Gastrointestinal-isolated Distress is Common in Alpha-gal Allergic Patients on Mammalian Meat Challenge

BACKGROUND AND AIMS

Alpha-gal allergy causes a delayed reaction to mammalian meats and has been reported worldwide. Patients with the allergy may present with isolated gastrointestinal (GI) symptoms, but this phenotype is poorly understood.

METHODS

We pooled and analyzed symptoms and demographics of patients from two prospective cohorts of patients with a diagnosis of alpha-gal allergy who reacted after eating mammalian meat under observation. We compared the characteristics of patients who demonstrated GI-isolated symptoms on a challenge with those who exhibited symptoms outside the GI tract (skin, respiratory, and circulatory).

RESULTS

Among the 91 children and adult alpha-gal allergic patients who exhibited symptoms after oral challenge with mammalian meat, 72.5% experienced GI distress with one or more GI symptoms, which was the most frequent class of symptoms, compared with skin changes in 57.1% and respiratory distress in 5.5%. The most common GI symptoms were abdominal pain (71%) and vomiting (22.0%). GI-isolated symptoms occurred in 37 patients (40.7%) who reacted, and those patients reacted more quickly than patients who exhibited systemic symptoms (median onset of symptoms in GI-isolated group 90 min vs 120 min) and were more likely to be children than adults (relative risk=1.94, 95% CI: 1.04-3.63).

CONCLUSIONS

Isolated-GI distress occurred in 4 in every 10 alpha-gal allergic individuals who developed symptoms on oral food challenge with mammalian meat. Alpha-gal allergic patients, particularly children, may exhibit GI distress alone, and adult and pediatric gastroenterologists should be aware of the diagnosis and management of the allergy.

AGA Clinical Practice Update on Alpha-Gal Syndrome for the GI Clinician: Commentary

DESCRIPTION

Alpha-gal syndrome is an emerging allergy first described in the early 2000s. The allergy can cause anaphylaxis, gastrointestinal (GI) symptoms, and skin changes one to several hours after ingestion of mammalian products. A GI phenotype that is increasingly recognized manifests with nonspecific symptoms like abdominal pain, diarrhea, nausea or vomiting without predominant skin, respiratory or circulatory symptoms. Though the syndrome has been reported on all continents except Antarctica, in the United States most reports are within the range of the Lone Star tick, extending from New York and Iowa to Texas and Florida. The purpose of this AGA Clinical Practice Update (CPU) Commentary is to increase awareness among gastroenterologists about the presentation and management of alpha-gal syndrome.

METHODS

This CPU commentary was commissioned and approved by the AGA Institute Clinical Practice Updates Committee (CPUC) and the AGA Governing Board to provide timely guidance on a topic of high clinical importance to the AGA membership and underwent internal peer review by the CPUC and external peer review through standard procedures of Clinical Gastroenterology and Hepatology. This expert commentary incorporates important as well as recently published studies in this field, and it reflects the experiences of the authors. Formal ratings regarding the quality of evidence or strength of the presented considerations were not included since systematic reviews were not performed.

Epigenome-wide association study reveals methylation pathways associated with childhood allergic sensitization

Epigenetic mechanisms integrate both genetic variability and environmental exposures. However, comprehensive epigenome-wide analysis has not been performed across major childhood allergic phenotypes. We examined the association of epigenome-wide DNA methylation in mid-childhood peripheral blood (Illumina HumanMethyl450K) with mid-childhood atopic sensitization, environmental/inhalant and food allergen sensitization in 739 children in two birth cohorts (Project Viva-Boston, and the Generation R Study-Rotterdam). We performed covariate-adjusted epigenome-wide association meta-analysis and employed pathway and regional analyses of results. Seven-hundred and five methylation sites (505 genes) were significantly cross-sectionally associated with mid-childhood atopic sensitization, 1411 (905 genes) for environmental and 45 (36 genes) for food allergen sensitization (FDR<0.05). We observed differential methylation across multiple genes for all three phenotypes, including genes implicated previously in innate immunity (DICER1), eosinophilic esophagitis and sinusitis (SIGLEC8), the atopic march (AP5B1) and asthma (EPX, IL4, IL5RA, PRG2, SIGLEC8, CLU). In addition, most of the associated methylation marks for all three phenotypes occur in putative transcription factor binding motifs. Pathway analysis identified multiple methylation sites associated with atopic sensitization and environmental allergen sensitization located in/near genes involved in asthma, mTOR signaling, and inositol phosphate metabolism. We identified multiple differentially methylated regions associated with atopic sensitization (8 regions) and environmental allergen sensitization (26 regions). A number of nominally significant methylation sites in the cord blood analysis were epigenome-wide significant in the mid-childhood analysis, and we observed significant methylation - time interactions among a subset of sites examined. Our findings provide insights into epigenetic regulatory pathways as markers of childhood allergic sensitization.

Epigenome-wide association study of total serum immunoglobulin E in children: a life course approach

Background

IgE-mediated sensitization may be epigenetically programmed in utero, but early childhood environment may further alter complex traits and disease phenotypes through epigenetic plasticity. However, the epigenomic footprint underpinning IgE-mediated type-I hypersensitivity has not been well-understood, especially under a longitudinal early-childhood life-course framework.

Methods

We used epigenome-wide DNA methylation (IlluminaHumanMethylation450 BeadChip) in cord blood and mid-childhood peripheral blood to investigate pre- and post-natal methylation marks associated with mid-childhood (age 6.7-10.2) total serum IgE levels in 217 mother-child pairs in Project Viva-a prospective longitudinal pre-birth cohort in eastern Massachusetts, USA. We identified methylation sites associated with IgE using covariate-adjusted robust linear regressions.

Results

Nineteen methylation marks in cord blood were associated with IgE in mid-childhood (FDR < 0.05) in genes implicated in cell signaling, growth, and development. Among these, two methylation sites (C7orf50, ZAR1) remained robust after the adjustment for the change in DNA methylation from birth to mid-childhood (FDR < 0.05). An analysis of the change in methylation between cord blood and mid-childhood DNA (Δ-DNAm) identified 395 methylation marks in 272 genes associated with mid-childhood IgE (FDR < 0.05), with multiple sites located within ACOT7 (4 sites), EPX (5 sites), EVL (3 sites), KSR1 (4 sites), ZFPM1 (3 sites), and ZNF862 (3 sites). Several of these methylation loci were previously associated with asthma (ADAM19, EPX, IL4, IL5RA, and PRG2).

Conclusion

This study identified fetally programmed and mid-childhood methylation signals associated with mid-childhood IgE. Epigenetic priming during fetal development and early childhood likely plays an important role in IgE-mediated type-I hypersensitivity.

Glycan and Peptide IgE Epitopes of the TNF-alpha Blockers Infliximab and Adalimumab - Precision Diagnostics by Cross-Reactivity Immune Profiling of Patient Sera

Biological drugs like therapeutic antibodies are widely used for the treatment of various diseases like inflammatory disorders and cancer. A drawback of these novel treatments is the substantial proportion of patients experiencing adverse reactions such as loss-of-drug effect or hypersensitivity reactions. These reactions are associated with pre-existing and/or developing anti-drug antibodies. Especially IgE development is a risk factor for life-threatening systemic anaphylaxis.

Methods: In order to characterize the individual drug-specific serum IgE, an IgE cross-reactivity immune profiling (ICRIP) assay was developed. Individual IgG epitopes of anti-drug antibodies against adalimumab were identified by epitope mapping via peptide microarray.

Results: ICRIP analyses of sera from patients treated with the therapeutic antibodies adalimumab (ADL) and infliximab (IFX) reveal individual, distinct IgE binding patterns. IgG epitopes were identified mostly located in the variable region of ADL.

Conclusions: Using ICRIP and peptide microarrays for pharmacovigilance of the TNF-α blockers IFX and ADL, risk factors and biomarkers before and during therapy shall be identified. These diagnostic systems provide the basis for a safe and efficacious therapy decision for each patient in cases of adverse drug reactions mediated by different types of anti-drug antibodies.

Eosinophilic Esophagitis From an Allergy Perspective: How to Optimally Pursue Allergy Testing & Dietary Modification in the Adult Population

Eosinophilic esophagitis (EoE) is a clinicopathologic condition characterized by symptoms of esophageal dysfunction and eosinophil-predominant inflammation. In adults, the three most common treatment options are swallowed steroids, elimination diets, and periodic esophageal dilations. Many different elimination diets have been studied in adults, including elemental diets, allergy testing-directed diets, and empiric elimination diets. This article will review the existing data on these dietary therapies and will propose an approach to dietary management in adult EoE.

The Developmental History of IgE and IgG4 Antibodies in Relation to Atopy, Eosinophilic Esophagitis, and the Modified TH2 Response

A common reaction from anyone confronted with allergy is the question: what prevents universal allergy? We will discuss recent findings in the mouse system that have provided us with clues on why allergy is not more common. We will also address one crucial aspect of atopic allergy in humans, which is absent in most mouse model systems, an IgG/IgE ratio <10. We consider the typical mouse IgE response to be more closely related to the "modified TH2" response in humans. We will discuss the similarities and differences between the IgE and IgG4 response to allergens and an update on the IgG4 B cell, partly derived from studies on eosinophilic esophagitis and IgG4-related diseases.

Analysis of cytokine production by peanut-reactive T cells identifies residual Th2 effectors in highly allergic children who received peanut oral immunotherapy

BACKGROUND

Only limited evidence is available regarding the cytokine repertoire of effector T cells associated with peanut allergy, and how these responses relate to IgE antibodies to peanut components.

OBJECTIVE

To interrogate T cell effector cytokine populations induced by Ara h 1 and Ara h 2 among peanut allergic (PA) children in the context of IgE and to evaluate their modulation during oral immunotherapy (OIT).

METHODS

Peanut-reactive effector T cells were analysed in conjunction with specific IgE profiles in PA children using intracellular staining and multiplex assay. Cytokine-expressing T cell subpopulations were visualized using SPICE.

RESULTS

Ara h 2 dominated the antibody response to peanut as judged by prevalence and quantity among a cohort of children with IgE to peanut. High IgE (> 15 kU(A)/L) was almost exclusively associated with dual sensitization to Ara h 1 and Ara h 2 and was age independent. Among PA children, IL-4-biased responses to both major allergens were induced, regardless of whether IgE antibodies to Ara h 1 were present. Among subjects receiving OIT in whom high IgE was maintained, Th2 reactivity to peanut components persisted despite clinical desensitization and modulation of allergen-specific immune parameters including augmented specific IgG4 antibodies, Th1 skewing and enhanced IL-10. The complexity of cytokine-positive subpopulations within peanut-reactive IL-4(+) and IFN-γ(+) T cells was similar to that observed in those who received no OIT, but was modified with extended therapy. Nonetheless, high Foxp3 expression was a distinguishing feature of peanut-reactive IL-4(+) T cells irrespective of OIT, and a correlate of their ability to secrete type 2 cytokines.

CONCLUSION

Although total numbers of peanut-reactive IL-4(+) and IFN-γ(+) T cells are modulated by OIT in highly allergic children, complex T cell populations with pathogenic potential persist in the presence of recognized immune markers of successful immunotherapy.

Sensitization to food and inhalant allergens in relation to age and wheeze among children with atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is common in children; however, persistence of AD with or without asthma is less common. Longitudinal studies remain limited in their ability to characterize how IgE antibody responses evolve in AD, and their relationship with asthma.

OBJECTIVE

To use a cross-sectional study design of children with active AD to analyse age-related differences in IgE antibodies and relation to wheeze.

METHODS

IgE antibodies to food and inhalant allergens were measured in children with active AD (5 months to 15 years of age, n = 66), with and without history of wheeze.

RESULTS

Whereas IgE antibodies to foods persisted at a similar prevalence and titre throughout childhood, IgE antibodies to all aeroallergens rose sharply into adolescence. From birth, the chance of sensitization for any aeroallergen increased for each 12-month increment in age (OR ≥ 1.21, P < 0.01), with the largest effect observed for dust mite (OR = 1.56, P < 0.001). A steeper age-related rise in IgE antibody titre to dust mite, but no other allergen was associated with more severe disease. Despite this, sensitization to cat was more strongly associated with wheeze (OR = 4.5, P < 0.01), and linked to Fel d 1 and Fel d 4, but not Fel d 2. Comparison of cat allergic children with AD to those without, revealed higher IgE levels to Fel d 2 and Fel d 4 (P < 0.05), but not Fel d 1.

CONCLUSIONS AND CLINICAL RELEVANCE

Differences in sensitization to cat and dust mite among young children with AD may aid in identifying those at increased risk for disease progression and development of asthma. Early sensitization to cat and risk for wheeze among children with AD may be linked to an increased risk for sensitization to a broader spectrum of allergen components from early life. Collectively, our findings argue for early intervention strategies designed to mitigate skin inflammation in children with AD.

Peanut, milk, and wheat intake during pregnancy is associated with reduced allergy and asthma in children

BACKGROUND

Maternal diet during pregnancy may affect childhood allergy and asthma.

OBJECTIVE

We sought to examine the associations between maternal intake of common childhood food allergens during early pregnancy and childhood allergy and asthma.

METHODS

We studied 1277 mother-child pairs from a US prebirth cohort unselected for any disease. Using food frequency questionnaires administered during the first and second trimesters, we assessed maternal intake of common childhood food allergens during pregnancy. In mid-childhood (mean age, 7.9 years), we assessed food allergy, asthma, allergic rhinitis, and atopic dermatitis by questionnaire and serum-specific IgE levels. We examined the associations between maternal diet during pregnancy and childhood allergy and asthma. We also examined the cross-sectional associations between specific food allergies, asthma, and atopic conditions in mid-childhood.

RESULTS

Food allergy was common (5.6%) in mid-childhood, as was sensitization to at least 1 food allergen (28.0%). Higher maternal peanut intake (each additional z score) during the first trimester was associated with 47% reduced odds of peanut allergic reaction (odds ratio [OR], 0.53; 95% CI, 0.30-0.94). Higher milk intake during the first trimester was associated with reduced asthma (OR, 0.83; 95% CI, 0.69-0.99) and allergic rhinitis (OR, 0.85; 95% CI, 0.74-0.97). Higher maternal wheat intake during the second trimester was associated with reduced atopic dermatitis (OR, 0.64; 95% CI, 0.46-0.90). Peanut, wheat, and soy allergy were each cross-sectionally associated with increased childhood asthma, atopic dermatitis, and allergic rhinitis (ORs, 3.6 to 8.1).

CONCLUSION

Higher maternal intake of peanut, milk, and wheat during early pregnancy was associated with reduced odds of mid-childhood allergy and asthma.

Physical deconditioning as a cause of breathlessness among obese adolescents with a diagnosis of asthma

BACKGROUND

Obese children frequently complain of breathlessness. Asthma and obesity can both contribute to the symptoms during exercise, and this symptom can contribute to a diagnosis of asthma in these children. Despite the high prevalence of obesity few studies have investigated the cardiopulmonary physiology of breathlessness in obese children with a diagnosis of asthma.

METHODS

In this case-control study, thirty adolescents between age 12 and 19 were studied with baseline spirometry and a cardiopulmonary exercise test. Ten adolescents were normal controls, ten had obesity without a diagnosis of asthma, and ten had obesity with a history of physician-diagnosed asthma.

RESULTS

Baseline characteristics including complete blood count and spirometry were comparable between obese adolescents with and without a diagnosis of asthma. During exercise, obese asthmatic and obese non-asthmatic adolescents had significantly reduced physical fitness compared to healthy controls as evidenced by decreased peak oxygen uptake after adjusting for actual body weight (21.7 ± 4.5 vs. 21.4 ± 5.4 vs. 35.3 ± 5.8 ml/kg/min, respectively). However, pulmonary capacity at the peak of exercise was comparable among all three groups as evidenced by similar pulmonary reserve.

CONCLUSION

In this study, breathlessness was primarily due to cardiopulmonary deconditioning in the majority of obese adolescents with or without a diagnosis of asthma.

IgE production to α-gal is accompanied by elevated levels of specific IgG1 antibodies and low amounts of IgE to blood group B

IgE antibodies to gal-α-1,3-gal-β-1,4-GlcNAc (α-gal) can mediate a novel form of delayed anaphylaxis to red meat. Although IgG antibodies to α-gal (anti-α-gal or anti-Gal) are widely expressed in humans, IgE anti-α-gal is not. We explored the relationship between the IgG and IgE responses to both α-gal and the related blood group B antigen. Contradicting previous reports, antibodies to α-gal were found to be significantly less abundant in individuals with blood group B or AB. Importantly, we established a connection between IgE and IgG responses to α-gal: elevated titers of IgG anti-α-gal were found in IgE-positive subjects. In particular, proportionally more IgG1 anti-α-gal was found in IgE-positive subjects against a background of IgG2 production specific for α-gal. Thus, two types of immune response to α-gal epitopes can be distinguished: a ‘typical’ IgG2 response, presumably in response to gut bacteria, and an ‘atypical’, Th2-like response leading to IgG1 and IgE in addition to IgG2. These results suggest that IgE to a carbohydrate antigen can be formed (probably as part of a glycoprotein or glycolipid) even against a background of bacterial immune stimulation with essentially the same antigen.

Desensitization of an adult patient with Pompe disease and a history of anaphylaxis to alglucosidase alfa

We report on the successful desensitization of an adult female with Pompe disease who had previously experienced anaphylaxis to intravenous alglucosidase alfa therapy. The starting alglucosidase alfa dose for desensitization was 10mg/kg with gradual dose escalation and desensitization via serial dilution was completed over five infusions. This methodology serves as a means to desensitize patients with prior anaphylactic response to alglucosidase alfa so that enzyme replacement therapy can be utilized.

Changes in regional airflow obstruction over time in the lungs of patients with asthma: evaluation with 3He MR imaging

PURPOSE

To determine changes in regional airflow obstruction over time in the lungs of patients with asthma, as demonstrated with hyperpolarized helium 3 ((3)He) magnetic resonance (MR) imaging, and to assess correlations with disease severity and use of asthma medications.

MATERIALS AND METHODS

Institutional review board approval and written informed consent were obtained for this HIPAA-compliant study. Use of (3)He was approved by the U.S. Food and Drug Administration. Forty-three patients underwent 103 MR imaging studies in total; 26 were imaged twice within 42-82 minutes (same day), and 17 were imaged on 3 days between 1 and 476 days (multiday). Each day, spirometry was performed, disease severity was determined, and the use of asthma medications was recorded. Images were reviewed in a pairwise fashion to determine total ventilation defect number, defects in same location between imaging studies, and size. Parametric and nonparametric statistical methods were used.

RESULTS

For the same-day examinations, the mean number of defects per image section was similar at baseline and repeat imaging (1.8 +/- 1.9 [standard deviation] vs 1.6 +/- 1.9, respectively; P = .15), with 75% of defects remaining in the same location and 71% of these not changing size. For the multiday examinations, the mean number of defects per section was higher for study 2 (2.4 +/- 1.5) than study 1 (1.7 +/- 0.9, P = .02), was lower for study 3 (1.5 +/- 1.1) than for study 2 (P < .01), and was similar for studies 1 and 3 (P = .56). Time between examinations was not associated with change in mean number of defects per section (median intrasubject correlation [r(m)] = 0.01, P = .64) or change in spirometric values (range of r(m) values: -0.56 to -0.31; range of P values: .09-.71). Defects in the same location decreased with time (r(m) = -0.83, P < .01), with 67% persisting between studies 1 and 2 (median interval, 31 days), 43% persisting between studies 2 and 3 (median interval, 41 days), and 38% persisting between studies 1 and 3 (median interval, 85 days); 46%-58% of defects remained unchanged in size. These trends were the same regardless of disease severity or medication use.

CONCLUSION

In asthma, focal airflow impediment within the lungs can be markedly persistent over time, regardless of disease severity or treatment.

Evaluation of Asthma With Hyperpolarized Helium-3 MRI

BACKGROUND

Accurate characterization of asthma severity is difficult due to the variability of symptoms. Hyperpolarized helium-3 MRI (H(3)HeMR) is a new technique in which the airspaces are visualized, depicting regions with airflow obstruction as "ventilation defects." The objective of this study was to compare the extent of H(3)HeMR ventilation defects with measures of asthma severity and spirometry.

METHODS

Patients with a physician diagnosis of asthma and normal control subjects underwent H(3)HeMR. For each person, the number and size of ventilation defects were scored and the average number of ventilation defects per slice (VDS) was calculated. The correlations of the imaging findings with measures of asthma severity and spirometry were determined.

RESULTS

There were 58 patients with asthma (mild-intermittent, n = 13; mild-persistent, n = 13; moderate-persistent, n = 20; and severe-persistent, n = 12) and 18 control subjects. Mean +/- SE VDS for asthmatics was significantly greater than for control subjects (0.99 +/- 0.15 vs 0.26 +/- 0.22, p = 0.004). Among asthmatics, VDS was significantly higher for the group with moderate-persistent and severe-persistent disease than for the group with mild-intermittent and mild-persistent disease (1.37 +/- 0.24 vs 0.53 +/- 0.12, p < 0.001). VDS correlated significantly with FEV(1)/FVC (r = - 0.51, p = 0.002), forced expiratory flow between 25% and 75% from the beginning of FVC (FEF(25-75%)) percentage of predicted for height, sex, and race (%predicted) [r = - 0.50, p = 0.001], and FEV(1) %predicted (r = - 0.40, p = 0.002), but not with FVC %predicted (r = - 0.26, p = 0.057) and peak expiratory flow %predicted (r = - 0.16, p = 0.231). Many asthmatics had an elevated VDS, but their spirometric indexes, except FEF(25%-75%), were normal. Most ventilation defects were < 3 cm in size for all asthmatics. In the group of patients with moderate-to-severe persistent asthma, there were more defects > or =3 cm than in the group with mild-intermittent and mild-persistent disease (p = 0.021).

CONCLUSIONS

Regional changes of airflow obstruction in asthmatics depicted by H(3)HeMR correlate with measures of asthma severity and spirometry.

IgE and IgG antibody responses to recombinant Alt a 1 as a marker of sensitization to Alternaria in asthma and atopic dermatitis

BACKGROUND

Sensitization to Alternaria alternata is a risk factor for the development of wheezing and asthma. Alt a 1 is the major Alternaria allergen causing sensitization in asthmatics. Some atopic dermatitis (AD) patients have very high immunoglobulin (Ig)E antibody (ab) to Alternaria as analysed by Pharmacia CAP, however, it is not clear whether these are specific responses or whether Alt a 1 is involved in disease symptoms.

OBJECTIVE

The aim of this study was to analyse specific IgE and IgG ab responses to recombinant Alt a 1 in asthmatic and AD patients and to compare these results to IgE ab against Alternaria measured by CAP.

METHODS

Sera from individuals who were IgE positive to Alternaria by CAP were obtained from 58 patients with asthma/rhinitis, 19 patients with AD, and 20 patients with cystic fibrosis (CF) who were included as specificity controls. IgE and IgG ab to recombinant Alt a 1 were measured by radioimmunoassay (RIA).

RESULTS

Of 43 asthma/rhinitis patients having an Alternaria CAP score > 2, a high percentage (93%) had both IgE and IgG ab to Alt a 1, emphasizing its importance as a major allergen. Only, 47% of AD patients with CAP score greater than 2 had ab to Alt a 1, and their levels were low when compared to the asthmatics. For CF controls, 75% of these patients had no IgE ab to Alt a 1, and those which were positive to Alt a 1 by RIA were also positive by CAP. Overall, patients with a low CAP (1-2) had a low prevalence (20-30%) of IgE or IgG ab to Alt a 1.

CONCLUSION

IgE and IgG ab to Alt a 1 in asthmatics are good markers for sensitization to Alternaria. Although AD patients gave high Alternaria CAP scores, they had low or undetectable levels of IgE to Alt a 1, suggesting that other Alternaria allergens may be important in AD or that the CAP results are non-specific. Recombinant allergens may provide more specific measures of sensitization to fungi.

Home intervention in the treatment of asthma among inner-city children

BACKGROUND

In Atlanta, as in other major urban areas of the United States, asthma is a leading cause of school absenteeism, emergency department use, and hospitalization. Recent guidelines for asthma management recommend reducing exposure to relevant allergens, but neither the feasibility nor the efficacy of this form of treatment has been established for children living in poverty.

OBJECTIVE

We sought to investigate allergen avoidance as a treatment for asthma among inner-city children.

METHODS

One hundred four children with asthma living in the city of Atlanta were enrolled into a controlled trial of avoidance without being skin tested. The children were randomized to an active avoidance group, a placebo avoidance group, and a second control group for which no house visits occurred until the end of the first year. Avoidance included bed and pillow covers, hot washing of bedding, and cockroach bait. Eighty-five children completed the study, and the outcome was measured as unscheduled clinic visits, emergency department visits, and hospitalization for asthma, as well as changes in mite and cockroach allergen levels.

RESULTS

There was a significant decrease in acute visits for asthma among children whose homes were visited (P < .001). However, there was no significant difference between the active and placebo homes either in the effect on asthma visits or in allergen concentrations. When the children with mite allergy were considered separately, there was a significant correlation between decreased mite allergen and change in acute visits (P < .01). The avoidance measures for cockroach allergen appeared to be ineffective, and the changes observed did not correlate with changes in visits.

CONCLUSIONS

Applying allergen avoidance as a treatment for asthma among children living in poverty is difficult because of multiple sensitivities and problems applying the protocols in this environment. The current results demonstrate that home visiting positively influences the management of asthma among families living in poverty. Furthermore, the results for children with mite allergy strongly suggest that decreasing relevant allergen exposure should be an objective of treatment in this population.

Diversity of the human allergen-specific T cell repertoire associated with distinct skin test reactions: delayed-type hypersensitivity-associated major epitopes induce Th1- and Th2-dominated responses

Distinct immune responses in humans to the Trichophyton rubrum Ag, Tri r 2, are associated with different patterns of T cell epitope recognition based on in vitro proliferation to peptides derived from this 29-kDa protein. Specifically, the amino-terminal immunodominant epitope, peptide 5 (P5), stimulates strong T cell proliferative responses in subjects with delayed (DTH), but not immediate (IH) hypersensitivity skin tests. Evidence of a role for cytokines or changes in epitope recognition over time was examined in responses to Trichophyton using primary PBMC cultures established from seven IH and seven DTH subjects. Responses stimulated by Tri r 2 were dominated by the Th1 cytokine IFN-gamma (IFN-gamma:IL-5 > or = 4:1) in five DTH subjects, even in the presence of Th2-dominated responses (IFN-gamma:IL-5 < or = 3:1) to a subset of major epitopes. Paradoxically, P5 induced IL-5 and IL-10 production in DTH, but not IH subjects (p = 0.003 (IL-5), p = 0.024 (IL-10)), with no significant difference in IFN-gamma levels between the two groups. In cultures from IH responders, no IL-5 was measurable after stimulation with P6 and P7 (as well as P5); this region of the molecule was shown previously to stimulate markedly reduced T cell proliferation in these individuals. Repeat proliferation assays confirmed no change in the pattern of peptide recognition after > or =20 mo in IH or DTH subjects. We conclude that T cell repertoires associated with distinct immune responses to Tri r 2 can be distinguished based on Th2 cytokine induction by DTH-associated major epitopes localizing to the amino-terminal region of the molecule.

The role of immunoglobulin E in allergy and asthma

It has been nearly a century since the first suggestion that a soluble factor in plasma or serum might be responsible for the symptoms of allergic disease and asthma, and more than 30 yr since immunoglobulin E (IgE) was identified as the key molecule in mediating what are now described as type 1 hypersensitivity reactions (allergic asthma, allergic rhinitis, food allergy, atopic dermatitis, some forms of drug allergy, and insect sting allergy). Since that time, many of the details of the inflammatory cascade underlying allergy and asthma have been elucidated, and IgE is now known to play a key upstream role. The goals of this report are to review the cellular and molecular events set in motion by IgE and to examine the evidence for its participation in both the immediate allergic response and the late-phase or chronic inflammatory response in the skin and lungs.

Association of specific allergen sensitization with socioeconomic factors and allergic disease in a population of Boston women

BACKGROUND

Socioeconomic differences in allergic disease prevalence have been reported; asthma has been associated with poverty in the United States and hay fever and eczema with relative affluence elsewhere. It is not yet established to what degree such differences in disease prevalence reflect patterns of sensitization and specific allergen sensitivities.

OBJECTIVE

We analyzed specific and total IgE measurements in a sample of 458 women, enriched for allergic disease, from the metropolitan Boston area to establish the relation of allergen sensitization to markers of socioeconomic status (SES) and to the prevalence and socioeconomic pattern of allergic disease in this community.

METHODS

Total and specific IgE antibodies were measured with the UNICAP System; self-reported allergic disease, household income, education, and race-ethnicity were ascertained with a questionnaire; and a further marker of poverty (percentage living below the poverty level) in the women's area of residence was established on the basis of zip codes. Analysis was performed with SAS statistical software.

RESULTS

Markers of low SES were univariately associated with increases in total IgE, number of allergen sensitizations, and levels of specific IgE. Socioeconomic differences in sensitization to cockroach (35% vs 6% in the highest and lowest poverty areas), animal (44% vs 26%), and ragweed (49% vs 23%) allergens were most marked. Sensitization primarily to indoor inhalant allergens (not ragweed or ryegrass) were associated with an increased risk of asthma, even after adjustment for SES.

CONCLUSION

We have demonstrated a socioeconomic gradient in sensitization that concords with increased rates of asthma in less affluent communities in this population.

The biology of dust mites and the remediation of mite allergens in allergic disease

In most temperate humid areas of the world, house dust mites are a major source of multiple allergens in house dust. Mite allergens sensitize and induce perennial rhinitis, asthma, or atopic dermatitis in a large portion of patients with allergic disease. There is convincing evidence that avoidance of mite allergen can effectively reduce allergic symptoms. Patients can be moved to a mite allergen-free environment, or mite and mite allergen abatement can be performed to reduce exposure in existing residences. Some knowledge of the biology of house dust mites is essential to understand the basis of the recommendations for reducing mites and mite allergens in homes and to appreciate the difficulty of eliminating house dust mites and mite allergens from homes. This article reviews key aspects of the biology of dust mites, the properties of mite allergens, recommendations for reducing mite and mite allergen concentrations in homes, and practical recommendations for treatment.

Hyperpolarized 3He MR lung ventilation imaging in asthmatics: preliminary findings

Asthma is a disease characterized by chronic inflammation and reversible obstruction of the small airways resulting in impaired pulmonary ventilation. Hyperpolarized 3He magnetic resonance (MR) lung imaging is a new technology that provides a detailed image of lung ventilation. Hyperpolarized 3He lung imaging was performed in 10 asthmatics and 10 healthy subjects. Seven asthmatics had ventilation defects distributed throughout the lungs compared with none of the normal subjects. These ventilation defects were more numerous and larger in the two symptomatic asthmatics who had abnormal spirometry. Ventilation defects studied over time demonstrated no change in appearance over 30-60 minutes. One asthmatic subject was studied twice in a three-week period and had ventilation defects which resolved and appeared in that time. This same subject was studied before and after bronchodilator therapy, and all ventilation defects resolved after therapy. Hyperpolarized 3He lung imaging can detect the small, reversible ventilation defects that characterize asthma. The ability to visualize lung ventilation offers a direct method of assessing asthmatics and their response to therapy.

Detection of IgA and IgG but not IgE antibody to respiratory syncytial virus in nasal washes and sera from infants with wheezing

BACKGROUND AND OBJECTIVE

The capacity of respiratory syncytial virus (RSV) to stimulate an IgE antibody response and enhance the development of atopy and asthma remains controversial. Nasal washes and sera from 40 infants (20 with wheezing, 9 with rhinitis, and 11 without respiratory tract symptoms) were obtained to measure IgE, IgA, and IgG antibody to the immunodominant, F and G, virion proteins from RSV.

STUDY DESIGN

Children (aged 6 weeks to 2 years) were enrolled in the emergency department during the mid-winter months and seen at follow-up when they were asymptomatic. All nasal washes were tested for RSV antigen. Determinations of antibody isotypes (IgE, IgA, and IgG) to RSV antigens were done in nasal washes and sera by using an enzyme-linked immunosorbent assay. In a subset of nasal washes, IgE to RSV was also evaluated by using a monoclonal anti-F(c)E antibody-based assay.

RESULTS

Fifteen patients with wheezing, two with rhinitis, and one control subject tested positive for RSV antigen at enrollment. Thirteen patients with wheezing were <6 months old, and most (77%) were experiencing their first attack. Among the children with positive test results for RSV antigen, an increase in both nasal wash and serum IgA antibody to RSV-F(a) and G(a) was observed at the follow-up visit. However, there was no evidence for an IgE antibody response to either antigen.

CONCLUSION

Both IgA and IgG antibodies to the immunodominant RSV-F(a) and G(a) antigens were readily detected in the nasal washes and sera from patients in this study. We were unable to demonstrate specific IgE antibody to these antigens and conclude that the production of IgE as a manifestation of a T(H)2 lymphocyte response to RSV is unlikely.

Serum IgG and IgG4 antibodies to Fel d 1 among children exposed to 20 microg Fel d 1 at home: relevance of a nonallergic modified Th2 response

Exposure to foreign antigens is an essential element of all immune responses, including allergic sensitization. For some allergens (e.g. mite and cockroach), the prevalence of sensitization is directly correlated with exposure. However, for allergens derived from domestic animals, several studies have suggested that children with a cat in the home have a decreased risk of sensitization and asthma. We have now shown that many children exposed to greater than 20 microg of Fel d 1/g of dust at home made an IgG and IgG4 antibody response to Fel d 1 without IgE antibody. This modified Th2 response is not associated with symptoms and should be regarded as a form of immunological tolerance. The fact that the dose-response relationship between cat exposure and sensitization is bell shaped, while that for mite exposure and sensitization is linear, is highly relevant to understanding the role of allergens in the increase in allergic disease.

The role of intervention in established allergy: avoidance of indoor allergens in the treatment of chronic allergic disease

Avoidance of exposure to indoor allergens is an important element in the treatment of allergic disease. The results of several studies provide strong evidence in support of a role for allergen avoidance; however, strategies that optimize allergen reduction in houses have not been determined. Complex issues regarding the efficacy of physical and chemical measures that target house dust mite, pet, and cockroach allergens in the home are discussed. The greatest challenge is to educate allergic patients so that they can play an important role in controlling their own disease.

Distinct human T cell repertoires mediate immediate and delayed-type hypersensitivity to the Trichophyton antigen, Tri r 2

The 29-kDa subtilase homologue, Tri r 2, derived from the dermatophyte fungus Trichophyton rubrum, exhibits unique immunologic characteristics in its ability to elicit immediate (IH) and delayed-type (DTH) hypersensitivity skin tests in different individuals. Thus, Tri r 2 provides a model for comparing the T cell repertoire in subjects with distinct immune responses to a single Ag. Recombinant Tri r 2 produced as a GST fusion protein in Escherichia coli stimulated strong in vitro lymphoproliferative responses in 10 IH and 10 DTH responders. Patterns of T cell epitope recognition were compared between skin test groups using 28 overlapping peptides (each in 12 replicate wells) derived from Tri r 2 to stimulate T lymphocyte proliferation in vitro. Peptide 5 (P5; aa 41-60) induced the strongest response in DTH subjects and showed the largest difference between DTH and IH responders in proliferation (mean standardized index, 2.22 and 0.82, respectively; p = 0.0047) and number of positive wells (81 vs 12). Responses to P5 were associated with diverse HLA haplotypes. These results showed that P5 contains an immunodominant epitope specifically associated with DTH and that this peptide is recognized in a permissive manner. Cross-validated linear discriminant analysis using T cell proliferative responses to two regions of Tri r 2 (aa 51-90 and 231-270) gave a 95% predictive accuracy for classification of subjects into IH or DTH groups. We conclude that different immune responses to Trichophyton are mediated by distinct T cell repertoires between individuals with IH and DTH reactions to Tri r 2.

Lactoferrin and eosinophilic cationic protein in nasal secretions of patients with experimental rhinovirus colds, natural colds, and presumed acute community-acquired bacterial sinusitis

To distinguish sinusitis from uncomplicated "colds," we examined lactoferrin and eosinophilic cationic protein (ECP) in nasal secretions. Lactoferrin titers were >/=1:400 in 4% of persons with uncomplicated colds and controls but in 79% of persons with sinusitis or purulent sputa. ECP levels were >200 ng/ml in 61% of persons with colds and >3,000 ng/ml in 62% of persons with sinusitis. Nasal lactoferrin helps distinguish sinusitis from colds.

Specific and nonspecific obstructive lung disease in childhood: causes of changes in the prevalence of asthma

Reversible airway obstruction in childhood includes two major groups of patients: those with recurrent wheezing following bronchiolitis in early childhood, and those with allergic asthma, which represents an increasingly large proportion of cases through the school years. Over the last 40 years of the 20th century, allergic asthma has increased in many countries and in relation to several different allergens. Although this increase has differed in magnitude in different countries and also in the social groups most affected, it has had several features in common. The increase generally started between 1960 and 1970, has been progressive since then, and has continued into the 1990s without a defined peak. Among children 5-18 years of age, the increase has predominantly been among allergic individuals. Theories about the causes of the increase in asthma have focused on two scenarios: a) that changes in houses combined with increased time spent indoors have increased exposure to relevant allergens, or b) that changes in diet, antibiotic use, immunizations, and the pattern of infections in childhood have led to a change in immune responsiveness such that a larger section of the population makes T(H)2, rather than T(H)1 responses including IgE antibodies to inhalant allergens. There are, however, problems with each of these theories and, in particular, none of the proposed changes can explain the progressive nature of the increase over 40 years. The fact that the change in asthma has much in common with epidemic increase in diseases such as Type II diabetes or obesity suggests that similar factors could be involved. Several lines of evidence are reviewed that suggest that the decline in physical activity of children, particularly those living in poverty in the United States, could have contributed to the rise in asthma. The hypothesis would be that the progressive loss of a lung-specific protective effect against wheezing has allowed allergic children to develop symptomatic asthma. What is clear is that current theories do not provide either an adequate explanation of the increase or a practical approach to reversing the current trend.

Quantitative IgE antibody assays in allergic diseases

During the past several years, immunoassays for specific IgE antibodies have been refined to permit reporting results in mass units. Thus quantitative immunoassays for IgE antibodies may be an adjunct to skin tests. In cases of food allergy among children with atopic dermatitis, cutoff values for IgE antibody concentrations to egg, milk, peanut, and fish have been derived to provide 95% positive and 90% negative predictive values. Food-specific IgE antibody determinations can also be used to predict which food allergies are resolving spontaneously. Elevated egg-specific IgE antibody levels in infancy are associated with significantly increased risk for development of inhalant allergies later in childhood. In cases of inhalant allergy, specific IgE antibody levels correlate closely with results of inhalation challenge studies in cat-sensitive persons. Also, mite-specific IgE antibody levels correlate significantly with the mite allergen contents of reservoir dust in the homes of mite-sensitive persons. Immunoassays for quantitation of specific IgE antibodies may be used to document allergen sensitization over time and to evaluate the risk of reaction on allergen exposure. However, immunoassays and skin tests are not entirely interchangeable, and neither will replace the other in appropriate circumstances.

Salivary cotinine levels in children presenting with wheezing to an emergency department

We set out to evaluate salivary cotinine concentrations to judge tobacco smoke exposure among infants and children, and to examine the results in relation to age and wheezing. This was a case-control study of wheezing children (n = 165) and children without respiratory tract symptoms (n = 106) who were enrolled in the Pediatric Emergency Department at the University of Virginia. The age range of both wheezing and control patients was 2 months to 16 years. Questionnaires were combined with cotinine assays in saliva to evaluate exposure to environmental tobacco smoke (ETS) for each child. The prevalence of exposure to one or more smokers at home was high (68%); and 43% of the children enrolled were exposed to ETS from their mothers. According to the questionnaires, and after adjusting for age and race, a wheezing child in this study was more likely than a control to be exposed to at least one smoker at home (odds ratio = 1.9; 95% CI = 1.1-3.4). However, the odds of exposure to ETS from smoking mothers did not differ significantly between wheezing and control patients, and no significant association was found between the presence of wheezing and salivary cotinine levels. Among children exposed to ETS at home, cotinine levels were significantly higher in saliva from those under the age of two years, and from toddlers aged 2 and 3 years, compared to values from children over age 4 years. Moreover, the number of smokers in the home strongly influenced cotinine levels from children under age 4 years. In addition, higher cotinine levels were observed in saliva from children under age 2 years who were exposed to ETS from their mothers. Cotinine levels were similar and significantly correlated in paired samples of saliva and serum from children under 4 years of age (n = 54), (r = 0.92, P < 0.001). Based on information gathered from questionnaires, the results indicate that wheezing children were more likely than controls to be exposed to ETS at home. However, significant differences in ETS exposure between wheezing and control groups with respect to maternal smoke exposure or comparisons of salivary cotinine levels were not apparent. It was clear that determinations of salivary cotinine for monitoring the prevalence and intensity of household smoke exposure in this study were most valuable during the first 4 years of life.

Socioeconomic predictors of high allergen levels in homes in the greater Boston area

In the United States, childhood asthma morbidity and prevalence rates are the highest in less affluent urban minority communities. More than 80% of childhood asthmatics are allergic to one or more inhalant allergens. We evaluated whether socioeconomic status was associated with a differential in the levels and types of indoor home allergens. Dust samples for an ELISA allergen assay were collected from the homes of 499 families as part of a metropolitan Boston, Massachusetts, longitudinal birth cohort study of home allergens and asthma in children with a parental history of asthma or allergy. The proportion of homes with maximum home allergen levels in the highest category was 42% for dust mite allergen (> or = 10 microg/g Der p 1 or Der f 1), 13% for cockroach allergen (> or = 2 U/g Bla g 1 or Bla g 2), 26% for cat allergen (> or = 8 microg/g Fel d 1), and 20% for dog allergen (> or = 10 microg/g Can f 1). Homes in the high-poverty area (> 20% of the population below the poverty level) were more likely to have high cockroach allergen levels than homes in the low-poverty area [51 vs. 3%; OR, 33; 95% confidence interval (CI), 12-90], but less likely to have high levels of dust mite allergen (16 vs. 53%; OR, 0.2; CI, 0.1-0.4). Lower family income, less maternal education, and race/ethnicity (black or Hispanic vs. white) were also associated with a lower risk of high dust mite levels and a greater risk of high cockroach allergen levels. Within a single U.S. metropolitan area we found marked between-community differences in the types of allergens present in the home, but not necessarily in the overall burden of allergen exposure.

A randomized trial of itraconazole in allergic bronchopulmonary aspergillosis

BACKGROUND

Allergic bronchopulmonary aspergillosis is a hypersensitivity disorder that can progress from an acute phase to chronic disease. The main treatment is systemic corticosteroids, but data from uncontrolled studies suggest that itraconazole, an orally administered antifungal agent, may be an effective adjunctive therapy.

METHODS

We conducted a randomized, double-blind trial of treatment with either 200 mg of itraconazole twice daily or placebo for 16 weeks in patients who met immunologic and pulmonary-function criteria for corticosteroid-dependent allergic bronchopulmonary aspergillosis. A response was defined as a reduction of at least 50 percent in the corticosteroid dose, a decrease of at least 25 percent in the serum IgE concentration, and one of the following: an improvement of at least 25 percent in exercise tolerance or pulmonary-function tests or resolution or absence of pulmonary infiltrates. In a second, open-label part of the trial, all the patients received 200 mg of itraconazole per day for 16 weeks.

RESULTS

There were responses in 13 of 28 patients in the itraconazole group (46 percent), as compared with 5 of 27 patients in the placebo group (19 percent, P=0.04). The rate of adverse events was similar in the two groups. In the subsequent open-label phase, 12 of the 33 patients who had not had a response during the double-blind phase (36 percent) had responses, and none of the patients who had a response in the double-blind phase of the trial had a relapse.

CONCLUSIONS

For patients with corticosteroid-dependent allergic bronchopulmonary aspergillosis, the addition of itraconazole can lead to improvement in the condition without added toxicity.

Endogenous airway acidification. Implications for asthma pathophysiology

Airway concentrations of many reactive nitrogen and oxygen species are high in asthma. The stability and bioactivities of these species are pH-dependent; however, the pH of the airway during acute asthma has not previously been studied. As with gastric and urinary acidification, asthmatic airway acidification could be expected dramatically to alter the concentrations and bioactivities/cytotoxicities of endogenous nitrogen oxides. Here, we demonstrate that the pH of deaerated exhaled airway vapor condensate is over two log orders lower in patients with acute asthma (5.23 +/- 0.21, n = 22) than in control subjects (7.65 +/- 0.20, n = 19, p < 0. 001) and normalizes with corticosteroid therapy. Values are highly reproducible, unaffected by salivary or therapeutic artifact, and identical to samples taken directly from the lower airway. Further, at these low pH values, the endogenous airway compound, nitrite, is converted to nitric oxide (NO) in quantities sufficient largely to account for the concentrations of NO in asthmatic expired air, and eosinophils undergo accelerated necrosis. We speculate that airway pH may be an important determinant of expired NO concentration and airway inflammation, and suggest that regulation of airway pH has a previously unsuspected role in asthma pathophysiology.

The relevance of allergen exposure to the development of asthma in childhood

Sensitization to 1 or more of the common indoor allergens has been consistently associated with asthma among children and young adults (odds ratios for asthma, 3-18). For dust mite and cockroach allergens, there is a dose response relationship between domestic exposure and sensitization. Given that allergen provocation can induce many of the features of asthma, the findings strongly suggest that there is a causal relationship between allergen exposure in the home and asthma. However, it remains unclear at what time the critical exposure occurs (ie, in infancy or later) and what role allergen exposure has played in the increasing prevalence and severity of asthma. Objective evidence of an immune response to allergens is generally not present until after 2 years of age. Viral infections play several different roles in asthma in childhood. In infancy, respiratory syncytial virus infection can induce bronchiolitis and set up recurrent wheezing over the next few years. However, the risk factors for this are maternal smoking and small lungs at birth, rather than allergy. By contrast, the role of rhinovirus in precipitating attacks in children and young adults is strongly associated with allergy. Thus the likely scenario is that allergen exposure over the first few years of life induces sensitization (ie, T(H2) cells and IgE antibodies). Continuing exposure can maintain inflammation in the nose and lungs. However, many other factors contribute to wheezing such that there is no simple relationship between allergen exposure and asthma. Nonetheless, it is clear that the changes that have increased asthma have acted on allergic children.

The message from the World Asthma Meeting. The Working Groups of the World Asthma Meeting, held in Barcelona, Spain, December 9-13, 1998

The 1998 World Asthma Meeting (WAM) has been the first multidisciplinary event aimed to consider asthma as a global public health problem in children and adults. The purpose of the meeting was to present state-of-the-art scientific information and to make recommendations on the research agenda for the coming years. Five Working Groups of invited experts were appointed to pin-point the established knowledge and the important questions in the areas of epidemiology, prevention, pathogenesis, management, and education. Their reports were discussed during the final plenary session, and are forming the current proceedings of the meeting. The message of the World Asthma Meeting provides a research agenda supported by the major international bodies involved in this disease. An integrated approach is considered to be essential in order to improve the prevention and care of asthma in all countries of the world.

Use of specific IgE in assessing the relevance of fungal and dust mite allergens to atopic dermatitis: a comparison with asthmatic and nonasthmatic control subjects

BACKGROUND

Although allergens have been implicated as aggravating factors in atopic dermatitis (AD), there is little epidemiologic data on the significance of specific IgE.

OBJECTIVE

We sought to compare sensitization to dust mite and fungi between patients with AD and asthmatic and nonasthmatic control subjects.

METHODS

Total IgE and specific IgE to Dermatophagoides pteronyssinus, Alternaria alternata, Aspergillus fumigatus, Candida albicans, Malassezia furfur, and Trichophyton rubrum were measured in 73 patients with moderate to severe AD. Total IgE and IgE specific for D pteronyssinus, A alternata, and M furfur were also measured in sera from 156 asthmatic and 212 nonasthmatic control subjects.

RESULTS

Positive correlations were found between total IgE and IgE antibodies specific for each of the antigens. IgE specific for M furfur was observed more frequently in adults compared with children with AD (P <.01). AD sera had higher levels of total IgE and a higher prevalence of positive sera to D pteronyssinus (95% vs 42% and 17% for subjects with AD, asthmatic subjects, and nonasthmatic subjects, respectively), M furfur (53% vs 1% and 0.5%), and A alternata (49% vs 29% and 18%). Among the sera from subjects allergic to mites, the contribution of IgE specific for D pteronyssinus to the total IgE levels was similar regardless of the clinical status.

CONCLUSIONS

Our results demonstrate that moderate-to-severe AD is strongly associated with sensitization to dust mite andM furfur (odds ratios, 45.6 and 132 vs pooled control sera). These results suggest that both environmental allergens and colonizing fungi contribute to the severity of disease, which is consistent with the view that mite avoidance and antifungal treatment can be beneficial in the treatment of these patients.

Assessment of vacuum cleaners and vacuum cleaner bags recommended for allergic subjects

BACKGROUND

High-quality vacuum cleaners and vacuum cleaner bags are often recommended to allergic patients as a means of reducing indoor allergen exposure. A number of vacuum cleaners on the market today claim to capture 99.9% of particles 0.3 microm or larger entering the vacuum cleaner, and many vacuum cleaner bags are now being sold as microfiltration bags.

OBJECTIVE

The purpose of this study was to compare the allergen-trapping abilities of vacuum cleaners and to use a new technique for testing vacuum cleaner bags that are recommended for allergic patients.

METHODS

Vacuum cleaners were tested in an 18-m(3) laboratory room permeated with dust containing high levels of cat allergen by using techniques previously described. Air was sampled with parallel filters in conjunction with a particle counter. The filters were assayed by ELISA for cat allergen (Fel d 1). Vacuum cleaner bags were tested by using a modified dust trap to pull sieved house dust containing a known amount of Fel d 1 across the material used for the bag. Allergen passing through the bag was trapped on a filter covering the exit of the trap and analyzed for Fel d 1.

RESULTS

In general, vacuum cleaners designed for allergic patients leaked lower amounts of allergen (<0.5-4.04 ng/m(3)) than that found in our previous studies (<0.5-100 ng/m(3)). Single-layer vacuum cleaner bags performed poorly (1250-2640 ng recovered) compared with most of the 2- and 3-layer microfiltration bags (0.53-2450 ng recovered). The range of allergen recovered from the 2-layer bags (0.93-2450 ng recovered) highlighted the variability found between manufacturers.

CONCLUSION

The results suggest that although allergen leakage has been reduced, there is still room for improvement. A method of testing allergen leakage by using Fel d 1 should be applied to vacuum cleaners and bags recommended for allergic patients.

Treatment of late-onset asthma with fluconazole

BACKGROUND

Although the etiology of intrinsic or late-onset asthma is generally not known, some cases are associated with overt dermatophyte infection and immediate hypersensitivity to proteins derived from fungi of the genus Trichophyton.

OBJECTIVE

We sought to test the efficacy of oral antifungal treatment for Trichophyton-induced asthma by using fluconazole in a placebo-controlled trial.

METHODS

Eleven patients with severe or moderately severe asthma were randomized to treatment with fluconazole 100 mg daily or placebo for 5 months (phase 1); during the following 5 months, all patients received active drug (phase 2). Subjects were evaluated by skin tests, bronchial provocation tests, and measurement of serum antibodies to Trichophyton species antigens. Clinical response was monitored by changes in peak flow values measured during a 2-week period at the end of each phase and by changes in bronchial sensitivity, symptoms, and steroid requirements.

RESULTS

At the end of the first 5 months of active treatment, there was a highly significant decrease in bronchial sensitivity to Trichophyton (P =.012) and in oral steroid requirement (P =.01). At the end of phase 2, mean peak expiratory flow rates increased in 9 of 11 patients. An improvement in symptoms, peak flow, and steroid use was maintained up to 36 months after starting fluconazole in patients who continued to receive treatment.

CONCLUSION

The results show that fluconazole can be useful in the treatment of patients with severe or moderately severe asthma who have dermatophytosis. These findings are consistent with the argument that proteins derived from fungi on the skin and nails can contribute to allergic disease.