Analysis of skin testing and serum-specific immunoglobulin E to predict airway reactivity to cat allergens

Factors associated with aeroallergen testing among adults with asthma in a large health system

Background

Aeroallergen testing informs precision care for adults with asthma, yet the epidemiology of testing in this population remains poorly understood.

Objective

We sought to identify factors associated with receiving aeroallergen testing, the results of these tests, and subsequent reductions in exacerbation measures among adults with asthma.

Methods

We used electronic health record data to conduct a retrospective, observational cohort study of 30,775 adults with asthma who had an office visit with a primary care provider or an asthma specialist from January 1, 2017, to August 26, 2022. We used regression models to identify (1) factors associated with receiving any aeroallergen test and tests to 9 allergen categories after the index visit, (2) factors associated with positive test results, and (3) reductions in asthma exacerbation measures in the year after testing compared with before testing.

Results

Testing was received by 2201 patients (7.2%). According to multivariable models, receiving testing was associated with having any office visit with an allergy/immunology specialist during the study period (odds ratio [OR] = 91.3 vs primary care only [P < .001]) and having an asthma emergency department visit (OR = 1.62 [P = .004]) or hospitalization (OR = 1.62 [P = .03]) in the year before the index visit. Age 65 years or older conferred decreased odds of testing (OR = 0.74 vs age 18-34 years [P = .008]) and negative test results to 6 categories (P ≤ .04 for all comparisons). Black race conferred increased odds of testing (OR =1.22 vs White race [P = .01]) and positive test results to 8 categories (P < .04 for all comparisons). Exacerbation measures decreased after testing.

Conclusion

Aeroallergen testing was performed infrequently among adults with asthma and was associated with reductions in asthma exacerbation measures.

The Importance of Nasal Provocation Testing in the Diagnosis of Dermatophagoides pteronyssinus-Induced Allergic Rhinitis

BACKGROUND

Allergen identification is the first step for allergen-specific immunotherapy (AIT) of allergic rhinitis (AR). Currently, the diagnosis of AR is based mainly on the positive results of the skin prick test (SPT) and/or serum specific immunoglobulin E (sIgE) measurement. However, the results of these two tests may not always directly correlate with AR.

OBJECTIVE

To investigate the importance of nasal provocation testing (NPT) in the diagnosis of Dermatophagoides pteronyssinus (Der p)-induced AR.

METHODS

Rhinitis patients willing to undergo AIT (n = 171) were enrolled. The correlations of Der p SPT, sIgE, NPT, and clinical symptom severity were assessed.

RESULTS

NPT-positive responses were more common in patients with higher SPT and sIgE levels. The optimal cut-off value for a NPT-positive response for SPT was 5.5 mm and for sIgE was 2.77 kUA/L, based on the respective receiver operating characteristic (ROC) curves. The area under the curve (AUC) of the ROCs was 0.814 (SPT only) and 0.794 (sIgE only) and increased to 0.828 with the combination of SPT and sIgE. The Der p-NPT concentration was inversely correlated with SPT and sIgE levels (r = -0.477, P < .001, and r = -0.461, P < .001, respectively), but none was correlated with the total nasal symptom score.

CONCLUSION

For patients who are willing to receive Der p AIT, NPT is a useful and safe test to confirm diagnosis prior to treatment initiation, especially in patients with lower levels of Der p SPT (< 5.5 mm) or sIgE (< 2.77 kUA/L).

Specific Dog Allergen Immunoglobulin G Antibodies in Patients with Allergic Conjunctivitis

Purpose:

The purpose of the study was to examine the role of total tear IgE, and specific serum dog IgG and IgE antibodies on the severity of allergic conjunctivitis.

Methods:

This study enrolled healthy subjects (control group, N=13), the patients with seasonal allergic conjunctivitis (seasonal group, N=13), and patients with perennial allergic conjunctivitis (perennial group, N=13). Skin prick test, tear IgE level, and serum specific dog IgE and IgG levels were examined. The severity of allergic conjunctivitis using a grading score (0-30) was also examined.

Results:

The levels of serum dog-specific IgE and IgG, and total tear IgE of the seasonal and perennial groups were higher as compared to those of the control group (all p<0.05). The levels of serum dog-specific IgG of the perennial group were higher than those of the seasonal group (0.4 ± 0.6 vs. 0.0 ± 0.0). Multivariate analysis confirmed that the skin prick test result for dog allergen was related to the serum dog-specific IgG levels, but not IgE levels (p<0.01). The severity of allergic conjunctivitis was related to the serum level of dog-specific IgG antibodies (p<0.01).

Conclusion:

It was concluded that dog-specific IgG antibodies level may be associated with the severity of dog-related perennial allergic conjunctivitis.

Effect of High-Intensity Focused Ultrasound Versus Plasma Radiofrequency Ablation on Recurrent Allergic Rhinitis

Background

High-intensity focused ultrasound (HIFU) and plasma radiofrequency ablation (PRA) have been used to treat recurrent allergic rhinitis (AR); however, there is a lack of literature comparing the efficacy of these 2 methods. We assessed and compared the therapeutic effects of HIFU and PRA on recurrent AR.

Material/Methods

We enrolled 66 patients with recurrent AR at West China Hospital of Sichuan University. Visual analogue score (VAS), pain score, rhinoconjunctivitis quality of life questionnaire (RQLQ), and nasal endoscopy were performed to evaluate the therapeutic effect.

Results

Nasal endoscopy showed that HIFU and PAR reduced the volume of the inferior turbinate, whereas HIFU reduced the amount of nasal secretions in patients. VAS scores showed that HIFU and PRA nasal congestion symptoms were significantly reduced (P<0.05). The preoperative VAS scores for nasal fluid and sneezing were significantly lower in patients receiving HIFU (P<0.05) than in those receiving PRA (P>0.05). HIFU-treated patients had significantly lower postoperative pain scores than those in the PRA group (P<0.05). RQLQ showed activity, sleep, and non-nasal or ocular symptoms, and both HIFU and PRA patients had significantly lower scores (P<0.05). Nasal symptom scores, actual problems, and mood in the HIFU group were significantly worse than those in the PRA group (P<0.05). However, neither treatment had a significant effect on ocular symptoms (P>0.05).

Conclusions

Compared with PRA, HIFU can significantly reduce the nasal symptoms of AR patients, improve the quality of life, and can be used as an adjuvant therapy with better therapeutic effect.

Is atopy a risk indicator of chronic obstructive pulmonary disease in dairy farmers?

Abstract

Allergic mechanisms related to environmental and occupational exposure have been suggested to contribute to the development of chronic obstructive pulmonary disease (COPD).

Objectives

To investigate the relationships between atopy markers, persistent airflow limitation (PAL) and occupational exposure in dairy farmers.

Methods

Clinical and biological (total IgE and 21 allergen specific IgE) markers of atopy were assessed in 101 dairy farmers with PAL (DF-PAL), 85 non-farmers with PAL (NF-PAL) (both groups were prospectively included from a screening program performed between 2011 and 2015), and matched controls, i.e. 98 farmers without PAL (DF-controls) and 89 non-farming subjects without PAL (NF-controls). Occupational exposure in farmers was estimated using a validated questionnaire.

Results

Prevalence of allergy history was significantly higher in DF-PAL and in NF-PAL than in controls. Polysensitization, and sensitization to seasonal and food allergens were more frequent in DF-PAL than in DF-controls, respectively: 13.8% vs 1% (adjusted odds ratio (aOR): 17.5 (2.2–134), 11.9% vs 3.1% (aOR: 4.4 (1.2–7.2) and 16.8% vs 4.1% (aOR: 5.2 (1.7–7.2)). The prevalence of atopy markers was similar between NF-PAL patients and NF-controls.

Conclusions

PAL in farmers is associated with a high rate of markers of atopy, supporting atopy as a risk indicator.

Clinical trial registered with ClinicalTrials.gov (NCT02540408).

Electronic supplementary material

The online version of this article (10.1186/s12931-019-1082-2) contains supplementary material, which is available to authorized users.

Baker's Asthma: Is the Ratio of Rye Flour-Specific IgE to Total IgE More Suitable to Predict the Outcome of Challenge Test Than Specific IgE Alone

Usually the diagnosis of baker's asthma is based on specific inhalation challenge with flours. To a certain extent the concentration of specific IgE to flour predicts the outcome of challenge test in bakers. The aim of this study was to evaluate whether the ratio of specific IgE (sIgE) to total IgE (tIgE) improves challenge test prediction in comparison to sIgE alone. Ninety-five bakers with work-related respiratory symptoms were challenged with rye flour. Total IgE, sIgE, and the sIgE/tIgE ratio were determined. Receiver operator characteristic (ROC) plots including the area under the curve (AUC) were calculated using the challenge test as gold-standard. Total IgE and sIgE concentrations, and their ratio were significantly higher in bakers with a positive challenge test than in those with a negative one (p < 0.0001, p < 0.0001, and p = 0.023, respectively). In ROC analysis, AUC was 0.83 for sIgE alone, 0.79 for tIgE, and 0.64 for the ratio. At optimal cut-offs, tIgE, sIgE, and the ratio reached a positive predicted value (PPV) of 95%, 84% and 77%, respectively. In conclusion, calculating the ratio of rye flour-sIgE to tIgE failed to improve the challenge test prediction in our study group.

Diagnosing environmental allergies: Comparison of skin-prick, intradermal, and serum specific immunoglobulin E testing

Background:

Allergists commonly perform intradermal skin testing (IDST) after negative skin-prick testing (SPT) to comprehensively diagnose environmental allergic sensitization. However, with the availability of modern methods to detect serum-specific immunoglobulin E (ssIgE), it is unclear if ssIgE testing could substitute for IDST.

Objective:

To determine the efficacy of ssIgE testing and IDST when added to SPT in diagnosing environmental allergic sensitizations.

Methods:

SPT, IDST, and ssIgE testing to nine common environmental allergens were analyzed in 75 patients with oculonasal symptoms who presented to our allergy clinics in the Bronx, New York, between January 2014 and May 2015.

Results:

A total of 651 SPT and 499 ssIgE tests were independently performed and revealed 162 (25%) and 127 (25%) sensitizations, respectively. When SPT results were negative, IDST results revealed 108 of 452 additional sensitizations (24%). In contrast, when SPT results were negative, ssIgE test results only revealed 9% additional sensitizations. When both SPT and IDST results were negative, ssIgE testing only detected 3% of additional sensitizations, and ssIgE levels were typically low in these cases (median, 1.25 kU/L; range, 0.357–4.47 kU/L). When both SPT and ssIgE test results were negative, IDST results detected 15% additional sensitizations.

Conclusion:

IDST detected more additional environmental sensitizations compared with ssIgE testing. IDST, therefore, may be useful when the SPT and/or ssIgE testing results were negative, but the exposure history indicated relevant allergic sensitization. Serology added only a little more information if both SPT and IDST results were negative but may be useful in combination with SPT if IDST cannot be performed.

Stem Cell Factor and Interleukin-31 Expression: Association with IgE among Egyptian Patients with Atopic and Nonatopic Bronchial Asthma

Bronchial asthma is a chronic inflammatory disorder which remains a significant cause of morbidity. Recently, it has been reported that the stem cell factor (SCF) and interleukin-31 (IL-31) may play a major role in bronchial asthma. The aim of the current study was to study the association of the stem cell factor and interleukin-31 expression with serum immunoglobulin E among Egyptian patients with atopic and nonatopic bronchial asthma. After measuring serum IgE using total enzyme linked immunosorbent assay (ELISA), Ribonucleic acid (RNA) was isolated to determine gene expression of SCF and IL-31 by real-time polymerase chain reaction (PCR). The levels of SCF mRNAs in atopic asthmatic patients' PBMCs were significantly higher than those in controls (p = 0.0001**) and nonatopic asthmatics (p = 0.0001**). There was a high statistical significant difference also with regard to IL-31 between atopic asthmatics and controls (p = 0.0001**) and between them and nonatopic patients (p = 0.014*). There was a strong significant direct correlation between SCF, IL-31 (r = 0.827 and p = 0.0001**) and between both of them and IgE in asthmatics (r = 0.543 and p = 0.0001**) (r = 0.443 and p = 0.0001**), respectively. A direct correlation between SCF, IL-31 and FEV-1/ FVC %, CRP and wheezing existed. These findings suggest that both SCF and IL-31 play an important role in mediating inflammation and enhancing severity of atopic asthma. Augmented inhaled glucocorticoid therapy was associated with significant reductions in SCF and IL-31 mRNA expression as well as improvements in lung function, symptom scores and bronchial hyperresponsiveness to methacholine (PD20) in atopic and nonatopic asthmatics.

Recent Understandings of Pet Allergies

Allergic reactions to pets have been recognized for at least a hundred years. Yet our understanding of the effects of all of the interactions between pet exposures and human immune responses continues to grow. Allergists, epidemiologists, and immunologists have spent years trying to better understand how exposures to pet allergens lead to allergic sensitization (the production of allergen-specific immunoglobulin class E [IgE] antibodies) and subsequent allergic disease. A major new development in this understanding is the recognition that pet exposures consist of not only allergen exposures but also changes in microbial exposures. Exposures to certain pet-associated microbes, especially in the neonatal period, appear to be able to dramatically alter how a child’s immune system develops and this in turn reduces the risk of allergic sensitization and disease. An exciting challenge in the next few years will be to see whether these changes can be developed into a realistic preventative strategy with the expectation of significantly reducing allergic disease, especially asthma.

Specific IgG for cat allergens in patients with allergic conjunctivitis

Immunoglobulin G (IgG) antibodies are involved in type II and type III hypersensitivity. We evaluated the relation between perennial allergic conjunctivitis and serum levels of specific IgG for cat allergens. A prospective study was conducted in patients with seasonal allergic conjunctivitis (seasonal group, n = 10), patients with perennial allergic conjunctivitis (perennial group, n = 10), and healthy control subjects (control group, n = 10). Serum levels of specific IgE and IgG for cat allergens and total tear IgE were measured, and a skin prick test was also performed. In addition, a severity score associated with allergic conjunctivitis was calculated (0-30). The positive rates and scores of for total tear IgE, serum cat-specific IgE, and serum cat-specific IgG were all higher in the seasonal and perennial groups than in the control group (all p < 0.05). Serum cat-specific IgG levels were higher in the perennial group than in the seasonal group (p = 0.0156), but there was no significant difference in the grade of cat-specific IgE between the two groups (p = 0.3008). On multivariate analysis, the mean wheal diameter for cat allergen was associated with the serum level of cat-specific IgG (not IgE) in all patients [odds ratio (OR) = 31.979, p < 0.0001]. Multivariate analysis revealed that the total objective score was strongly associated with serum cat-specific IgG (OR = 23.015, p < 0.0001). These findings suggest that specific IgG antibodies may be involved in perennial allergic symptoms caused by indoor allergens such as cat allergens.

Airborne biogenic particles in the snow of the cities of the Russian Far East as potential allergic compounds

This paper presents an analysis of airborne biogenic particles (1 mkm–1 mm) found in the snow in several cities of the Russian Far East during 2010–2013. The most common was vegetational terraneous detritus (fragments of tree and grass leaves) followed by animal hair, small insects and their fragments, microorganisms of aeroplankton, and equivocal biological garbage. Specific components were found in samples from locations close to bodies of water such as fragments of algae and mollusc shells and, marine invertebrates (needles of sea urchins and shell debris of arthropods). In most locations across the Far East (Vladivostok, Khabarovsk, Blagoveshchensk, and Ussuriysk), the content of biogenic particles collected in the winter did not exceed 10% of the total particulate matter, with the exception of Birobidzhan and the nature reserve Bastak, where it made up to 20%. Most of all biogenic compounds should be allergic: hair, fragments of tree and grass leaves, insects, and microorganisms.

Skin testing versus serum-specific IgE testing: which is better for diagnosing aeroallergen sensitization and predicting clinical allergy?

An accurate diagnosis of aeroallergen sensitization is pivotal to clinical practice and research. Given the recent technological advances in analyzing serum allergen-specific IgE, the question of which testing method, skin or serum testing, is superior in diagnosing allergic sensitization must be readdressed, as well as their value in predicting clinical disease. This review article provides a detailed summary of recent studies addressing these questions. Conclusively, most studies show substantial discordance between serum-specific IgE and skin testing results, suggesting that the two testing methods compliment each other and cannot be used interchangeably. On average, using only one testing method may misdiagnose every fourth allergically sensitized patient as non-sensitized. In addition, depending on the allergen tested, skin prick testing and serum-specific IgE testing appear to be the methods of choice in predicting outcomes of experimental allergen challenge, while intradermal testing is less contributory.

Reduction of the number of major representative allergens: from clinical testing to 3-dimensional structures

Vast amounts of allergen sequence data have been accumulated, thus complicating the identification of specific allergenic proteins when performing diagnostic allergy tests and immunotherapy. This study aims to rank the importance/potency of the allergens so as to logically reduce the number of allergens and/or allergenic sources. Meta-analysis of 62 allergenic sources used for intradermal testing on 3,335 allergic patients demonstrated that in southern China, mite, sesame, spiny amaranth, Pseudomonas aeruginosa, and house dust account for 88.0% to 100% of the observed positive reactions to the 62 types of allergenic sources tested. The Kolmogorov-Smironov Test results of the website-obtained allergen data and allergen family featured peptides suggested that allergen research in laboratories worldwide has been conducted in parallel on many of the same species. The major allergens were reduced to 21 representative allergens, which were further divided into seven structural classes, each of which contains similar structural components. This study therefore has condensed numerous allergenic sources and major allergens into fewer major representative ones, thus allowing for the use of a smaller number of allergens when conducting comprehensive allergen testing and immunotherapy treatments.

Inhaled allergen bronchoprovocation tests

The allergen bronchoprovocation test is a long-standing exacerbation model of allergic asthma that can induce several clinical and pathophysiologic features of asthma in sensitized subjects. Standardized allergen challenge is primarily a research tool, and when properly conducted by qualified and experienced investigators, it is safe and highly reproducible. In combination with validated airway sampling and sensitive detection techniques, allergen challenge allows the study of several features of the physiology of mainly TH2 cell-driven asthma in relation to the kinetics of the underlying airway pathology occurring during the allergen-induced late response. Furthermore, given the small within-subject variability in allergen-induced airway responses, allergen challenge offers an adequate disease model for the evaluation of new (targeted) controller therapies for asthma in a limited number of subjects. In proof-of-efficacy studies thus far, allergen challenge showed a fair positive predicted value and an excellent negative predictive value for the actual clinical efficacy of new antiasthma therapies, underscoring its important role in early drug development. In this review we provide recommendations on challenge methods, response measurements, sample size, safety, and harmonization for future applications.

Bronchial allergen challenges in children - safety and predictors

BACKGROUND

In allergic asthma, the diagnosis of house dust mite (HDM) allergy is mainly based on the patient's history, allergy testing by the skin prick test (SPT) or the levels of allergen-specific IgE. We retrospectively analysed data from 350 bronchial provocations with HDM and related it to the following parameters: specific IgE, bronchial hyperresponsiveness (BHR) to methacholine testing (MCT) and exhaled NO (eNO).

METHODS

Approximately 350 patients (5-18 yr of age) with allergic asthma and a positive SPT to HDMs were included. To define the sensitivity and specificity for the detection method of an early asthmatic response (EAR), a receiver-operating characteristic (ROC) curve was plotted. The accuracy was measured by the area under the ROC curve (AUC). A logistic regression model was used to predict the individual probability of a positive challenge. The results of the regression model were validated in a prospective group of n = 75 patients.

RESULTS

The following cut-off values showed the best combination of sensitivity and specificity: specific IgE Dermatophagoides farinae 19.6 kU/l (AUC, 0.88), PD(20) FEV(1) 0.13 mg methacholine (AUC, 0.73) and eNO 20.1 ppb (AUC, 0.71). The following equation predicted the individual probability of a positive challenge in the retrospective and prospective group: p = 1(.) [1 + exp[-(-1.78 + 2.46.(10) log D. far - 1.25(.10) logPD(20) metha)]](-1) , (AUC = 0.88).

CONCLUSIONS

The value of using the specific IgE and MCT as predictors was confirmed in a large number of patients. We also showed, for the first time, that the eNO predicted the EAR. The logistic regression model is repeatable with a good accuracy.

Asthma related to Alternaria sensitization: an analysis of skin-test and serum-specific IgE efficiency based on the bronchial provocation test

BACKGROUND

It is difficult to find a causal relationship between exposure to Alternaria spores and the development of asthma symptoms in sensitized individuals due to the complexity of clinical situations in which positive diagnostic tests are often found.

OBJECTIVE

To analyse the diagnostic efficiency of skin testing (ST) and serum-specific IgE to Alternaria, based on the results of a bronchial specific challenge with Alternaria extracts.

METHODS

Seventy-four asthmatic patients sensitized to Alternaria underwent a specific bronchial challenge with this mould. Skin-testing weal sizes, serum-specific IgE values (CAP-system) and bronchial challenge results were analysed by receiver operating characteristics curves (ROC curves) and logistic regression. The sensitivity, specificity, positive and negative predictive values were calculated for different cut-off points.

RESULTS

Bronchial challenges to Alternaria elicited a positive result in 45 patients (61%). Skin prick testing almost perfectly predicted the outcome of bronchoprovocation tests (area under the ROC curve of 0.957), whereas intradermal skin testing had moderate efficacy. A negative result for skin prick test (SPT) showed a 4% probability of a positive bronchial challenge in the logistic regression analysis. However, weals around 5.5 mm in diameter had 90% probability of a positive challenge. Quantification of serum-specific IgE correctly classified 86% of the cases. In the logistic regression analysis, a CAP value 16 kU(A)/L predicted a positive bronchial challenge result with 99% accuracy, whereas for a CAP value <0.35 kU(A)/L, this probability was 33%.

CONCLUSIONS AND CLINICAL RELEVANCE

Most asthmatic patients with positive SPT results to Alternaria would have a positive bronchial challenge. As atmospheric mould levels may vary significantly with the weather conditions, sensitized patients should be instructed on the risk situations, environmental control measures and the importance of correct medication compliance. Immunotherapy with Alternaria could also be taken into account as a valid therapeutic option.

Asthma in humans and cats: is there a common sensitivity to aeroallegens in shared environments?

Cats spontaneously develop eosinophilic airway inflammation and airway hyperreactivity that is very similar to human allergic asthma. In addition, household cats share environmental exposures to aeroallergens with humans. We review the scientific literature concerning the pathophysiology of feline asthma, including similarities to human asthma and evidence regarding environmental aeroallergen triggers. Results of pathophysiological studies suggest important similarities between human and feline responses to inhaled allergens. Only a few studies were found that examined the development of disease in cats to environmental aeroallergens. Limited evidence suggests that some environmental allergens can cause disease in both cats and humans. It appears that there is a need for greater communication between human and animal health professionals regarding environmental causes of asthma. Specifically, additional research into linkages between human and feline asthma using both molecular techniques and clinical epidemiological approaches could lead to improved understanding of the environmental risks. Finally, there should be consideration of use of naturally affected and/or experimentally induced (using clinically relevant allergens) asthmatic cats in preclinical trials for novel therapeutic interventions.

Diagnosis and management of work-related asthma: American College Of Chest Physicians Consensus Statement

BACKGROUND

A previous American College of Chest Physicians Consensus Statement on asthma in the workplace was published in 1995. The current Consensus Statement updates the previous one based on additional research that has been published since then, including findings relevant to preventive measures and work-exacerbated asthma (WEA).

METHODS

A panel of experts, including allergists, pulmonologists, and occupational medicine physicians, was convened to develop this Consensus Document on the diagnosis and management of work-related asthma (WRA), based in part on a systematic review, that was performed by the University of Alberta/Capital Health Evidence-Based Practice and was supplemented by additional published studies to 2007.

RESULTS

The Consensus Document defined WRA to include occupational asthma (ie, asthma induced by sensitizer or irritant work exposures) and WEA (ie, preexisting or concurrent asthma worsened by work factors). The Consensus Document focuses on the diagnosis and management of WRA (including diagnostic tests, and work and compensation issues), as well as preventive measures. WRA should be considered in all individuals with new-onset or worsening asthma, and a careful occupational history should be obtained. Diagnostic tests such as serial peak flow recordings, methacholine challenge tests, immunologic tests, and specific inhalation challenge tests (if available), can increase diagnostic certainty. Since the prognosis is better with early diagnosis and appropriate intervention, effective preventive measures for other workers with exposure should be addressed.

CONCLUSIONS

The substantial prevalence of WRA supports consideration of the diagnosis in all who present with new-onset or worsening asthma, followed by appropriate investigations and intervention including consideration of other exposed workers.

Prediction of challenge test results by flour-specific IgE and skin prick test in symptomatic bakers

BACKGROUND

Wheat and rye flours are among the most important allergens causing occupational asthma. Usually, the diagnosis of baker's asthma is based on inhalation challenge tests with flours.

AIMS OF THE STUDY

To evaluate the relevance of flour-specific serum immunoglobulin E (IgE) and skin prick test (SPT) in the diagnosis of baker's asthma and to define flour-specific IgE concentrations and wheal sizes that allow a prediction of the outcome of challenge testing.

METHODS

Bronchial and nasal challenge tests with wheat (rye) flour were performed in 71 (95) symptomatic bakers. Determinations of flour-specific IgE as well as SPTs were performed in all subjects. Analyses included the calculation of sensitivity, specificity, positive (PPV) and negative predictive values (NPV) at different IgE concentrations and different wheal sizes, and receiver-operating characteristics (ROC) plots with the challenge result as gold standard.

RESULTS

Thirty-seven bakers were positive in the challenge with wheat flour, while 63 were positive with rye flour. Depending on the flour-specific IgE concentrations (wheal size), PPV was 74-100% (74-100%) for wheat and 82-100% (91-100%) for rye flour, respectively. The minimal cut-off values with a PPV of 100% were 2.32 kU/l (5.0 mm) for wheat flour and 9.64 kU/l (4.5 mm) for rye flour. The shapes of the ROC plots were similar for wheat and rye flour.

CONCLUSION

High concentrations of flour-specific IgE and clear SPT results in symptomatic bakers are good predictors for a positive challenge test. Challenge tests with flours may be avoided in strongly sensitized bakers.

SCF and IL-31 rather than IL-17 and BAFF are potential indicators in patients with allergic asthma

BACKGROUND

Although the prevalence of allergic asthma increased quickly in the past decade, the diagnostic criteria have not been well established. The aim of the present study was to explore whether stem cell factor (SCF), B cell-activating factor (BAFF), and cytokines interleukin (IL)-17 and IL-31 are usable parameters for the diagnosis of allergic asthmatics.

METHODS

Blood samples were collected from patients with allergic asthma, control patients, and healthy control subjects. The serum concentrations of SCF, BAFF, IL-17, and IL-31 were measured by enzyme-linked immunosorbent assay. The corresponding mRNA levels in peripheral blood mononuclear cells (PBMCs) were determined by real-time reverse-transcription polymerase chain reaction.

RESULTS

A good correlation existed between protein levels of SCF and IL-31 and their mRNA levels (SCF: r = 0.6162; IL-31: r = 0.5463). The serum concentrations of SCF and IL-31 in allergic asthmatic patients, but not control patients, were significantly higher than those in normal control subjects (SCF: median 1.83 vs 0.85 ng/ml, P < 0.01; IL-31: 50.15 vs 10.01 pg/ml, P < 0.001). Consistently, the levels of SCF and IL-31 mRNAs in allergic asthmatic patients' PBMCs were also significantly higher than those in normal control subjects (P = 0.002 and P < 0.001, respectively).

CONCLUSIONS

These findings suggest that allergic asthma is characterized by an elevation of cytokines SCF and IL-31 and the measurement of their expression at either protein level in serum or mRNA level in PBMCs will be a valuable parameter for the diagnosis of allergic asthma.