Diagnosis of food allergy: tests in vivo and in vitro

Trends of sensitization pattern to aeroallergens among the patients with allergic rhinitis and/or bronchial asthma in Bangalore: A cross sectional study

Background

Allergic rhinitis (AR) is rather erroneously viewed as a trivial disease. It is a chronic or recurrent allergen-specific, IgE-mediated inflammation that primarily affects the membrane lining the nose. However, due to the united airway concept, it is also found to be associated with bronchial asthma. AR commonly remains underdiagnosed or misdiagnosed and thus, leads to either undertreatment or inappropriately prolonged medication.

Methods

Four hundred adults having allergic rhinitis and/or bronchial asthma, fulfilling the criteria as per Allergic Rhinitis and its Impact on Asthma (ARIA) guidelines, underwent skin prick test (SPT). Those having rhinitis due to nonallergic causes were excluded. SPT was carried out using a customized panel of 21 aeroallergens. The result was compared with the reaction of histamine, which was taken as a positive control.

Results

Majority of 228 (58.02%) of the patients showed a positive reaction to the tested panel of allergens. However, 165 (41.98%) showed no reaction to the tested panel of allergens can be due to various factors like reduced skin sensitivity, antihistaminic medications, etc.

Conclusion

Skin prick test accurate test for determining offending allergens in allergic conditions. House dust mites (41%) were the most common offending aeroallergen among patients with allergic rhinitis and/or bronchial asthma residing in Bangalore. The identification of offending aeroallergens have helped patients in avoiding unnecessary medications, take appropriate preventive measures or plan appropriate immunotherapy.

IgE allergy diagnostics and other relevant tests in allergy, a World Allergy Organization position paper

Currently, testing for immunoglobulin E (IgE) sensitization is the cornerstone of diagnostic evaluation in suspected allergic conditions. This review provides a thorough and updated critical appraisal of the most frequently used diagnostic tests, both in vivo and in vitro. It discusses skin tests, challenges, and serological and cellular in vitro tests, and provides an overview of indications, advantages and disadvantages of each in conditions such as respiratory, food, venom, drug, and occupational allergy. Skin prick testing remains the first line approach in most instances; the added value of serum specific IgE to whole allergen extracts or components, as well as the role of basophil activation tests, is evaluated. Unproven, non-validated, diagnostic tests are also discussed. Throughout the review, the reader must bear in mind the relevance of differentiating between sensitization and allergy; the latter entails not only allergic sensitization, but also clinically relevant symptoms triggered by the culprit allergen.

Determinants of airflow limitation in Danish adults - findings from the Health2006 cohort

Background and aim

Airflow limitation may be found in patients with both asthma and COPD and is often associated with more symptoms and poorer outcome. We aimed to identify factors associated with airflow limitation in a well-characterized, population-based sample of adults.

Methods

From the Health2006 cohort, we selected participants aged ≥35 years at enrolment (n=2,959). Airflow limitation was defined as FEV₁/FVC < lower limit of normal. Participants with (cases) and without (controls) airflow limitation were compared with regard to self-reported symptoms, medical history, atopy, lung function and exhaled nitric oxide. Between-group differences were analyzed using Chi-square and Mann–Whitney U tests, and effect size was estimated by logistic regression (reported as OR and 95% CI).

Results

We identified 313 cases, majority of which were female, reported poor overall health, physically inactivity and experienced respiratory symptoms within the previous year. The presence of airflow limitation was associated with BMI (OR 3.1 for overweight, P<0.001, CI 1.97–4.78), age (OR 2.3, P<0.001 for age 55+, CI 1.7–3.2), tobacco exposure (OR 1.6, P=0.01, CI 1.1–2.32, and OR 1.76, P=0.019, CI 1.2–2.3 for former and current smokers, respectively), sex (OR 1.6 for being female, P=0.002, CI 1.2–2.2), presence of specific IgE to common aeroallergen(s) (OR 1.4, P=0.041, CI 1.2–2.0), and ever being diagnosed with asthma (OR 1.6, P=0.003, CI 1.3–2.0).

Conclusion

Apart from tobacco exposure and age, the presence of airflow limitation was associated with being overweight, female, sensitized to common aeroallergens or ever having a diagnosis of asthma.

Diagnostic accuracy of skin-prick testing for allergic rhinitis: a systematic review and meta-analysis

BACKGROUND

Allergic rhinitis is the most common form of allergy worldwide. The accuracy of skin testing for allergic rhinitis is still debated. Our primary objective was to evaluate the diagnostic accuracy of skin-prick testing for allergic rhinitis using the nasal provocation as the reference standard. We also evaluated the diagnostic accuracy of intradermal testing as a secondary objective.

METHODS

We searched EBM Reviews from 2005 to March 2015; Embase from 1980 to March 2015; and Ovid MEDLINE(R) from 1946 to until March 2015. We included any study with at least 10 subjects including children. We excluded non-English studies. We performed data extraction and quality assessment using the QUADAS-2 tool.

RESULTS

We meta-analysed seven studies assessing the accuracy of skin-prick testing using the bivariate random-effects model, including a total of 430 patients. The pooled estimate for sensitivity and specificity for skin-prick testing was 85 and 77 % respectively. We did not pool results for intradermal testing due to few number of studies (n = 4), each with very small sample size. Of these, two evaluated the accuracy of intradermal testing in confirming skin-prick testing results, with sensitivity ranging from 27 to 50 % and specificity ranging from 60 to 100 %. The other two evaluated the accuracy of intradermal testing as a stand-alone test for diagnosing allergic rhinitis with sensitivity ranging from 60 to 79 % and specificity ranging from 68 to 69 %.

CONCLUSIONS

Findings from this review suggest that skin-prick testing is accurate in discriminating subjects with or without allergic rhinitis.

Characterization of the sensitization profile to lupin in peanut-allergic children and assessment of cross-reactivity risk

BACKGROUND

Case reports of allergy to lupin, due to primary sensitization or cross-reactions with other legumes, are increasing as a consequence of the augmented use of lupin flour in bakery, pasta formulations and other food items. The main allergens that have been associated with the sensitization to lupin are α- and β-conglutins and, to a lesser extent, γ- and δ-conglutin, but no conclusive data are available so far. The aim of this study was to characterize the sensitization pattern to lupin in a group of 12 Italian children allergic to peanut and identify the specific lupin proteins involved in the cross-reactivity with peanut.

METHODS

The immunochemical cross-reactivity among peanut and lupin was evaluated by both in vitro immunoblotting and in vivo fresh food skin prick test (FFSPT).

RESULTS

The results showed that β-conglutin was recognized by cutaneous IgEs from 7/12 peanut-allergic children in FFSPT and serum IgEs from 5/12 in immunoblotting, while 4/12 and 8/12 patients tested positive to γ-conglutin in FFSPT and immunoblotting, respectively. No significant immunoreactive responses were observed to α- and δ-conglutins under non-reducing conditions, but they were bound in FFSPT by the sera of 5/12 and 3/12 patients, respectively.

CONCLUSION

In this group of allergic children, β-conglutin has been identified as the major lupin allergen involved both in vitro and in vivo cross-reactivity with peanut proteins. The role of γ-conglutin in the cross-reactivity between lupin and peanut proteins was also relevant and clear, despite the observed unspecificity of the immunoblotting responses.

The Effect of Acupuncture on Allergic Rhinitis: A Randomized Controlled Clinical Trial

Allergic rhinitis is a common health problem usually treated with drug therapy. Some patients experience side effects of drug therapy while others fear the use of drugs. Acupuncture is an interesting alternative to traditional treatment. The few studies evaluating acupuncture indicate a possible clinical effect on allergic rhinitis. This study compared active versus sham acupuncture in 40 consecutive patients with a history of allergic rhinitis and a positive skin test. Patients were randomized and assessed prior to treatment and then reassessed after 12 months. Improvements in symptoms using visual analogue scales, reduction in skin test reactions and levels of specific immunoglobin E (IgE) were used to compare the effect of treatment. For one allergen, mugwort, a greater reduction in levels of specific IgE ( p =0.019, 0.039) and skin test reaction ( p =0.004) was seen in the group receiving active acupuncture compared to the group receiving sham acupuncture. However, this finding might be an artifact. No differences in clinical symptoms were seen between active versus sham acupuncture, thus the conclusion being that the effect of acupuncture on allergic rhinitis should be further evaluated in larger randomized studies.

IgE-mediated cross-reactivity among leguminous seed proteins in peanut allergic children

The immunological cross-reactivity among major protein- and oil-crops, including lupin, lentil, pea, peanut, kidney bean and soybean, has been studied by a combination of in vitro and in vivo experimental approaches: SDS-PAGE separations of legume protein extracts and immuno-blot revelations with 12 peanut-sensitive subjects' sera, Immuno-CAP and Skin Prick tests on the same subjects. The immuno-blotting data showed a wide range of IgE-binding responses both displayed by one subject towards different plant extracts and among subjects. Differences were both quantitative and qualitative. The prevalent responses of most subjects' sera were seen with peanut polypeptides, as expected, as well as with various polypeptides of the other legumes, the most recurrent of which were the basic subunits of the 11S globulins. The distribution of in vivo responses generally paralleled those obtained by in vitro approaches with strong responses elicited by peanut, lentil and pea protein extracts, especially by most sensitive subjects, thus providing a consistent overall set of results. In this work, the comparison of various approaches has allowed us to get an overall broad picture of the immunological cross-reactivities among proteins of widely used different seed species and to hypothesize the role of most conserved specific polypeptides.

Atopy patch test in the diagnosis of food allergy in children with gastrointestinal symptoms

PURPOSE

To evaluate the diagnostic accuracy of the atopy patch test (APT) in detection of delayed-type sensitization to different food allergens, in children with digestive symptoms and with/or without cow's milk allergy.

MATERIAL AND METHODS

28 children suspected of food allergy-related gastrointestinal symptoms were underwent diagnostic procedures as skin prick test (SPT), specific immunoglobulin E (sIgE), APT, oral food challenge and then divided into two groups according to the results of oral food challenge: A - 17 children with cow's milk allergy, B - 11 children without cow's milk allergy. Sensitivity, specificity, positive (PPV) and negative (NPV) predictive values of APT were calculated.

RESULTS

A positive challenge response to milk was found in 60,7% of examined children. No statistical difference in the prevalence of positive SPT and sIgE to milk has been found between the groups. The prevalence of positive APT to other food allergens was significantly higher in children with allergy to milk (p<0,005). No statistical difference of positive APT to other food allergens has been found in children with/or without cow's milk allergy. APT sensitivity and specificity in children with cow's milk allergy obtained on 77%/73%; where PPV obtained on 71%.

CONCLUSIONS

High sensitivity and specificity of APT confirm its accuracy in diagnostics of delayed-type reactions in children with gastrointestinal symptoms. Combined atopy patch test and oral food challenge is essential for avoidance of unnecessary elimination diet. Delayed-type sensitization to other food allergens is common in children with cow's milk allergy.

Adverse reactions to skin prick testing in children - prevalence and possible risk factors

Skin prick test (SPT) is usually considered to be a safe procedure, but recently there have been occasional case reports of generalized allergic reactions. This study was performed to delineate the prevalence of, and evaluate possible risk factors for, adverse reactions to SPT in a prospective study. Altogether 5,908 patients aged < or =18 yr from 11 different pediatric settings were included. The adverse reactions were classified into two groups: (1) Generalized allergic reactions (GAR), (2) Vasovagal reactions (VVR). Adverse reactions were observed in 14 out of 5,908 children examined with SPT. Seven of the adverse reactions were GARs and required medication, yielding a 0.12% risk for GAR. Seven of 14 were VVRs, giving the same risk, 0.12%. Identified risk factors for GAR were low age (<1 yr) (RR 6.28) and active eczema (RR 16.98). For VVR, the risk factors were female sex (RR 7.32) and multiple skin pricks performed on a single patient (p < 0.05). We conclude that GARs do occur, albeit rarely, so the need for proper emergency handling should always be acknowledged. The risk factors suggested may help to identify patients who need extra attention.

Safe administration of an inactivated virosomal adjuvanted influenza vaccine in asthmatic children with egg allergy

In order to evaluate whether the virosomal adjuvanted influenza vaccine that has been shown to have the lowest egg protein content (Inflexal V, Berna Biotech) could be administered to children with even severe egg allergy without any risk of allergic reactions, we used epicutaneous skin testing with the undiluted vaccine in 88 asthmatic children (44 with and 44 without egg allergy), none of whom had a positive response. They were then vaccinated with the whole dose of Inflexal V intramuscularly in a one-dose protocol, and the occurrence of any immediate or delayed adverse events were actively monitored for 28 days. The results showed the safety of the administration, and demonstrated that Inflexal V can be safely given without performing a vaccine skin test in children with any kind of egg allergy.

Diagnosis and natural course of allergy to cooked potatoes in children

BACKGROUND

Allergy to heat stable potato proteins can cause severe allergic disease in children.

OBJECTIVE

To study diagnostic criteria for allergy to cooked potatoes and to describe its clinical characteristics and natural history.

METHODS

Thirty-six children, aged 4-36 months, with atopic symptoms and having a positive potato-CAP and/or skin prick test (SPT) were included. Potato allergy was documented by means of provocation, or elimination and reintroduction or an unequivocal clinical history. Potato-CAP and SPT with a commercial extract were evaluated for diagnostic performance.

RESULTS

Presenting symptoms in children with proven potato allergy (n = 17) were eczema (16 of 17), gastrointestinal complaints (eight of 17), urticaria and/or angioedema (five of 17), wheezing/rhinitis (three of 17) and anaphylaxis (two of 17). Fifteen children had previously diagnosed cow's milk protein allergy and were egg-sensitized. Potato-CAP at cut-off >2 kU/l provided a 100% sensitivity and a 62.5% specificity for diagnosis of potato allergy, while a SPT score >/= 3 had a 100% sensitivity and a score >/= 4 had a 100% specificity. Tolerance to cooked potato was achieved in 80% of subjects at age 16-102 months. Of 12 subjects having reached the age of 3 years during the study, 10 were re-evaluated at age 3-6 years: seven of 10 subjects had developed clinical pollen allergy, compared with four of 18 atopic controls (P < 0.05).

CONCLUSIONS

Potato-CAP and SPT at specific cut-off are valuable tools in the diagnosis of allergy to cooked potato. Most children with potato allergy develop tolerance at mean age of 4 years. Allergy to cooked potatoes is a risk factor for the development of pollen allergy.

Allergy in bakers’ apprentices and factors associated to non-participation in a cohort study of allergic sensitization

OBJECTIVE

To describe the prevalence of atopy and respiratory symptoms among baker apprentices at the start of the education and factors associated with non-participation in the study.

METHODS

A total of 346 students, 22.1(0.6) years of age, mean (SD), from the food production programme of technical colleges in Denmark were invited to participate in a 3 year study. Of the students, 187 agreed to participate and filled in a physician-administered questionnaire. The presence of atopy was determined by skin prick test (SPT) and serum allergen specific IgE (SpIgE). Bronchial hyper responsiveness to methacholine (PD(20) <or= 1,440 microg) was determined.

RESULTS

Prevalence of atopy was 32%. The prevalence of symptoms from the lungs and nose was 19.8 and 25.5%, respectively. Significantly, more SPT reactions were seen in males compared to females (39 vs. 22%, P < 0.05). Sensitization towards flour was significantly more frequent if determined as SpIgE (7.3%) compared to SPT (0.5%). We found a positive association between atopy and lung symptoms OR 6.1 (2.8-13.2 SD) and nasal symptoms OR 3.7 (1.8-7.5 SD). The major reason for non-participation was fear of blood sampling (25.5%).

CONCLUSION

The prevalence of atopy in bakers' apprentices was of the same magnitude in the general Danish population. Significantly, more male bakers' apprentices had atopy. This finding has major impact on the diagnostic procedures of occupational allergy in bakery workers emphasizing the need for standardization of the clinical tests. The main reasons for non-participation were, fear of blood-sampling (57%) and the 3 years commitment to the follow-up study (39%).

Allergen-specific IgE testing in the diagnosis of food allergy and the event of a positive match in the bioinformatics search

Current documents on risk assessment of genetically modified foods recommend including IgE-binding tests on sera from allergic patients. However, there is no generally accepted recommendation on technical aspects of the testing procedures or on the interpretation of the results, despite that fact that both false positive and false-negative results may be caused by variability of the test procedures. The present article discusses the state-of-the-art of serological test procedures for qualitative and quantitative determination of specific IgE and interpretation of test results. It is emphasized that the use of sera from clinically well-characterized subjects is of high importance. In the case of a positive test result, the biological activity of the detected IgE antibodies, i. e., the potential to trigger mediator release from basophils or mast cells in an allergen-specific manner, should be taken into account. However, present data also indicate that validation of such mediator release tests is required, both in terms of experimental protocols and with respect to correlation of the test results with the clinical situation. Further studies are also required to prove the usefulness of targeted serum screening, i. e., the testing of gene products from organisms not known to be allergenic with sera from subjects allergic to related species.

A hydrolysed rice-based formula is tolerated by children with cow's milk allergy: a multi-centre study

BACKGROUND

Children allergic to cow's milk are fed a soy- or a hydrolysed cow's milk-based substitute. Neither can rule out a sensitization risk. Previous studies have shown that hydrolysed rice is tolerated by animals and children with multiple food hypersensitivities.

OBJECTIVE

A prospective clinical assessment of tolerance to a rice-based hydrolysed formula was carried out in children allergic to cow's milk. Patients and methods One hundred children (42 girls and 58 boys, mean age 3.17+/-2.93 years, median 2.20, range 0.18-14.6 years) with a history of immediate reactions to cow's milk and confirmed at double-blind, placebo-controlled food challenge (DBPCFC) when not contraindicated were assessed for clinical tolerance to cow's milk proteins. Their allergy work-up included skin prick tests with whole milk, alpha-lactalbumin (ALA), beta-lactoglobulin (BLG) and total caseins, and specific IgE determinations using CAP technology were performed against whole milk, ALA, BLG and casein. Sensitization to rice and rice-based hydrolysed formula was similarly investigated. Patients' sera were evaluated at immunoblotting for specific IgE to cow's milk proteins, rice and rice-based hydrolysed formula. DBPCFC was carried out with increasing doses of a rice-based hydrolysed formula.

RESULTS

All patients were sensitized to cow's milk and/or at least one cow's milk protein fraction. Eighty-seven out of 99 were positive to cow's milk and/or a cow's milk protein fraction at skin prick test. Positive (>0.35 kUA/L) specific IgE determinations were found for cow's milk and/or milk fractions (92/95), rice (21/91) and hydrolysed rice infant formula (4/91). At immunoblotting, sera from 96 children were positive to alpha-casein (n=54), beta-casein (n=38), ALA (n=57), BLG (n=37) and bovine serum albumin (n=61). Similarly, although patients' sera often contained specific IgE against rice proteins at CAP (21/91) and immunoblotting (70/96), only six very weakly positive responses were observed against rice-based hydrolysed formula. All DBPCFC with rice-based hydrolysed formula were negative.

CONCLUSIONS

Rice-based hydrolysed formula is a possible alternative not only for children with multiple allergies, but also for children with cow's milk allergy.

Significant improvement of eczema with skin care and food elimination in small children

AIM

To evaluate common methods of investigation and treatment in children younger than 2 y of age with eczema, with or without sensitization to food allergens.

METHODS

One hundred and twenty-three children younger than 2 y of age with eczema and suspected food allergy were included in this prospective study. The children underwent skin-prick test with cow's milk, fresh hen's egg white and wheat. Specific IgE to milk and egg white was analysed. The eczema extent and severity was estimated with SCORAD before and after treatment. Children with a positive skin-prick test were instructed to exclude that food item from their diet. All children were treated with emollients and topical steroids when needed.

RESULTS

Sixty-two of the children were skin-prick positive to at least one of the allergens; 62% had mild, 30% moderate and 8% severe eczema at their first visit. After treatment, 90% had mild, 10% moderate and 0% severe eczema. Forty-six per cent of the children had circulating IgE antibodies to milk or egg white. Ten per cent had specific IgE but negative skin-prick test to the same allergen. This subgroup improved their eczema significantly without elimination diet.

CONCLUSION

The conventional treatments for children with eczema, i.e. skin care and food elimination, are effective. The beneficial effect of skin care as the first step should not be neglected, and it may not be necessary to eliminate food allergens to relieve skin symptoms in all food-sensitized children with eczema.

Dietary prevention of allergic diseases in infants and small children. Part II. Evaluation of methods in allergy prevention studies and sensitization markers. Definitions and diagnostic criteria of allergic diseases

The role of primary prevention of allergic disease has been a matter of debate for the last 40 years. In order to shed some light into this issue a group of experts of the Section of Pediatrics EAACI critically reviewed the existing literature on the subject. The design of observational and interventional studies was evaluated with relevance to the important factors influencing outcome of studies on allergy development/prevention. in this analysis the statements of evidence as defined by WHO were applied. Best evidence of recommendations are those fulfilling the criteria for statements category 1 and 2 and grade of recommendations A and B as proposed by WHO. This survey include target group for dietary prevention and methods and diagnostic criteria of atopic dermatitis, asthma and food allergy for prevention studies.

Dietary prevention of allergic diseases in infants and small children. Part I: immunologic background and criteria for hypoallergenicity

The role of primary prevention of allergic diseases has been a matter of debate for the last 40 years. In order to shed some light into this issue, a group of experts of the Section of Pediatrics EAACI critically reviewed the existing literature on the subject. In this paper, the immunology of the fetus and newborn is reviewed as well as the post-natal development of the immune system. The influence of post-natal environment and breastfeeding on tolerance induction and sensitization are examined. Allergic diseases result from a strong relationship between genetic and environmental factors. Sensitization to food allergens occurs in the first year of life and cow's milk allergy is the first food allergy to appear in the susceptible infants. Hypoallergenicity of food formulas to be used is a critical issue both for treatment of cow's milk-allergic children and for prevention. Methods to document hypoallergenicity are discussed and evaluated in the preclinical and clinical steps.

Infectious and uterus related complications during pregnancy and development of atopic and nonatopic asthma in children

BACKGROUND

It has been suggested that environmental factors early in life, particularly related to hygiene and infections, seem to be involved in the increase of asthma and allergic disease observed recently in developed countries. The possible effect of these factors also in utero have yet to be completely clarified. The aim of this study was to investigate the association between infective and uterus related complications during pregnancy, as well as related drug factors, with atopic and nonatopic asthma in children.

METHODS

This was a case-controlled study enrolling 338 children with asthma and 467 controls, who had never suffered from wheeze or asthma. Fever episodes, flu episodes, threatened abortions and related drug factors were retrospectively assessed by parental report via a standardized questionnaire. Atopy was determined by skin-prick tests to 10 prevalent allergens at the time of examination.

RESULTS

Flu episodes during pregnancy were significantly associated with development of asthma in children [adjusted odds ratio (aOR) 1.91; 95% confidence interval (95% CI) 1.1-3.2], mainly with nonatopic asthma. Fever episodes showed similar results (aOR 2.16; 95% CI 1.2-3.9), but were associated with both atopic and nonatopic asthma. The effect seems mainly due to flu and fever episodes contracted in the third trimester. Exposure to isoxsuprine was significantly associated with asthma (aOR 1.54; 95% CI 1.08-2.19) while threatened abortions were more frequent in the asthma group than in controls, although the difference was statistically significant only when such events occurred in the second trimester (aOR 2.06; 95% CI 1.07-3.94). Both threatened abortions and exposure to isoxsuprine were associated only with nonatopic asthma.

CONCLUSIONS

This study confirms that prenatal infective complications may contribute to the development of asthma in children and show a possible role for a new risk factor for asthma, that is exposure to isoxsuprine. Therefore, larger prospective studies, capable of separating atopic and nonatopic asthma, would serve to confirm these results and to explain the possible mechanism through which these factors may act.

A comparison of different allergometric tests, skin prick test, Pharmacia UniCAP and ADVIA Centaur, for diagnosis of allergic diseases in children

BACKGROUND

The diagnosis of allergic disease is performed by skin prick tests (SPT) or through the demonstration of specific IgE in a blood sample via an in vitro test. The measurement of IgE concentration against allergens provides critical information in clinical allergy. Standardized and reproducible methods contribute to the quality of diagnosis and treatment of allergic disease.

METHODS

In this study we evaluated the performance of a new specific IgE method, developed by ALK-Abellò for Bayer Diagnostics to run on their ADVIA Centaur immunoassay system. One hundred and fifty-one children with allergic diseases (both food and inhalant allergies) were tested for specific IgE (sIgE) via SPT and in vitro tests (UniCAP system, Pharmacia, and ADVIA Centaur immunoassay system, Bayer Diagnostics) and the test results were correlated with the clinical data.

RESULTS

Statistical analysis revealed no significant difference between the two in vitro tests compared with clinical history. The sensitivities and specificities are similar, but the UniCAP system method has higher sensitivity. In the children with cow's milk allergy, the UniCAP system has sensitivity of 91% and specificity of 70%; the ADVIA Centaur immunoassay has sensitivity of 82% and specificity of 74%. In hen's egg allergy, UniCAP system has 94% sensitivity and 64% specificity, and the ADVIA Centaur system has 88% sensitivity and 52% specificity. In inhalant allergies, the two methods show statistically similar performances for both grass pollen allergies (UniCAP sensitivity 100%, specificity 73%; ADVIA Centaur sensitivity 95%, specificity 79%) and in the dust mites allergies (UniCAP sensitivity 91%, specificity 62%; ADVIA Centaur sensitivity 86%, specificity 64%). In cat allergies, the systems showed equivalent results (UniCAP sensitivity 100%, specificity 71%; ADVIA Centaur sensitivity 100%, specificity 70%). Using the UniCAP system, the geometric mean of sIgE values in children with clinical allergy is significantly higher than in sensitized ones. The ADVIA Centaur system shows a similar trend with the exclusion of cow's milk and Dermatophagoides farinae allergens. With this last method the mean value of sIgE is higher in sensitized than in symptomatic children.

CONCLUSION

The new ADVIA Centaur method compares favorably with the results obtained on the UniCAP system. If other studies continue to confirm this data, then the advantages are numerous: the use of only a small quantity of serum (25 micro l per allergen), rapid turnaround time, minimal hands-on time, and no interference from IgG.