Phadiatop compared to skin-prick test as a tool for diagnosing atopy in epidemiological studies in schoolchildren

Performance of EAST in diagnosing inhalant allergens in children with allergic rhinitis

The performance of enzyme linked immunosorbent assays (EAST) for identifying six indoor allergens was evaluated using skin prick test (SPT) as reference tests in 154 children with allergic rhinitis. Sensitivity of EAST ranged from 9% (cat) to 54% (HDM) with specificity of 74%(cockroach) to 100% (cat) with an agreement ranged from 58 to 86%. Cut off values ​> ​0.35 kU/L showed best sensitivity and specificity. Our findings agree with extant literature which suggests that the ability of EAST to determine the precipitating allergen is moderate. Assays for definitively identifying the inhalant allergen are currently not available.

Biomarkers of Type 2 Airway Inflammation as Predictors of Loss of Asthma Control During Step-Down Therapy for Well-Controlled Disease: The Long-Acting Beta-Agonist Step-Down Study (LASST)

BACKGROUND

Biomarkers that can predict loss of asthma control among patients being considered for step-down therapy in well-controlled disease are lacking.

OBJECTIVE

To evaluate whether baseline biomarkers of type 2 airway inflammation and/or serial measurement of fractional exhaled nitric oxide (Feno) predict loss of asthma control as therapy is stepped down.

METHODS

In subanalyses of a multicenter randomized, double-blind, parallel 3-arm trial comparing strategies for step-down therapy in well-controlled asthma (Long-Acting Beta-Agonist Step-Down Study), we assessed whether baseline atopy as determined by serum aeroallergen allergy screening test (Phadiatop), baseline serum eosinophil peroxidase, or baseline or serial Feno measurements during follow-up predicted the time to loss of asthma control among participants. Loss of asthma control was defined in the study protocol. We analyzed these associations in adjusted models including all participants, after testing for interactions with assignment to each of the 3 treatment groups (continuation of stable dose of combination inhaled corticosteroid-long-acting beta-agonist, step-down of inhaled corticosteroid, or discontinuation of long-acting bronchodilator).

RESULTS

Four hundred forty-seven of the 553 Long-Acting Beta-Agonist Step-Down Study participants who were randomized to 1 of 3 treatment arms and had at least 1 biomarker measurement were included in this analysis. At baseline, higher levels of Feno were significantly associated with greater levels of multiallergen IgE levels (P < .001), but not with serum eosinophil peroxidase (P = .742). Among all participants as a group, elevations in baseline biomarkers were not predictive of a higher risk of treatment failure. In addition, Feno levels measured serially at 6-week intervals demonstrated that compared with participants with low levels (<25 parts per billion), those with intermediate (25-50 parts per billion) and high (>50 parts per billion) levels did not have significantly increased likelihood of subsequent treatment failure (hazard ratios, 1.03 [95% CI, 0.59-1.78] and 1.29 [95% CI, 0.65-2.54], respectively). There were no significant interactions of treatment group and baseline biomarkers.

CONCLUSIONS

In patients with well-controlled asthma, neither baseline levels of type 2 airway inflammatory biomarkers nor serial measures of Feno are strong predictors of treatment failure.

Skin Prick Test Versus Phadiatop as a Tool for Diagnosis of Allergic Rhinitis in Children

BACKGROUND

Skin prick test (SPT) or Phadiatop, a multi-allergen IgE screening test, was used as a tool for detecting aeroallergen sensitization.

OBJECTIVE

To compare SPT and Phadiatop as a tool for diagnosis allergic rhinitis (AR) using the nasal provocation test (NPT) as a comparative standard.

METHODS

Children aged 5-18 years with rhinitis symptoms more than 6 times in the past year were enrolled. SPT to 13 common aeroallergens, serum for Phadiatop, and NPT to Dermatophagoides pteronyssinus (Der p) were performed. NPT to mixed cockroach (CR) were performed in children who had CR sensitization and negative NPT to Der p. Children who had a disagreement between the result of SPT and Phadiatop or having negative results were evaluated for specific IgE (sIgE) to common aeroallergens.

RESULTS

One hundred-forty children were enrolled with the mean age of 9.8 ± 3 years, 56% were male. Of 92 children (65.7%) with positive SPT to any aeroallergens, 88 children (95.6%) were sensitized to house dust mite (HDM). NPT showed positive results in 97 children (69.3%). Of 48 children who showed negative SPT, 4 children (8.3%) had sIgE to aeroallergens but NPT was positive in 1 child. Eighty-eight children (62.9%) had positive tests for Phadiatop and 4 (4.5%) of them had negative results for NPT to Der p. Among 52 children who had negative results for Phadiatop, 4 children (7.6%) had sIgE to aeroallergens but NPT was positive in 2 children (3.8%). SPT and Phadiatop showed 94.2% agreement: with Kappa 0.876, p < 0.001. Using NPT as a comparative standard for diagnosis for AR, SPT showed a sensitivity of 89.6% and specificity of 88.3% and Phadiatop provided the sensitivity of 88.6% and specificity of 95.3%.

CONCLUSIONS

SPT to aeroallergen and Phadiatop have good and comparable sensitivity and specificity for the diagnosis of AR in children.

Phadiatop, Phadiatop Infant and total IgE evaluated in allergic Brazilian children and adolescents

The clinical history is of importance in the investigation of allergic diseases but does have limitations. Many allergic conditions will be over-diagnosed if anamnesis alone is used for diagnostic criteria. Serum total immunoglobulin E (TIgE) quantification, as well as panels containing allergens prevalent in the studied population, may serve as screening tests and facilitate the diagnosis of allergic disease or its exclusion. We assessed the positivity of two versions of these tests, Phadiatop Europe® (PhEU) and Phadiatop Infant® (PhInf), as well as total IgE (TigE) values in patients with a medical diagnosis of allergic disease and non-allergic individuals.

METHODS

A cross-sectional study performed in eleven Brazilian pediatric allergy centers with patients divided into groups according to the primary condition and a group of assessed control subjects. They were submitted to TIgE measurement and screening tests (PhEu and PhInf).

RESULTS

TIgE mean serum levels were significantly higher among allergic patients, especially those with asthma/rhinitis or atopic dermatitis. The positivity of the screening tests, considering the total population, was 63.8% for PhEU and 72.6% for PhInf. These increased when we evaluated only the allergic subjects. The concordance index of the two tests was Kappa=0.7 and higher among those of greater age.

CONCLUSIONS

In the assessed population, there were significantly higher levels among those with positive screening tests and PhInf showed better performance in the identification of sensitized individuals, regardless of age. This is the first study to evaluate Phadiatop and Phadiatop Infant in the same population.

The practical benefit of Phadiatop test as the first-line in vitro allergen-specific immunoglobulin E (sIgE) screening of aeroallergens among Chinese asthmatics: a validation study

Background

Phadiatop test is a variant of ImmunoCAP assay that covers a mixture of common aeroallergens. Its diagnostic efficiency in Chinese population remains so far inadequate. We validated Phadiatop testing with ImmunoCAP assays in a Chinese cohort.

Methods

Phadiatop test was performed for serum samples from 290 asthmatics and 92 healthy controls previously tested with "classic" ImmunoCAP for house dust mix (hx2), molds and yeasts mix (mx2), tree pollen mix (tx4) and weed mix (wx5).

Results

Phadiatop positivity was shown in 46.2% of 290 asthmatic patients. Using ImmunoCAP as the gold standard, the concordance rate was 91.7%; negative predictive value, 92.9%; and positive predictive value, 90.2%. The sensitivity of Phadiatop test was high for hx2 (98.2%), tx4 (100%) and wx5 (95.5%), but not for mx2 (78.4%). Yet the mx2 allergen-specific immunoglobulin E (sIgE) level in all missed cases was relatively low (0.35 to 0.90 kU_A/L). The total Phadiatop sIgE level was correlated with the ImmunoCAP sIgE levels for all allergen mixes combined (r_s =0.941, P<0.001) or each allergen mix, particularly the hx2 (r_s =0.924) (all P<0.001), 0.53 kU_A/L used as a cut-off would optimize the diagnostic performance of Phadiatop testing, yielding 89.4% sensitivity and 97.5% specificity in indentifying serums positive to any of these allergen mixes.

Conclusions

Overall, Phadiatop test may efficiently detect sensitization to common aeroallergen mixes. In light of the currently rigorous administration on crude extracts for skin tests in China, using Phadiatop as the first-line test for suspected atopy can be cost-effective.

Atopic endotype in childhood

BACKGROUND

The term atopic disorder is an early attempt to define specific endotypes of children with asthma, eczema, or both and increased IgE levels.

OBJECTIVE

We performed a longitudinal analysis of the relevance of the atopic endotype from birth to age 13 years.

METHODS

Allergic sensitization against 28 inhalant and food allergens was assessed at ½, 1½, 4, 6, and 13 years of age in 399 children from the Copenhagen Prospective Study on Asthma in Childhood2000 birth cohort by using both skin prick test responses and specific IgE levels. Asthma and eczema were diagnosed longitudinally by strictly adhering to predefined algorithms. Associations between allergic sensitization, asthma, and eczema were estimated by means of logistic regression, and a machine learning approach was used to identify temporal phenotype clusters of these traits.

RESULTS

Allergic sensitization showed no association with asthma through early childhood (0-6 years) when analyzed as any sensitization (odds ratio [OR] range, 0.78-1.29; P ≥ .48). However, at 13 years of age, any sensitization was associated with asthma (OR range, 4.02-5.94; all P < .001). In contrast, any sensitization was associated with eczema at ½, 1½, and 6 years of age (OR range, 2.06-6.02; P ≤ .01) and borderline associated at 4 years of age (OR, 1.61 [95% CI, 0.96-2.69]; P = .07) but not at 13 years of age (OR, 1.57 [95% CI, 0.78-3.16]; P = .21). We identified 4 latent patterns of disease development that were either dominated by sensitization (37%), eczema (26%), asthma (14%), or healthy status (24%).

CONCLUSION

We found very little interdependency between asthma, eczema, and allergic sensitization through childhood. The associations between those entities were strongly dependent on age, type of allergens, and method of testing for sensitization. Therefore, atopy in children is unlikely to represent a true endotype.

Serum 25-hydroxyvitamin D levels are lower in chronic rhinosinusitis with nasal polyposis and are correlated with disease severity in Taiwanese patients

BACKGROUND

Vitamin D deficiency is reported to be associated with increased incidence of allergic airway diseases and is correlated with the severity of asthma. This study was designed to determine if serum Vitamin D level is lower in chronic rhinosinusitis with nasal polyposis (CRSwNP) patients and if low serum Vitamin D level is correlated with the severity of CRSwNP.

METHODS

New CRSwNP patients undergoing elective endoscopic sinus surgery were recruited. Patients with malignancies or asthma were excluded. Twenty chronic rhinosinusitis without nasal polyposis (CRSsNP) patients were used as control. Demographic characteristic information was collected. The severity of CRSwNP was assessed with the Lund-Mackay (LM) score and polyp grading system. Vitamin D status was assessed by measuring circulating 25-hydroxyvitamin D (25OHD) by using commercial chemiluminescence immunoassay. Data were stratified by factors known to affect serum 25OHD, including sex, race, and body mass index.

RESULTS

Serum 25OHD levels (ng/mL ± SD) were significantly lower in patients with CRSwNP (21.4 ± 5.7) than in those with CRSsNP (28.8 ± 6.2; p < 0.001). The incidences of vitamin D deficiency (<20 ng/mL) in CRSwNP and CRSsNP patients were 45.5 and 6.3%; however, the incidences of vitamin D insufficiency (20-30 ng/mL) in these patients were 50.0 and 62.5%, respectively. A significantly negative relationship was found between serum 25OHD level and polyp grade (r = -0.63; p = 0.001), indicating lower serum 25OHD was associated with higher polyp grade. Serum 25OHD was inversely related to both LM score and total IgE level as well; however, statistical significance was not found.

CONCLUSION

A significantly lower vitamin D level was found in a group of Taiwanese CRSwNP patients, which revealed an association with greater nasal polyp size. Serum vitamin D levels could be added to the routine workup of patients suffering from CRS and these data could be used to potentially help determine the disease severity.

Clinical availability of component-resolved diagnosis using microarray technology in atopic dermatitis

Background

Various allergens play a role in the elicitation or exacerbation of eczematous skin lesions in atopic dermatitis (AD), and much research effort has been focused on improving diagnostic tests to identify causative allergens.

Objective

The purpose of this study was to evaluate the diagnostic effectiveness of a newly introduced microarray-based specific immunoglobulin E detection assay, ImmunoCAP ISAC, for use in AD patients.

Methods

The serum samples of 25 AD patients were tested by using ISAC and a multiple allergen simultaneous test-enzyme immunoassay (MAST-EIA). In addition, 10 of the 25 patients underwent skin prick testing (SPT). The positive reaction rates to allergens in each test and the agreements, sensitivities, and specificities of ISAC and MAST-EIA were evaluated versus the SPT results.

Results

For ISAC versus SPT, the overall results were as follows: sensitivity, 90.0%; specificity, 98.2%; positive predictive value (PPV), 90.0%; and negative predictive value (NPV), 98.2%. The total agreement and κ value for ISAC versus SPT were 96.9% and 0.882, respectively. For MAST-EIA versus SPT, the sensitivity was 80.0%, specificity 92.7%, PPV 66.7%, and NPV 96.2%. The total agreement and κ value for MAST-EIA versus SPT were 90.8% and 0.672, respectively. The overall agreement between the ISAC and MAST-EIA results was 88%.

Conclusion

The ISAC results in AD correlated well with the SPT results, and compared favorably to the MAST-EIA results. This study demonstrates the potential of ISAC as a convenient allergic diagnostic method in AD patients.

Serum eosinophil cationic protein level in Chinese subjects with nonallergic and local allergic rhinitis and its relation to the severity of disease

BACKGROUND

Nonallergic rhinitis (NAR) is a common disease, and local allergic rhinitis (LAR) is a newly described entity that is called "entopy" in recent years. However, the etiology and incidence of NAR and LAR are uncertain. This study evaluates the incidence of LAR in Chinese subjects and serum eosinophil cationic protein (ECP) levels in patients with NAR and LAR and its relationship with symptom scores.

METHODS

Positive skin-prick tests (SPT), nasal allergen provocation testing (NAPT) to Dermatophagoides farinae (DF), serum Phadiatop tests, and symptom score evaluations were performed in 147 patients with nonatopic persistent rhinitis. LAR was diagnosed by positive NAPT to DF results. The serum ECP level was measured using the UniCAP100 automated system by enzyme-linked immunosorbent assay (Pharmacia Diagnostics, Uppsala, Sweden).

RESULTS

Twelve patients were diagnosed with LAR, and 135 patients were diagnosed with NAR. There was no statistical difference of the visual analog scale scores between the two groups. Serum ECP was significantly increased in the patients with NAR. Serum ECP in the LAR group showed no difference compared with the NAR group or the controls. In the NAR group, nasal obstruction, rhinorrhea, and total scores had close and statistically significant relationships with serum ECP level.

CONCLUSION

The present study provides the first evidence that LAR exists in Chinese subjects. This study also suggests that eosinophils and ECP take part in the pathogenesis of NAR. A local examination for ECP and specific IgE in nasal lavage fluid or secretions in patients with LAR should be performed in a future study.

Corelationship between matrix metalloproteinase 2 and 9 expression and severity of chronic rhinosinusitis with nasal polyposis

BACKGROUND

Matrix metalloproteinase (MMP) is involved in the remodeling process of inflammatory airway diseases and is correlated with the severity of asthma. We hypothesized that MMP was associated with the severity of chronic rhinosinusitis with nasal polyps (CRSwNPs). We also investigated the effect of allergy on the expression of MMP in the polyp.

METHODS

The expression of MMP-2 and -9 was investigated in recurrent nasal polyps of 30 patients and in nonrecurrent nasal polyps of 31 patients undergoing endoscopic sinus surgery. These expressions were then compared with those in control nasal mucosal samples obtained from 32 patients with chronic hypertrophic rhinitis. Demographic data, Lund-Mackay (LM) score, polyp grade, and allergy status were obtained for all patients. Tissue samples were assessed via immunohistochemistry.

RESULTS

MMP-2 and -9 were constantly expressed in recurrent NPs, primary NPs, and control nasal mucosa. The expression of MMP-9 was significantly enhanced in glands and MMP-2 positivity was significantly increased in surface epithelium for patients with NPs when compared with control nasal mucosa. The expression of MMP-9 and -2 was not correlated with polyp grade and LM score. Allergic status is an independent factor in the expression of MMP-2 and -9.

CONCLUSION

These results suggested up-regulation of MMP-9, and MMP-2 in gland and surface epithelium, respectively, were characteristic of NPs. Therefore, patients with allergy will exhibit greater MMP-2 and -9 positivity. However, the MMP-2 and -9 expression intensity was not correlated with the severity of CRS with nasal polyposis.

Associations between atopic markers in asthma and intestinal helminth infections in Cuban schoolchildren

Total serum IgE (tIgE), allergen-specific IgE (sIgE), and skin prick test (SPT) are commonly used markers for atopy and atopic disease. The association between these measures and their relationship to clinical symptoms differs in affluent and non-affluent countries. We investigated the role of intestinal helminth infections in observed variations in atopic markers and asthma, and possible diagnostic and epidemiological consequences. A cross-sectional study was conducted in Cuban schoolchildren (n = 1285; 4-14 yrs). Atopy was determined by SPT, sIgE, and tIgE; asthma by International Study of Asthma and Allergies in Childhood questionnaire; and intestinal helminth infections by stool examination. Percentages of tIgE, sIgE, and SPT positives were 88.9%, 25.5%, and 16.5%, respectively. Asthma was found in 20.8%, and helminth infections in 20.9% of the children. All three atopic markers were significantly associated with each other and with asthma. Median tIgE levels were higher in helminth-infected than in uninfected children, irrespective of their status of atopy/asthma. Discordant results between SPT and sIgE were observed in 22.6% of the children. Among SPT positives, 41% were sIgE negative. The proportion of SPT negatives among sIgE positives was 74% in helminth-infected and 58.4% in uninfected children (p < 0.05). Helminth infections affected tIgE levels, reconfirming the limited value of tIgE for diagnosis of atopy and asthma in tropical areas. Higher frequencies of sIgE than positive SPTs were observed, especially in helminth-infected children. This corresponds with current hypothesis on the role of helminths in atopy. However, the observed proportion of sIgE negatives among children with positive SPT suggests that other mechanisms may also be involved.

Asthma outcomes: biomarkers

BACKGROUND

Measurement of biomarkers has been incorporated within clinical research studies of asthma to characterize the population and associate the disease with environmental and therapeutic effects.

OBJECTIVE

National Institutes of Health institutes and federal agencies convened an expert group to propose which biomarkers should be assessed as standardized asthma outcomes in future clinical research studies.

METHODS

We conducted a comprehensive search of the literature to identify studies that developed and/or tested asthma biomarkers. We identified biomarkers relevant to the underlying disease process progression and response to treatment. We classified the biomarkers as either core (required in future studies), supplemental (used according to study aims and standardized), or emerging (requiring validation and standardization). This work was discussed at an National Institutes of Health-organized workshop convened in March 2010 and finalized in September 2011.

RESULTS

Ten measures were identified; only 1, multiallergen screening to define atopy, is recommended as a core asthma outcome. Complete blood counts to measure total eosinophils, fractional exhaled nitric oxide (Feno), sputum eosinophils, urinary leukotrienes, and total and allergen-specific IgE are recommended as supplemental measures. Measurement of sputum polymorphonuclear leukocytes and other analytes, cortisol measures, airway imaging, breath markers, and system-wide studies (eg, genomics, proteomics) are considered as emerging outcome measures.

CONCLUSION

The working group participants propose the use of multiallergen screening in all asthma clinical trials to characterize study populations with respect to atopic status. Blood, sputum, and urine specimens should be stored in biobanks, and standard procedures should be developed to harmonize sample collection for clinical trial biorepositories.

Influence of maternal asthma on the cause and severity of infant acute respiratory tract infections

Background

Respiratory syncytial virus (RSV) and rhinovirus infections are the most common significant infant respiratory tract illnesses and are associated with increased but differential risks of childhood asthma.

Objective

We sought to determine whether maternal asthma is associated with higher odds of infant respiratory tract infection with rhinovirus versus RSV and increased infection severity.

Methods

Mother-infant dyads were enrolled from 2004-2008 during an infant respiratory tract infection (104 with rhinovirus and 279 with RSV). Mothers were classified into mutually exclusive groups (atopic asthma, nonatopic asthma, and no asthma). We determined viral cause using PCR and the severity of the infant’s respiratory tract infection using the bronchiolitis severity score. Adjusted relative odds of maternal asthma with viral cause were calculated by using logistic regression. Proportional odds models assessed the association of maternal asthma and infant infection severity.

Results

Infants with a mother with atopic asthma compared with infants whose mothers did not have asthma were more likely to have rhinovirus versus RSV infection (adjusted odds ratio, 2.42; 95% CI, 1.19-4.90). Similarly, among infants with rhinovirus, having a mother with atopic asthma was associated with increased infection severity (adjusted odds ratio, 3.10; 95% CI, 1.21-7.98). This relationship was not seen among infants with RSV.

Conclusions

Clinically significant rhinovirus infection during infancy was more strongly associated with having a mother with atopic asthma than clinically significant RSV infection. Having a mother with atopic asthma was associated with increased severity of infant rhinovirus but not RSV infections. Infants with rhinovirus were more likely to have a familial atopic predisposition, which might partly explain the subsequent increased asthma risk.

Pollen-specific immunoglobulin E positivity is associated with worsening of depression scores in bipolar disorder patients during high pollen season

OBJECTIVE

An association between allergic disease and depression has been consistently reported, but whether the key mediating ingredients are predominantly biological, psychological, or mere artifacts remains unknown. In the current study, we examined a hypothesized relationship between allergen-specific immunoglobulin E (IgE) status and changes in allergy symptoms with worsening in depression scores.

METHODS

In patients with recurrent mood disorders, we individually coupled sensitization to specific seasonal aeroallergens (as assessed by allergen-specific IgE) with temporal windows of exposure to aeroallergens (low versus high tree or ragweed pollen counts, measured according to the National Allergy Bureau guidelines). We compared Structured Interview Guide for the Hamilton Depression Rating Scale-Seasonal Affective Disorder Version (SIGH-SAD) depression score changes in 41 patients with mood disorders [25 with major depression and 16 with bipolar I disorder, diagnosed by Structured Clinical Interview for DSM (SCID)] seropositive for tree or ragweed pollen-specific IgE antibody versus 53 patients with mood disorders (30 with major depression and 23 with bipolar I disorder) seronegative for aeroallergen-specific IgE.

RESULTS

Worsening in total depressive scores from low to high pollen exposure was greater in allergen-specific IgE-positive patients as compared to allergen-specific IgE antibody-negative patients (p = 0.01). When stratified by polarity, the association was significant only in patients with bipolar I disorder (p = 0.004). This relationship was resilient to adjustment for changes in allergy symptom scores.

CONCLUSION

To our knowledge, this is the first report of coupling a molecular marker of vulnerability (allergen-specific IgE) with a specific environmental trigger (airborne allergens) leading to exacerbation of depression in patients with bipolar I disorder.

Validation and refinement of the Millennium Criteria for atopic dermatitis

There is no gold standard for a definite diagnosis of atopic dermatitis. For the time being, several lists of diagnostic criteria have been proposed, some of them in actual use. The Millennium Criteria have been proposed to diagnose atopic dermatitis and to differentiate it from atopiform dermatitis. Our aim was to further refine the Millennium Criteria into a manageable set that can differentiate between atopic and atopiform dermatitis and other entities. The hereby refined Millennium Criteria will be compared with the UK Working Party Criteria and the Hanifin & Rajka Criteria. Data of 210 included patients were used. After multiple logistic regression, a minimum set of five criteria was identified as best discriminators: (i) typical morphology; (ii) early age of onset; (iii) Dennie-Morgan fold; (iv) historical and (v) actual flexural involvement. The refined Millennium Criteria were constituted from these criteria. When comparing the different list for validity in diagnosing atopic dermatitis, the refined Millennium Criteria showed a sensitivity of 81.8% and a specificity of 98.8% compared to a sensitivity of 97.7% and specificity of 72.9% of the UK Criteria and a sensitivity of 100% and specificity of 48.8% of the Hanifin & Rajka Criteria. This refinement and validity study shows that the refined Millennium Criteria are a valid tool to diagnose atopic and atopiform dermatitis in a hospital-based setting and therefore could be incorporated in clinical practice and trials.

Premenstrual asthma and atopy markers

BACKGROUND

The frequency of atopy in women with premenstrual asthma (PMA) and its possible effect on the premenstrual exacerbation of asthma are unknown.

OBJECTIVE

To analyze the relation between atopy markers (total IgE, Phadiatop, and specific IgE) and PMA.

METHODS

Asthmatic women of reproductive age completed a questionnaire about respiratory symptoms and recorded peak flow during an entire menstrual cycle to be classified as asthmatic patients with or without PMA. Their asthma severity was graded according to the 2005 Global Initiative for Asthma scale. PMA was defined as a clinical or functional exacerbation (>or=20%) in the premenstrual phase compared with the preovulatory phase. Blood tests for several atopy markers were conducted for: total IgE and screening for aeroallergens (Phadiatop) and specific IgE.

RESULTS

Blood determinations were performed in 59 asthmatic women, of whom 31 (53%) had PMA. Twenty-six patients with PMA (84%) and 12 without PMA (43%) had total IgE values greater than 100 kU/L (P=.001). Twenty-one patients with PMA (68%) and 14 without PMA (50%) tested positive for Phadiatop (P=.17). Those who were positive for Phadiatop were also tested for specific IgE. No relation was found between specific IgE and PMA; values for ryegrass (63%), olive (60%), and Dermatophagoides pteronyssinus (54%) exceeded 0.35 kU/L.

CONCLUSIONS

PMA seems to be closely linked to total IgE levels but not to specific allergens. The atopy affects the clinical manifestations of PMA in women of reproductive age.

Risks of exposure to occupational asthmogens in atopic and nonatopic asthma: a case-control study in Taiwan

RATIONALE

Asthma is often work-related and can be classified as atopic or nonatopic on the basis of its pathogenesis. Few studies have reported an association between exposure to occupational asthmogens and asthma with and without atopy.

OBJECTIVES

We investigated, in adults with asthma, whether occupational exposure to asthmogens influenced the risk of having atopic or nonatopic asthma, and their level of lung function.

METHODS

We recruited 504 hospital-based adults with current asthma, 504 community-based control subjects, and 504 hospital-based control subjects in southern Taiwan. Asthma with atopy was defined as having asthma in combination with an increase in total IgE (≥100 U/ml) or a positive Phadiatop test (≥0.35 Pharmacia arbitrary unit/L) (Pharmacia ImmunoCAP; Pharmacia, Uppsala, Sweden). Occupational exposure to asthmogens was assessed with an asthma-specific job exposure matrix.

MEASUREMENTS AND MAIN RESULTS

We found a significant association between atopic asthma and exposure to high molecular weight asthmogens (adjusted odds ratio [AOR], 4.0; 95% confidence interval [CI], 1.8-8.9). Nonatopic asthma was significantly associated with exposure to low molecular weight asthmogens (AOR, 2.6; 95% CI, 1.6-4.3), including industrial cleaning agents and metal sensitizers. Agriculture was associated with both atopic and nonatopic asthma (AOR, 7.8; 95% CI, 2.8-21.8; and AOR, 4.1; 95% CI, 1.3-13.0, respectively). The ratio of FEV₁ to FVC in the high-risk group was significantly lower than in the no-risk group (P = 0.026) in currently employed patients with asthma.

CONCLUSIONS

In adults with asthma, occupational exposure to high and low molecular weight asthmogens appears to produce differential risks for atopic and nonatopic asthma.

[Allergen specific IgE measurement with Polycheck Allergy: comparison of three multiple allergen simultaneous tests]

BACKGROUND

The in vivo skin prick test (SPT) or in vitro detection of allergen specific IgE in serum is commonly used for the diagnosis of allergic disease. In this study, we evaluated the usefulness of a new multiple allergen simultaneous test (MAST) immunoblot assay, Polycheck Allergy (Biocheck GmbH, Germany).

METHODS

A total of 100 patients with clinical findings of allergic diseases were tested by SPT and three different MAST assays: Polycheck Allergy (Biocheck GmbH, Germany), MAST CLA allergy system (Hitachi Chemical Diagnostics, USA) and Allergy Screen (R-biopharm, Germany). The results of MAST assays were compared with those of SPT.

RESULTS

Concordance rates of MAST assays with SPT were 79-100% for Polycheck Allergy, 88.9-100% for MAST CLA and 72.7-98.3% for Allergy Screen. In ROC curve analysis, significant differences were observed in four of 25 allergens analysed: Alternaria, Birch, Hazelnut and D. farinae. For Alternaria and Birch, Polycheck Allergy (P<0.001) and Allergy Screen (P=0.0075) showed significantly larger AUC (area under the curve) than MAST CLA. For Hazelnut, Polycheck Allergy (P=0.0021), and for D. farinae, MAST CLA (P=0.015) showed significantly larger AUCs than the other two tests. The ROC analysis for overall 16 food allergens showed better results in Polycheck Allergy (P<0.001), and that for overall 21 inhalants did not show significant differences among three MAST assays (P>0.05).

CONCLUSIONS

Since Polycheck Allergy showed similar or superior result to the others, it can be used for the detection of allergen specific IgE antibodies.

Accuracy of ImmunoCAP Rapid in the diagnosis of allergic sensitization in children between 1 and 14 years with recurrent wheezing: the IReNE study

It is estimated that at least one out of three children with recurrent wheezing is atopic. Reliable diagnostic tools are needed in primary care that allow for adequate identification of these children. The purpose of this study was to assess the value of ImmunoCAP Rapid (ICR) Wheeze-Rhinitis Child in the identification of atopy with the use of 10 selected allergens in children with recurrent episodes of wheezing. A multicenter population study is based on primary care. It included children managed consecutively at the health center, who had three or more episodes of wheezing, at least one of them in the last 12 months. Each child completed a physical examination, an epidemiological survey, one capillary blood sampling (110 microl) for ICR, and one venous blood sampling for determination of Phadiatop Infant, total IgE and 10 specific IgE measurements. The children were identified as atopic, based on their clinical signs and symptoms and at least one positive specific IgE (0.35 kU(A)/l or higher), before knowing the results of ICR, Phadiatop Infant and total IgE. ICR was read by two independent observers. Six classes were evaluated, negative without any color and five positive degrees of pink-red color. Two hundred and fifteen children aged between 1 and 14 years were studied (138 boys); 50.7% were identified as atopic, 39.1% were sensitized only to inhalant allergens, 6.5% to food allergens and 5.1% to both. The predominant allergen was the dust mite (39.3%). For ICR, there were 2134 valid double observations. The Kappa index, comparing the negative results vs. any positive result, was 0.91 (95% CI: 0.88-0.94). The intraclass correlation coefficient was 0.98 (95% CI: 0.98-0.99). In the identification of a child as atopic, the positive post-test probability of ICR depended on the color degrees considered: 88.4% for any positive and 97.6% for the most intense tones. The positive post-test probability of Phadiatop Infant and total IgE was 95.6% and 68.2% respectively. ICR showed good reliability for the most prevalent allergen, the dust mite, with a sensitivity of 90.5% (95% CI: 82.1-95.8) and specificity of 88.5% (95% CI: 81.7-93.4). The analysis of the other allergens was limited by the small number of sensitized children. The analysis of receiver operating characteristic curves revealed an area under the curve of 0.84 (95% CI 0.80-0.88) for the cut-off point of specific IgE of 0.35 kU(A)/l and of 0.94(CI 0.91-0.97) for 2 kU(A)/l. A greater intensity of color of the lines of ICR was related to higher levels of specific IgE in blood. ICR is a reliable test for the identification of atopy in children, which identifies most children as atopic, and shows a good correlation in allergen-by-allergen identification. This suggests that it should be regarded as a first-rate tool, in the primary care clinic, for the evaluation of children with recurrent wheezing.