Commercial Skin Prick Test Research Articles

Procedure for a standardized preparation of skin prick test solutions for the diagnosis of occupational type I allergies in the absence of commercial extracts.

In order to ensure valid diagnostics for occupational test allergen solutions despite the ongoing reduction in the availability of commercial test extracts, a plan B was initiated for the possible production of skin prick test (SPT) solutions in public pharmacies. For important occupational allergen sources (wheat and rye, storage mites, animal epithelia, mold material) laboratory extraction methods were analyzed in comparison to pharmacy compatible extraction methods regarding protein quantity and quality in SDS-PAGE combined with silver staining. Subsequently, using the example of bovine epithelia, adapted extraction procedures as well as in-process and final product controls were transferred to a public pharmacy. Allergen sources with a high protein content, such as wheat and rye grains as well as storage mites, showed good comparability of the extractable protein quantity and protein pattern, regardless of the applied extraction method. In contrast, allergen source materials with a low total protein content, such as animal epithelia and molds, can benefit from laboratory extraction conditions such as mechanical disruption and specific buffer additives. In the qualitative protein silver staining, characteristic protein patterns were identified for each allergen source. Depending on the extraction method, only minor differences in total protein patterns were observed in animal epithelia and molds. Using source materials from two suppliers, the resulting allergen extracts displayed clear differences in protein content in storage mites and quantitative and qualitative differences in molds. A practical preparation attempt of SPT solutions in a public pharmacy was successful. SPT solutions prepared with adapted pharmacy extraction methods showed a comparable protein and Bos d 2 allergen content and equivalent qualities in the protein pattern compared to a previously available commercial SPT solution. Accordingly, it can be assumed that standardized SPT solutions with sufficient allergen quality for occupational allergen sources can be prepared in public pharmacies if certified allergen sources with appropriate protein content are available.

Allergens in dog extracts: Implication for diagnosis and treatment.

Five to ten percent of the population in affluent countries are allergic to dog. Diagnosis and treatment is based on allergen extracts from natural sources where composition and concentration are poorly defined. We aimed to quantify six dog allergens (Can f 1-6) in commercial skin prick test (SPT) solutions and to determine individual allergen profiles in dogs. The allergen content of SPT solutions from five vendors and allergen source material from three anatomical sites were analyzed. Fur and saliva samples were collected from a mixed population of 120 dogs. Can f 1-6 were quantified by inhibition ELISA using purified recombinant or natural allergens and polyclonal or monoclonal antibodies. Allergenicity was analyzed by basophil activation test. Extensive variation in allergen composition was observed in commercial SPT vials resulting in a patient-dependent ability to activate basophils. Extract heterogeneity depended on collection site and allergen composition in individual dogs and source materials. Can f 2 and Can f 6 exhibited low levels in fur and SPT solutions, whereas Can f 4, which was the dominating allergen in fur samples, did not display similar high proportions in SPT solutions. Can f 3 varied most among SPT solutions. There is a great variation of dog allergens in natural extracts raising questions of source, sampling, processing and ultimately of standardization and minimum allergen levels for accurate diagnosis and treatment.

The Reliability of Self-reported Food Allergy in Thai Adults

The prevalence of IgE-mediated food allergies in children has been increasing, in particular self-reported food allergy, while the data in adults are lacking. This study aimed to determine the reliability of self-diagnosed IgE-mediated food allergies in Thai adults Adult patients who were referred for evaluation of presumed food allergy to the Allergy Clinic, Samitivej Sukhumvit Hospital, Bangkok, Thailand, between January 2015-December 2016 were retrospectively reviewed. Ninety-five patients were evaluated. Sixty-four were female (67%). The mean age at presentation was 33 years (20-76). The history of atopic diseases, known food allergy and family history of atopy were present in 19 (20%), 4 (4%) and 8 (8%), respectively. Eighty patients (84%) presented with various dermatologic symptoms of which urticaria accounted for about half (36 patients). Anaphylaxis was found in 4 patients (4%). Twenty-two patients (23%) reported shellfish as the culprit while 12 patients (13%) reported multiple food allergies and 44 patients (46%) had no food in suspicion. Twenty-three patients (24%) underwent allergy testing in which commercial skin prick test (CSPT), fresh food skin prick test (FFSPT), specific IgE levels and open food challenge were performed in 17, 3, 9 and 2 patients, respectively. Only 4 patients (4%) had confirmed IgE-mediated food allergy by CSPT and/or specific IgE levels in 3 patients and FFSPT in 1 patient. Most adult patients presented with dermatologic reactions in self-reported food allergy. However, the clinical correlation was poor. Proper evaluation and reassurance might be beneficial to reduce unnecessary referral, investigations and food avoidance.

Prevalence of Atopic Dermatitis Criteria among Textile Workers with Occupational Allergic Contact Dermatitis and Effects of Having Atopic Dermatitis on Contact Antigenic Diversity.

Objectives:Contact dermatitis (CD) is a common skin disease. Occupational contact dermatitis (OCD) is the most frequently seen occupational skin disease and includes both occupational allergic CD (OACD) and occupational irritant CD (OICD). One of the most common sources of OACD is textile products. Individuals with atopic dermatitis (AD) have an increased risk for development of allergic contact dermatitis (ACD). However, the role of AD in the etiopathogenesis of the development of OACD among textile industry workers is not well known. The aim of the present study was to determine the prevalence of AD among textile workers with OACD and to analyze contact antigenic diversity between the workers with and without AD.Methods:A prospective, cross-sectional study was conducted with 352 textile workers who had previously been diagnosed with OACD. The patients were questioned and examined with respect to AD criteria, demographic features, disease duration, duration of employment until first symptoms, phototype, workplace (subsectors), and location of lesions at control visits. Immediate skin test reactivity was evaluated with a commercial skin prick test panel. The data obtained and the patients’ previously recorded patch test results were compared in OACD groups with and without a diagnosis of AD. The results were statistically evaluated with a significance level of p value <0.05.Results:The study population consisted of 124 males and 227 females. The mean age was 35.69±13.65 years. The most commonly seen employment duration, phototype, subsector, and location were 4 to 8 months (26.14%), 9 to 12 months (34.66%), Fitzpatrick type-III (37.50%), dyeing (33.52%), and exclusively the hands (60.51%), respectively. In all, 193 patients (54.83%) met the criteria for the diagnosis of AD. In the OACD group with AD, there was a significant number with 4 major and 16 minor criteria, as well as positivity for 14 contact allergens.Conclusion:Most AD criteria, or a diagnosis of AD, are highly detectable among workers with textile-related OACD. The results for patch test allergens may be significantly higher than those of individuals without AD. Textile workers with AD should be warned about the possibility of the early development of OACD.

Oil body-associated hazelnut allergens including oleosins are underrepresented in diagnostic extracts but associated with severe symptoms.

BackgroundOil body-associated allergens such as oleosins have been reported for important allergenic foods such as peanut, sesame and hazelnut. Here we investigate whether oil body associated proteins (OAPs) are linked with specific clinical phenotypes and whether they are represented in skin prick test (SPT) reagents.MethodsA hazelnut OAP fraction was characterized by mass-spectrometry (MS) to identify its major constituents. Polyclonal rabbit antibodies were generated against hazelnut OAPs. The presence of OAPs in commercially available hazelnut SPTs was studied by immunoblot and spiking experiments. OAP-specific IgE antibodies were measured in sera from patients with a convincing history of hazelnut allergy by RAST (n = 91), immunoblot (n = 22) and basophil histamine release (BHR; n = 14).ResultsHazelnut OAPs were analysed by MS and found to be dominated by oleosins at ~14 and ~17 kDa, and a 27 kDa band containing oleosin dimers and unidentified protein. In 36/91 sera specific IgE against hazelnut OAPs was detected, and confirmed to be biologically active by BHR (n = 14). The majority (21/22) recognized the oleosin bands at 17 kDa on immunoblot, of which 11 exclusively. These OAP-specific IgE responses dominated by oleosin were associated with systemic reactions to hazelnut (OR 4.24; p = 0.015) and negative SPT (χ2 6.3, p = 0.012). Immunoblot analysis using OAP-specific rabbit antiserum demonstrated that commercial SPT reagents are virtually devoid of OAPs, sometimes (3/9) resulting in false-negative SPT. Spiking of SPT reagents with OAP restored serum IgE binding of these false-negative patients on immunoblot at mainly 17 kDa.ConclusionHazelnut allergens found in oil bodies dominated by oleosin are associated with more severe systemic reactions and negative SPT. Defatted diagnostic extracts are virtually devoid of these allergens, resulting in poor sensitivity for detection of IgE antibodies against these clinically relevant molecules.

Biochemical and immunological analysis of mould skin prick test solution: current status of standardization

Sensitization prevalence to moulds reached from less than 10% in the general population to more than 25% in atopic and/or asthmatic subjects. To diagnose IgE-mediated mould sensitization, skin prick test (SPT) and specific IgE (sIgE) measurement are recommended. However, concordance of SPT and sIgE results is often less than 50% and standardization of the extracts is required to achieve reliable test results. The aim of our study was to analyse mould SPT solutions (SPTs) with respect to quantity and quality of protein, antigen and human IgE-binding content as a prerequisite for further in vivo studies. Commercial SPTs of Alternaria alternata, Aspergillus fumigatus, Cladosporium herbarum and Penicillium chrysogenum from six manufacturers as well as two in-house extracts from Aspergillus versicolor were investigated. Protein-, antigen- and IgE-binding contents were quantified by Bradford assay, sandwich ELISA and IgE-ImmunoCAP-inhibition tests. Protein composition and IgE and IgG binding were analysed by SDS-PAGE and immunoblotting, respectively. Median protein concentrations were similar in all mould SPT extracts (90-110μg/mL). In contrast, antigen contents and IgE-binding capacity showed a high variability with median antigen values from 4 to 118μg/mL and IgE inhibition results between 30 to 95%. Whereas almost all SPTs of A.alternata and A.versicolor showed complete sIgE inhibition with mean values >80%, only three extracts for A.fumigatus, two extracts for C.herbarum and none of the tested extracts for P.chrysogenum exceeded 50% sIgE reduction. Quantitative amounts of protein, antigenic and IgE-binding structures were not comparable with the quality of the corresponding protein or immunoblot pattern, with the exception of A.alternata SPTs. Commercially available mould SPT extracts showed high variability raising the question of comparability and reliability of SPT results. Possible consequences for diagnostic test outcome will be investigated in the next step.

Evaluation of commercial skin prick test solutions for selected occupational allergens

Skin prick testing (SPT) is an important step in the diagnosis of IgE-mediated occupational allergic diseases. The outcome of SPT is related to the quality of allergen extracts. Thus, the aim of the study was to assess different commercially available SPT solutions for selected occupational allergens. SPT was performed in 116 bakers, 47 farmers and 33 subjects exposed to natural rubber latex (NRL), all with work-related allergic symptoms. The SPT solutions from different manufacturers (n=3-5) for wheat flour, rye flour, soy, cow hair/dander, storage mites (Tyrophagus putrescentiae, Lepidoglyphus destructor, Acarus siro) and NRL were analysed with respect to their protein and antigen contents. SPT was carried out in 16 allergy centres in six European countries using standardized procedures. Specific IgE values were used as the gold standard to calculate the sensitivity and specificity of SPT solutions. The optimal cut-point for each SPT solution was determined by Youden Index. Protein and antigen contents and patterns of the SPT solutions varied remarkably depending on the manufacturer. While SPT solutions for wheat flour and soy reached overall low sensitivities, sensitivities of other tested SPT solutions depended on the manufacturer. As a rule, solutions with higher protein and antigen content showed higher sensitivities and test efficiencies. There is a wide variability of SPT solutions for occupational allergens, and the sensitivity of several solutions is low. Thus, improvement and standardization of SPT solutions for occupational allergens is essential.

A case of peripheral and eosphagatic hypereosinophilia and food wllergy after liver’s transplantation in adult

From one year of liver's transplantation and cyclosporin (CSA) maintenance treatment(100 mg a day), a 43 years old women presented with abdominal pain and diarrhea immediately after eating milk and egg. She underwent the transplantation after an acute liver toxicity caused by isoniazid during tuberculosis treatment. Increasing hyperosinophilia (40%) and eosinophilic oesophagitis (EE) presented with food allergy. Total IgE were low (45UI). Commercial skin prick test and prick by prick as specific IgEs detection (IMMUNOCAP) were positive for milk's proteins, egg, rice and wheat flour. Hypereosinophilia persisted inspite of an elimination diet for the culprit allergens while the clinical symptoms of food allergy improved. Other causes of hypereosinophilia were excluded. Interestingly only an inhaled fluticasone propionate treatment (FP,250 mcg bid) for three months was followed by an outstanding reduction of EE and hypereosinophilia (less than 1000/mm3 and <25%) without changing CSA dosage. Food allergy and hypereosinophilia has been increasingly reported in children in the setting of liver transplantation during tacrolimus treatment.On the contrast reports in adults are very rare expecially during CSA treatment. In our patient elimination diet wasn't followed by a reduction of hypereosinofilia as generally occurs in pediatric cases. Our patient didn't present any allergy before the transpantation.No information was available on donor's known allergy. Different meccanisms are supposed underlying the new onset of food allergy and hypereosinophilia in liver's transplantation: • An imbalance between Th1/Th2 cells or an increased enteric permeability. • Immune effects of viral infections associated with the immunosoppressive state. • Acquired food allergy and hypereosinophilia due to a transfer of hepatic hematopoietic stam cells or active IGE from the donor's liver. More studied are needed in a controlled setting to identify similar findings among liver transplants.Moreover in the pretransplant investigation should be inlcluded the allergic status both of the donor as the recipient.

Skin Prick Test Extracts for Dog Allergy Diagnosis Show Considerable Variations Regarding the Content of Major and Minor Dog Allergens

Background: Commercial skin prick test (SPT) extracts used for the diagnosis of dog allergy are prepared by extracting allergens from natural sources, e.g. dog hair and dander. Due to different starting material and extraction methods used, it is likely that extracts differ regarding their allergen contents. Methods: The total protein content and composition of dog SPT extracts from 5 European manufacturers were compared by silver-stained SDS-PAGE. Specific antibody probes were generated to detect major and minor allergens in each extract by immunoblotting. Additionally, sera of patients suffering from dog allergy were used to detect dog allergens in SPT extracts. Results: SPT extracts showed a 20-fold variation regarding the total protein content. The contents of the major dog allergen Can f 1 and of Can f 2 varied considerably between the extracts. In one of the extracts, neither Can f 1 nor Can f 2 could be detected by immunoblotting. The contents of the minor dog allergen Can f 3, albumin, also showed great variability. In one of the dog SPT extracts, the presence of human serum albumin (HSA) was detected with HSA-specific antibodies. Conclusion: The observed variability of commercial dog SPT extracts regarding their allergen contents likely has a negative influence on the accuracy of diagnosis of dog allergy.

How Accurate and Safe Is the Diagnosis of Hazelnut Allergy by Means of Commercial Skin Prick Test Reagents?

Background: Allergy to tree nuts, like hazelnuts, ranks among the most frequently observed food allergies. These allergies can start at early childhood and are, in contrast to other food allergies, not always outgrown by the patient. Tree nut allergy is frequently associated with severe reactions. Diagnosis partially relies on in vivo testing by means of a skin prick test (SPT) using commercially available SPT reagents. Methods: Protein and allergen composition of nine commercial SPT solutions was evaluated using standard protein detection methods and specific immunoassays for measurement of five individual allergens. Diagnostic performance was assessed by SPT in 30 hazelnut-allergic subjects, of which 15 were provocation proven. Results: Protein concentrations ranged from 0.2–14 mg/ml. SDS-PAGE/silver staining revealed clear differences in protein composition. The major allergen Cor a 1 was present in all extracts but concentrations differed up to a factor 50. An allergen associated with severe symptoms, Cor a 8 (lipid transfer protein), was not detected on immunoblot in three products, and concentrations varied by more than a factor 100 as was shown by RAST inhibition. Similar observations were made for profilin, thaumatin-like protein and a not fully characterized 38-kD allergen. Ratios of individual allergens were variable among the nine extracts. SPT showed significant difference, and 6/30 patients displayed false-negative results using 3/9 products. Conclusion: Variability in the composition of products for the diagnosis of hazelnut allergy is extreme. Sometimes, allergens implicated in severe anaphylaxis are not detected by immunoblotting. These shortcomings in standardisation and quality control can potentially cause a false-negative diagnosis in subjects at risk of severe reactions to hazelnuts.

The relationship between latex skin prick test responses and clinical allergic responses

BACKGROUND: Allergic responses to latex have been reported more frequently in the past 5 years. Although commercial skin prick test solutions are available and can be used in the diagnosis of latex allergy in some countries, the characteristics of patients sensitized to latex relative to their skin test responses have not been reported. OBJECTIVE: The purpose of this study is to relate the clinical characteristics of patients with latex sensitivity to the size of their latex skin prick test response. METHODS: A retrospective review of patients who were attending a hospital-based allergy and asthma clinic and who had positive skin test responses to a commercial latex skin test solution was undertaken. RESULTS: Of 47 patients who had skin test responses to latex, 36 had a mean wheal diameter at least 3 mm greater than the negative control (diluent). Sixty-eight percent were health care workers. There was a positive association between the size of skin test response and severity of latex-induced symptoms (p < 0.001). A history of banana sensitivity was also associated with larger skin test responses (p < 0.05). CONCLUSION: The size of the skin prick test response to latex solution that is commercially available in Canada reflects the severity of latex-induced clinical allergic responses. (J Allergy Clin Immunol 1996;97:1202-6.)