervention in patients with moderate-to-severe AERD. Although the incremental cost-effectiveness of clopidogrel in individuals with aspirin allergy is marginal, if available, ambulatory desensitization remains a less-expensive option for secondary cardiovascular prophylaxis.

Advances in allergic skin disease, anaphylaxis, and hypersensitivity reactions to foods, drugs, and insects

This review highlights some of the research advances in anaphylaxis and hypersensitivity reactions to foods, drugs, and insects and in allergic skin disease that were reported primarily in the Journal in 2006. Advances in diagnosis include identification of food proteins to which IgE binding is associated with severe reactions; elucidation of diagnostic relationships of skin prick test wheal size with outcomes of egg, tree nut, and sesame allergy; evaluation of the diagnostic utility of atopy patch testing for food; and the observation that yellow jacket sting outcomes are influenced by species. Mechanistic observations include the following: heating of birch pollen-related foods disrupts IgE binding but not T-cell epitopes; a simple imbalance of T(H)1/T(H)2 response does not explain variations in clinical expression of peanut allergy; and elucidation of the role of dendritic cells in drug hypersensitivity. With regard to treatment, a rapidly disintegrating epinephrine tablet showed promise for sublingual treatment of anaphylaxis, RNA interference techniques showed promise in creating lower-allergenic foods, and anti-IL-5 showed promise for treatment of eosinophilic esophagitis. Progress in our understanding of the immunology and the etiology of skin barrier dysfunction in atopic dermatitis has also been made. These observations will likely contribute toward optimizing management of these common allergic disorders.

The relationship between historical aspirin-induced asthma and severity of asthma induced during oral aspirin challenges

BACKGROUND

Historical aspirin- or nonsteroidal anti-inflammatory drug (NSAID)-induced reactions might provide predictive information about the severity of reactions in patients with aspirin-exacerbated respiratory disease (AERD) undergoing oral aspirin challenge (OAC).

OBJECTIVE

We sought to assess the relationship between historical aspirin- or NSAID-induced bronchial reactions and the severity of bronchial reactions during OAC in patients with AERD.

METHODS

Data regarding the provoking doses, treatments, and treatment settings of historical aspirin/NSAID-induced reactions were recorded, analyzed, and compared with the provoking doses, maintenance regimens, and observed decreases in FEV(1) that occurred during OAC in 210 consecutive patients referred with suspected AERD.

RESULTS

Of 147 patients who reported seeking acute medical care for their historical aspirin/NSAID-induced asthma attacks, 101 (69%) were treated in an emergency department and released, and 46 (31%) required hospitalization. During OAC in these 147 subjects, 23 (16%) had a 20% to 29% decrease and 14 (10%) had a 30% or greater decrease in FEV(1) values from baseline. Of the 46 patients previously hospitalized for aspirin/NSAID-induced asthma attacks, 9 (20%) had a 20% to 29% decrease and 6 (13%) had a 30% or greater decrease in FEV(1) during OAC. By contrast, of the 63 patients who treated their prior aspirin/NSAID-induced reactions at home, 5 (8%) had a 20% to 29% decrease and 5 (8%) had a 30% or greater decrease in FEV(1) during OAC (P = not significant for both).

CONCLUSION

The severity of the historical aspirin/NSAID-induced asthma attack was not predictive of asthma severity during OAC.

CLINICAL IMPLICATIONS

These data provide further reassurance regarding the safety of outpatient aspirin desensitization.