HLA antigens, nasal polyps and asthma

Genetics and epigenetics of chronic rhinosinusitis

Discerning the genetics and epigenetics of chronic rhinosinusitis (CRS) may optimize outcomes through early diagnostics, personalized and novel therapeutics, and early prognostication. CRS associated with cystic fibrosis and primary ciliary dyskinesia has well-characterized genetic mutations. Most CRS subjects, however, do not exhibit identifiable monogenic alterations. Clustering in related individuals is seen in CRS with nasal polyps. Spouses of subjects with CRS without nasal polyps also may be at increased risk of the same disease. These observations generate questions on genetic and environmental influences in CRS. Genome-wide association studies have identified variations and polymorphisms between CRS and control subjects in genes related to innate and adaptive immunity. Candidate gene and transcriptomics studies have investigated and identified genetic variations related to immunity, inflammation, epithelial barrier function, stress-response, antigen processing, T-cell regulation, and cytokines in CRS. Epigenetic studies have identified mechanisms through which environmental factors may affect these gene functions. However, causality is not determined for most variations. Inferences drawn from these data must be measured because most investigations report unreplicated results from small study populations. Large, replicated studies in tight cohorts across diverse populations remain a pressing need in studying CRS genetics.

Rapid and sustained effect of dupilumab on clinical and mechanistic outcomes in aspirin-exacerbated respiratory disease

BACKGROUND

Dupilumab, a mAb targeting IL-4Rα, improves upper and lower airway symptoms in patients with aspirin-exacerbated respiratory disease (AERD), but the mechanisms leading to clinical improvement are not fully elucidated.

OBJECTIVE

Our aim was to identify the mechanistic basis of clinical improvement in patients with AERD treated with dupilumab.

METHODS

A total of 22 patients with AERD were treated with dupilumab for 3 months for severe asthma and/or chronic rhinosinusitis with nasal polyps. Clinical outcomes were assessed at baseline and at 1 and 3 months after initiation of dupilumab. Nasal fluid, urine, blood, and inferior turbinate scrapings were collected at the 3 time points for determination of mediator levels, cellular assays, and RNA sequencing.

RESULTS

Participants had rapid improvement in clinical measures, including sense of smell, sinonasal symptoms, and lung function after 1 month of treatment with dupilumab; the improvements were sustained after 3 months of dupilumab. Baseline severity of smell loss was correlated with lower nasal prostaglandin E₂ levels. Dupilumab increased nasal prostaglandin E₂ level and decreased levels of nasal albumin, nasal and urinary leukotriene E₄, and serum and nasal IgE. Transcripts related to epithelial dysfunction and leukocyte activation and migration were downregulated in inferior turbinate tissue after treatment with dupilumab. There were no dupilumab-induced changes in nasal eosinophilia.

CONCLUSION

Inhibition of IL-4Rα in AERD led to rapid improvement in respiratory symptoms and smell, with a concomitant improvement in epithelial barrier function, a decrease in inflammatory eicosanoid levels, and an increase in the anti-inflammatory eicosanoid prostaglandin E₂ level. The therapeutic effects of dupilumab are likely due to decreased IL-4Rα signaling on respiratory tissue granulocytes, epithelial cells, and B cells.

A family-based genome-wide association study of chronic rhinosinusitis with nasal polyps implicates several genes in the disease pathogenesis

BACKGROUND

The pathogenesis of chronic rhinosinusitis with nasal polyps is largely unknown. Previous studies have given valuable information about genetic variants associated with this disease but much is still unexplained. Our goal was to identify genetic markers and genes associated with susceptibility to chronic rhinosinusitis with nasal polyps using a family-based genome-wide association study.

METHODS

427 patients (293 males and 134 females) with CRSwNP and 393 controls (175 males and 218 females) were recruited from several Swedish hospitals. SNP association values were generated using DFAM (implemented in PLINK) and Efficient Mixed Model Association eXpedited (EMMAX). Analyses of pathway enrichment, gene expression levels and expression quantitative trait loci were then performed in turn.

RESULTS

None of the analysed SNPs reached genome wide significant association of 5.0 x 10-8. Pathway analyses using our top 1000 markers with the most significant association p-values resulted in 138 target genes. A comparison between our target genes and gene expression data from the NCBI Gene Expression Omnibus database showed significant overlap for 36 of these genes. Comparisons with data from expression quantitative trait loci showed the most skewed allelic distributions in cases with chronic rhinosinusitis with nasal polyps compared with controls for the genes HLCS, HLA-DRA, BICD2, VSIR and SLC5A1.

CONCLUSION

Our study indicates that HLCS, HLA-DRA, BICD2, VSIR and SLC5A1 could be involved in the pathogenesis of chronic rhinosinusitis with nasal polyps. HLA-DRA has been associated with chronic rhinosinusitis with nasal polyps in previous studies and HLCS, BICD2, VSIR and SLC5A1 may be new targets for future research.

Allergic and Nonallergic Asthma Have Distinct Phenotypic and Genotypic Features

BACKGROUND

Identification of asthma phenotypes enables a better understanding and management of this heterogeneous disease. Studies have reported associations between human leukocyte antigens (HLA) and asthma in different populations, but the results have been inconclusive and they have rarely considered the distinct disease phenotypes. Our objective was to characterize allergic and nonallergic asthma phenotypes and evaluate possible associations with the HLA system.

METHODS

A total of 109 patients with asthma were prospectively followed during 2 years. They were divided into 2 groups, i.e., allergic and nonallergic asthma, according to their clinical history and skin prick test and serum-specific immunoglobulin E (IgE) results. The control group comprised 297 deceased donors of solid organs. Patients' features and HLA class I and II genotypes were assessed and compared.

RESULTS

This study showed different features between asthma phenotypes. Nonallergic patients were older at the onset of asthma symptoms and had a higher rate of intolerance to nonsteroidal anti-inflammatory drugs. Allergic patients had higher total serum IgE levels, reported atopic dermatitis and rhinoconjunctivitis more frequently, and, unexpectedly, had a greater disease severity. New associations between the HLA genotypes and allergic and nonallergic asthma were identified. The HLA-B*42, HLA-C*17, HLA-DPA1*03, and HLA-DPB1*105 genotypes were associated with allergic asthma and the HLA-B*48 genotype with the nonallergic phenotype. The presence of the haplotype HLA-DPA1*03 DQA*05 was associated with allergic asthma, and the presence of HLA-DPA1*03 and the absence of HLA-DQA*05 with nonallergic asthma.

CONCLUSIONS

Allergic and nonallergic asthma have distinct phenotypic and genotypic features. New associations between asthma phenotypes and HLA class I and II were identified.

Association of HLA-DR3 and HLA-DR4 with Sinonasal Polyposis in Mexican Mestizos

OBJECTIVE: The pathogenesis of sinonasal polyposis (SNP) is not clear; it has been suggested that it is polygenic and multifactorial. The major histocompatibility complex is a useful tool to predict genetic susceptibility to diseases, especially to autoimmune diseases. Since such susceptibility is influenced by ethnicity, it is necessary to have a wide knowledge of the structure of the population to which the patient belongs. The purpose of the study was to determine the association of HLA-DRB1 alleles with sinonasal polyposis in the Mexican Mestizo population.

STUDY DESIGN: We studied the HLA-DR alleles in 34 adult Mexican Mestizo patients with SNP and compared them to those present in 99 healthy controls.

METHODS: Genomic DNA from mononuclear cells was obtained by using the “salting out” technique and high-resolution DNA typing of the HLA-DRB1 alleles was performed after PCR amplification.

RESULTS: We found a statistically significant increased frequency of the HLA-DRB1∗03 allele ( P = 0.03, odds ratio [OR] = 2.9, 95% confidence interval [CI]: 1.0–7.8) and of the HLA-DRB1∗04 allele ( P = 0.009, OR = 2.2, 95% CI: 1.2–4.2) in patients with SNP as compared to controls, and a statistically significant decreased frequency of the HLA-DRB1∗08 allele ( P = 0.01, OR = 0.2, 95% CI: 0.05–0.8).

CONCLUSION: The HLA-DR locus seems to be associated with the genetic susceptibility to develop SNP in Mexicans.

EBM rating: B-2b

ICON: chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a public health problem that has a significant socio-economic impact. Moreover, the complexity of this disease due to its heterogeneous nature based on the underlying pathophysiology - leading to different disease variants - further complicates our understanding and directions for the most appropriate targeted treatment strategies. Several International/national guidelines/position papers and/or consensus documents are available that present the current knowledge and treatment strategies for CRS. Yet there are many challenges to the management of CRS especially in the case of the more severe and refractory forms of disease. Therefore, the International Collaboration in Asthma, Allergy and Immunology (iCAALL), a collaboration between EAACI, AAAAI, ACAAI, and WAO, has decided to propose an International Consensus (ICON) on Chronic Rhinosinusitis. The purpose of this ICON on CRS is to highlight the key common messages from the existing guidelines, the differences in recommendations as well as the gaps in our current knowledge of CRS, thus providing a concise reference. In this document we discuss the definition of the disease, its relevance, pharmacoeconomics, pathophysiology, phenotypes and endotypes, genetics and risk factors, natural history and co-morbidities as well as clinical manifestations and treatment options in both adults and children comprising pharmacotherapy, surgical interventions and more recent biological approaches. Finally, we have also highlighted the unmet needs that wait to be addressed through future research.

HLA and asthma phenotypes/endotypes: a review

Asthma is a complex chronic inflammatory disease of the airways caused by the interaction of genetic susceptibility with environmental influences. Genome-wide association studies (GWAS) represent the most powerful approach for asthma, that have identified several genes (e.g., IL18R1, IL33, SMAD3, ORMDL3, HLA-DQ and IL2RB loci). HLA super-locus is a genomic region in the chromosomal position 6p21. Since no gene can be considered as an asthma gene, able to reflect the complex etiology and the heterogeneity of the disease the terms 'phenotype' and more recently 'endotype' have been used. This review, according to literature availability, focuses on the relationship between human leukocyte antigens (HLA) region specifically the HLA class II genes and different asthma phenotypes/endotypes, such as allergic asthma/Th2 associated, occupational and aspirin-sensitive asthma. The most common HLA haplotypes in the different asthma phenotypes are HLA-DRB1in allergic asthma, HLA-DQB1in occupational asthma and HLA-DPB1 in aspirin-sensitive asthma. However, it is difficult to study the role of class II genes in vivo because of the heterogeneity of human population, the complexity of MHC, and the strong linkage disequilibrium among different class II genes. Despite the variation and the inconsistency of the HLA haplotypes and alleles in different types of asthma, the association between HLA class II genes and asthma has been demonstrated in the majority of studies.

Zn/Ga-DFO iron-chelating complex attenuates the inflammatory process in a mouse model of asthma

Background

Redox-active iron, a catalyst in the production of hydroxyl radicals via the Fenton reaction, is one of the key participants in ROS-induced tissue injury and general inflammation. According to our recent findings, an excess of tissue iron is involved in several airway-related pathologies such as nasal polyposis and asthma.

Objective

To examine the anti-inflammatory properties of a newly developed specific iron–chelating complex, Zn/Ga−DFO, in a mouse model of asthma.

Materials and methods

Asthma was induced in BALBc mice by ovalbumin, using aluminum hydroxide as an adjuvant. Mice were divided into four groups: (i) control, (ii) asthmatic and sham-treated, (iii) asthmatic treated with Zn/Ga−DFO [intra-peritoneally (i/p) and intra-nasally (i/n)], and (iv) asthmatic treated with Zn/Ga−DFO, i/n only. Lung histology and cytology were examined. Biochemical analysis of pulmonary levels of ferritin and iron-saturated ferritin was conducted.

Results

The amount of neutrophils and eosinophils in bronchoalveolar lavage fluid, goblet cell hyperplasia, mucus secretion, and peri-bronchial edema, showed markedly better values in both asthmatic-treated groups compared to the asthmatic non-treated group. The non-treated asthmatic group showed elevated ferritin levels, while in the two treated groups it returned to baseline levels. Interestingly, i/n-treatment demonstrated a more profound effect alone than in a combination with i/p injections.

Conclusion

In this mouse model of allergic asthma, Zn/Ga−DFO attenuated allergic airway inflammation. The beneficial effects of treatment were in accord with iron overload abatement in asthmatic lungs by Zn/Ga−DFO. The findings in both cellular and tissue levels supported the existence of a significant anti-inflammatory effect of Zn/Ga−DFO.

Asthma pathophysiology was shown to be associated with iron overload.

A therapeutic effect of the novel iron–chelating complexes was demonstrated.

Histological and cytological markers of inflammation were studied.

The complexes could be administered intranasally or by intraperitonneal injections.

Genetics of chronic rhinosinusitis: state of the field and directions forward

The cause of chronic rhinosinusitis (CRS) remains unclear. Study of the genetic susceptibility to CRS might be a valuable strategy to understand the pathogenesis of this burdensome disorder. The purpose of this review is to critically evaluate the current literature regarding the genetics of CRS in a comprehensive fashion. The most promising findings from candidate gene studies include the cystic fibrosis transmembrane conductance regulator gene (CFTR), as well as genes involved in antigen presentation, innate and adaptive immune responses, tissue remodeling, and arachidonic acid metabolism. We also review the few hypothesis-independent genetic studies of CRS (ie, linkage analysis and pooling-based genome-wide association studies). Interpretation of the current literature is limited by challenges with study design, sparse replication, few functional correlates of associated polymorphisms, and inadequate examination of linkage disequilibrium or expression quantitative trait loci for reported associations. Given the relationship of CRS to other airway disorders with well-characterized genetic components (eg, asthma), study of the genetics of CRS deserves increased attention and investment, including the organization of large, detailed, and collaborative studies to advance knowledge of the mechanisms that underlie this disorder.

Aspirin sensitivity and chronic rhinosinusitis with polyps: a fatal combination

Aspirin-exacerbated respiratory disease (AERD) refers to aspirin sensitivity, chronic rhinosinusitis (CRS), nasal polyposis, asthma, eosinophil inflammation in the upper and lower airways, urticaria, angioedema, and anaphylaxis following the ingestion of NSAIDs. Epidemiologic and pathophysiological links between these diseases are established. The precise pathogenesis remains less defined, even though there is some progress in the understanding of several molecular mechanisms. Nevertheless, these combinations of diseases in patients classified by AERD constitute a fatal combination and may be difficult to treat with standard medical and surgical interventions. This paper reviews in brief the epidemiology, clinical features, diagnosis, molecular pathogenesis, and specific therapies of patients classified by AERD and postulates future attempts to gain new insights into this disease.

Distribution of Inflammatory Cells, Adhesion Molecules, Intermediate Filaments, and Chemokine Receptors in Subgroups of Nasal Polyp Patients

Background

The pathogenesis of nasal polyps (NPs) is incompletely understood. The aim of this study was to investigate the distribution of inflammatory cells, adhesion molecules, intermediate filaments, and chemokine receptors in subgroups of NP patients.

Methods

In total, 35 patients were enrolled (group 1, 10 patients with Samter syndrome; group 2, 10 patients with diffuse polyposis without signs of Samter syndrome; group 3: 5 patients with solitary nasal polyps; group 4, 10 controls). Immunohistochemical staining was performed for CD105, CD106, CD62E, CD4, CD8, CXCR4, CD147, CD90, CD104, BF45, vimentin, pancytokeratin, and muscle-specific actin (MSA) in all patients’ specimens.

Results

Expression of CD4, CD8, and CD106 were similar between the groups. Number of patients expressing CD4 in groups 1, 2, and 3 were higher than the controls. Number of patients expressing CD8 antigen were significantly higher in all three groups than in the control group. Expression of CD147 in groups 3 and 4 was significantly higher than in groups 1 and 2. CD98 expression was higher in groups 1, 2, and 3 than in group 4. The number of patients expressing vimentin in groups 1, 2, and 3 was significantly higher than in group 4. Immunostaining for pancytokeratin was positive in all patients.

Conclusion

In conclusion, inflammatory cell, adhesion molecule, intermediate filament, and chemokine receptor profiles in nasal polyps differ among different patient groups and control subjects. Additional specific immunohistochemical studies are necessary for development of more specific immunotherapies.

Evaluation of HLA-A, -B, -Cw, and -DRB1 alleles frequency in Turkish patients with nasal polyposis

OBJECTIVE

To evaluate whether there is a relationship between HLA-A, -B, -Cw, and -DRB1 alleles and developing nasal polyposis (NP).

STUDY DESIGN

Data from 66 patients with NP were compared with data from 100 healthy randomly selected controls. Asthma, ASA (acetylsalicylic acid) triad, polyp score, and previous sinonasal surgery were also recorded.

SUBJECTS AND METHODS

Genotyping of the HLA-A, -B, -Cw, and -DRB1 alleles were performed with polymerase chain reaction (PCR) with the sequence-specific primer (SSP) method. Data were analyzed by using a Pearson chi(2) test.

RESULTS

The HLA-B*07 and -Cw*12 alleles were found to be significantly higher in the NP patients compared with the control group, whereas the HLA-B*57 and HLA-Cw*04 alleles were significantly lower (P < 0.05). The HLA-A*24, HLA-Cw*12, and HLA-DRB1*04 alleles were determined to be significantly higher in the NP patients with asthma and ASA triad (P < 0.05).

CONCLUSIONS

Our results show that some of the HLA alleles seem to be associated with the genetic susceptibility to develop NP in the Turkish population.

[Diversity of nasal polyps in microarray technology research]

Nasal polyps, according to many authors, generate as a result of chronic inflammation process with activation of cytokines, immunological reaction mediators that regulate proliferation, differentiation and cell apoptosis. Clarifying molecular mechanisms present in those disturbances may have diagnostic and prognostic value in evaluation of recurrence, dynamics and differentiation of nasal polyps as well as in their therapy.

AIM

The aim of the work was an analysis of nasal polyps on the basis of molecular, histopathological and clinical picture as well as comparing differentiated genes transcription in nasal polyps and proper nasal mucosa.

MATERIAL AND METHOD

Oligonucleotide array with HGU 133A - Affymetrix were used to analyze the expression of 22,283 genes in nasal polyp tissues from 17 patients. The control group consisted of 8 tissue samples from patients after nasal septoplasty surgery.

RESULTS

All the samples could be classified to nasal polyps group or proper mucosa group, it reflected significant differences in genes profile expression in both groups. The evaluation of 22,283 genes transcriptions showed that in most cases nasal polyps tissue reflect classification connected with dominant inflammation cells infiltration. The data obtained let distinguish subgroups connected with clinical condition of the patients. The subgroup with massive nasal and sinus polyposis, eosinophilia and differentiated lower respiratory airways hyperactivity and the subgroup without eosinophilia infiltration may be distinguished. The data obtained suggest that molecular mechanisms may influence on the promotion and kind of inflammation process as well as the clinical course of nasal polyps.

Pathogenesis of nasal polyps: an update

The cause of nasal polyp formation is still unknown. Genetic predisposition has been suggested, but there are scanty data to support such theories. Activated epithelial cells may be the major source of mediators inducing influx of inflammatory cells (mostly eosinophils) and proliferation and activation of fibroblasts leading to nasal polyp formation. Infectious agents (including viruses, bacteria, or fungi) may be potential primary factors activating nasal epithelial cells. Proinflammatory cytokines and growth factors play important roles in the persistence of mucosal inflammation associated with nasal polyps. Arachidonic acid metabolites seem to be particularly important in the pathogenesis of nasal polyps in patients with aspirin hypersensitivity rhinosinusitis/asthma syndrome.

Nasal mucosal gene expression in patients with allergic rhinitis with and without nasal polyps

BACKGROUND

Nasal polyps are a common problem that is difficult to diagnose and treat, in part because the cause of nasal polyposis is unknown. Although information on the pathogenesis of polyposis is lacking, there are reports suggesting that a genetic predisposition underlies this disorder.

OBJECTIVE

We sought to better understand the basis of nasal polyposis associated with allergic rhinitis. We hypothesize that the expression of unique genes is associated with the nasal polyposis phenotype.

METHODS

We examined 12000 human genes transcribed in the nasal mucosa of patients with allergic rhinitis with and without nasal polyps. Biopsy specimens of the mucosa of patients with and without polyps were obtained after the patients refrained from the use of topical or systemic steroid therapy for 2 weeks.

RESULTS

Thirty-four genes were differentially expressed between the patient groups, including those for inflammatory molecules and putative growth factors. The greatest differential expression identified by the array analysis was for a group of genes associated with neoplasia, including mammaglobin, a gene transcribed 12-fold higher in patients with polyps compared with control patients with rhinitis alone. Quantitative RT-PCR confirmed this differential expression and documented that the number of mammaglobin mRNA copies is actually 64-fold greater in tissues of patients with polyps versus control patients. The specificity of mammaglobin protein expression was evaluated by means of immunohistochemistry, which showed specific staining in nasal polyp mucosal goblet cells only in patients with polyps.

CONCLUSION

These data suggest that nasal polyposis involves deregulated cell growth, using gene activation in some ways similar to a neoplasm. In addition, mammaglobin, a gene of unknown function associated with breast neoplasia, might be related to polyp growth.

Nasal polyposis: role of subclinical delayed food hypersensitivity

Nasal polyposis is a common problem in otolaryngology. The cause remains unclear, and treatment with medication and surgery is often unsatisfactory. We present our controlled study, which suggests a strong association between food allergy and nasal polyposis. The study was conducted in 2 parts. A postal survey of 900 patients with nasal polyps showed 53 respondents (5.9%) had a known food allergy. In the prospective study, 80 nasal polyp patients and 36 control subjects completed intradermal tests for food allergy. Sixty-five nasal polyp patients (81%) and 4 control subjects (11%) had positive intradermal food test results. This is highly significant. We believe that food allergy may play a significant role in the pathogenesis of nasal polyposis and should be further studied.

Inflammatory rheumatism and nasal polyposis

We report five cases of seronegative inflammatory rheumatism associated with nasal polyposis. The patients were four women and one man, mean age 49.5 years (range 42-59 yrs.). Two patients had polyarthralgia predominating in the hands, wrists and knees and two patients had symmetrical acromelic polyarthritis. The fifth patient, a woman, had oligoarticular arthritis. In a single female patient, X-rays showed moderate erosions of both tarsometatarsal bones. The inflammatory syndrome was moderate with mean ESR 23 (12-38) and immunological investigations were negative except for the presence of pANCA (50-200 U) in three patients. HLA-A1, B8, and Bw35 antigens were found in three of the five patients. In all cases, nasal and sinus polyposis (NSP) preceded rheumatism and the joint symptoms were accompanied by worsening of the ENT symptoms. NSP was confirmed by CT scan of the nasal fossae and sinuses. Polyps were surgically removed in four patients and the histology showed neither granuloma nor vasculitis. In four patients the joint symptoms, which responded poorly to nonsteroidal anti-inflammatory drugs (NSAIDs), improved markedly after ENT treatment (surgery and topical steroids) and synthetic antimalarials. The concomitant course of the joint and ENT symptoms suggests there may be a link between inflammatory rheumatism and NSP.

Nasal polyps in identical twins

Nasal polyps are multifactorial in aetiology but are associated with respiratory diseases, particularly late onset asthma. Several members of a family may be affected with nasal polyps but there is little evidence for a genetic basis for this. Some evidence to support a genetic predisposition comes from the development of polyps in identical twins.

Aspirin-sensitive asthma

Aspirin intolerance is particularly common in asthmatic patients who additionally have chronic rhinitis and/or nasal polyps. These individuals differ in several respects from patients who experience urticaria and/or angioedema after aspirin administration, and differing mechanisms may be involved. Data regarding the latter are indirect and incomplete, but suggest that ASA-sensitive asthma is most likely to be related in some manner to the capacity of ASA to inhibit cyclooxygenases, enhanced lipoxygenase metabolism perhaps playing a crucial role. Current research employing ASA "desensitization" may help to elucidate these enigmas.

Antigen induced histamine release from mucosa in nasal polyposis

This study was designed to detect local immediate-type hypersensitivity in patients with nasal polyposis. For this purpose, 20 patients were tested for antigen-induced histamine release from biopsies of nasal mucosa and nasal polyps. Compared with controls, histamine-release was increased after incubation with bacterial but not synthetic antigens. Fourteen patients allergic to pollen were studied; biopsy specimens of their nasal mucosa released more histamine on incubation with pollen than with synthetic antigens. These findings suggest that, like pollen allergy, nasal polyposis is a manifestation of immediate type hypersensitivity, possibly to bacterial antigens.

Acetaminophen and aspirin challenges in subgroups of asthmatics

To determine whether the different modes of action of aspirin and acetaminophen are associated with different incidences of bronchoconstriction, and whether there is cross-reactivity in terms of intolerance, selected asthmatics were challenged with both analgesics. Clinical profiles were observed to characterize more precisely the aspirin-intolerant asthmatic. Inhalational challenges with PGF2 alpha were then performed on nine selected subjects. It was determined that a positive history of aspirin intolerance is a reliable indicator of potential for anaphylactoid reactions but is not associated with any detectable risk of acetaminophen intolerance. Inhalational PGF2 alpha tends to involve the larger airways; oral aspirin affects both large and small airways.