Bronchial allergen challenge in subjects with low levels of allergic sensitization to indoor allergens

BACKGROUND: Low skin reactivity to common inhalant allergens is frequently found in asymptomatic individuals as well as in patients with respiratory complaints. However, most studies on bronchial allergen challenge concern patients with high levels of allergic sensitization. The present study was directed to bronchial reactions after allergen challenge in subjects with low skin reactivity to Dermatophagoides pteronyssinus or cat dander. METHODS: Titrated intracutaneous skin tests, skin prick tests, specific IgE assays, histamine release on washed leukocytes, and bronchial histamine and allergen-challenge tests were performed in 20 subjects with an intracutaneous skin test threshold for cat dander (Felis domesticus) or D. pteronyssinus above 0.1 BU/ml (mean wheal diameter in skin prick test with 10000 BU/ml: 4.4mm). Ten of the 20 patients had specific IgE below the detection limit in at least one of the three IgE assays which were done. Fifteen patients had a specific IgE level below 2 kU/I in all three tests. As a positive control group, the same parameters were studied in seven moderately sensitized patients with an intracutaneous skin test threshold below 0.1 BU/ml (mean wheal diameter with 10000 BU/ml: 7.2mm). RESULTS: The 20 subjects with low levels of allergic sensitization had an early decrease in FEV1 of 8.6% (P<0.01) and a mean late decrease of 6.3% (P<0.05). There was a trend for decrease in PC20 histamine 24h after allergen challenge (-0.4 doubling doses, P=0.09). CONCLUSIONS: In this group of subjects with low levels of allergic sensitization, a statistically significant early and late decrease in FEV1 was found. However, the decrease in lung function was small and unnoticed by most patients. The increase in nonspecific bronchial hyperresponsiveness after bronchial allergen challenge did not reach statistical significance in the study group. The results indicate that allergen exposure in patients with low levels of allergic sensitization may lead to airways changes in the absence of acute symptoms.     

Evaluation of the nasal provocation test for its necessity in the diagnosis of nasal allergy to house dust mite

The aim of this study was to evaluate rhinomanometric responses to nasal allergen provocation in children with allergic rhinitis sensitized to house dust mite. We studied 51 children, aged 6-16 years (mean: 11.5 +/- 2.6 years), with clinical symptoms of perennial allergic rhinitis without asthma and 20 non-atopic healthy controls in the same age range (mean: 11.8 +/- 3.8 years). All of the patients had positive skin prick test (SPT) results and serum specific IgE above 0.70 kU/l to Dermatophagoides pteronyssinus (Dp). Nasal provocation testing (NPT) was performed with increasing concentrations of Dp extracts and the nasal response was evaluated by active anterior rhinomanometry. A 100% increase of resistance in one or both nasal cavities was considered positive. There was a statistically significant difference of baseline nasal resistance (total, right and left sides) between the control and the patient groups (p < 0.001). A positive response to house dust mite allergens was recorded in 47/51 (92.2%) patients by rhinomanometry. The NPT presented no significant correlation with age, weight, height, SPT diameter, serum total and specific IgE levels to Dp and baseline nasal airway resistance values. This study suggests that a nasal provocation test with allergen is unnecessary in children with positive skin prick test and serum IgE specific to house dust mite. The rhinomanometric response to the allergen provocation does not correlate with the diameter of the skin prick test and the level of serum specific IgE.     

Total Serum IgE Concentrations in Adolescents and Adults Using the Phadebas IgE PRIST® Technique

Total serum IgE measured with the Phadebas PRIST® technique was titrated in 117 normal non-allergic subjects, 237 allergic adolescents or adults and 89 non-allergic patients who suffered from asthma, rhinitis, or conjunctivitis. All subjects were of Caucasian origin. In normal subjects, mean total serum IgE was 38±43 kU/l. This value is exactly the same as that found in a study of Caucasian New Zealanders and very similar to the values found in most U.S. studies. This suggests that the mean total serum IgE concentration is remarkably constant in normal non-allergic Caucasians. The upper limit of the normal range is considered to be 150 kU/l. 38% of allergic patients have total IgE concentrations within the normal range Some pollen or hymenoptera venom-sensitive patients have a total serum IgE concentration of 94±93 kU/I The non-allergic patients had a mean IgE concentration below 20% kU/l. The non-allergic patients had a mean IgE concentration of 94±93 kU/l, and 25% of them had a total serum IgE above the normal range. Asthmatic patients had higher mean IgE levels than those who were suffering from either rhinitis or conjunctivitis.     

Does pertussis infection induce manifestation of allergy?

Summary To evaluate whether pertussis induces the development of allergy, a prospective study was performed in 25 children aged 0.8–12.2 years. The patients underwent allergy diagnostics during pertussis infection and at a follow-up visit 8–14 months later. Diagnostic criteria included the medical history of the patients and their families, a modified skin prick test, measurement of serum IgE and radio-allergosorbent test screening for specific sensitizations. At the time of pertussis, serum IgE concentration in the study group was 62+ 30 kU/ml. At the follow-up visit, there was a significant increase in serum IgE to 137 ± 51 kU/ml, which was also significantly higher than IgE in an age-matched control group. Children at a significantly higher risk for developing IgE increase or new allergic sensitizations were those with a family history of allergy or potentially allergic disease in their personal history. Our results indicate that pertussis may induce IgE production in affected children.Abbreviation SPT skin prick test Dedicated to Prof. Dr. N. Zöllner on the occasion of his 70th birthday     

Mastocytosis and atopy: a study of 33 patients with urticaria pigmentosa

Thirty-three patients with histologically verified urticaria pigmentosa were studied for coexisting atopic disease by means of history, skin prick testing with five common inhalants and serological investigation for total IgE and specific IgE antibodies to five common inhalants. The prevalence of atopy in urticaria pigmentosa was similar to that observed in the normal Swiss population, both on the basis of history (7/33 = 21%) and of positive skin prick tests to common inhalants (12/33 = 36%). However, total serum IgE levels were significantly lower (geometric mean value 16.8 kU/l) than in a control group of 52 Swiss blood donors of comparable age and sex distribution (geometric mean value 43.0 kU/l, t = 2.93, P less than 0.005). Specific IgE antibodies to common inhalants were also observed less frequently in urticaria pigmentosa patients than in controls, although this difference was not statistically significant. Low total and specific IgE values in patients with urticaria pigmentosa may be explained by increased absorption of circulating IgE to abundant tissue mast cells.     

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

BACKGROUND: When the clinical history is not conclusive, it may be difficult to make an accurate interpretation of the value of skin tests and serum-specific IgE to cat allergens in asthma cases. OBJECTIVE: To analyse the diagnostic efficiency of skin testing (ST) and serum-specific IgE to cat allergens, based on the results of bronchial-specific challenge with cat epithelium. METHODS: Sixty-four asthma patients (49 with cat exposure and 15 without) who did not clearly relate their asthma symptoms to cat exposure and had a positive skin prick testing and/or a positive cat dander-specific IgE determination (CAP-system) underwent intradermal skin tests and specific bronchial challenge with cat epithelium. The results were analysed by receiver operating characteristics curves (ROC curves) and logistic regression. Sensitivity, specificity, positive predictive values and negative predictive values were calculated for different cut-off points. RESULTS: Twenty-seven patients (42.2%) had a positive bronchial-specific challenge. The area under the ROC curve for serum-specific IgE quantification is 0.85, which makes a good diagnostic tool out of this test. Intradermal ST predicts the outcome of the bronchoprovocation test better than skin prick testing (area under the ROC curve of 0.74 vs. area under the ROC curve of 0.54, respectively). The logistic regression analysis shows that the estimated probability of a positive bronchial challenge is > or =93% if CAP values are > or =17 kU(A)/L, whereas if CAP values are less than 0.35 kU(A)/L the estimated probability of a positive bronchial challenge is 16%. When the intradermal skin test is negative, the estimated probability of a positive bronchoprovocation test is 9%, being the test that better identifies patients with a negative bronchoprovocation test. CONCLUSIONS: Levels of serum-specific IgE to cat allergens and intradermal ST can be used to diagnose and treat more accurately asthmatic patients sensitized to cat epithelium when there is uncertainty about cat epithelium causality.     

Atopy and bronchial responsiveness in random population sample of 527 children and adolescents.

The relationship between bronchial responsiveness, lung function, and results of skin prick testing was studied in 527 children and adolescents from Copenhagen. All participants completed a questionnaire concerning allergic symptoms (asthma, rhinitis, atopic dermatitis, and urticaria). Furthermore, skin prick test reactivity to nine common aeroallergens, lung function, serum IgE and bronchial responsiveness to histamine and exercise were measured. A total of 53 subjects were atopic, (skin prick 3+), 105 subjects had moderate skin reactivity (1-2+), and 366 subjects had no signs of atopic disease (prick test negative); 58% of the subjects with skin test reactivity (1-3+) were asymptomatic. Increasing degree of atopy was correlated significantly with symptoms such as asthma, rhinitis, dermatitis, and urticaria (P less than .001); increasing level of IgE (P less than .001); month of birth (P = .001); and family history of allergic diseases (P less than .05). The most important markers for the degree of bronchial responsiveness to inhaled histamine were the presence of respiratory symptoms (P less than .001), the degree of atopy (P = .001), a history of asthma in at least two first degree relatives (P less than .01), and the skin reactivity to house dust mites (P = .001), horse epithelium (P = .01), Alternaria iridis, and dog epithelium (P less than .05). In contrast, the degree of bronchial responsiveness to exercise was significantly correlated with asthma (P less than .001), the level of IgE (P less than .05), month of birth (P less than .001), and birth weight (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)     

A case of allergy to cow's milk hydrolysate

We here report a girl, now 3 years old, who has suffered from severe food allergy since her first year of life. She was strongly allergic to cow's milk, and had high levels of IgE antibody (AB) to casein (210 kU/I), beta-lactoglobulin (43 kU/I), and alpha-lactalbumin (23 kU/l) at 12 months of age. In addition, at the same age, she showed positive (2-4+) skin prick reactions to both unboiled and boiled formulas (Profylac, Nutramigen, and Neocate), besides being positive in RAST to Nutramigen (0.6 kU/l). During the first 3 years, IgE Ab levels against casein and Nutramigen increased to 310 and 1.6 kU/l, respectively. Furthermore, at 3 years of age, she had positive RAST to 14 of 15 tested food allergens, being negative only to codfish. Assessment of eosinophil-related markers revealed high total eosinophil count, increased eosinophil activity, and a low ratio of interferon (IFN)-gamma:IL-5, indicating enhanced IL-5 production. The food allergy was correlated to poor weight gain and increasing problems with atopic allergy in the airways.     

Diagnosis and immunotherapy of mould allergy

The IgE-response was evaluated by skin prick test, bronchial provocation test and RAST in a 1-year placebo-controlled double-blind immunotherapy study. Eleven adult asthmatics were treated with a Cladosporium allergen preparation and 11 comparable patients received histamine placebo. The bronchial sensitivity (PC20) decrease greater than 0.5 log step in 8/11 (73%) Cladosporium-treated versus 3/11 (27%) in the placebo group. Corresponding figures for skin prick test sensitivity was 10/11 (91%) and 1/11 (9%) respectively. Circulating IgE showed a temporary boost in the Cladosporium group and then values approaching the pretreatment value. Only minimal and insignificant changes were found in the placebo-treated patients. Changes in IgE-reactivity were not related to allergen dose, clinical efficacy or to the occurrence of side effects. Some interrelation between changes in skin prick test, bronchial provocation test and RAST was found indicating a differentiated effect of immunotherapy on various IgE compartments. In spite of the pathogenetic role of IgE in allergic diseases, changes in IgE-reactivity do not seem directly involved in the mechanisms underlying the clinical efficacy of immunotherapy but might be of importance in a complex interaction with other immunological parameters.     

Quantitative analysis of IgE antibodies to food and inhalant allergens in 4-year-old children reflects their likelihood of allergic disease

BACKGROUND: It is well established that early diagnosis of allergic disease is warranted. METHODS: In a prospective birth cohort study (BAMSE) 3743 children at 4 years of age were included. Children were classified as having any allergic disease, e.g. asthma, suspected allergic rhinitis (suspAR), eczema or oro-gastro-intestinal symptoms with questionnaire. Blood was obtained from 2612 of these children and analysed for IgE antibodies (ab) towards 14 common food and airborne allergens. RESULTS: Positive IgE ab results were found in 38% of the children with any allergic disease, whereas such IgE ab results were found in 17% among those without any allergic disease. Furthermore, among children with any allergic disease the median summated IgE ab levels were 10.7 kU(A)/l compared with 1.5 kU(A)/l among those without such symptoms. The highest IgE ab levels were found to birch, peanut, cat and horse. When the sum of the IgE-ab levels towards the selected allergens was at least 34 kU(A)/l, or, alternatively, more than four allergen tests were positive, there was a 75% likelihood of identifying the individual with any allergic disease. To identify those with asthma, as well as those with suspAR, a significant interaction was found for the combination of the sum of IgE-ab levels and number of allergens positive at test. For eczema only, the number of positive allergens at test was associated to the likelihood of such disease. CONCLUSIONS: In children, 4 years of age, allergic disease was frequently not associated with the presence of single positive IgE antibody results, whereas increased IgE ab levels were significantly more prevalent among those with allergic disease. Thus, testing a certain profile of airborne and food allergens, and utilizing the sum of the IgE-ab levels in combination with the number of allergens positive at tests, may represent a more efficient diagnostic tool then to use just single positive IgE-ab results.     

Beef allergy: a review of 12 cases

BACKGROUND: Although beef allergy has long been considered a rare condition, the number of studies regarding the nature, epidemiology, and symptoms of beef allergy has been increasing. We aimed to describe the results of allergy work-up of 12 patients who have a convincing history of acute allergic symptoms following beef ingestion. METHODS: Detailed histories of 10 children and two adult relatives were obtained and patients underwent skin prick tests with commercial beef extract, raw beef and cooked beef. Serum total and beef-specific IgE were measured. Labial, and in selected cases, open food challenges were undertaken. RESULTS: Interestingly, the rate of family history of beef allergy was 67% (8/12). Three patients (two with commercial extract, and one with cooked beef) had positive skin test responses to beef. Ten (83%) patients had elevated serum IgE concentrations (median 316.5 kU/l, range 9-1321 kU/l) and the beef-specific IgE was positive in all patients (median 6.23 kUA/l, range 0.83-36.6 kUA/l). Labial food challenge was positive in four (30%) patients. Of the five patients who underwent open food challenges, three were positive and two tolerated the beef administered. CONCLUSIONS: We conclude that skin prick tests do not accurately diagnose IgE-mediated sensitization to beef. Thus, patients with suspected beef allergy should be screened additionally for beef-specific IgE antibodies, and in selected cases oral food challenge should be carried out to verify the diagnosis.     

Immunotherapy with cat- and dog-dander extracts. II. In vivo and in vitro immunologic effects observed in a 1-year double-blind placebo study

The effects of immunotherapy on the skin prick test, allergen-specific IgE, and IgG in 39 patients (19 adults and 20 children), treated with partially purified cat- or dog-dander extracts or placebo for 1 year, were studied by use of a double-blind protocol. IgG levels were measured by three different assays: IgG RAST, IgG4 RAST, and Staph A IgG1, 2, and 4. The skin prick test reaction decreased continuously in the allergen-treated patients, the decrease being the first sign of an immunologic effect of the therapy. Allergen-specific IgE levels increased during the first 9 months in both children and adults. The RAST activity during the last 3 months continued to rise for the children, whereas it declined for the adults. IgG levels measured by all three methods demonstrated an increase in the allergen-treated patients and no increase in the placebo-treated patients. The children developed higher values on IgG RAST and IgG4 RAST than the adults. IgG RAST correlated negatively with IgE levels in the cat allergen-treated group. No correlation between skin prick test results, IgE levels, and IgG levels was found, nor was there any correlation between these parameters and the patients' own subjective evaluation or the allergen bronchial challenge test. In summary, the expected change in skin prick test reaction and allergen-specific IgE and IgG levels was found. The children tended to be more immunologically active than the adults.     

Prevalence and predictors of bronchial hyperresponsiveness in children aged 7-16 years

To study the prevalence and possible predictors of bronchial responsiveness we examined a cross-section of 527 children aged 7-16 years from Copenhagen. The method used included an interview with the child and the parents, skin prick test with common allergens and se-IgE. Bronchial responsiveness was measured by a histamine inhalation test. We found that 79 (16%) of the children had bronchial hyperresponsiveness (BH), defined as a 20% fall in FEV1 with a provoking concentration of histamine (PC20) at 8 mg/ml or less. Atopic symptoms defined as asthma, rhinitis or eczema were significantly (P less than 0.001) correlated to BH both in prevalence and degree of BH. None of the children with urticaria had BH. The degree of bronchial responsiveness was also significantly influenced (P less than 0.001) by family disposition to atopy, whereas we found no correlation between BH and "passive" smoking, specific skin test in unselected children, or elevation of IgE in children without atopic symptoms. We conclude that BH is severest in children with asthma, independent of elevated IgE or positive skin prick test. Children with rhinitis, dermatitis, or asymptomatic BH have the same degree of BH; this differed from that in children with asthma.     

Association of features of atopy and diagnostic parameters in hymenoptera venom allergy.

In a total of 525 patients with hypersensitivity reactions to hymenoptera stings diagnostic parameters of hymenoptera venom (HV) allergy (severity of reactions, skin test threshold and RAST for bee and vespid venoms) were investigated for their relationship to the following indicators of atopy: positive history of atopic diseases, elevated (less than or equal to 100 kU/l) total serum IgE and positive prick test reactions to common inhalant allergens (CIA) (grass pollen, cat epithelium, house dust mite). There was a conclusive history of atopic disease in 25%, a total serum IgE greater than or equal to 100 kU/l in 48%, and at least one positive reaction to CIA in 53%. Total IgE greater than or equal to 100 kU/l correlated with a higher frequency of RAST classes greater than or equal to 2 (P less than 0.01) and with less severe reactions to hymenoptera stings (P less than 0.05). In the presence of at least one positive reaction to CIA, there were more frequently skin test thresholds less than or equal to 10 micrograms/ml (P less than 0.05) and RAST classes greater than or equal to 2 (P less than 0.01) for HV than in CIA prick test negative individuals. There was no significant, relationship between the other pairs of parameters evaluated. Thus, reactivity to HV in diagnostic tests is increased in the presence of certain indicators of atopy. This has to be considered in the interpretation of skin test and RAST results obtained with HV.     

Neuropsychologic status at the age 4 years and atopy in a population-based birth cohort

Background:  Mental health has been reported to be associated with allergy, but only a few cohort studies have assessed if neurodevelopment predicts atopy.
Objective:  To investigate if neurobehavioral status of healthy 4-year-old children was associated with specific immunoglobulin E (IgE) at the same age and skin prick test results 2 years later.
Methods:  A population-based birth cohort enrolled 482 children, 422 of them (87%) provided neurobehavioral data, 341 (71%) had specific IgE measured at the age of 4 years; and 395 (82%) had skin prick tests completed at the age of 6 years. Atopy was defined as IgE levels higher than 0.35 kU/l to any of the three tested allergens at the age of 4 or as a positive skin prick test to any of the six tested allergens at the age of 6. McCarthy Scales of Child Abilities and California Preschool Social Competence Scale were the psychometric instruments used.
Results:  Twelve percent of children at the age of 4 and 17% at the age of 6 were atopic. Neurobehavioral scores were negatively associated with 6-year-old atopy after adjustment for socio-demographic and allergic factors, A relative risk of 3.06 (95% CI: 1.30–7.24) was associated with the lowest tertile (scorings ≤90 points) of the general cognitive scale. Similar results were found for verbal abilities, executive functions, and social competence. Asthma, wheezing, rhinitis, and eczema at the age of 6, but not at the age of 4, were associated with neurodevelopment at the age of 4.
Conclusions:  Neuropsychologic functioning and later atopy are negatively associated in preschool age children.     

Linkage to atopy on chromosome 19 in north-eastern Italian families with allergic asthma

BACKGROUND: Allergic asthma is a multifactorial disease for which there is a widely assessed, although poorly understood, genetic involvement. Genome-wide screens reported evidence for linkage of allergic asthma-related phenotypes to several chromosomal locations. Markers on chromosome 19 have been linked to allergic asthma phenotypes in different populations in independent studies. OBJECTIVE: The aim of this study was to perform a genetic linkage analysis on chromosome 19 to search for DNA markers linked to phenotypes related to allergic asthma. METHODS: Using non-parametric multipoint linkage analysis on a total of 22 random DNA markers in 2 stages, a sample of 111 families (542 subjects) from north-eastern Italy, recruited through an asthmatic allergic proband, was investigated. Phenotypes examined were: clinical asthma, total serum elevated IgE, skin prick test positivity, bronchial hyper-responsiveness, and atopy defined as skin prick test positivity and/or elevated IgE. Simulation studies were performed to confirm the significance of the results. RESULTS: A novel linkage of atopy and skin prick test positivity to marker D19S601 (19q13.3) was found. Modest evidence for linkage of atopy, skin prick test positivity, and IgE was also found to marker D19S591 (19p13.3). Simulation analysis for atopy gave an NPL-Z > 3.326 in 2 replicates out of 1000 (P = 0.002) for D19S601, and an NPL-Z > 2.56 in 16 replicates out of 1000 (P = 0.016) for D19S591. CONCLUSIONS: On chromosome 19, suggestive linkage of atopy and skin prick test positivity with marker D19S601 (19q13.3) and modest evidence of linkage of marker D19S591 (19p13.3) to the atopic phenotypes investigated were found. These results suggest that these regions may contain susceptibility loci associated to atopic phenotypes.     

Basophil histamine release in the diagnosis of house dust mite and dander allergy of asthmatic children

The aim of the study is to compare the glass fibre-based basophil histamine release test with skin test (Phazet), RAST (Phadebas) and bronchial provocation test in children with allergic asthma. The study comprised 68 selected children with a case history of extrinsic allergic asthma to danders (cat and dog) and house-dust mite. Skin prick test, RAST, and histamine release were performed in all children and the bronchial provocation test was used as a reference of "true allergic asthma". A total of 81 allergen bronchial challenges were performed and 44 children experienced 49 positive provocations. In 2.9% (2/68) of the children histamine release could not be performed due to technical difficulties (low histamine release with anti-IgE). Concordances in the range 76-87% were observed with no significant difference between the tests. The highest concordance (87%) was found between histamine release and bronchial provocation test followed by skin prick test vs bronchial provocation (84%) and RAST vs bronchial provocation (80%). The sensitivity and specificity were calculated for each test. All tests showed sensitivities in the range 90-94% and no significant difference between them was observed. The specificity of histamine release, skin prick test, and RAST was 0.78, 0.69, and 0.63, respectively. The specificity of histamine release was better than RAST demonstrated by 95% confidence intervals. In conclusion, it was found that the histamine release test is a convenient diagnostic method and the study indicates a diagnostic value comparable to the common diagnostic methods in clinical allergy.     

Extraordinarily high serum IgE levels and consequences for atopic phenotypes.

BACKGROUND: IgE plays a central role in allergic diseases. Recent studies have postulated an association between serum IgE levels and bronchial asthma. OBJECTIVE: To examine the differences of atopic phenotypes in a group of individuals with extraordinarily high serum IgE levels (>10,000 kU/L) compared with children with moderately elevated IgE levels (400-1,000 kU/L). METHODS: We investigated 20 children with serum IgE levels greater than 10,000 kU/L and compared them with 56 age-matched children with serum IgE levels of 400 to 1,000 kU/L regarding prevalences of atopic dermatitis, bronchial asthma, allergic rhinoconjunctivitis, allergic sensitization, and history of anaphylaxis. RESULTS: The mean eczema severity score as determined by the Severity Scoring of Atopic Dermatitis Index was 56 vs 18 (P < 0.003), and anaphylactic reactions were reported in 20% of the group with very high serum IgE levels vs 7% in the group with moderate levels (P < 0.02). Sensitization to both aeroallergens and food allergens was detected in 80% of the group with very high serum IgE levels vs 32% of the group with moderate levels (P < 0.001). CONCLUSIONS: Our results indicate that children with very high serum IgE levels are at risk for anaphylactic reactions and more severe atopic dermatitis.     

Cord blood IgE. III. Prediction of IgE high-response and allergy

Screening of total IgE in 2814 cord blood samples was analysed by Phadebas IgE PRIST in 2 1-year birth cohorts (1983–1984 and 1985–1986) in Denmark (n= 1189 + 1625). For follow-up we chose all infants with cord blood IgE≥0.5 kU/1 and a randomly chosen group of the same size with cord blood IgE < 0.5 kU/1. A total group of 762 infants were clinically evaluated at 18 months of age, and in 688 of these we evaluated total and specific IgE. A diagnosis of definite atopy, probable atopy or no atopy was established. In the present study we defined allergic disease as atopic disease combined with elevated total IgE. We found a statistically significant correlation between cord blood IgE and IgE at 18 months of age. Significantly more infants with elevated cord blood IgE had developed allergic disease at 18 months. A cut-off value of 0.3 kU/1 for cord blood IgE was superior to the originally suggested 0.5 kU/1. Significantly more infants with elevated cord blood IgE had developed specific IgE antibodies at 18 months. The most frequent specific IgE antibody was towards cow's milk. Specific IgE antibodies were very rarely found when total IgE was not elevated. A total IgE at the age of 18 months > 26 kU/1 could be regarded as elevated. With regard to allergic disease the positive predictive values of cord blood lgE≥0.3 kU/1 in the 2 series were 21 % and the corresponding sensitivities 67% and 46%, respectively. The risk of developing allergic disease was elevated with a factor 3 to 4 when cord blood IgE ≥ 0.3 kU/1. In a high-risk group based on atopic predisposition and elevated eord blood IgE ≥0.5 kU/1 the relative risk of allergic disease was 5, the predictive value of positive test 38%, the sensitivity 24% and the specificity 96%. Clinical aspects Cord blood IgE was a good predictor of allergic disease at the age of 18 months. A cord blood cut-off IgE value of 0.3 kU/l was superior to other cord blood IgE values with the Phadebas IgE PRIST method.     

Influence of total IgE levels on the severity of sting reactions in Hymenoptera venom allergy

BACKGROUND: Detection of specific IgE for Hymenoptera venoms and skin tests are well established diagnostic tools for the diagnosis of insect venom hypersensitivity. The aim of our study was to analyze the effect of total IgE levels on the outcome of generalized anaphylactic reactions after a Hymenoptera sting. METHODS: Two hundred and twenty patients allergic to bee, wasp, or European hornet venom were included in the study. Their specific and total IgE levels, serum tryptase levels, skin tests, and sting history were analyzed. RESULTS: In patients with mild reactions (grade I, generalized skin symptoms) we observed higher total IgE levels (248.0 kU/l) compared to patients with moderate reactions (grade II, moderate pulmonary, cardiovascular, or gastrointestinal symptoms; 75.2 kU/l) and severe reactions (grade III, bronchoconstriction, emesis, anaphylactic shock, or loss of consciousness; 56.5 kU/l; P < 0.001). Accordingly, 25% of the patients with low levels of total IgE (<50 kU/l), but no individual with total IgE levels >250 kU/l, developed loss of consciousness (P = 0.001). Additionally, specific IgE levels were related to total IgE levels: Specific IgE levels increased from 1.6 to 7.1 kU/l in patients with low (<50 kU/l) and high (>250 kU/l) total IgE levels, respectively (P < 0.001). Specific IgE levels correlated inversely to the clinical reaction grades, however, this trend was not statistically significant (P = 0.083). CONCLUSION: Patients with Hymenoptera venom allergy and high levels (>250 kU/l) of total IgE, predominantly develop grade I and grade II reactions and appear to be protected from grade III reactions. However, this hypothesis should be confirmed by extended studies with sting challenges.