Phadiatop Test Research Articles

Efficacy of a single diagnostic test for sensitization to common inhalant allergens.

UniCAP Phadiatop is a single laboratory test designed to determine the presence or absence of specific IgE to a variety of common inhalants. Its purpose is to aid in the differentiation of patients with symptoms attributable to allergic disease from other common causes. Consecutive children and adolescent patients (n = 145) at two centers were examined by having their history and physical examination performed by two board certified allergists. Their conclusions along with skin prick tests and specific IgE measurements regarding seven common inhalants (mite, oak, ragweed, grass, dog, cat, Alternaria) were compared with UniCAP Phadiatop test results. This was done using concordance of all test results. Attempts to resolve test discrepancies, when found, included specific RAST inhibitions, total IgE values, and physicians' judgment after testing. All patients with resolved diagnoses (143 of 145, 103 positive and 40 negative) were identified correctly by the UniCAP Phadiatop test. Skin test results and specific IgE measurements correlated well, but neither correlated well with the history by itself, suggesting a minimal false-positive component of the history of 23%. UniCAP Phadiatop results demonstrated a quantitative relationship between the patient's score and the amount of IgE specific to these individual allergens. The UniCAP Phadiatop test was shown to be highly sensitive and specific in differentiating individuals who are sensitized to common inhalants from those who are not. This test is recommended to all physicians as an aid in diagnostic and referral decisions for patients suspected of having an inhalant allergic diathesis.

Vernal keratoconjunctivitis in a Stockholm ophthalmic centre ‐ epidemiological, functional, and immunologic investigations

To classify a cohort of 62 patients with vernal keratoconjunctivitis (VKC) in immunologic, functional, and epidemiological terms. A retrospective chart review was conducted to establish the patients' ethnic origin and to ascertain the results of standard in vitro and in vivo testing for atopic allergy. The latter data were compared with tear Phadiatop, an allergy screening test, in 31 subjects. Further subgroup analyses included methacholine bronchial provocations, serum screening for chlamydial antibodies and epidemiological calculations of the observed prevalence of VKC in the Stockholm area in 1994. Thirty-seven subjects (59.7%) were sensitised to common allergens. No additional allergic subjects were diagnosed with the tear Phadiatop test. The serology for ocular chlamydial disease was negative. Only 6 out of 17 subjects displayed bronchial reactivity to methacholine of whom 4 had a history of asthma. VKC was clearly more common in individuals with an Asian and African origin. Sensitivity to allergens is a strong determinant for the disease but in a large proportion of the subjects this immunologic abnormality is absent. The varying prevalence of the condition in different ethnic groups indicates a genetic predisposing factor.

Asthma in tunnel workers exposed to synthetic resins.

The prevalence of asthma among tunnel workers exposed to synthetic resins was studied by determining airway symptoms, methacholine responsiveness, and lung function. Nineteen injection workers were compared with a group of 104 other tunnel workers with similar exposure, except for that to synthetic resins. A questionnaire on respiratory symptoms, smoking habits, use of respiratory protection, and work tasks was used. Lung function was studied using a bellows spirometer. Bronchial reactivity was tested with methacholine. Allergy screening with Phadiatop and radioallergosorbent tests for toluene-diisocyanate-HSA, diphenylmethane-4.4-diisocyanate-HSA, and formaldehyde-HSA (HSA = human serum albumin) were carried out. Methylene diphenyl diisocyanate (MDI) and MDI prepolymer exposure was estimated by filter sampling, and the filters were analyzed by high-performance liquid chromatography. The most common work situations were simulated for an estimation of exposure to isocyanates. The injection workers reported more respiratory symptoms than the reference group, and they had higher prevalences of bronchial hyperresponsiveness (37% versus 14%), asthma (26% versus 1%), and airflow limitation (37% versus 4%). Toluene-diisocyanate-HSA-specific immunoglobulin E antibodies were found in 2 of the 19 injection workers, but in none of the other tunnel workers. By simulation at a worksite, the average exposure to polymerized MDI was estimated to be 5.5-300 microg/m3 during injection work and 18-4300 microg/m3 during short-term exposure, the highest exposure occurring when cured polyurethane was ground. Exposure to partly decomposed MDI in tunnel work enhances the risk for respiratory symptoms, methacholine hyperresponsiveness, asthma, and airflow limitation.

Prevalence of muscle relaxant sensitivity in a general population: implications for a preoperative screening.

Muscle relaxants (MR) are responsible for 59% of peroperative anaphylactic reactions. A major issue would be to determine whether a systematic preoperative screening in the general population should be recommended. The purpose of the study was to evaluate the prevalence of muscle relaxant sensitivity in a sample of the general population and to assess the role of possible risk factors. Two hundred and fifty-eight subjects, aged 20-40 years, visiting a health care centre for a check-up were evaluated. Protocol included a questionnaire (occupation, symptoms of atopy, previous surgery, history of drug allergy), skin-prick tests to four commercial muscle relaxants and measurement of specific IgE against quaternary ammonium ions. Atopy was evaluated by skin-prick tests to common inhalant allergens and by a Phadiatop test. Of the study group, 9.3% had either a positive skin test to one or more muscle relaxant or a presence of specific IgE to quaternary ammonium ions. No risk factor was identified in the studied group. Since the rate of MR sensitivity is much higher than the anticipated rate of peroperative reactions due to allergy, a systematic preoperative screening for MR allergy should not be recommended for adults in a general population.

Airways inflammation and glucan in a rowhouse area.

A study was undertaken in a number of rowhouses, some of which had had previous problems related to dampness and water leakage. The aim of the study was to assess the relation between exposure to airborne (1--> 3)-beta-D-glucan, a cell-wall substance in molds, and airways inflammation. The study involved 75 houses with indoor (1--> 3)-beta-D-glucan levels ranging from 0 to 19 ng/m3. Of 170 invited tenants, 129 (76%) participated in the study. A questionnaire relating to symptoms was used, and measurements were made of lung function and airway responsiveness. Myeloperoxidase (MPO), eosinophilic cationic protein (ECP), and C-reactive protein (CRP) were measured in serum. Atopy was determined with the Phadiatop test. The major findings were a relation between exposure to (1--> 3)- beta-D-glucan and an increased prevalence of atopy, a slightly increased amount of MPO, and a decrease in FEV1 over the number of years lived in the house. The results suggests the hypothesis that exposure to (1--> 3)-beta-D-glucan or molds indoors could be associated with signs of a non-specific inflammation.

Aetiology of allergic rhinitis in Hong Kong

In a 1993 survey, allergic rhinitis was identified as the most common allergic disease in Hong Kong, affecting 29.1% of schoolchildren. Recently (1995), the International Study of Asthma and Allergies in Childhood (ISAAC) also reported 44.5% current rhinitis among Hong Kong teenagers. Our objective was to study the aetiology of allergic rhinitis in Hong Kong using serological tests of allergen sensitization. In 57 allergic rhinitis patients and in the same number of age- and sex-matched controls the following were measured: serum total IgE, mixed aeroallergen IgE (Phadiatop™) and specific IgE versus house dust mite (HDM), cockroach, cat and dog dander, mould mixture ( Penicillium, Cladosporium, Aspergillus and Alternaria species) and four local pollens (Bermuda grass, Timothy, ragweed and mugwort). Compared with controls, allergic rhinitis patients (26 males, 31 females; mean (± SD) age 25 ± 11 years) had a significantly elevated serum total IgE concentration (mean ± SEM: 496 ± 88 vs 179 ± 38 kU/L) and an increased proportion of positive Phadiatop (95 vs 33%) and specific IgE tests versus HDM (90 vs 44%) and cockroach (42 vs 9%; Mann-Whitney U-test and χ 2 tests all P < 0.005). There was no significant difference in sensitization to other allergens tested. House dust mite and cockroach are ubiquitous in Hong Kong with a warm, humid climate and crowded living conditions. Their identification as aetiological agents of allergic rhinitis should help in the development of environmental strategies for reducing the inhalant allergen load to prevent and control this prevalent and costly health problem in our community.

Increased allergic reactivity of atopic type in mood disorders and schizophrenia

SummaryThe allergic reactivity of atopic type was investigated in 54 patients with mood disorders in the course of depressive episode and in 39 patients with schizophrenia. The assessment was done by three methods: intradermal tests, determination of IgE concentration and determination of specific immunoglobulin E (IgE) antibodies. The hypersensitivity to three or more allergens on intradermal tests was found in 40% of depressive and in 27% of schizophrenic patients. The concentration of IgE &gt; 100 IU/mL was found in 45% of patients with depression and in 46% of patients with schizophrenia, more frequently in subjects with hyperactivity of hypothalamic-pituitary-adrenal axis, and in depression, in patients with higher intensity of symptoms. The positive results of the Phadiatop test which detects specific antibodies for inhalatory antigens, were found in 46% of depressive and in 40% of schizophrenic patients The indices of atopy for all three tests were higher in males than in females in both mood disorders and in schizophrenia. However, these indices were similar for unipolar and bipolar depressed patients as well as for patients with paranoid or residual schizophrenia.

IgE levels, atopy markers and hay fever in relation to age, sex and smoking status in a normal adult Swiss population. SAPALDIA (Swiss Study on Air Pollution and Lung Diseases in Adults) Team.

Within the framework of the SAPALDIA survey (Swiss study on Air Pollution and Lung Diseases in Adults), we studied the influence of sex, age and smoking habits on total serum IgE and allergen-specific IgE antibody concentrations (assessed by means of the Phadiatop test) and on the prevalence of hay fever. A total of 8,344 subjects aged 18-60 years, comprising 2,776 current smokers, 1,888 former smokers and 3,680 nonsmokers, were included in the study. Smokers had both a statistically significant (p<0.001) higher mean serum IgE concentration (geometric mean 39.7 kU/l), and a higher percentage (27.5%) of persons with elevated serum IgE (> 100 kU/l) than nonsmokers (27.2 kU/l; respectively 20.5%). The IgE level was significantly lower in women than men (p<0.001) in all smoking categories. The percentage of persons with positive atopic markers (positive Phadiatop test, positive skin prick tests to common inhalant allergens) and self-reported hay fever was significantly higher in nonsmokers than in smokers or former smokers. In Phadiatop positive (atopic) subjects, the IgE levels were highest, with a mean of 104.3 kU/l (99.0-109.8), and lowest in Phadiatop-negative nonsmokers at 27.2 kU/L (25.9-28.6). These findings correlate well with the current interpretation of total serum IgE values in screening for atopic diseases in adults (IgE < 20 kU/l: atopy improbable; IgE > 100 kU/l: atopy probable). In multivariate logistic regression models, the prevalence of positive Phadiatop tests, positive skin tests, and atopy decreased significantly with age. The odds of having a positive Phadiatop and skin test, or being atopic were found to decrease on average by 23.0, 21.1 and 21.0%, respectively, with every 10-year increase in age. With respect to smoking status, the odds ratios for the three atopic markers were significantly lower in current and former smokers than in nonsmokers. The prevalence of (self-reported) hay fever was highest in nonsmokers, intermediate in former smokers (odds ratio = 0.81, p<0.05) and lowest in current smokers (odds ratio = 0.76 in comparison to former smokers, p<0.01). The odds ratio of self-reported current hay fever decreased with age at an estimated average of 23% every 10 years. The decrease in former smokers might be slightly faster than in the other two categories. In conclusion, the present results demonstrated that tobacco smoking is associated with increased IgE levels and negatively related to atopy and hay fever. In addition, it is shown that atopy prevalence decreases with age.

Atopic family history. Validation of instruments in a multicenter cohort study.

In order to identify newborns at risk for atopic diseases, we developed a family questionnaire and selected specific answers which were suitable to identify atopic family members. The validity of the questionnaire was evaluated by the Phadiatop test results of 793 mothers and 353 fathers. As both screening instruments do not measure the same, the Phadiatop test identifies sensitization to inhalant allergens and the history reflects the clinical manifestation of atopic disease, the agreement between sensitization and manifestation is incomplete. Sensitivity and specificity of the questionnaire screening conditions to reproduce the Phadiotop test result was 64% and 84% for mothers, and 58% and 88% for fathers, respectively. The relative risk for lifetime prevalence of atopic manifestations in Phadiatop positive over negative mothers was calculated to be 3.88 (95% confidence interval = 3.12 to 4.81), and for Phadiatop positive over negative fathers to amount 4.84 (95% confidence interval 3.25 to 7.23). A few relevant answers of 20 were identified by logistic regression analysis to predict the Phadiatop test result nearly, as well as the total questionnaire.

Clinical Manifestations of Allergy and Their Relation to HIV Infection

In this retrospective study 141 HIV positive subjects were included. Allergy was studied by a specific questionnaire and the Phadia Top Test, an in vitro screening test for specific IgE. Both were related to the patients' history, clinical symptoms and the treatment used. Allergy was studied in reference to HIV negative controls and in relation to the clinical and biological subgroups of HIV patients. The statistical analysis (x 2 test) demonstrated a relationship between allergy and HIV infection and the clinical stage of AIDS-IKEL among patients with CD4 > 300 microliters, which may suggest that allergy contributes to the functional deficiency of these cells. We also demonstrated a high frequency of hypersensitivity reactions (75%) in HIV asymptomatic patients with CD4 < 300 microliters, which indicates that allergy could contribute to the early destruction of these cells. The allergic patients declared to be hypersensitive before contamination. Both mechanisms, functional deficiency and destruction of CD4 T-lymphocytes could be the result of the mediators, cytokines and enzymes released from the mast cells during IgE allergic reaction. Thus this study demonstrated that allergy could be a predisposing factor for the contamination and a polyvalent co-factor for the clinical and biologic evolution of HIV infection.

Reliability of respiratory symptoms to diagnose atopy

As reliance of responses to epidemiological questionnaires on atopic symptoms is doubtful, we studied the predictive value of these questions relative to atopy, defined by the presence of serum specific IgE, taking into account some extraneous variables such as age and sex. The study population included 2067 adults, 20-60 years old. The protocol consisted of a standardized questionnaire and an evaluation of serum specific IgE using the Phadiatop (Pharmacia Diagnostics, Uppsala, Sweden) test. The predictive value of each symptom suggestive of atopy was quite low, but was much dependent on age and sex. Women more often than men reported atopic symptoms in the absence of atopy. Similarly, the predictive value of each symptom decreased with age. Thus atopic symptoms do not have the same value as predictors of atopy. These findings have both clinical and epidemiological important implications.

The phadiatop test allows adequate screening for atopy with a marked reduction in cost

Sera from 35 patients aged 5 years or younger and sera from 95 patients 6 years and older were assayed for both total IgE level, allergen-specific IgE by RAST and either the Phadiatop Paediatric or Phadiatop procedures, depending on age. Good agreement was found allowing exclusion of specimens anticipated to be RAST negative with an expected reduction in RAST testing of up to 80% of the present workload, without significant exclusion of RAST positive specimens.

Value of a multiantigen radioallergosorbent test in diagnosing atopic disease in young children

The purpose of this study was to investigate the value of a new multiantigen radioallergosorbent test, Phadiatop Paediatric, in the diagnosis of atopy in children less than 7 years of age. The diagnosis of atopic disease was established by history, physical examination, total serum IgE concentration, and the results of prick skin tests or radioallergosorbent tests or both, and then compared with the result of the Phadiatop Paediatric test for each patient. One hundred two patients (62 boys) between the ages of 4 months and 7.3 years were enrolled (median age 3.2 years). After the history and physical examination, 42% of the patients were believed to be atopic and 32% to be nonatopic; the diagnosis was uncertain in 26%. Skin prick test reactions to a variety of foods and inhalants were positive in 41 of 63 children tested; results of radioallergosorbent tests were positive in 35 of 61 children. Overall, atopy was diagnosed in 53 children and 49 were found to be nonatopic. When the clinical diagnosis was used as the gold standard, the Phadiatop test resulted in a correct diagnosis of atopy in 49 of 53 cases and of no atopy in 43 of 49 cases: sensitivity = 92%, specificity = 88%, and efficiency = 90%. Although the Phadiatop Paediatric test does not indicate specific sensitivities, it provides the clinician with a useful screening test for atopic disease in children 7 years of age or less, and the researcher with a means of validating atopic populations.

Atopy and systemic reactions to drugs

To elucidate whether systemic reactions (SR) to drugs should be included in the atopic status in epidemiological studies, we compared the distribution of atopy in subjects with or without a history of SR to drugs. The studied population comprised 2067 adults, 20 to 60 years old, visiting a health care center for a check-up examination. The protocol included a questionnaire related to history of SR to drugs and a Phadiatop test which evaluates on a blood sample the presence of specific IgE against common aeroallergens. Overall, 14.7% of the study group, including 66% women, reported reliable histories of SR to drugs. The cumulative prevalence of asthma, hay fever and childhood dermatitis was higher in the SR group. By contrast, the percentage of positive Phadiatop tests was similar in subjects with or without a history of SR. Thus atopy, defined by an objective criterion, i.e. the presence of specific IgE against common aero-allergens, is not associated with the occurrence of SR to drugs. Such a history should not be included as part of the atopic status.

The Phadiatop In Vitro Test for Allergy in General Practice: Is it Useful?

A study was performed in order to assess the value of the Phadiatop, a new in vitro allergy test, in general practice. A total of 248 patients were screened for bronchial allergy with PRIST, RAST and the Phadiatop. Information about the patient's history and the results of the PRIST, Phadiatop and RAST tests were presented consecutively to the general practitioner and his diagnoses based on and evolving from these were evaluated and compared with the diagnosis of a specialist. The general practitioner's diagnosis based on the results of the Phadiatop was the closest of all the tests to the specialist diagnosis. It is concluded that Phadiatop is of great use in diagnosing bronchial allergy in general practice.