The clinical and immunological effects of Pru p 3 sublingual immunotherapy on peach and peanut allergy in patients with systemic reactions

BACKGROUND

The peach non-specific lipid transfer protein, Pru p 3, is the primary sensitizer in fruits and responsible for severe reactions in the Mediterranean area. Peach allergy is frequently associated with other allergies such as peanut. Therefore, it is important to assess how specific immunotherapy to Pru p 3 could affect both peach and peanut tolerance.

OBJECTIVES

To evaluate peach and peanut desensitization and immunological changes after 1 year of Pru p 3 sublingual immunotherapy (SLIT) in patients with systemic allergic reactions to peach and/or peanut.

METHODS

Forty-eight peach allergic patients, 36 treated with SLIT and 12 non-treated, were monitored for 12 months. Treated patients were subclassified as peanut allergic (Group A), sensitized (Group B) or tolerant (Group C). SLIT effect was evaluated by skin prick test (SPT) reactivity and food challenge. Immunological changes were evaluated by monitoring sIgE and sIgG4 levels and basophil reactivity.

RESULTS

After 1 year of SLIT, the weal area in SPT significantly decreased and a significant increase in peach threshold in treated patients was observed (P < 0.001). Patients in Group A showed a significant decrease in peanut SPT weal area and an increase in peanut threshold (P < 0.001). Immunological changes were observed in treated patients only, with a significant decrease in sIgE and a parallel increase in sIgG4, sIgG4/sIgE and basophil reactivity for both Pru p 3 and Ara h 9.

CONCLUSIONS AND CLINICAL RELEVANCE

After 1 year, Pru p 3 SLIT induces both desensitization and immunological changes not only for peach but also for other food allergens relevant in the induction of severe reactions such as peanut.

Anaphylaxis to hidden potato allergens in a peach and egg allergic boy

More than 170 foods have been identified as being potentially allergenic. However, a minority of these foods cause the majority of reactions. Sweets are frequently implicated in allergic reactions in children with cow's milk, egg, nuts or fruits allergy, and they are the most relevant foods investigated as responsible allergens. We report an anaphylactic reaction to candies in an egg and peach allergic boy. We performed a study to identify responsible allergens for the reaction. We investigated hidden egg and peach allergens in the candies, but they were not found. Finally, the causative allergen resulted to be a vegetable protein from potato peel. We diagnosed a new allergy in our patient and Sol t 4 was identified as the responsible allergen of the anaphylactic reaction. We conclude that responsible allergens should always be studied and identified in whatever allergic reaction in order to prevent new reactions.

Influence of age on IgE response in peanut-allergic children and adolescents from the Mediterranean area

BACKGROUND

Peanut allergens are common triggers of food allergy. Analyses of sensitization patterns, relationships with other allergens, clinical symptoms, and variation with age are needed. We studied sensitization to Ara h 2, Ara h 9, and Pru p 3 in a peanut allergic children/adolescents and the relationship with peach and pollen.

METHODS

Peanut allergic patients aged between 1 and 20 years old were classified into two groups: A) allergic to peanut only and B) allergic to peach and peanut. The IgE response was measured to Ara h 2, Ara h 9, and Pru p 3.

RESULTS

Of 964 subjects evaluated, 28% were allergic to peanut. From this group, 68% were also sensitized to pollen. Urticaria was the most frequent entity followed by anaphylaxis and OAS. Fifty-eight percent had Ara h 2- and/or Ara h 9-specific IgE. More than half reported symptoms with peanut alone (Group A) and 35% to peanut and peach (Group B). We observed significant differences in sex, age, onset of symptoms, and sensitization to Artemisia between groups. IgE response to Ara h 2 was more frequent in Group A, and Ara h 9 and Pru p 3 in Group B. We observed a decrease in sensitization to Ara h 2 and an increase to Ara h 9 and Pru p 3 with increasing age.

CONCLUSION

Peanut allergy is frequent in subjects with allergy to plant foods, with Ara h 2 and Ara h 9 being two important allergens. In younger patients, Ara h 2 predominates over Ara h 9. The reverse was observed in older patients.

Immune Polarization in Allergic Patients: Role of the Innate Immune System

Allergens come into contact with the immune system as components of a very diverse mixture. The most common sources are pollen grains, food, and waste. These sources contain a variety of immunomodulatory components that play a key role in the induction of allergic sensitization. The way allergen molecules bind to the cells of the immune system can determine the immune response. In order to better understand how allergic sensitization is triggered, we review the molecular mechanisms involved in the development of allergy and the role of immunomodulators in allergen recognition by innate cells.

Basophil response to peanut allergens in Mediterranean peanut-allergic patients

Ara h 1, Ara h 2, and Ara h 3 are important sensitizers in peanut allergy. Ara h 9 has also been shown to be relevant in the Mediterranean area. We evaluated the basophil response to peanut allergens and Pru p 3 in Mediterranean patients: Group 1, peanut and peach allergy; Group 2, peanut allergy and tolerance to peach; Group 3, peach allergy and tolerance to peanut; Group 4, nonallergic subjects that tolerate both peanut and peach. Compared to controls (Group 4), there was an increased basophil activation with Ara h 2 (P = 0.031) and Pru p 3 (P = 0.009) in Group 1 and with Ara h 1 (P = 0.016), Ara h 2 (P = 0.001), and Ara h 9 (P = 0.016) in Group 2. Importantly, only Ara h 2 showed an increased activation (P = 0.009) in Group 2 compared to Group 3. Ara h 2 is the best discriminating allergen for peanut allergy diagnosis in a Mediterranean population showing two patterns: patients also allergic to peach, responding to Ara h 2 and Pru p 3, and patients allergic only to peanut, responding to Ara h 1, Ara h 2, and Ara h 9.

Wheat allergens associated with Baker's asthma

Baker's asthma is a frequent occupational allergic disease caused mainly by inhalation of cereal flour, particularly wheat flour. This review deals with the current diagnosis and immunomodulatory treatments, as well as the role of wheat allergens as molecular tools to enhance management and knowledge of this disease. The review also discusses the current status of several salt-soluble proteins (albumins and globulins)--cereal alpha-amylase/trypsin inhibitors, peroxidase, thioredoxin, nonspecific lipid transfer protein, serine proteinase inhibitor, and thaumatin-like protein-as well as salt-insoluble storage proteins (prolamins, namely, gliadins and glutenins) as allergens associated with baker's asthma. Finally, current limitations to using these proteins as molecular tools for diagnosis and immunotherapy are highlighted.

Recombinant lipid transfer protein Tri a 14: a novel heat and proteolytic resistant tool for the diagnosis of baker's asthma

BACKGROUND

Baker's asthma is an important occupational allergic disease. Wheat lipid transfer protein (LTP) Tri a 14 is a major allergen associated with wheat allergy. No panel of wheat recombinant allergens for component-resolved diagnosis of baker's asthma is currently available.

OBJECTIVE

To evaluate the potential role of recombinant Tri a 14 as a novel tool for the diagnosis of baker's asthma, and to test the heat and proteolytic resistance of the wheat LTP allergen.

METHODS

A cDNA encoding Tri a 14 was isolated and sequenced, the recombinant allergen produced in Pichia pastoris and purified by chromatographic methods. Physicochemical and immunological comparison of the natural and recombinant forms of Tri a 14 was carried out by N-terminal amino acid sequencing, matrix-assisted laser desorption/ionization mass spectrometry, circular dichroism (CD) analysis, IgE immunodetection, and specific IgE determination and ELISA-inhibition assays using a pool or individual sera from 26 patients with baker's asthma. Thermal denaturation and simulated gastrointestinal digestion of both Tri a 14 forms were checked by spectroscopic and electrophoretic methods, respectively, and biological activity by basophil activation test (BAT).

RESULTS

Natural and recombinant Tri a 14 were similarly folded, as indicated by their nearly identical CD spectra and heat denaturation profiles. A high interclass correlation coefficient (0.882) was found between specific IgE levels to both Tri a 14 proteins in individual sera from baker's asthma patients, but a slightly lower IgE-binding potency of rTri a 14 was detected by ELISA-inhibition assays. Natural and recombinant Tri a 14 elicited positive BAT in two and one out of three patients, respectively. Heat denaturation profiles and simulated gastrointestinal digestion assays indicated that Tri a 14 displayed a high heat and digestive proteolytic resistance, comparable to those of peach Pru p 3, the model food allergen of the LTP family.

CONCLUSIONS

Recombinant Tri a 14 is a potential tool for baker's asthma diagnosis, based on its physicochemical and immunological similarity with its natural counterpart. Wheat Tri a 14 shows a high thermal stability and resistance to gastrointestinal digestion.

Plant non-specific lipid transfer proteins as food and pollen allergens

Several members of the plant non-specific lipid transfer protein (LTP) family have been identified as relevant allergens in foods and pollens. These allergens are highly resistant to both heat treatment and proteolytic digestion. These characteristics have been related with the induction of severe systemic reactions in many patients, and with the possibility of being primary sensitizers by the oral route. A specific geographical distribution pattern of sensitization to LTP allergens has been uncovered. This allergen family is particularly important in the Mediterranean area, but shows a very limited incidence in Central and Northern Europe. The potential role in the plant, as well as the biochemical and allergenic properties of the LTP family, are reviewed here.

cDNA cloning and heterologous expression of the major allergens from peach and apple belonging to the lipid-transfer protein family

BACKGROUND

Lipid-transfer proteins (LTPs) have been identified as major allergens of Rosaceae fruits in populations living in areas virtually free of Fagales trees, such as several Mediterranean communities. Pru p 3 and Mal d 3, the allergens from peach and apple, respectively, have a main clinical relevance in these areas.

OBJECTIVE

To isolate and characterize cDNAs for Pru p 3 and Mal d 3, and to produce recombinant Pru p 3 in the yeast Pichiapastoris.

METHODS

cDNAs for both allergens were isolated by polymerase chain reaction using nondegenerated primers. Expression of Pru p 3 was performed in P. pastoris using the pPIC 9 vector. The recombinant product was purified by gel-filtration chromatography followed by RP-HPLC. Immunodetection and immunoblot inhibition assays were carried out with sera from peach-allergic patients.

RESULTS

The cDNAs for both Pru p 3 and Mal d 3 showed a 273 open reading frame coding for the 91 amino acid mature polypeptides. The deduced amino acid sequences exhibited N-terminal regions fully identical to those previously determined for the natural peach and apple allergens. Pru p 3 was expressed in P. pastoris at 20 mg/L of culture medium. The recombinant allergen showed the same N-terminal sequence (plus a glutamic acid added for proper extracellular expression) and apparent molecular size as natural Pru p 3. Both the recombinant and natural forms of Pru p 3 displayed similar immunoglobulin (Ig)E-binding capacity in immunodetection and immunoblot inhibition assays.

CONCLUSIONS

Comparison of the complete primary structures of mature Pru p 3 and Mal d 3 deduced from their corresponding cDNA clones supports the close relationship between both allergens. Recombinant Pru p 3 binds IgE in vitro like its natural counterpart. Therefore, it can be a useful tool for specific diagnosis and structural studies.

The role of plant panallergens in sensitization to natural rubber latex

Latex allergy represents an increasing occupational problem, mainly among healthcare workers. An association between latex allergy and hypersensitivity to some plant foods, particularly fruits (the latex-fruit syndrome), has been established. Class I chitinases with an N-terminal hevein-like domain from avocado, chestnut, banana and other foods, and latex hevein seem to be the allergens responsible for the cross-reactions involved in the latex-fruit syndrome. The potential role of other latex allergens, such as profilin, Hev b 5, Hev b 7 and beta-1,3-glucanases, in the co-sensitization to latex and plant foods is also discussed.

Cross-reactions in the latex-fruit syndrome: A relevant role of chitinases but not of complex asparagine-linked glycans

BACKGROUND

Cross-reactions between latex and plant foods (mainly fruits) have been widely reported. Although the cross-reactive components have not been well identified, class I chitinases seem to be the most credible candidates in chestnut, avocado, and banana.

OBJECTIVE

We sought to evaluate the potential role of chitinases and complex glycans as cross-reactive determinants linked to latex-food allergy.

METHODS

Extracts from 20 different plant foods and from latex were obtained. These preparations were immunodetected with anticomplex glycans and antichitinase sera raised in rabbits, as well as with sera from patients with latex-fruit allergy and sera from patients allergic to latex without food allergy. Immunoblot inhibition assays were carried out by using a purified class I chitinase from avocado or latex extract as inhibitors.

RESULTS

Reactive proteins of approximately 30 to 45 kd (putative class I chitinases) were recognized by both specific polyclonal antibodies to chitinases and sera from patients with latex-fruit allergy in chestnut, cherimoya, passion fruit, kiwi, papaya, mango, tomato, and flour wheat extracts. Prs a 1, the major allergen and class I chitinase from avocado, and the latex extract strongly or fully inhibited IgE binding by these components when tested in immunoblot inhibition assays. Additional bands of 16 to 20 kd, 23 to 28 kd, and 50 to 70 kd were detected by the antichitinase serum but not with the patients' pooled sera. The putative 30- to 45-kd chitinases present in different food extracts did not react with a pool of sera from subjects allergic to latex but not to fruit. Very different immunodetection patterns were produced with the anticomplex glycan serum and the sera from allergic patients.

CONCLUSIONS

Putative class I chitinases seem to be relevant cross-reactive components in foods associated with the latex-fruit syndrome, but do not play a specific role in allergy to latex but not to fruit. Cross-reactive carbohydrate determinants are not important structures in the context of latex-fruit cross-sensitization.

Class I chitinases as potential panallergens involved in the latex-fruit syndrome

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.

Class I chitinases with hevein-like domain, but not class II enzymes, are relevant chestnut and avocado allergens

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.