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Background: Recombinant human C1 inhibitor (rhC1INH) for on-demand treatment of hereditary angioedema is purified from milk of transgenic rabbits. It contains low amounts (<0.002%) of host-related impurities, which could trigger hypersensitivity reactions in patients with rabbit allergy (RA) and/or cow's milk allergy (CMA)., Objective: This study is an assessment of allergenicity and safety of rhC1INH in patients with RA and/or CMA., Methods: Patients with CMA and/or RA underwent skin prick test (SPT), intracutaneous test (ICT), and, when results for both were negative, subcutaneous (SC) challenge with up to 2100U (14 mL) rhC1INH. The negative predictive value of the skin test protocol was calculated, defined as the ratio of patients without systemic symptoms of hypersensitivity following SC challenge, over the number of patients having tested negative for both the SPT and the ICT. Adverse events after exposure to rhC1INH were recorded., Results: Twenty-six patients with RA and/or CMA were enrolled. Twenty-four had negative SPT and ICT results for rhC1INH, whereas 2 had negative SPT result but positive ICT result to rhC1INH (only the highest concentration). Twenty-two patients with negative SPT and ICT results underwent SC challenge. None developed allergic symptoms. Local treatment-emergent adverse events occurred in 7 patients (32%) after SC challenge. In 5 these were considered drug related. All were mild., Conclusions: None of the patients with negative SPT and ICT results for rhC1INH had allergic symptoms during rhC1INH challenge. The negative predictive value of the combination of SPT and ICT for the outcome of the SC challenge was 100% (95% CI, 84.6%-100%). SC administration of rhC1INH was well tolerated., (Copyright © 2016 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Background: Component-resolved diagnosis has been shown to improve the diagnosis of food allergy., Objective: We sought to evaluate whether component-resolved diagnosis might help to identify patients at risk of objective allergic reactions to hazelnut., Method: A total of 161 hazelnut-sensitized patients were included: 40 children and 15 adults with objective symptoms on double-blind, placebo-controlled food challenges (DBPCFCs) and 24 adults with a convincing objective history were compared with 41 children and 41 adults with no or subjective symptoms on DBPCFCs (grouped together). IgE levels to hazelnut extract and single components were analyzed with ImmunoCAP., Results: IgE levels to hazelnut extract were significantly higher in children with objective than with no or subjective symptoms. In 13% of children and 49% of adults with hazelnut allergy with objective symptoms, only sensitization to rCor a 1.04 was observed and not to other water-soluble allergens. Sensitization to rCor a 8 was rare, which is in contrast to rCor a 1. Sensitization to nCor a 9, rCor a 14, or both was strongly associated with hazelnut allergy with objective symptoms. By using adapted cutoff levels, a diagnostic discrimination between severity groups was obtained. IgE levels to either nCor a 9 of 1 kUA/L or greater or rCor a 14 of 5 kUA/L or greater (children) and IgE levels to either nCor a 9 of 1 kUA/L or greater or rCor a 14 of 1 kUA/L or greater (adults) had a specificity of greater than 90% and accounted for 83% of children and 44% of adults with hazelnut allergy with objective symptoms., Conclusion: Sensitization to Cor a 9 and Cor a 14 is highly specific for patients with objective symptoms in DBPCFCs as a marker for a more severe hazelnut allergic phenotype., (Copyright © 2013 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.)

Background: A diagnostic prediction model for peanut allergy in children was recently published, using 6 predictors: sex, age, history, skin prick test, peanut specific immunoglobulin E (sIgE), and total IgE minus peanut sIgE., Objectives: To validate this model and update it by adding allergic rhinitis, atopic dermatitis, and sIgE to peanut components Ara h 1, 2, 3, and 8 as candidate predictors. To develop a new model based only on sIgE to peanut components., Methods: Validation was performed by testing discrimination (diagnostic value) with an area under the receiver operating characteristic curve and calibration (agreement between predicted and observed frequencies of peanut allergy) with the Hosmer-Lemeshow test and a calibration plot. The performance of the (updated) models was similarly analyzed., Results: Validation of the model in 100 patients showed good discrimination (88%) but poor calibration (P < .001). In the updating process, age, history, and additional candidate predictors did not significantly increase discrimination, being 94%, and leaving only 4 predictors of the original model: sex, skin prick test, peanut sIgE, and total IgE minus sIgE. When building a model with sIgE to peanut components, Ara h 2 was the only predictor, with a discriminative ability of 90%. Cutoff values with 100% positive and negative predictive values could be calculated for both the updated model and sIgE to Ara h 2. In this way, the outcome of the food challenge could be predicted with 100% accuracy in 59% (updated model) and 50% (Ara h 2) of the patients., Conclusions: Discrimination of the validated model was good; however, calibration was poor. The discriminative ability of Ara h 2 was almost comparable to that of the updated model, containing 4 predictors. With both models, the need for peanut challenges could be reduced by at least 50%., (Copyright © 2012 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.)

Background: Cyclosporin A (CsA) is frequently used in the treatment of severe atopic dermatitis (AD). Enteric-coated mycophenolate sodium (EC-MPS) may be an alternative with equal efficacy and fewer side effects., Objective: The aim of this observer-blinded randomized controlled trial was to compare EC-MPS with CsA as long-term treatment in adult patients with severe AD., Methods: Fifty five patients with AD were treated with CsA (5 mg/kg) in a 6-week run-in period. Thereafter, patients either received CsA (3 mg/kg; n = 26) or EC-MPS (1440 mg; n = 24) during a maintenance phase of 30 weeks and there was a 12-week follow-up period. Disease activity was measured using the objective SCORAD and serum thymus and activation-regulated chemokine (TARC) levels and side effects were registered., Results: During the first 10 weeks the objective SCORAD and serum TARC levels in the EC-MPS study arm were higher in comparison with the CsA study arm. In addition, 7 of the 24 patients treated with EC-MPS required short oral corticosteroid courses. During maintenance phase disease activity was comparable in both study arms. Side effects in both study arms were mild and transient. After study medication withdrawal, disease activity of the patients in the CsA study arm significantly increased compared with the EC-MPS study arm., Limitation: The nonblinding of patients and prescriber of rescue medication are limitations., Conclusions: This study shows that EC-MPS is as effective as CsA as maintenance therapy in patients with AD. However, clinical improvement with EC-MPS is delayed in comparison with CsA. Clinical remission after stopping EC-MPS lasts longer compared with CsA., (Copyright © 2010 American Academy of Dermatology, Inc. Published by Mosby, Inc. All rights reserved.)

Introduction: There is concern about the development of glaucoma and cataracts associated with topical corticosteroid use in patients with atopic dermatitis (AD)., Objective: We evaluated glaucoma and cataract development in patients with AD to determine whether they are associated with the cumulative dose of topical steroids and the use of topical corticosteroids on the eyelids and periorbital region., Methods: In all, 88 patients with AD were recruited from the University Medical Centre Utrecht. Patients were interviewed and completed a questionnaire assessing different factors such as AD involvement of eyelids and periorbital skin. The use of corticosteroids in previous years was obtained from pharmacy records. A complete ophthalmologic examination was performed for the presence of glaucoma and cataracts., Results: Of the 88 patients (41 men and 47 women), with an average age of 37.2 ± 14.3 years (mean ± SD), one patient had transient ocular hypertension and one patient had optic disc cupping without any glaucomatous defects in his visual field. Seven patients were given the diagnosis of cataracts (one AD-related, two corticosteroid-induced, and 4 age-related). Both patients with corticosteroid-induced cataracts had also used systemic corticosteroids. In all, 37 of the 88 patients had used topical corticosteroids (class III and IV) on the eyelids and periorbital region, with an average frequency of 3.9 days per week and 6.4 months per year for 4.8 years., Limitations: Small sample size, objectiveness of patient recall about the use of topical corticosteroids on the eyelids/periorbital region, overestimation of topical corticosteroid use from pharmacy records, and lack of information on lifetime corticosteroid use were limitations., Conclusions: In this retrospective study glaucoma was not seen; two patients with AD had corticosteroid-induced cataracts, which were probably caused by the use of systemic corticosteroids. The application of topical corticosteroids to the eyelids and periorbital region, even over longer periods of time, was not related to the development of glaucoma or cataracts in this study population., (Copyright © 2010 American Academy of Dermatology, Inc. Published by Mosby, Inc. All rights reserved.)

Background: Phototesting is an important diagnostic tool to objectify light-related symptoms. Data on phototesting procedures in children are scarce., Objective: The aim of this study was to evaluate phototest results in photosensitivity disorders in children., Methods: The phototest procedures are described. All children phototested in our department between 1995 and 2007 were included in this retrospective study. Children given the diagnosis of polymorphic light eruption (PLE) were selected for follow-up., Results: A total of 92 children (39 boys and 53 girls, age range 4-16 years) were successfully phototested. A photosensitivity disorder was confirmed in 56 children (61%, 24 boys and 32 girls). PLE was diagnosed in 39%, photosensitivity associated with atopic dermatitis in 23%, and erythropoietic protoporphyria in 23%. Other diagnoses were less common. Ten children with PLE were followed up for at least 5 years. Seven reported their photosensitivity had not changed over time, in two cases it had diminished, and in one patient the photosensitivity had disappeared., Limitations: Retrospective study design is a limitation., Conclusion: Phototesting in children is feasible when performed in a case- and child-dependent manner. PLE was the most prevalent diagnosis in our series followed by photosensitivity in atopic dermatitis., (Copyright © 2009 American Academy of Dermatology, Inc. Published by Mosby, Inc. All rights reserved.)

Background: Low bone mineral density (BMD) has been reported in 30.4% of adult patients with atopic dermatitis (AD)., Objective: The aim of this study was to determine the prevalence of low BMD in children with moderate to severe AD and to investigate the relation between BMD and corticosteroid and cyclosporine therapy., Methods: Lumbar spine BMD was measured by dual-energy X-ray absorptiometry in 60 children (age 5-16 years) with moderate to severe AD. BMD (in g/cm(2)) was expressed in Z-scores, the number of SD above or below the mean value of an age- and sex-matched reference population. In children, low BMD was defined as a Z-score less than -2. Information on lifestyle parameters and bone fractures were collected by use of a standardized questionnaire. The cumulative dose of corticosteroids and cyclosporine therapy was calculated for the previous 5-year period., Results: Three patients (5%) had low BMD; one patient (1.7%) had osteoporosis. The observed prevalence of low BMD in this study (6.7%; 95% confidence interval 1.8%-16.2%) does not differ from the expected prevalence of low BMD in the general population (P = .06). Overall, use of topical corticosteroids in the previous 5 years was not associated with a decrease in BMD (Z-score). When children received additional systemic treatment (oral corticosteroids and/or cyclosporine) in the previous 5 years, BMD decreased, although the decrease was not statistically significant. Correction for lifestyle parameters did not change these associations., Limitations: The number of patients studied was limited. The cumulative dose of corticosteroids and cyclosporine therapy was only registered for the previous 5 years, and relatively low amounts of topical corticosteroids were used. The definition of low BMD differs between adults (Z-score < -1) and children (Z-score < -2). Because there is no Dutch BMD reference population for children, normative BMD references were obtained from a different population (US children)., Conclusions: Low BMD did not occur more frequently in this population of children with moderate to severe AD compared with the general population. Use of topical corticosteroids in the previous 5 years was not associated with a decrease in BMD., (Copyright © 2010 American Academy of Dermatology, Inc. Published by Mosby, Inc. All rights reserved.)

Background: Phototherapy may be effective in atopic dermatitis (AD). Medium-dose (MD) ultraviolet (UV) A1 was introduced for the treatment of AD. Few immunohistochemical data are available pertaining to phototherapy in AD. Regulatory T cells may play a role in clearing AD., Objectives: We sought to compare the clinical and immunohistochemical effects of narrowband (NB) UVB and MD UVA1 treatment in patients with AD., Methods: Thirteen adult patients with AD were included in this randomized investigator-blinded half-sided comparison study between NB UVB and MD UVA1. Disease activity was measured using the Leicester sign score. Skin biopsy specimens were taken before and after phototherapy. Regulatory T cells were stained with the forkhead box protein P3 (FoxP3)., Results: NB UVB and MD UVA1 both significantly decreased AD severity (P < .01) and the dermal cellular infiltrate. The percentage of FoxP3(+)CD3(+) T cells did not change after NB UVB or MD UVA1 treatment., Limitation: MD UVA1 therapy was given 3 times per week instead of the preferred regimen of 5 times per week. This was necessary to achieve good blinding of the study., Conclusions: NB UVB and MD UVA1 seem equally effective in the treatment of patients with moderate to severe AD. Neither MD UVA1 nor NB UVB had an effect on the percentage of FoxP3(+)CD3(+) T cells.

Background: Better understanding of the relationship between antibody response to peanut and clinical sensitivity might lead to more accurate prognostication., Objective: We sought to investigate peanut-specific IgE and IgG4 epitope diversity in relation to challenge-defined clinical sensitivity to peanut in a group of peanut-sensitized children., Methods: Clinical sensitivity was determined by means of double-blind, placebo-controlled peanut challenges in 24 sensitized children. Six atopic control subjects were included. Specific IgE and IgG4 binding to 419 overlapping 15-amino-acid peptides representing the sequence of recombinant Ara h 1, Ara h 2, and Ara h3 was analyzed by means of microarray immunoassay., Results: Peanut-sensitized patient sera bound significantly more IgE and IgG4 epitopes than control sera. This patient group reacted to the same Ara h 1, Ara h 2, and Ara h 3 epitopes as reported previously. There was a positive correlation between IgE epitope diversity (ie, number of epitopes recognized) and clinical sensitivity (r = 0.6), such that patients with the greatest epitope diversity were significantly more sensitive than those with the lowest diversity (P = .021). No specific epitopes were associated with severe reactions to peanut. IgG4 binding was observed to largely similar epitopes but was less pronounced than IgE binding and did not relate to the clinical sensitivity to peanut. IgE and IgG4 epitope-recognition patterns were largely stable over a 20-month period., Conclusion: Clinical sensitivity, as determined by means of double-blind, placebo-controlled peanut challenge, is positively related to a more polyclonal IgE response, which remains stable over time.

Background: Hazelnut allergy in birch pollen-exposed areas is usually due to cross-reactivity (Cor a 1 and 2) and is usually mild in nature (oral allergy). In areas without birches, severe reactions are more prevalent and linked to sensitization to the lipid transfer protein (LTP) Cor a 8., Objective: We sought to investigate whether sensitization to LTP plays a role in more severe (objective) hazelnut-induced symptoms in children from a birch-endemic area., Methods: Sensitization to Cor a 8, Cor a 2, Cor a 1, and Bet v 1 was determined by means of RASTs and immunoblotting in hazelnut-sensitized children with (n = 8) and without (n = 18) objective reactions during double-blind, placebo-controlled food challenges. Additionally, samples from 191 hazelnut-sensitized nonchallenged children were analyzed., Results: Children with objective reactions during double-blind, placebo-controlled food challenge had higher IgE titers to hazelnut (P < .001) and recognized more allergens on immunoblotting (P = .001) than those without such reactions. All children with objective symptoms were sensitized to Cor a 8 (0.51-23.3 IU/mL) compared with only 1 child without objective reactions (0.90 IU/mL). In a multivariate analysis only IgE against Cor a 8 remained as an independent risk factor (undefined odds ratio; P < .0001). In the group of nonchallenged children (n = 191), the prevalence of LTP sensitization was greater than 30%. Unexpectedly, sensitization to Cor a 1 was observed in children not sensitized to Bet v 1., Conclusion: Sensitization to hazelnut LTP is a risk factor for objective symptoms in children from a birch-endemic area.

Background: Reports of lupine allergy are increasing as its use in food products increases. Lupine allergy might be the consequence of cross-reactivity after sensitization to peanut or other legumes or de novo sensitization. Lupine allergens have not been completely characterized., Objectives: We sought to identify allergens associated with lupine allergy, evaluate potential cross-reactivity with peanut, and determine eliciting doses (EDs) for lupine allergy by using double-blind, placebo-controlled food challenges., Methods: Six patients with a history of allergic reactions to lupine flour were evaluated by using skin prick tests, CAP tests, and double-blind, placebo-controlled food challenges. Three of these patients were also allergic to peanut. Lupine allergens were characterized by means of IgE immunoblotting and peptide sequencing., Results: In all 6 patients the ED for lupine flour was 3 mg or less for subjective symptoms and 300 mg or more for objective symptoms. The low ED and moderate-to-severe historical symptoms indicate significant allergenicity of lupine flour. Two patients allergic to lupine but not to peanut displayed IgE binding predominantly to approximately 66-kd proteins and weak binding to 14- and 24-kd proteins, whereas patients with peanut allergy and lupine allergy showed weak binding to lupine proteins of about 14 to 21 or 66 kd. Inhibition of binding was primarily species specific., Conclusion: Lupine allergy can occur either separately or together with peanut allergy, as demonstrated by 3 patients who are cosensitized to peanut and lupine., Clinical Implications: Lupine flour is allergenic and potentially cross-reactive with peanut allergen, thus posing some risk if used as a replacement for soy flour.

Background: Patients with cutaneous lupus erythematosus (LE) and a history of disease- related photoaggravation, confirmed by phototesting, may not respond to photoprotection and/or medical intervention. Ultraviolet B-hardening therapy may improve tolerance for environmental ultraviolet radiation (UVR) in photosensitive disorders., Objective: We studied the effect of UVB hardening on the cutaneous manifestations of patients with LE and their tolerance for UVR., Patients and Methods: A retrospective study of continuous, home-based, UVB-hardening therapy in 44 patients with cutaneous LE (systemic LE: 9 patients; chronic LE: 21 patients; subacute cutaneous LE: 10 patients; cutaneous LE not specified: 4 patients) who had confirmed photosensitivity. Exposure to the UVB source was performed year-round, 3 times weekly, with increasing doses to a maximum of 10 minutes per session. Tolerance for environmental UVR was established through questionnaires, phototesting, and assessment of disease activity by physician and patient., Results: Of 44 patients, 35 were able to gradually increase their monthly UVB doses. Nine patients dropped out because of insufficient efficacy or skin irritation, or were unable to adhere to the hardening regimen. Of the 35 patients who succeeded in hardening their skin with UVB, 28 patients reported an improved tolerance for environmental UVR. This outcome was confirmed by repeat phototesting in a subgroup. In only 5 patients, an improvement of cutaneous LE symptoms was noted by either physician or patient. No serious adverse events were encountered., Limitations: This was a retrospective study and no control group was used., Conclusion: This is the first report that describes UVB hardening as a potential therapy in patients with cutaneous LE and confirmed photosensitivity. This intervention may lead to improved tolerance for environmental UVR and, in a minority of patients, even to decreased cutaneous activity of LE.

Background: Current labeling practices for allergenic foods like peanut can be inadequate. For future regulatory and industry guidelines, information on no-observed-adverse-effect levels (NOAELs) and eliciting doses (EDs) for allergenic foods is necessary., Objective: To determine NOAEL and ED in a representative group of peanut-sensitized children, relate these data to history and sensitization, and evaluate the outcome of dietary management., Methods: From an overall eligible group of 96 peanut-sensitized children, a representative group of 27 was evaluated by questionnaires, skin prick test, determination of specific IgE, and double-blind placebo-controlled food challenge (DBPCFC) with peanut according to the international consensus protocol, with 9 doses ranging from 10 microg to 3 g peanut flour. Dietary management was evaluated over a 12-month period., Results: Twenty-two children (81%) had a positive DBPCFC. The NOAEL in this group was 1 mg peanut flour, corresponding to 2 mg whole peanut. The ED for subjective symptoms (10 mg to 3 g) was significantly lower than for objective symptoms (100 mg to 3 g; P = .002). Severe reactions occurred only at high doses. EDs were not correlated to previous reactions by history, skin prick test, or specific IgE levels. All patients with a positive DBPCFC were advised to follow a strict diet. During the follow-up period, 10 patients had a less strict diet likely containing traces of peanut. In 3 cases, a mild reaction occurred with food products labeled "may contain peanut.", Conclusion: The NOAEL in a representative group of children with peanut allergy was 2 mg. Dietary compliance in half of this group was inadequate.

Background: Apple cultivars have been reported to differ in allergenicity on the basis of in vitro and skin prick tests with apple extracts., Objectives: We sought to evaluate the efficacy of the prick-to-prick method in assessing differences in allergenicity of apple cultivars and to confirm differences by means of double-blind, placebo-controlled food challenge (DBPCFC)., Methods: Intra-assay and intracultivar variation of prick-to-prick test results were determined in 6 Dutch and 8 Spanish patients with apple allergy by using 5 apples of the cultivars Golden Delicious, Fuji, and Ecolette in duplicate. In addition, 21 cultivars were screened for allergenicity in 15 Dutch patients with birch pollen and apple allergy. Two selected cultivars (Golden Delicious and Santana) were tested with DBPCFCs. The influence of storage conditions on allergenicity was assessed in 5 cultivars., Results: Intra-assay variation of skin prick testing was 3.9%, and intracultivar variation was 4.1%. A ranking of 21 cultivars was made on the basis of prick-to-prick tests in 9 patients. Apple cultivars were classified as of low, intermediate, and high allergenicity, with a significant difference between low and high allergenicity (P < .001). A significant difference in allergenicity determined between Golden Delicious and Santana cultivars (P < .05) was confirmed by means of DBPCFC. With 5 cultivars, controlled atmosphere (2.5% oxygen/1% carbon dioxide) was shown to reduce allergenicity (P < .001) by 15% compared with storage at 2 degrees C., Conclusions: Prick-to-prick testing with fresh apples is a reproducible method of assessing allergenicity. Apples can be classified as of low or high allergenicity for the majority of patients. This was confirmed by using DBPCFCs. Selection of cultivars and control of storage conditions are both viable strategies for reduction of symptoms in patients with apple allergy.

Background: The role of antigen-specific T cells in the mechanism of food allergy or maintenance of tolerance toward an innocuous antigen, such as cow's milk, is not yet fully understood., Objective: The cow's milk-specific T-cell response of donors with various allergic backgrounds was investigated., Methods: Cow's milk-specific T-cell clones (TCCs) were generated from the blood of children with persistent cow's milk allergy (CMA) and the blood of cow's milk-tolerant allergic and nonallergic control subjects. The TCCs were characterized by their antigen-specific proliferation, cytokine production, and activation status., Results: Cow's milk-specific TCCs of children with persistent CMA were T(H)2 skewed, and the production of IL-4 and IL-13 was significantly correlated with the expression of the activation marker CD25. TCCs of the allergic control subjects were characterized by a high production of IL-10, which was positively correlated with the production of IL-4 and IFN-gamma and with the expression of CD25. TCCs derived from nonallergic control subjects had an attenuated response toward cow's milk in that they did not produce high levels of cytokines nor did they express high levels of surface markers. As in the allergic control subjects, in the nonallergic control subjects IL-10 production was positively correlated with the expression of CD25., Conclusion: The activation status of T cells derived from persistent donors with CMA was associated with the production of IL-4 and IL-13, whereas activated TCCs of cow's milk-tolerant control subjects were characterized by the production of IL-10 and, to a lesser extent, IFN-gamma. These findings suggest that activated CD4(+) T cells (characterized by a high CD25 expression) might contribute to the tolerogenic immune response toward an antigen, such as cow's milk, through the production of IL-10.

Background: Hidden peanut in consumer products can endanger patients with peanut allergy. Individual threshold doses for eliciting allergic reactions need to be elucidated to assess the risks for development of allergic reactions after accidental ingestion of peanut in a population with peanut allergy., Objective: We sought to determine the distribution of individual threshold doses in a population with peanut allergy and to correlate these thresholds to the severity of peanut-induced symptoms., Methods: Twenty-six adult patients with a convincing history of peanut-related symptoms, a specific IgE level of 0.7 kU/L or greater, or a positive skin prick test response of 2+ or greater to peanut were included. These patients underwent double-blind, placebo-controlled food challenges with increasing doses of peanut. A threshold dose could be established when objective or repetitive subjective reactions occurred after active doses., Results: All patients had subjective oral symptoms (n = 26), prior subjective gastrointestinal symptoms (n = 14), or objective symptoms (n = 5). Reactions started within 30 minutes after ingestion of peanut, but in 2 patients additional symptoms were delayed by 1 to 2 hours. Threshold doses for allergic reactions ranged from a dose as low as 100 microg up to 1 g of peanut protein. Fifty percent of the study population (95% CI, 30%-70%) already had an allergic reaction after ingestion of 3 mg of peanut protein. Patients with severe symptoms had lower threshold doses compared with those of patients with mild symptoms (P =.027)., Conclusions: A substantial part of a population with peanut allergy will react to very low amounts of peanut, requiring accurate declaration of peanut content in consumer products. This is even more important because patients with severe reactions react to lower doses than patients with mild symptoms.

Background: Individuals with pollen allergy often have IgE against plant-derived foods. This can be due to cross-reactive IgE against Bet v 1 and homologues, profilins, and/or cross-reactive carbohydrate determinants., Objective: The aim of this study was to correlate sensitization to Bet v 1 and profilin with individual recognition patterns to plant foods and clinical relevance., Methods: Fifty-two patients with pollen allergy and IgE against at least one plant-derived food were included in the study. Adverse reactions to plant-derived foods were documented by using standardized interviews. Skin prick tests were performed for pollen (grass, birch, and mugwort) and 14 plant-derived foods. In addition, recombinant (r) Bet v 1 and rBet v 2 (profilin) were tested intracutaneously. Specific IgE against the abovementioned allergens were determined by means of RAST. Cross-reactivity was studied by means of RAST inhibition., Results: Eighty-five percent of patients were sensitized to Bet v 1, and 71% were sensitized to profilin. Profilin was associated with a higher number of positive RAST results to plant-derived foods than Bet v 1. In contrast, Bet v 1 was associated with more positive skin prick test responses and more food-related symptoms. Sensitization to Bet v 1 was associated with IgE against apple, hazelnut, and peach, whereas sensitization to profilin was associated with positive RAST results to all investigated plant-derived foods except apple, peach, and melon., Conclusions: IgE antibodies against Bet v 1 have a more limited spectrum of cross-reactivity than those against profilin, but they frequently give rise to clinically relevant cross-reactivities to food. In analogy to anticarbohydrate IgE, cross-reactive IgE against food profilins have no or very limited clinical relevance.

Background: House dust mite (HDM) allergen might induce and maintain atopic dermatitis (AD). Reduction of allergen load by applying encasings might improve the clinical symptoms of AD., Objective: We sought to investigate, in a randomized, double-blind, placebo-controlled study, whether reducing HDM allergen levels by using mattress, duvet, and pillow encasings for 12 months will result in improvement in AD symptoms., Methods: Patients with AD (8-50 years old and allergic to HDM), having a Leicester sign score (a dermatitis score) of at least 1% extent and a severity score of 6 points or greater, were randomly allocated to an active (n = 45) or a placebo allergen-avoidance group (n = 41). Avoidance measures consisted of applying HDM-impermeable encasings for mattresses, pillows, and duvets for the active treatment group and cotton encasings for the placebo group. Effect on allergen concentrations (Der p 1 and Der p 1 plus Der f 1), Leicester sign score extent and severity, visual analogue scale scores for itching and sleeplessness, intradermal test results, atopy patch test results, total serum IgE levels, anti-Der p 1-specific IgE levels, and total blood eosinophil counts were studied., Results: The active encasings reduced the Der p 1 allergen concentration in the mattress after 12 months with a factor 2.1 (P =.007) and the Der p 1 plus Der f 1 allergen concentration with a factor of 2.5 (P =.005); no significant change in allergen concentrations in mattresses was seen in the placebo group. Although the decrease in allergen load was significant, no differences in treatment-induced changes were seen between the placebo and active groups., Conclusions: Use of HDM-impermeable encasings resulted in a significant decrease in Der p 1 and Der p 1 plus Der f 1 allergen concentrations. However, this reduction in allergen load did not result in significant changes in clinical parameters between the groups. Reduction of allergens in other environments (work, school, and outdoors) might be equally important in improving symptoms of AD.

Background: The release of T(H)2 cytokines by food-specific T cells is thought to be important in the etiology of food allergy. It has been suggested that the activation state of food-specific T cells also plays a significant role, but this has not yet been studied at the single-cell level., Objective: Differences in the expression of cell-surface markers by cow's milk protein (CMP)-specific T cells between infants with and without cow's milk allergy (CMA) were evaluated at the clonal level. In addition, expression after the spontaneous development of tolerance of cow's milk in infants with CMA was analyzed., Methods: We established CMP-specific T-cell clones (TCCs) from blood of infants with CMA and atopic dermatitis, from atopic controls with atopic dermatitis but without CMA, and from nonatopic controls. In addition, we established TCCs from infants with CMA after they had spontaneously developed tolerance to cow's milk. Expression levels of CD25, CD26, and CD30 by each TCC were analyzed by use of flow cytometry., Results: Cow's milk protein-specific T cells from infants with CMA expressed much higher levels of CD25 and CD30 than CMP-specific T cells from infants without CMA. Expression of CD26 was much lower than in normal controls. After development of tolerance for cow's milk, expression of CD25 and CD30 was decreased, whereas the expression of CD26 was increased to normal levels., Conclusion: Antigen-specific T cells from patients with food allergy display an increased expression of cell-surface markers of activation compared with cells of patients without food allergy. This suggests an intrinsically stronger food-specific T-cell response in food-allergic patients, and points to the key role of food-specific T cells in the pathogenesis of food allergy.

Background: Cow's milk is the most important food antigen in infancy and may lead to acute cutaneous symptoms and atopic dermatitis (AD). The role of circulating allergen-specific T cells in the pathogenesis of food-allergic skin symptoms is still under investigation., Objective: This study was designed to analyze the cow's milk protein (CMP)-specific T-cell response at the clonal level in infants with AD and cow's milk allergy (CMA) in comparison with infants with AD without CMA., Methods: We used an antigen-specific culturing system with autologous B cells as antigen-presenting cells to establish CMP-specific T-cell clones derived from PBMCs in infants with AD. T-cell reactivity, measured by using a lymphocyte stimulation test, and cytokine production, measured by using ELISA, was compared between infants with AD with and without CMA., Results: Both infants with and without allergy to cow's milk had a CMP-specific T helper cell response directed against the major proteins in milk. Analysis of antigen-specific cytokine production showed that this response was T(H)2 skewed in infants with CMA, with production of high levels of IL-4, IL-5, and IL-13. In contrast, infants without CMA had a T(H)1-skewed response, with high levels of IFN-gamma and low levels of IL-4, IL-5, and IL-13., Conclusion: These data confirm for the first time at the clonal level that food allergy in infants with AD is associated with production of T(H)2 cytokines by circulating antigen-specific CD4(+) T cells, whereas tolerance to food antigens is associated with low levels of these cytokines. This suggests a key role for the T helper cell-derived T(H)2 cytokines in food allergy-related skin symptoms.

Background: Pharmacologic studies in atopic eczema (AE) are difficult to standardize. Patients with AE differ in the stage of their skin disease (acute, subacute, chronic)., Objective: This study was designed to assess macroscopic and microscopic effects of pretreatment with topical glucocortico-steroids (GCSs) and tar on the atopy patch test (APT) reaction in patients with atopic eczema., Methods: Nonlesional skin of the back of patients with AE (n = 6) was treated for 3 weeks at 3 different sites with triamcin-olonacetonide 0.1% in cetamacrogol ointment (GCSs), pix liquida 10% in cetamacrogol ointment (tar), and cetamacrogol ointment (vehicle), respectively. APTs were performed, and biopsy specimens were taken from all these sites (time = 0 and 24 hours) for immunohistochemical analysis., Results: Treatment with both GCSs and tar was able to reduce the macroscopic outcome of the APT reaction. Furthermore, both treatment modalities had an almost equally inhibiting effect on the influx of T cells, eosinophils, and CD1(+), RFD1(+), IFN-gamma(+), and IL-4(+) cells, as well as on the percentage of vessels expressing the adhesion molecules vascular cell adhesion molecule 1 and E-selectin in response to epicutaneous aeroallergen challenge., Conclusion: Although both treatments significantly reduced the various cellular constituents of allergic inflammation, all cell types remained present. In addition, this study shows that the APT can be used to evaluate the effect of topical anti-inflammatory treatments on allergic inflammation in patients with AE.

Background: Epicutaneous application of aeroallergens induces a positive atopy patch test (APT) response in about 50% of patients with atopic eczema (AE) and sensitization for these allergens., Objective: To elucidate the mechanisms determining the outcome of the APT, the following questions were addressed. Are there differences in clinical features between patients with AE who have positive versus negative APT responses? Is a macroscopically negative APT response also histologically negative, and if so, are there differences in clinically noninvolved skin between the two groups regarding (1) the sensitivity toward an irritant, (2) the composition of cellular infiltrate, (3) the presence of aeroallergen-specific T cells, and (4) the number of IgE(+) cells?, Methods: Punch biopsy specimens from both house dust mite patch tested and the clinically noninvolved skin of patients with AE who have positive APT responses (n = 10) and negative APT responses (n = 10) and those from the normal skin of atopic individuals without AE (n = 10) and nonatopic volunteers (n = 10) were analyzed by using immunohistochemistry with mAbs against eosinophil cationic protein, IgE, the high-affinity receptor for IgE, and CD3 and CD25 mAbs. Furthermore, T-cell lines were propagated from noninvolved skin of all patient and control groups. The T-cell lines were tested for house dust mite specificity., Results: Negative APT sites were immunohistochemically similar to clinically noninvolved AE skin. There were no significant differences between patients with AE who had positive and negative APT results regarding either clinical features, the composition of cellular infiltrate, or the presence of allergen-specific T cells in clinically noninvolved skin. However, differences were observed regarding the presence of IgE on epidermal CD1a(+) cells., Conclusion: Our results indicate that a positive APT reaction requires the presence of epidermal IgE(+) CD1a(+) cells in clinically noninvolved skin, but that also other, as yet unknown, discriminatory factors are involved.

Background: Atopic dermatitis (AD) is characterized by skin infiltrates of leukocytes, such as lymphocytes and eosinophils., Objective: To describe the mechanisms determining this inflammatory process, we have analyzed expression of adhesion molecules and their regulation on skin endothelial cells (ECs)., Methods: Expression of adhesion molecules on ECs was analyzed by immunohistochemistry by using Ulex europaeus agglutin 1 as a pan-endothelial marker., Results: Vascular cell adhesion molecule-1 (VCAM-1), E-selectin, and P-selectin were not found in skin of nonatopic individuals, whereas expression of these surface molecules was observed in nonlesional skin of patients with AD and was even more pronounced in lesional skin or after epicutaneous application of aeroallergen. Induction of adhesion molecule expression was examined on both macrovascular ECs from human umbilical cord vein (HUVECs) and human microvascular ECs (HMEC-1) from skin. TNF-alpha very potently upregulated adhesion molecule expression in vitro on both EC cell types. To verify the in vivo relevance of TNF-alpha, we performed TNF-alpha staining in the skin. TNF-alpha was observed in the dermis of nonatopic skin, both in chymase-containing mast cells and CD68+ macrophages. The increase in the number of TNF-alpha-containing cells was concomitant with the increase in adhesion molecule expression in the skin of patients with AD. IL-4 is supposed to be important in atopic diseases because of its IgE- and VCAM-1-inducing properties. However, IL-4 addition failed to induce VCAM-1 expression on HMEC-1, although in the same set of experiments, a clear induction of VCAM-1 expression by IL-4 on HUVECs was demonstrated. Flow cytometry revealed the absence of 11-4 receptor alpha-chains on HMEC-1 and their presence on HUVECs. Immunohistochemistry examination on skin sections showed no binding of the IL-4R alpha-chain antibodies to ECs., Conclusion: We conclude that adhesion molecule expression is increased in the skin of patients with AD. Most probably, this increased expression is not a (direct) effect of IL-4 on skin endothelium, but other cytokines, such as TNF-alpha, might be responsible for this increased adhesion molecule expression. Continuous adhesion molecule expression may facilitate T-cell extravasation in a nonantigen-specific manner, thus explaining the presence of increased T-cell numbers in nonlesional skin of patients with AD.

Atopic dermatitis (AD) is a chronic skin disorder, characterized by infiltration of activated memory CD4+ T cells into skin. A model to study the onset of allergic inflammation in a patient with AD is the atopy patch test (APT), in which, by epicutaneous application of aeroallergen, an eczematous reaction is induced in 50% of sensitized patients with AD. Extravasation of T cells into skin is thought to be critically dependent on expression of the surface molecule cutaneous lymphocyte-associated antigen (CLA), which recognizes and binds its ligand E-selectin on endothelium. We studied the dynamics of expression of CLA and the gut homing receptor alphaE beta7 (HML-1) on T cells in the skin of patients with AD and in APT reactions and nickel and sodium lauryl sulfate patch test reactions by means of immunohistochemical double staining of skin biopsy specimens. The results show an increase in the number of CD3+ T cells in the lesional skin of patients with AD, APT reactions, and nickel and sodium lauryl sulfate patch test reactions as compared with nonlesional skin of the same patients and nonatopic individuals. In contrast, the percentages of CLA+ T cells in the lesional skin of patients with AD, in the APT reactions, and in sodium lauryl sulfate and nickel patch test reactions were decreased. In addition, we found a marked expression of alphaE beta7 by T cells present in skin, indicating a nonspecific influx of T cells during allergic skin inflammation. We propose that during allergic skin inflammation CLA expression is not a prerequisite for cutaneous T-cell infiltration. CLA expression may be important for T cells to extravasate from blood into skin during immune surveillance or for retention of allergen-specific T cells in skin.

Objective: The study was designed to evaluate the atopy patch test (APT) and the late-phase reaction (LPR) after intracutaneous allergen injection as models for the study of allergic inflammation in atopic eczema., Methods: Immunocytochemistry was used to analyze skin biopsy specimens from sites of APTs and LPRs at 2 and 24 hours and to compare these with lesional and nonlesional skin of patients with atopic eczema., Results: A lack of neutrophil infiltration in specimens from both the APT and lesional skin sites was observed, whereas neutrophils were abundantly present in the specimens from LPR sites. With double-staining techniques it was demonstrated that the few neutrophils present in specimens from APT sites and in lesional skin were mostly located in intravascular areas, whereas in the LPR specimens they were located predominantly in extravascular areas. Eosinophils infiltrated at an earlier time point in the LPR as compared with the APT. Furthermore, there was a decrease of intact mast cells in the LPR site compared with the APT sites and lesional skin. No significant difference in T-cell number was observed between the two tests. Upregulation of E-selectin expression on endothelial cells occurred at an earlier time point in the LPR as compared with the APT., Conclusion: There are important differences in cellular infiltrate between the APT and the LPR. The close macroscopic and microscopic similarities between the specimens from APT sites and lesional skin of patients with atopic eczema support the argument that the APT is a more valid in vivo model with which to study allergic inflammation in atopic eczema than the LPR.

In the pathogenesis of atopic dermatitis (AD), IgE plays an important role; and TH2 cells, producing IL-4, have been ascribed a key role in allergic diseases such as AD. To investigate the role of TH subpopulations in the onset and continuation of AD, we performed atopy patch tests (APTs) with house dust mite allergen in patients with AD. Punch biopsy specimens were taken from the APT site, and sections were immunocytochemically double-stained for IL-4 and interferon-gamma together with different membrane markers. This provides a unique model for studying the kinetics of the TH0, TH1, and TH2 responses in situ. The results show that in lesional skin interferon-gamma-positive cells predominate over IL-4-positive cells. The interferon-gamma-positive cells are mainly CD3+ and, in particular, CD4+ cells; the remainder are CD8+, RFD-1+, and RFD-7+ cells. The IL-4-positive cells are exclusively CD4+ T cells; no eosinophils or mast cells were found to stain for IL-4. With regard to the TH cell response, a clear dichotomy of the eczematous response to allergen in skin was observed. In the initiation phase IL-4 production by TH2 and TH0 cells is predominant over interferon-gamma production by TH1 and TH0 cells. In the late and chronic phases the situation is reversed and interferon-gamma production by TH1 and TH0 cells predominates over IL-4 production by TH2 and TH0 cells. Understanding the relationship between the observed biphasic response and clinical manifestation of AD is important for the development of therapeutic strategies.

Background: The number of positive atopy patch test (APT) results in patients with atopic eczema (AE) varies in different studies, probably because of different test techniques. Variables that may influence the outcome of the APT were evaluated., Methods: APTs were performed in 84 patients with AE, 30 control patients with atopic disease, and 85 healthy volunteers, with house dust mite and grass pollen allergens in concentrations of 100, 1000, 10,000, and 100,000 allergenic units/ml. The influence of 0, 10, or 20 tape strippings was investigated. The tests were performed on the back and/or the antecubital fossa and evaluated after 20 minutes and 24, 48, and 72 hours. In all patients the total and specific serum IgE levels were measured., Results: The maximal number of positive APT results were obtained under the following conditions: an allergen concentration equal to 10,000 allergenic units/ml, 10 tape strippings and readings at 24 and 48 hours. Positive APT results were observed in five of 30 control patients with atopic disease and in none of 85 healthy volunteers. Statistically significantly higher total and allergen-specific serum IgE levels were found in the group of patients with AE with positive APT results., Conclusions: We recommend the previously described conditions to get an optimal method for APT. The correlation between the APT and the total and specific serum IgE suggests an important role for IgE in the reaction mechanism behind the APT.

T-cell lines have been derived from aeroallergen-induced eczematous patch test sites of patients with atopic dermatitis (AD). Biopsy specimens were obtained 24 hours after allergen application to the skin, and only in vivo-activated T cells were propagated. From one patient, the T-cell lines were subcloned at 0.3 cells per well. With allergen-induced interleukin (IL) production, all clones tested (n = 13) were found to be specific for the allergen, producing IL-4 and granulocyte-macrophage-colony-stimulating factor. No IL-2 or interferon-gamma was found. The allergen-specific proliferative response of these clones, although the response was dependent on exogenous IL-2 or IL-4, also proved that all clones were allergen specific. Under optimal stimulation (aCD3 plus phorbol myristate acetate), 15% of the clones appeared to be of Th0 phenotype and 70% of Th2 phenotype. In 15% of the clones, IL-4 was produced in the absence of IL-2, IL-5, or interferon-gamma. Supernatants of all clones tested induced IgE production by B cells from normal non-atopic donors. The T-cell lines of the other patient demonstrated similar results; allergen-specific proliferation was dependent on exogenous IL-2 or IL-4 and stimulation with aCD3 plus phorbol myristate acetate demonstrated that the T cells in these lines were of the Th2 phenotype. In conclusion, our data reveal that, in AD, percutaneous sensitization to aeroallergens may occur and indicate that allergen-specific Th2 type T cells may be responsible for the high levels of (specific) IgE found in 80% of patients with AD.