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The study of cross-reactivity in allergy is key to both understanding. the allergic response of many patients and providing them with a rational treatment In the present study, protein microarrays and a co-sensitization graph approach were used in conjunction with an allergen microarray immunoassay. This enabled us to include a wide number of proteins and a large number of patients, and to study sensitization profiles among members of the LTP family. Fourteen LTPs from the most frequent plant food-induced allergies in the geographical area studied were printed into a microarray specifically designed for this research. 212 patients with fruit allergy and 117 food-tolerant pollen allergic subjects were recruited from seven regions of Spain with different pollen profiles, and their sera were tested with allergen microarray. This approach has proven itself to be a good tool to study cross-reactivity between members of LTP family, and could become a useful strategy to analyze other families of allergens.

Background: Shellfish allergy is a long-lasting disorder usually persisting throughout life. Despite its high prevalence, there is limited information about allergenic shrimp proteins., Objective: Characterization of shrimp allergens., Methods: Fifty-two adults and children with a history of immediate allergic reactions to shrimp and elevated serum IgE to shrimp were selected for this study. Tryptic digests from a 20-kd IgE-binding protein were analyzed by LC-MS/MS, identifying the protein as a sarcoplasmic-calcium-binding protein. cDNA encoding sarcoplasmic calcium-binding protein (SCP) from a shrimp cDNA library (Litopenaeus vannamei) was amplified by PCR, cloned into an expression vector, and sequenced. Recombinant SCP was tested with patients' sera. ELISA inhibition experiments determined the fraction of total shrimp IgE recognizing SCP. A functional assay with a rat basophilic leukemia cell line was used to determine the capacity for mediator release induced by SCP., Results: Immunoblotting demonstrated IgE binding by 31 of 52 (59.6%) of the sera to a 20-kd shrimp protein. The protein was identified as a SCP. Amplified cDNA encoding SCP was isolated and sequenced. Open reading frame translation provided the complete amino acid sequence of shrimp SCP. Recombinant SCP was recognized by serum IgE from 20 of 52 (38.4%) subjects, of whom 17 of 20 (85%) were children. ELISA inhibition of pooled sera IgE reactivity to BS extract using recombinant SCP was significant (as high as 79%). For some subjects, mediator release induced by recombinant SCP was higher than that induced by recombinant tropomyosin., Conclusion: We have identified and cloned a new shrimp allergen, Lit v 4.0101, an SCP, which appears to be of particular importance in the pediatric population.

Background: Shellfish allergy is a prevalent, long-lasting disorder usually persisting throughout life. Few options are available for treatment, and avoidance is the only therapy recommended., Objective: We sought to identify relevant crustacean allergens for use as diagnostic and safe immunotherapeutic agents for subjects with shellfish allergy., Methods: Thirty-eight patients were selected with immediate allergic reactions to shrimp and increased shrimp-specific serum IgE levels. One-dimensional and 2-dimensional electrophoresis of shrimp extracts were followed by IgE immunoblotting. Protein identification was done with matrix-assisted laser desorption/ionization-mass spectrometry and Edman sequencing. A cDNA library was generated from white pacific shrimp (Litopenaeus vannamei) and screened with primers designed on the basis of internal sequences obtained from 2-dimensional tryptic digests. Full-length cDNA clones were isolated from the library and sequenced. Recombinant protein was expressed and tested with sera from patients with shrimp allergy., Results: Immunoblotting demonstrated IgE binding to a 20-kDa shrimp protein by 21 (55%) of 38 sera. Tryptic digestion of the protein followed by matrix-assisted laser desorption/ionization-mass spectrometric analysis and Edman sequencing identified it as a myosin light chain (MLC). Screening of the shrimp cDNA library resulted in isolation of a novel protein cDNA. Open reading frame translation provided the amino acid sequence of a new allergenic shrimp protein with high similarity to Bla g 8 (cockroach MLC). Recombinant protein was recognized by 17 patients, confirming the allergenicity of shrimp MLC., Conclusions: We have identified and cloned a new major shrimp allergen, Lit v 3.0101, an MLC protein.

Background: Green kiwifruit allergy is on the rise. However, no surveys testing purified major kiwi allergens have been carried out in a large population, including both kiwi-sensitized [skin prick test (SPT)-positive] and truly kiwi-allergic patients., Objective: To isolate major kiwifruit allergens, and to explore their relevance by in vitro and in vivo methods in a large kiwi-sensitized and -allergic population., Methods: A large group (n=92) of kiwi-sensitized patients with different clinical symptoms were selected, and double-blind, placebo-controlled, food challenges to kiwi were performed in 52 of them. The three major IgE-binding proteins from kiwifruit extracts were isolated and characterized by N-terminal amino acid sequencing and molecular size and glycosylation analysis. The allergenic potency of the three kiwi allergens, and of avocado Pers a 1 as a model allergen associated with the latex-fruit syndrome, was tested by specific IgE quantitation, immunodetection assays and SPTs., Results: The isolated kiwifruit allergens were identified as actinidin Act d 1, glycosylated thaumatin-like Act d 2 and a novel 40 kDa glycoprotein designated as Act d 3.02. Specific IgE to each of the three allergens was found in over 60% of sera from kiwi-sensitized patients, and Act d 1 and Act d 2 induced positive SPT responses in over 50% of the tested patients. A significant link between IgE levels to Act d 1 and Act d 3 and anaphylaxis was uncovered. Avocado Pers a 1 showed an in vitro sensitization prevalence of around 45%, but a low in vivo reactivity., Conclusion: Act d 1, Act d 2 and Act d 3 are major allergens in the population studied. Severe symptoms after kiwi ingestion are associated with high IgE levels to Act d 1 and Act d 3.

Background: Hevea brasiliensis (Hev b) 2 and Hev b 13 have recently been identified as major latex allergens by detecting specific IgE antibodies in >50% of sera from Hev b latex-allergic individuals., Objective: We assessed the prevalence rates for sensitization to extensively purified latex allergens in patients from three diverse geographical areas., Methods: Native Hev b 2, Hev b 5, Hev b 6.01 and Hev b 13 were purified by non-denaturating chromatography and were used in ELISAs to assess sera from 215 latex-allergic patients and 172 atopic non-sensitized controls from Finland, Spain and the United States to detect allergen-specific IgE antibodies., Results: Unexpectedly, even highly purified Hev b 13 contained epitope(s) to which Hev b 6-specific human IgE antibodies bound effectively. Further purification, however, reduced the prevalence of IgE antibody reactivity to low levels: 15%, 5% and 11% for Hev b 2, and 18%, 30% and 27% for Hev b 13 among latex-allergic Finnish, Spanish and American patients, respectively. Interestingly, Finnish patients had a lower prevalence of Hev b 5-specific IgE antibody (28%) as compared with Spanish (49%) and American (71%) patients. The prevalence of Hev b 6.01-specific IgE reactivity was uniformly >50% in all three populations., Conclusion: Neither Hev b 2 nor Hev b 13 appear to be major latex allergens when evaluated in serological assays using highly purified allergens. The reason(s) for the observed differences in published sensitization rates in various geographic regions requires further study. The purity of the allergen preparations has a marked impact on the accuracy of latex-specific IgE antibody detection in epidemiological studies and in the serological diagnosis of latex allergy.

Background: Chestnut allergy has been almost exclusively considered in the context of the latex-fruit syndrome. Chestnut allergens not linked to latex hypersensitivity have not been studied., Objective: We sought to explore whether differences in sensitization patterns between chestnut allergy with or without associated latex-fruit syndrome can be detected., Methods: Twelve patients sensitized to chestnut but not to latex and 3 control patients with latex-chestnut allergy were analyzed. A major chestnut allergen was purified and characterized. IgE immunoblotting, specific IgE determination, and skin prick tests with 5 isolated allergens involved in food allergy or latex-fruit syndrome were also performed., Results: A major 9-kd allergen was detected in chestnut extract, isolated, and identified as lipid transfer protein (LTP) Cas s 8. Specific IgE to this allergen was found in 91% (by means of IgE immunoblotting) and 58% (by means of ELISA) of sera from patients with chestnut but not latex allergy. Moreover, 66% of these patients had positive skin prick test responses to Cas s 8. Additionally, allergenic LTPs from peach fruit and Artemisia vulgaris pollen were also reactive. In contrast, avocado class I chitinase and latex hevein, allergens associated with the latex-fruit syndrome, showed no reaction. The opposite situation was exhibited by patients with latex-chestnut allergy., Conclusions: Patients with chestnut allergy with or without associated latex hypersensitivity present different patterns of major allergens (LTPs and class I chitinases, respectively)., Clinical Implications: LTPs and class I chitinases can be used as diagnostic tools in patients with chestnut allergy to predict whether an associated latex sensitization and a risk of potential cross-reactivity with other plant foods and pollens exist.

Background: Food IgE-mediated allergy to members of the Brassicaceae family has been increasingly reported., Objective: To characterize cabbage-Brassica oleracea var capitata-allergy and its major allergens., Methods: A prospective study was performed, recruiting 17 patients allergic to cabbage, and control subjects. Skin prick tests and double-blind placebo-controlled food challenges were performed. A major allergen was isolated from cabbage by RP-HPLC and characterized by N-terminal amino acid sequencing and matrix-assisted laser desorption/ionization mass spectrometry analysis. Specific IgE determinations, IgE immunoblots, and CAP-inhibition assays were also performed., Results: Skin prick test and specific IgE were positive to cabbage in all patients. Five of them referred anaphylactic reactions when eating cabbage, and in another 5 patients, cabbage allergy was further confirmed by double-blind placebo-controlled food challenge. Most of them showed associated sensitizations to mugwort pollen, mustard, and peach. A 9-kd cabbage IgE-binding protein, Bra o 3, was identified as a lipid transfer protein (LTP) with 50% of identity to peach LTP Pru p 3. Skin prick test with Bra o 3 showed positive results in 12 of 14 cases (86%). On CAP inhibition assays, Bra o 3 managed to inhibit significantly the IgE binding to cabbage, mugwort pollen, and peach. Both Bra o 3 and Pru p 3 were recognized by IgE from the patients' sera., Conclusion: Bra o 3, a cabbage LTP, is a major allergen in this food, cross-reacting with mugwort pollen and with other plant foods, such as peach., Clinical Implications: Cabbage IgE-mediated allergy is a potentially severe condition that can present with other plant food and pollen allergies.

Background: Resistance to pepsin digestion has been claimed to be a characteristic of food allergens that can induce severe adverse reactions. Moreover, pepsin treatment is included in protocols to evaluate the potential allergenicity of transgenic foods. Allergenic plant class I chitinases, such as avocado Prs a 1, are the panallergens involved in the latex-fruit syndrome. Previous reports indicated their susceptibility to simulated gastric fluid (SGF) digestion., Objective: We sought to evaluate the IgE-binding capacity and the in vivo reactivity of the SGF products of the avocado allergen Prs a 1., Methods: Patients with a clinical history of latex-fruit allergy syndrome, a positive skin prick test (SPT) response to Prs a 1, and specific IgE to avocado were selected. Untreated and SGF-digested Prs a 1 samples were analyzed by means of IgE and IgG immunoblotting, IgE immunoblotting and ELISA-inhibition assays, and SPTs. Peptides from SGF-digested samples were fractionated by means of HPLC, characterized by N-terminal amino acid sequencing and matrix-assisted laser desorption/ionization analysis, and tested for in vivo reactivity with SPTs., Results: Neither protein staining nor IgE immunoblotting with a pool of sera from allergic patients resulted in the detection of any band after SDS-PAGE separation of an SGF-digested sample of Prs a 1. However, this sample showed a similar inhibitory potency to that of untreated Prs a 1 in both immunoblot- and ELISA-inhibition assays (up to 70% inhibition of the IgE binding to crude avocado extract) and induced positive SPT responses in 5 of 8 allergic patients. Peptides from SGF-digested Prs a 1 were separated by means of HPLC, and 4 of them reached more than 50% inhibition values when using avocado extract as the solid phase in ELISA-inhibition assays. Reactive peptides were located both in the N-terminal hevein-like domain and in the catalytic domain of Prs a 1. Those corresponding to the hevein-like domain (approximately 5100 d) produced positive SPT responses in 5 of 8 allergic patients, whereas 2 peptides located in the catalytic domain (approximately 1400 and 2500 d) were reactive in 2 or 3 of the 8 patients., Conclusion: Prs a 1 was extensively degradated when subjected to SGF digestion. However, the resulting peptides, particularly those corresponding to the hevein-like domain, were clearly reactive both in vitro and in vivo.

Background: Occupational asthma (OA) can be a debilitating disease even when removal from the workplace is achieved. Today, the "gold standard" in the assessment of OA is the bronchial provocation test (BPT). Induced sputum is a non-invasive method of exploring airway inflammation which can provide additional information about such challenges and thus could be applied in OA diagnosis and monitoring., Methods: We report the study carried out in a grain worker sensitized to Lepidoglyphus destructor (Ld), who suffered from mild asthma at the workplace. Skin prick test and specific serum IgE were measured. Ld-BPT was performed, and the changes in eosinophil rates, and ECP and tryptase levels in induced sputum were studied 30 min and 18 h after Ld-BPT. We also determined the changes in nonspecific bronchial hyperresponsiveness (NSBH), given as PD20 values. To assess the specificity of the changes, we also carried out sputum induction and methacholine challenge after barley-BPT., Results: An isolated immediate response was obtained with Ld-BPT, while barley-BPT was negative. Induced sputum showed higher tryptase levels 30 min after Ld-BPT, and higher eosinophil and epithelial cell percentages and ECP levels 18 h after Ld-BPT. There was also a decrease in methacholine PD20 values after Ld-BPT. Those changes were not observed after barley-BPT., Conclusions: The study of eosinophilic and mast-cell markers in induced sputum provides additional knowledge about the inflammatory process occurring in the airways, suggesting that the study of induced sputum should be considered in the assessment of OA.

Background: Banana allergy has been associated with the latex-fruit syndrome. Several IgE-binding components, the relevant ones being proteins of 30-37-kDa, have been detected in banana fruit, but none of them have been isolated and characterized yet. Objective To purify and characterize the 30-37 kDa banana allergens., Methods: Fifteen patients allergic to banana were selected on the grounds of a latex-allergic population. Prick by prick tests to this fruit were performed. Total and specific IgE to banana were determined. Banana allergens were isolated by affinity chromatography, followed by cation-exchange chromatography. Their characterization includes N-terminal sequencing, enzymatic activity assays, immunodetection with sera from allergic patients and with antichitinase antibodies, and CAP and immunoblot inhibition tests. Skin prick tests with banana extracts and with the purified allergens were also carried out., Results: Two major IgE-binding proteins of 34 and 32 kDa, also recognized by polyclonal antibodies against chestnut chitinases, were immunodetected in crude banana extracts. Purification and characterization of both proteins have allowed their identification as class I chitinases with an hevein-like domain. Each isolated allergen reached inhibition values higher than 90% in CAP inhibition assays, and fully inhibited the IgE-binding by the crude banana extract when tested by an immunoblot inhibition method. The two purified allergens provoked positive skin prick test responses in more than 50% of the banana-allergic patients., Conclusions: Class I chitinases with an hevein-like domain are major allergens in banana fruit. Their presence in other fruits and nuts, such as avocado and chestnut, could explain the cross-sensitization among these foods.

Background: Latex-fruit cross-sensitization has been fully demonstrated. However, the antigens responsible for this "latex-fruit syndrome" have not been identified. We have recently shown that class I chitinases are relevant chestnut and avocado allergens., Objective: We sought to evaluate the in vivo and in vitro reactions of purified chestnut and avocado chitinases in relation to the latex-fruit syndrome., Methods: From a latex-allergic population, eighteen patients allergic to chestnut, avocado, or both were selected. Skin prick tests (SPTs) were performed with crude chestnut and avocado extracts, chitinase-enriched preparations, and purified class I and II chitinases from both fruits. CAP-inhibition assays with the crude extracts and purified proteins were carried out. Immunodetection with sera from patients with latex-fruit allergy and immunoblot inhibition tests with a latex extract were also performed. Eighteen subjects paired with our patients and 15 patients allergic to latex but not food were used as control groups., Results: The chestnut class I chitinase elicited positive SPT responses in 13 of 18 patients with latex-fruit allergy (72%), and the avocado class I chitinase elicited positive responses in 12 of 18 (67%) similarly allergic patients. By contrast, class II enzymes without a hevein-like domain did not show SPT responses in the same patient group. Each isolated class I chitinase reached inhibition values higher than 85% in CAP inhibition assays against the corresponding food extract in solid phase. Immunodetection of the crude extracts and the purified class I chitinases revealed a single 32-kd band for both chestnut and avocado. Preincubation with a natural latex extract fully inhibited the IgE binding to the crude extracts, as well as to the purified chestnut and avocado class I chitinases., Conclusion: Chestnut and avocado class I chitinases with an N-terminal hevein-like domain are major allergens that cross-react with latex. Therefore they are probably the panallergens responsible for the latex-fruit syndrome.

Background: Tobacco is a plant belonging to the Solanaceae family. This plant is usually used as a contact insecticide for several infestations in some areas, such as the Canary Islands. Allergy induced by inhalation of this plant is unusual. Identification of the potential allergen in growing areas is essential., Objective: We report a patient with occupational sensitivity to an aqueous solution of cut tobacco whose clinical manifestations were rhinoconjunctivitis and urticaria. Past medical history was significant for seasonal allergic rhinoconjunctivitis to mugwort pollen and oral allergy syndrome with avocado., Methods: Green tobacco and cured tobacco leaf extracts were prepared, skin prick tests were performed with green tobacco, cured tobacco leaf extracts, and certain aeroallergens. Conjunctival challenge test was carried out with green tobacco and cured tobacco leaf extract. Serum-specific IgE against tobacco leaf was performed by commercial CAP. CAP inhibition experiments were carried out with tobacco and Artemisia vulgaris., Results: Skin prick tests and conjunctival challenge tests with green tobacco and cured tobacco leaf extracts were positive, as well as serum-specific IgE by CAP, indicating an IgE-mediated sensitization. CAP inhibition experiments were carried out and it was found that tobacco, mugwort pollen, and tomato extracts inhibited the binding of the patient's serum to solid-phase tobacco leaf. No inhibition was observed when Alternaria, D. pteronyssinus, and potato were used as control inhibitors. Inhibition of immunoCAP to mugwort was obtained with mugwort and tobacco extracts and no cross-reactivity to D. pteronyssinus was shown., Conclusion: The results suggest that tobacco can induce IgE-mediated reactions that are mediated by the existence of common antigenic epitopes between tobacco and mugwort pollen. This allergy can be a hazard of employment in the agricultural areas.

Background: Atopy is a multifactorial disease, the pathogenesis of which is influenced by both genetic and environmental conditions. Genes in the HLA region have been involved in the control of the IgE response., Objective: In order to investigate whether allergy to house dust mite is associated with HLA in our population, we performed sib-pair analysis in 18 families and a case/control study of 161 non-related individuals., Methods: Levels of total and specific IgE were determined, skin-prick tests were carried out and clinical history was reviewed for every subject in the study. HLA class II typing was performed by the polymerase chain reaction with sequence specific primers., Results: We observed a significant difference from expected values in haplotypes shared by affected sibs; however, the case/control study did not reveal any association with any particular allele., Conclusion: These results suggest that any particular HLA-DRB1/DQA1/DQB1 allele is responsible for the development of allergy to house dust mite in the Spanish population. Some other locus in or close to the HLA region might be involved, e.g., the tumour necrosis factor gene, a possibility that would explain the significant difference from expected values in the segregation of HLA haplotypes.

Background: Carica papaya (CP) trees are widely cultivated in tropical and subtropical areas; however, CP pollen allergy has not been previously described., Objective: To study patients with CP pollen hypersensitivity., Methods: A CP pollen extract was elaborated. Skin prick tests (SPTs) with this extract, as well as with commercial papaya fruit and papain extracts, were performed. Specific IgE levels to CP pollen, papaya fruit, and papain were determined. Specific conjunctival challenge tests to the CP pollen extract were also performed. RAST inhibition studies among CP pollen, papaya fruit, and papain were carried out. Twenty atopic patients were used as a control group for in vivo and in vitro tests., Results: Six patients with clinical histories of seasonal rhinoconjunctivitis or bronchial asthma in relation to CP trees exposure, suggestive of IgE-mediated respiratory allergy, were studied. Commercial SPT and specific serum IgE to papaya fruit and papain were positive in our patients. An IgE-mediated hypersensitivity to a CP pollen extract was demonstrated in all patients, by means of SPTs, specific serum IgE determinations, and conjunctival challenge tests. Control atopic subjects showed negative SPTs, specific IgE, and conjunctival challenge tests to the CP pollen extract. On RAST inhibition studies using CP pollen extract in solid phase, a significant crossreactivity was found among CP pollen, papaya fruit, and papain., Conclusions: Our study suggests that papaya flower pollen is able to induce respiratory IgE-mediated allergy. The existence of common allergens among papaya flower pollen, papaya fruit, and papain has been demonstrated by RAST inhibition.

Background: Several foods associated with the latex-fruit syndrome present relevant allergens of around 30 kd. Neither these components nor any other responsible for the reported cross-reactions have been identified and purified., Objective: We sought to isolate and characterize the 30 kd allergens from avocado fruit and chestnut seed, two of the main allergenic foods linked with latex allergy., Methods: Sera from patients allergic to chestnut and avocado were selected according to clinical symptoms, specific IgE levels, and positive skin prick test responses. Class I and II chitinases were purified by affinity and cation-exchange chromatography and characterized by specific IgE and anti-chitinase immunodetection, immunoblot inhibition assays, enzymatic activity tests, and N-terminal sequencing., Results: Relevant 32 kd allergens were detected by specific IgE immunodetection in both avocado and chestnut crude extracts. The same bands, together with others of 25 kd, were revealed by a monospecific antiserum against class II chitinases. Purification and characterization of the 32 kd allergens from both plant sources allowed their identification as class I chitinases with an N-terminal hevein-domain. The purified allergens fully inhibited IgE binding by the corresponding crude extract when tested in immunoblot inhibition assays. Highly related 25 kd class II chitinases that lack the hevein-like domain were also isolated from the same protein preparations. No IgE-binding capacity was shown by these class II enzymes., Conclusion: Class I chitinases are relevant allergens of avocado and chestnut and could be the panallergens responsible for the latex-fruit syndrome. The hevein-like domain seems to be involved in their allergenic reactivity.

Background: Indoor allergens are common causes of sensitization and asthma. Climatic and home conditions can modify their levels., Objective: We studied the influence of climatic conditions and home characteristics on the exposure to indoor allergens of mite allergic asthmatic subjects in two Spanish cities with different climates (Las Palmas and Pamplona)., Methods: We included 65 subjects diagnosed with asthma caused by Dermatophagoides pteronyssinus. A questionnaire about their dwellings was completed. Home dust samples were collected. Mite (Der p1, Der f1, Der 2) and cat (Fel d1) allergens were measured by a monoclonal-antibodies based ELISA., Results: Characteristics of dwellings were similar in both areas. Der p1 was the main allergen (0-44 micrograms/g). Der p1, Der f1 and Der 2 levels were higher in the homes in Las Palmas (p < 0.001, p < 0.01 and p < 0.001, respectively). Damp homes in Pamplona had higher Der p1 levels, similar to those detected in homes in Las Palmas. Fel d1 levels (0-78.90 micrograms/g) were only related to the presence of cats in the dwelling (p < 0.001)., Conclusions: D. pteronyssinus allergen exposure was influenced by climatic conditions and dampness in homes in temperate regions. Humidity in homes can generate an ideal environment for mite growth despite unfavorable outdoor climatic conditions. Fel d1 levels were only related to the presence of a cat in the house.

Four patients with occupational asthma were studied. All patients were exposed to African maple dust and two of them were also exposed to Ramin dust. Skin tests and bronchial provocation tests with African maple extracts revealed an immediate response in all patients, and the same tests performed with Ramin extracts again revealed an immediate reaction in either exposed or non-exposed patients to Ramin wood dust. Specific IgE antibodies against African maple extracts were demonstrated in all patients as measured by a reverse enzyme immunoassay. Cross reactivity between both woods was demonstrated by a reverse enzyme immunoassay inhibition study. Unexposed persons and exposed asymptomatic workers did not exhibit reactivity to both woods in any of the tests listed above. To the best of our knowledge, this is the first article in which occupational asthma due to Ramin is defined, and cross sensitivity between two different woods is demonstrated.

Latex used in the manufacture of surgical gloves should be included in a list of allergens. It is found in the tree Hevea braziliensis. For approximately the last year, minutes after using surgical gloves, a female doctor had severe pruritus followed by a rash and angio-oedema of the contact areas. During the last 4 months, on opening the glove-bag, she experienced severe rhinitis and respiratory distress. The symptoms ceased in 1 h. standard patch tests and with substances used in the manufacture of rubber were negative. Prick tests with glove and natural latex were strongly positive. The presence of specific IgE against natural latex was demonstrated by means of a histamine release assay as well as by immunoenzymatic methods. The antigen seems to have a MW higher than 30,000 d and is trypsin-sensitive. These facts suggest that the allergen could be a protein present in the "crude natural latex". [ABSTRACT FROM AUTHOR]