The association of individual allergen reactivity with respiratory disease in a national sample: data from the second National Health and Nutrition Examination Survey, 1976-80 (NHANES II)

Changing prevalence of allergic rhinitis and asthma

OBJECTIVE

This review will enable the reader to discuss prevalence, risk factors, and prognosis of allergic rhinitis and asthma.

DATA SOURCES

MEDLINE (PubMed) search using the terms allergic rhinitis, asthma, prevalence, risk factors.

STUDY SELECTION

Human studies published in the English language since 1978, especially studies of relatively large populations in the United States, Great Britain, Australia, and New Zealand, with cross referencing to earlier relevant studies.

RESULTS

Current prevalence of allergic rhinitis at 16 years of age in cohorts of British children born in 1958 and 1970 increased from 12% in the earlier cohort to 23% and in the later cohort. Local surveys of allergic rhinitis at approximately 18 years of age in the United States in 1962 to 1965 disclosed prevalence of 15% to 28%, while the national survey of 1976 to 1980 disclosed a prevalence of 26%. Thus, it is uncertain whether prevalence of allergic rhinitis has changed in the United States based on these limited data. Data from several sources indicate worldwide increases in prevalence of asthma. Annual Health Interview surveys indicate increases in prevalence of asthma in the United States from 3.1% in 1980 to 5.4% in 1994, but prevalence among impoverished inner city children has been much higher. Combined prevalence of diagnosed and undiagnosed asthma among inner city children has been 26% and 27% at 9 to 12 years of age in Detroit and San Diego. Positive family history and allergy are important risk factors for allergic rhinitis and asthma. Prognosis is guarded; allergic rhinitis resolves in only 10% to 20% of children within 10 years, and at least 25% of young adults who have had asthma during early childhood are symptomatic as adults.

CONCLUSION

Increases in prevalence remain unexplained, but avoidance of recognized allergens should reduce the prevalence of allergic rhinitis and asthma.

The role of IgE in asthma

Asthma is a multifactorial and complex disease in which allergic factors and non-allergic triggers interact and result in bronchial obstruction and inflammation. Allergenic sensitization is important in the development of asthma and, although links between inhalant allergy and asthma have been known for many years, they have recently been re-emphasized. Indoor allergens are associated with asthma prevalence, severity and exacerbations whereas outdoor allergens such as pollens are associated with exacerbations. Moreover, there is a link between total IgE and asthma which appears to be independent of allergen sensitization. One of the typical aspects of airway inflammation of asthma is the infiltration of the airway wall by T helper type 2 (Th2) cells. These cells are attracted to inflammatory sites by adhesion molecules and chemokines among which CCR3 and CXCR4 receptors appear to be of importance. Differentiation of B cells into IgE-secreting plasma cells is a complex cascade of events in which cytokines play a crucial role. Both IL-4 and IL-13 are inducing IgE synthesis whereas IFN-gamma and IL-12 are blocking IgE synthesis. IgE production by B cells not only requires the presence of IL-4 or IL-13, but also a physical interaction between T and B cells, involving a number of surface and adhesion molecules such as CD40-CD40L and CD28/CD80. Production of TH2-cytokines is not restricted to T cells as basophils and mast cells can produce them indicating that these cells may be of importance in the synthesis of IgE.

Factors determining the severity of asthma

Asthma typically can range from a disease of very mild and intermittent symptoms to one of debilitating and life-threatening disease. However, the factors that control these differences remain poorly understood. It is likely that the factors controlling the severity of asthma are many and dependent on each other. Potential factors include: (i) inflammatory; (ii) structural; (iii) hereditary/congenital; (iv) environmental; and (v) psychological/emotional; each potentially interacting and influencing the other. Finally, the question remains as to whether all asthmatics, no matter what their initial severity, potentially can develop severe disease, or whether only a certain subgroup will become severe.

Prevalence of sensitization to aeroallergens in California patients with respiratory allergy. Allergy Skin Test Project Team

BACKGROUND

The number of allergy skin tests required to evaluate patients with respiratory allergy has recently been challenged by the managed care community.

OBJECTIVES

The purpose of this study was to determine which aeroallergens are prevalent in patients with respiratory allergy (allergic rhinitis and bronchial asthma) in California.

METHODS

Utilizing aeroallergens thought to be relevant from recent aerobiologic and botanic data, 141 allergic and 17 asymptomatic control subjects were tested for the prevalence of 103 allergens. A standardized prick puncture technique and standardized interpretation of wheal/flare responses were utilized using the same lot of allergen for 13 allergy practices distributed throughout California. Frequency curves based on prevalence were established to determine the number of tests required to give up to 90% of positive responses for tree, weed and grass pollen, mold spores, and miscellaneous allergens which included house dust mite, cat, dog, and cockroach allergens.

RESULTS

Positive responses in allergic subjects for grasses ranged from 46% to 54%, for weeds 19% to 37%, and for trees 10% to 42%. For molds the range was from 11% to 22%. The response rate for Dermatophagoides pteronyssinus was 53%, for Dermatophagoides farinae 42%, for cat pelt 39% and cat hair 37%, for cockroach 23% and dog dander 19%. Asymptomatic control subjects responded to only 4% of all allergens tested. Ninety percent of all positive tests required three miscellaneous allergens (house dust mite, cat, and cockroach), 9 molds, 2 grasses, 16 weeds, and 27 trees for a total of 57 allergens (56% of total tested). There was no clear relationship between locale and specific allergen response, probably related to the limited number of subjects tested and variability within the same geographic region. Several seldom tested tree and weed allergens showed a higher prevalence rate than several commonly tested for allergens.

CONCLUSIONS

This preliminary study suggests that approximately 57 aeroalleroens might be adequate to detect 90% of all positive responses in patients with respiratory allergy in California. This study was limited by subject number and variability between study sites. It is hoped a standardized model can be developed from this pilot study to definitively determine which aeroallergens are relevant in the United States.

Prevalence of atopy in students from Málaga, Spain

BACKGROUND

Epidemiologic studies are necessary to determine the prevalence of allergic diseases. This varies widely depending on allergen preparations and patients studied.

OBJECTIVE

To investigate the prevalence of atopic disease, skin test reactivity, total and specific IgE to common allergens, and other variables in a sample of students from Málaga, southern Spain.

METHODS

Three hundred sixty-five students (age 17.9 +/- 1.18) were interviewed by an allergist. Skin prick tests were performed with Dermatophagoides pteronyssinus, Artemisia vulgaris, Plantago lanceolata, Chenopodium album, Olea europaea, Phleum pratense, Parietaria judaica, Cynodon dactylon, Alternaria tenuis, and cat dander. Total and specific IgE to D. pteronyssinus, Olea, and Parietaria were determined.

RESULTS

Of all subjects studied, 19.9% suffered from rhinoconjunctivitis, 4.1% rhinoconjunctivitis plus asthma, 3.1% asthma alone, and 0.8% atopic dermatitis; 46.4% had a positive skin test to at least one allergen (28.2% to D. pteronyssinus, 20.4% to Olea, 13.8% to Phleum); and 43% had total IgE > 100 kU/L and 44.7% a family history of atopy. Allergic symptoms were strongly associated with skin test positivities and family allergic history. Patients with asthma or skin prick test positive had higher total IgE values than others (P < .01). There was a significant correlation between specific IgE values and wheal size in skin test.

CONCLUSIONS

Our findings confirm the high prevalence of atopic diseases, and the close relationship of skin tests reactivity (or presence of specific IgE) to allergens with symptoms of asthma and rhinitis. The presence of a family history of allergic diseases influences the development of positive skin tests and atopic illness. Dermatophagoides pteronyssinus and pollen of Olea europaea were found to be the most common allergens.

Purification and characterization of an arginine-specific peptidase from ragweed (Ambrosia artemisiifolia) pollen

Ragweed (Ambrosia artemisiifolia) is clinically the most important source of seasonal aeroallergens, as it is responsible for the majority and most severe cases of hay fever (allergic rhinitis). Extracts from pollen grains have been shown to contain numerous proteins with various functions, including a novel serine proteolytic enzyme with chymotrypsin-like specificity that has been previously described (J. Biol. Chem. 1996; 271:26227-26232). We now report the isolation and properties of a second, trypsin-like enzyme with a molecular mass near 80 kD, from ragweed pollen extracts. This enzyme has a blocked N-terminus, a pH optimum near 9.0, and requires Ca2+ for stability and activity, but not reducing agents. The enzyme is inhibited by diisopropyl fluorophosphate, a general serine class proteinase inhibitor, and more specifically by N-p-tosyl-L-lysine chloromethyl ketone. Activity toward protein substrates was not detected, but various synthetic substrates and small biologically active peptides were efficiently cleaved, with a strong preference for Arg in the P1 position and either Arg or Gly in the P2 position. This specificity was confirmed through inhibition studies with both peptidyl chloromethyl ketone and organophosphate inhibitors. Significantly, atrial natriuretic peptide and angiotensin 2, whose degradation would amplify kinin activity and influence inflammatory diseases of the respiratory tract and nasal passages, were also rapidly hydrolyzed. Thus, the ragweed pollen endopeptidase may be involved in the inactivation of regulatory neuropeptides during pollen-initiated allergic reactions.

Genetic and environmental risk factors for asthma: a cotwin-control study

In complex diseases of genetic etiology such as asthma and atopy, it is difficult to differentiate causes of disease from consequences, and quantitate the importance of such causative factors. We examined possible risk factors for the development of wheezing and bronchial hyperresponsiveness in a cotwin-control study nested within a larger community-based twin-family study. In 62 monozygotic (MZ) twin pairs discordant for a history of wheezing, skin prick test to house dust extract was the most important discriminator, followed by sensitization to cat and cockroach allergens. In contrast, 62 dizygotic (DZ) discordant twin pairs differed additionally in sensitization to grass pollens and fungi. Markers such as serum haptoglobin, serum magnesium, and alpha-1-antitrypsin levels did not differ significantly between discordant twins. This MZ/DZ difference suggests that pollen allergy in asthmatics is more an epiphenomenon due to a genetic correlation between asthma and the allergic diathesis, whereas indoor allergens are likely to be direct environmental causes of asthma.

Prevalence of sensitization to Alternaria in allergic patients in Italy

BACKGROUND

The actual prevalence of sensitization to Alternaria is not known, partly due to the unreliability of diagnostic extracts.

OBJECTIVE

To assess skin positivity to extracts of Alternaria in a wide population of Italian patients suffering from respiratory symptoms using a biologically standardized extract.

METHODS

A total of 2942 patients were skin prick tested with Alternaria, and a panel of common inhalant allergens. Blood samples for specific IgE quantitation were taken both from patients positive and from patients negative (control group) to Alternaria extract.

RESULTS

Three hundred six patients (10.4%, ranging from 1.8% in Turin to 29.3% in Cagliari) were positive to Alternaria; 37 were sensitized to only this mold, while the remaining 269 were sensitized to at least one other allergen. Of the Alternaria-positive patients, 79.7% suffered from rhinitis and 53.3% from asthma, either alone or associated with other symptoms.

CONCLUSIONS

We suggest that, at least in Italy and in countries with similar climatic and environmental situations, standardized Alternaria extract should be included in the panel commonly used in investigating the allergen responsible in patients suffering from respiratory allergy.

A novel animal model for investigating persistent airway hyperresponsiveness

The present study investigates the development and maintenance of airway hyperresponsiveness in neonatally immunized rabbits. Rabbits were immunized within 24 hr of birth with the antigen Alternaria tenuis together with aluminum hydroxide as an adjuvant, followed by repeated antigen and adjuvant administration up to 3 months of age. Anesthetized, spontaneously breathing rabbits immunized according to this protocol exhibited a 3.7- (p < 0.01) and 1.8-fold (p < 0.05) increase in airway responsiveness to inhaled histamine when compared with groups of naive or sham-immunized rabbits, respectively. In the absence of further antigen challenge, these changes in airway responsiveness to histamine in a subpopulation of antigen-immunized rabbits persisted for up to 12 months of age. This hyperresponsiveness was not associated with an alteration in either total or differential inflammatory cell numbers as assessed by bronchoalveolar lavage (BAL), and no significant differences in isolated bronchial smooth muscle responsiveness to methacholine, histamine, theophylline, or electrical field stimulation were observed. These results demonstrate that neonatal immunization of rabbits with Alternaria tenuis can lead to the development of persistent airway hyperresponsiveness, and that the maintenance of this state is unrelated to either a detectable alteration in cellular infiltration within the airway lumen or changes in bronchial smooth muscle responsiveness. It is suggested that neonatal exposure to antigen and adjuvant may be important determinants for the development of persistent airway hyperresponsiveness. This animal model may provide a useful way to investigate the effects of drugs on airway hyperresponsiveness.