First-in-human phase 2 trial with mite allergoids coupled to mannan in subcutaneous and sublingual immunotherapy.

BACKGROUND: Polymerized allergens conjugated to non-oxidized mannan (PM-allergoids) are novel vaccines targeting dendritic cells (DCs). Previous experimental data indicate that PM-allergoids are readily taken up by DCs and induce Treg cells. This first-in-human study was aimed to evaluate safety and to find the optimal dose of house dust mite PM-allergoid (PM-HDM) administered subcutaneously (SC) or sublingually (SL). METHODS: In a randomized, double-blind, double-dummy, placebo-controlled trial, 196 subjects received placebo or PM-HDM at 500, 1000, 3000, or 5000 mannan-conjugated therapeutic units (mTU)/mL in 9-arm groups for 4 months. All subjects received 5 SC doses (0.5 ml each) every 30 days plus 0.2 ml SL daily. The primary efficacy outcome was the improvement of titrated nasal provocation tests (NPT) with D. pteronyssinus at baseline and at the end of the study. All adverse events and reactions were recorded and assessed. Secondary outcomes were the combination of symptom and medication scores (CSMS) and serological markers. RESULTS: No moderate or severe adverse reactions were reported. Subjects improving the NPT after treatment ranged from 45% to 62% in active SC, 44% to 61% in active SL and 16% in placebo groups. Statistical differences between placebo and active groups were all significant above 500 mTU, being the highest with 3000 mTU SL (p = 0.004) and 5000 mTU SC (p = 0.011). CSMS improvement over placebo reached 70% (p < 0.001) in active 3000 mTU SC and 40% (p = 0.015) in 5000 mTU SL groups. CONCLUSIONS: PM-HDM immunotherapy was safe and successful in achieving primary and secondary clinical outcomes in SC and SL at either 3000 or 5000 mTU/ml.

In vivo diagnosis with purified tropomyosin in mite and shellfish allergic patients.

BACKGROUND: Tropomyosin is the most studied shellfish allergen and has been involved in cross-reactivity among different invertebrates (crustacean, mollusks, mites, insects, and nematodes). OBJECTIVE: To determine the relevance of tropomyosin in mite- and shellfish-sensitized patients using tropomyosin skin testing. METHODS: Patients were divided into 3 groups: group M included mite allergic patients (ie, individuals with respiratory symptoms and a positive result on skin prick testing [SPT] to house dust mites), group S included shellfish allergic patients (ie, individuals who reported symptoms with shellfish), and group MS included mite- and shellfish allergic patients (ie, individuals who simultaneously fulfilled the inclusion criteria for groups M and S). Tropomyosin was purified from shrimp, characterized, and used in SPT for diagnosis in the patient population. RESULTS: Eight hundred fifty patients were included in the study: 790 (92.9%) in group M, 21 (2.5%) in group S, and 39 (4.6%) in group MS. Tropomyosin was purified from shrimp with a purity higher than 95%. Forty-two individuals tested positive to tropomyosin: the prevalence was 2.7% in group M, 28.6% in group S, and 38.5% in patients of group MS. Twenty-one (50%) of the tropomyosin-positive individuals had symptoms with shellfish, and 3 (14.3%) reported anaphylaxis. CONCLUSION: The prevalence of tropomyosin was low in mite-sensitized patients (2.7 %) and high in shellfish allergic patients (28.6%). The higher prevalence of tropomyosin was found in patients sensitized to both mite and shellfish (38.5%). The selection of tropomyosin-sensitized patients by SPT might help in the choice of appropriate treatments or management for these patients.

Prevalence of sensitization to Cannabis sativa. Lipid-transfer and thaumatin-like proteins are relevant allergens.

BACKGROUND: Although allergy to Cannabis sativa was first reported over 40 years ago, the allergenicity has scarcely been studied. The objectives of this study were to investigate the frequency of sensitization to this plant, to analyze the clinical characteristics and allergenic profile of sensitized individuals and to identify the allergens involved. METHODS: Five hundred and forty-five individuals in Spain attending allergy clinics with respiratory or cutaneous symptoms underwent a skin-prick test (SPT) with C. sativa leaf extract. The extract was characterized by SDS-PAGE and 2-dimensional electrophoresis. Specific IgE to C. sativa was measured in positive SPT individuals. The clinical and allergenic profiles of sensitized individuals were investigated and the most-recognized allergens sequenced and characterized by liquid chromatography-mass spectrometry/mass spectrometry. RESULTS: Of this preselected population, 44 individuals had positive SPT to C. sativa (prevalence 8.1%). Prevalence was higher in individuals who were C. sativa smokers (14.6%). Two individuals reported mild symptoms with C. sativa. Twenty-one individuals from 32 available sera (65.6%) had positive specific IgE to C. sativa. Twelve sera recognized at least 6 different bands in a molecular-weight range of between 10 and 60 kDa. Six of them recognized a 10-kDa band, identified as a lipid transfer protein (LTP) and 8 recognized a 38-kDa band, identified as a thaumatin-like protein. CONCLUSIONS: There is a high prevalence of sensitization to C. sativa leaves. The clinical symptoms directly attributed to C. sativa were uncommon and mild. The sensitization profile observed suggests that C. sativa sensitization may be mediated by two mechanisms, i.e. cross-reactivity, mainly with LTP and thaumatin-like protein, and exposure-related 'de novo' sensitization.

Identification and quantification of tomato allergens: in vitro characterization of six different varieties.

BACKGROUND: The prevalence of sensitization to tomato has been estimated in 6.5% in a Mediterranean population. OBJECTIVES: To characterize the allergenic profile of 6 commonly ingested varieties of tomato and to identify and quantify the most representative allergens. METHODS: Rama, Rambo, Canario, Kumato, Pera and Raf tomato varieties were carefully peeled and extracts from peel and pulp prepared. The extracts were characterized by SDS-PAGE and immunoblot. Lyc e 3 and osmotin-like protein (OLP) were identified by LC MS/MS and PG2A by immunoblot with a specific polyclonal antibody. Protein content and allergen concentration (Lyc e 3 and PG2A) were measured by scanning densitometry after identification. One hundred and ninety-one patients were enrolled in the study. Specific IgE to all tomato extracts was evaluated by direct ELISA. RESULTS: Eighty (41.7%) individuals reported symptoms after contact/ingestion with tomato, most of them oral symptoms. Protein profile and allergen quantification of the 6 varieties showed differences in the allergen composition. Lyc e 3 was visualized in all extracts, being the most abundant in all cases. PG2A and OLP were identified in all peel extracts and in some pulp extracts. Higher specific IgE values were obtained for the Kumato variety. Immunoblot showed the existence of several bands with IgE-binding capacity, especially at 12 and 45-50 kDa. CONCLUSIONS: The study demonstrates differences in the antigenic and allergenic profiles of the analyzed varieties and variations in their allergenic composition, affecting the diagnostic capacity. LTP and PG2A are important tomato allergens in our population but other IgE-binding capacity proteins are also involved.

Electrochemical degradation of perchloroethylene in aqueous media: an approach to different strategies.

An approaching study to the electrochemical degradation of perchloroethylene (PCE) in water has been carried out using controlled current density degradation electrolyses. The different electrochemical strategies to degrade perchloroethylene in aqueous media (i.e. cathodic, anodic and dual treatments) have been checked using divided and undivided configurations. The influence of the initial concentration, pH and current density on the general behavior of the system has been studied, and special attention was paid to the nature of the byproducts formed and to the analysis of the closed mass balance at the end of the reaction. Results from several analytical techniques have been compared. Undivided configuration provides the best results in these experimental conditions, with degradation percentages higher than 50% and with only 6% of the initial perchloroethylene concentration remaining in the system.

Sensitization and allergy to Cannabis sativa leaves in a population of tomato (Lycopersicon esculentum)-sensitized patients.

BACKGROUND: Cases of allergy to Cannabis sativa have occasionally been reported, but both the allergenic profile and eventual cross-reactivity pattern remain unknown. OBJECTIVE: To analyze the allergenic profile of a population of patients from Spain sensitized to C. sativa and to characterize the C. sativa leaf extract. METHODS: A total of 32 subjects were enrolled in the study: group A, 10 individuals sensitized to tomato, reporting reactions by contact or inhalation to Cannabis; group B, 14 individuals sensitized to tomato, without reactions to Cannabis; group C, 8 individuals not sensitized to tomato and without reactions to Cannabis. Sensitivity to Cannabis, tomato and peach peel, Platanus hybrida and Artemisia vulgaris pollen extracts was measured by skin tests and specific IgE. Individual immunoblots and inhibition experiments with a pool of sera were conducted. RESULTS: All tomato-sensitized subjects (and 1 negative) had positive skin tests to C. sativa leaves and hashish. Specific IgE to C. sativa and peach peel was more common than to tomato. Immunoblot experiments showed 2 prominent bands of 10 and 14 kDa and 2 weakly recognized bands of 30 and 45 kDa. Tomato, peach and A. vulgaris extracts inhibited most of the bands present in C. sativa. P. hybrida inhibited only the high-molecular-weight bands. CONCLUSION: Sensitization to C. sativa with or without symptoms is frequent among patients in Spain sensitized to tomato. C. sativa leaves are a potential allergenic source and their allergens may cross-react with other allergenic sources from plants (fruit peels and pollen).

Usefulness of manufactured tomato extracts in the diagnosis of tomato sensitization: Comparison with the prick-prick method.

BACKGROUND: Commercial available skin prick test with fruits can be negative in sensitized or allergic patients due to a reduction in biological activity during the manufacturing process. Prick-prick tests with fresh foods are often preferred, but they are a non-standardized procedure. The usefulness of freeze-dried extracts of Canary Islands tomatoes, comparing the wheal sizes induced by prick test with the prick-prick method in the diagnosis of tomato sensitization has been analyzed.The objective of the study was to assess the potential diagnostic of freeze-dried extracts of Canary Islands tomatoes, comparing the wheal sizes induced by prick test with the prick-prick method. METHODS: Two groups of patients were analyzed: Group I: 26 individuals reporting clinical symptoms induced by tomato contact or ingestion. Group II: 71 control individuals with no symptoms induced by tomato: 12 of them were previously skin prick test positive to a tomato extract, 39 were atopic and 20 were non-atopic. All individuals underwent prick-prick with fresh ripe peel Canary tomatoes and skin prick tested with freeze-dried peel and pulp extracts obtained from peel and pulp of Canary tomatoes at 10 mg/ml. Wheal sizes and prick test positivity (>/= 7 mm2) were compared between groups. RESULTS: In group I, 21 (81%) out of 26 patients were prick-prick positive. Twenty patients (77%) had positive skin prick test to peel extracts and 12 (46%) to pulp extracts. Prick-prick induced a mean wheal size of 43.81 +/- 40.19 mm2 compared with 44.25 +/- 36.68 mm2 induced by the peel extract (Not significant), and 17.79 +/- 9.39 mm2 induced by the pulp extract (p < 0.01).In group II, 13 (18%) out of 71 control patients were prick-prick positive. Twelve patients (all of them previously positive to peel extract) had positive skin prick test to peel and 3 to pulp. Prick-prick induced a mean wheal size of 28.88 +/- 13.12 mm2 compared with 33.17 +/- 17.55 mm2 induced by peel extract (Not significant), and 13.33 +/- 4.80 mm2 induced by pulp extract (p < 0.05 with peel extract and prick-prick). CONCLUSION: Canary peel tomato extract seems to be as efficient as prick-prick tests with ripe tomatoes to diagnose patients sensitized to tomato. The wheal sizes induced by prick-prick and peel extracts were very similar and showed a high correlation coefficient.

Recently introduced foods as new allergenic sources: sensitisation to Goji berries (Lycium barbarum).

Goji berries (GB) have been introduced in Western diet. Preliminary reports have demonstrated its allergenic capacity. The objectives of the study were to investigate the frequency of sensitisation and the allergens involved. 566 individuals, with respiratory or cutaneous symptoms were skin-prick tested with GB extract. Thirty three were positive (5.8%). 94% were sensitised to other allergens. Specific IgE to GB, peach, tomato and nut-mix was measured. Thirteen individuals from 24 available sera (54.2%) had positive specific IgE. 92.3% of GB positive patients were positive to peach. Seven individuals recognised 8 bands and six recognised a 7kDa band. This band was identified as a LTP by MS/MS. Cross-reactivity was demonstrated with tomato, tobacco, nutmix, Artemisia pollen and purified Lyc e 3 and Pru p 3. GB are a new allergenic source with high prevalence of sensitisation. LTP seems to be the major allergen involved in sensitisation and cross-reactivity.

In vitro cross-reactivity between tomato and other plant allergens.

BACKGROUND: Cross-reactivity among fruits and different pollen and fruit species has been extensively reported. OBJECTIVES: To investigate the in vitro cross-reactivity between tomato and pollen, fruit, and latex extracts and to identify the proteins involved. METHODS: A serum pool was prepared from 18 individuals residing on the Spanish Mediterranean coast (9 men and 9 women; mean [SD] age, 27.4 [10.1] years) who had positive skin prick test reactions to tomato peel. Extracts from 10 pollens, 12 fruits, and latex were tested. Levels of specific IgE to each extract were measured. The allergenic profile was evaluated by means of immunoblot. The percentage of inhibition between extracts and tomato peel extract was analyzed by means of CAP inhibition, and the allergens implicated were elucidated by immunoblot inhibition. RESULTS: For pollens, the highest specific IgE values were obtained for grasses. Most pollen extracts showed a capacity of inhibition similar to that of tomato peel extract; high percentages were obtained with Artemisia vulgaris and Poa pratensis. The most strongly inhibited allergens in tomato corresponded to bands of 32 and 45 kDa. For fruits, the highest value of specific IgE was detected for peach. High percentages of inhibition were obtained with peach and hazelnut. No inhibition was detected with latex. Peach, chestnut, and melon inhibited high molecular weight bands (32 and 45 kDa) and a band of approximately 10 kDa. CONCLUSIONS: Cross-reactivity between tomato and pollen and fruit extracts has been demonstrated. Allergens with a high molecular weight range seem to be responsible in pollen extracts. A 10-kDa band seems to be responsible in Platanus acerifolia, Salsola kali, peach, chestnut, and melon.

The use of raw or boiled crustacean extracts for the diagnosis of seafood allergic individuals.

BACKGROUND: Seafood plays an important role in human nutrition and is responsible for severe hypersensitivity reactions. OBJECTIVE: To evaluate how the cooking process may alter the in vivo and in vitro allergenicity of these extracts. METHODS: Raw and boiled extracts of shrimps and 2 types of lobsters were manufactured. Boiled extracts were prepared after the raw material was boiled for 15 minutes in phosphate-buffered saline. Raw and boiled extracts were homogenized and extracted for 4 hours. Afterward, the extracts were centrifuged, dialyzed, filtered, and freeze-dried. Seventy-eight patients were skin prick tested with these raw and boiled extracts. Specific IgE against the 6 extracts was measured by enzyme-linked immunosorbent assay (ELISA). Immunoblots and ELISA inhibition studies were performed with a pool of sera. RESULTS: In vivo results showed that boiled extracts induced statistically significant larger wheals than raw extracts. More patients with positive results were also detected with boiled extracts. In vitro experiments by direct ELISA confirmed the in vivo results. The protein content in the boiled extracts decreased, and important differences were detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Cross-reactivity experiments showed that both types of extracts retained similar allergenic characteristics, even if the immunoblots revealed some differences in IgE binding. CONCLUSIONS: More patients were identified using boiled extracts of shrimp and American and spiny lobsters than with raw extracts. The wheal sizes of the skin test reactions and specific IgE levels were also significantly greater using boiled extracts. The use of boiled extracts seems to be more effective in diagnosing seafood allergy.

Genetically engineered hybrid proteins from Parietaria judaica pollen for allergen-specific immunotherapy.

BACKGROUND: Despite the use of conventional allergen-specific immunotherapy in clinical practice, more defined, efficient, and safer allergy vaccines are required. OBJECTIVE: The aim of the study was to obtain hypoallergenic molecules by deleting B-cell epitopes, which could potentially be applied to Parietaria judaica pollen allergy treatment. METHODS: Three hybrid molecules (Q1, Q2, and Q3) derived from fragments of the 2 major P judaica pollen allergens, Par j 1 and Par j 2, were engineered by means of PCR. Hybrid structures were compared with their natural components by means of circular dichroism, and their biologic activities were compared by using T-cell proliferation assays. Their IgE-binding activity was determined with Western blotting, skin prick tests, and enzyme allergosorbent and ELISA inhibition tests. RESULTS: The hybrid proteins, especially Q2 and Q3, revealed significantly reduced IgE reactivity compared with the natural allergens, as well as with the whole P judaica extract. Furthermore, in vivo skin prick tests showed that the hybrid proteins had a significantly lower potency to induce cutaneous reactions than the whole P judaica extract. Two (Q1 and Q2) of the 3 hybrid proteins induced a comparable T-cell proliferation response as that produced by the whole extract and natural allergens. CONCLUSION: Considering its reduced anaphylactogenic potential, together with its conserved T-cell reactivity, the engineered Q2 protein could be used in safe and shortened schedules of allergen-specific immunotherapy against P judaica pollen allergy. CLINICAL IMPLICATIONS: Recombinant hybrid Q2 is able to induce T-cell proliferation, thus evidencing a potential therapeutic effect. Its reduced IgE-binding capacity envisages an excellent safety profile.

Allergenicity of 10 different apple varieties.

BACKGROUND: More than 100 apple varieties are consumed worldwide. However, the allergenic composition of most apple varieties has not been fully characterized. OBJECTIVE: To analyze the antigenic and allergenic profiles of 10 different commercially available apple varieties. METHODS: Golden, Golden Perlim, Reineta, Reineta Parda, Fuji, Verdedoncella, Granny-Smith, Pink Lady, Royal Gala, and Starking apple varieties were carefully peeled. Peels were individually extracted and centrifuged, and the supernatants were collected, dialyzed, filtered, frozen, and freeze-dried. The extracts were characterized using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblots. Protein content was measured using the Lowry-Biuret method. Twenty-two Spanish patients with oral allergy syndrome after apple ingestion were included in the study. Specific IgE to all apple varieties and birch pollen was evaluated. Eleven patients underwent skin prick testing using extracts of Golden, Starking, and Reineta Parda varieties to determine differences in their in vivo allergenicity. RESULTS: The antigenic profile of the 10 varieties showed differences using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. A 9-kDa band, which could correspond to Mal d 3, was visualized in all the extracts. The Starking variety had the highest protein content. Higher specific IgE values were also obtained for the Starking variety, and the lowest values were for Reineta Parda and Royal Gala. The largest wheals were obtained in all patients with the Starking variety, and the smallest with Reineta Parda. Fourteen patients (64%) recognized Mal d 3 in the Golden variety using immunoblots; 6 patients (27%), who also had specific IgE to Betula, recognized bands with higher molecular weights. CONCLUSIONS: We demonstrated differences in the antigenic and allergenic profiles of the analyzed varieties and a significant variation in Mal d 3 content.

Occupational allergic rhinoconjunctivitis and asthma to goat and cross-reactivity with cow epithelium.

BACKGROUND: The development of sensitization and symptoms after the inhalation of epithelial allergens is common. OBJECTIVES: To investigate the allergic response (in vivo and in vitro) of 3 individuals clinically sensitive and occupationally exposed to cow and goat and to evaluate the allergenic cross-reactivity between cow and goat epithelium extracts. METHODS: Three patients--a butcher and 2 doctors in veterinary medicine--were evaluated. These patients reported allergic respiratory symptoms after occupational exposure to goats and cows. Extracts were prepared from epithelia of both animals. All the patients underwent organ-specific allergen challenges with cow and goat extracts. Four nasal and 2 bronchial challenges were conducted following standardized procedures. RESULTS: All 3 patients had positive challenge results with the offending allergen extract. Specific IgE to goat allergens was detected in all patients. Several IgE-binding bands were detected. Inhibition assays (enzyme allergosorbent test and immunoblots) confirmed moderate-to-high cross-reactivity between goat and cow extracts. CONCLUSIONS: We confirm clinical sensitivity and specific IgE binding to goat and cow allergens in occupationally exposed individuals. There was good correlation among the clinical history, exposure, and the laboratory findings.

Occupational asthma to carmine in a butcher.

UNLABELLED: Hypersensitivity to carmine (E120) has been identified as a cause of food intolerance and occupational asthma. We present a case of occupational asthma following exposure to carmine in a manufacturer of sausages and review the literature. CASE REPORT: A 42-year-old non-atopic male presented with a 5-year history of rhinoconjunctivitis and asthma on occupational exposure to food additive dusts. Symptoms increased after work. The patient had been exposed for more than 20 years. METHODS: Skin prick tests were performed with a battery of common inhalant allergens and spices. Cochineal, carmine lake and additive mixes used by the patient were extracted and subsequently used for skin prick test, bronchial provocation and in vitro measurements (specific IgE, Western blot and chromatographic fractionation). RESULTS: Prick tests were positive to carmine and carmine-containing additives; carmine-specific IgE and bronchial challenge tests were also positive (PC20 = 0.0004 mg/ml and 1.6 kU/l). Western blot showed IgE binding to bands of about 30 kDa on cochineal extract and a diffuse pattern at 40-97 kDa on carmine. This result was confirmed by gel filtration chromatography and dot blot. Carmine completely inhibited IgE binding to cochineal extract. DISCUSSION: Carmine is a potential sensitizer in an occupational setting: 18 cases of occupational asthma have been described to date. Carmine allergens are poorly defined; in general, proteins from cochineal not removed by the extraction process are considered as the main allergens in carmine. Our results are consistent with this, but show that these proteins may be subject to chemical modification.

Characterization and improvement of apple extracts for the diagnosis of apple IgE-mediated allergy.

BACKGROUND: The production process of reliable fruit extracts is not well established. OBJECTIVES: To improve the overall quality of apple extracts by reducing protein loss during the manufacturing process and to evaluate the improved extracts using in vivo and in vitro experiments. METHODS: Two types of extracts were prepared from peels of Golden Delicious apples (Malus domesticus). Extract A was extracted, 1:2 wt/vol, for 30 minutes at 40 degrees C in 0.01 M phosphate-buffered saline, and extract B was extracted, 1:2 wt/vol, in phosphate-buffered saline with 20% polyvinylpolypyrrolidone and 2-mmol/L EDTA. Both extracts were filtered, dialyzed in 3.5-kDa dialysis membranes, and lyophilized. The antigenic and allergenic profiles were analyzed using immunoblot and enzyme-linked immunosorbent assay. Nine patients clinically sensitive to apples and 12 controls underwent skin testing with both extracts. RESULTS: Extracts A and B had dry weight yields of 0.71% and 1.86% and protein contents of 104.6 and 257 microg/mg of freeze-dried material, respectively. A steady and progressive loss of protein, greater in extract A than in extract B, was detected at different intervals during the manufacturing process of both extracts. Extract B produced larger wheal sizes than extract A (P = .008). Enzyme-linked immunosorbent assay inhibition results confirmed that extract B had a greater inhibition capacity than extract A. CONCLUSIONS: A progressive loss of protein content occurs during the manufacturing of apple extracts. Wheal sizes induced by extract B were significantly larger than those induced by extract A and prick-by-prick solutions. Extract B was also more potent in vitro than extract A.

Diagnosis of Alternaria alternata sensitization with natural and recombinant Alt a 1 allergens.

BACKGROUND: Diagnosis of Alternaria alternata sensitization is hampered by the variability and complexity of fungal extracts, and thus simplification of the diagnostic procedures with purified allergens should be pursued. OBJECTIVE: We sought to compare A alternata extract and purified natural Alt a 1 (nAlt a 1) and recombinant Alt a 1 (rAlt a 1) allergens for their diagnostic value. METHODS: Forty-two patients allergic to A alternata , 10 atopic patients with negative skin prick test responses to A alternata extract, and 10 healthy subjects were investigated. Skin prick tests and determination of specific IgE levels were performed with nAlt a 1 and 2 different types of rAlt a 1: rbAlt a 1, expressed in Escherichia coli , and ryAlt a 1, expressed in the yeast Yarrowia lipolytica . RESULTS: Prevalence for Alt a 1, Alt a 2, and Alt a 11 by IgE dot-blot testing was 98%, 0%, and 15%, respectively, and therefore Alt a 1 was used as a marker for A alternata sensitization. Immunoblotting and inhibition analysis showed no IgE-binding differences between nAlt a 1 and rAlt a 1. The whole group of patients with allergy to A alternata had positive skin test reactions to purified allergens at 100 microg/mL, whereas no false-positive reactions were detected. Natural or ryAlt a 1 elicited a similar response in skin tests compared with A alternata extract, although a reduced reactivity was observed with rbAlt a 1. Specific IgE levels to nAlt a 1 or rAlt a 1 showed significant correlation and similar sensitivity and specificity. CONCLUSIONS: Alt a 1, either in its natural or recombinant form, is sufficient for a reliable diagnosis of A alternata sensitization and induces skin prick reactivity comparable with that produced by A alternata extract.