Anna Cistero-Bahima

The non‐specific lipid transfer protein, Ara h 9, is an important allergen in peanut

Background Plant food allergy in the Mediterranean area is mainly caused by non‐specific lipid transfer proteins (nsLTP). The aim of this study was to characterize peanut nsLTP in comparison with peach nsLTP, Pru p 3, and assess its importance in peanut allergy.

Identification of a plane pollen lipid transfer protein (Pla a 3) and its immunological relation to the peach lipid-transfer protein, Pru p 3

Background An association between plane tree pollen allergy and plant food allergy has been described, but the cross‐reacting allergens have not yet been identified. The aim of this study was the identification of homologous non‐specific lipid‐transfer proteins (nsLTPs) in plane pollen, and to investigate its immunological relationship with the peach LTP, Pru p 3.

A critical assessment of allergen component-based in vitro diagnosis in cherry allergy across Europe.

Background Food allergy to cherry occurs throughout Europe, typically with restricted oral reactions in the central and northern parts but with frequent systemic reactions in the Mediterranean region. Previous studies have demonstrated insufficient sensitivity of commercially available cherry extract reagents in the diagnosis of cherry allergy.

Lettuce anaphylaxis : Identification of a lipid transfer protein as the major allergen

Background:  Allergy to plant‐derived foods is associated with birch pollinosis in central and northern Europe. Symptoms elicited are usually limited to the oropharyngeal system. By contrast, in the Mediterranean area, allergy to the same foods manifests more frequently with systemic reactions caused by nonspecific lipid transfer proteins (nsLTP), independently of an associated pollinosis.

Enhancement of hazelnut extract for IgE testing by recombinant allergen spiking

Background:  Hazelnuts are a common cause of food allergic reactions. Most hazelnut allergic individuals in central and northern Europe are sensitized to Cor a 1, a member of the PR‐10 protein family, while the lipid transfer protein Cor a 8 acts as a major allergen in the south of Europe. Other allergens, including profilin and seed storage proteins, may be important in subgroups of patients. Reliable detection of specific IgE in the clinical diagnosis of food allergy requires allergen reagents with a sufficient representation of all relevant allergen components. Some reported observations suggest that natural hazelnut extract may not be fully adequate in this respect.

Comparison of IgE-binding capacity, cross-reactivity and biological potency of allergenic non-specific lipid transfer proteins from peach, cherry and hazelnut.

Background: Whether the observed clinical pattern of non-specific lipid transfer protein (nsLTP)-mediated food allergies is attributable to a primary sensitization by Pru p 3 from peach and subsequent cross-reactivity with Rosaceae- and non-Rosaceae-derived foods expressing homologous allergens is still unclear. Objective: To investigate the allergenic properties of nsLTPs from Rosaceae and non-Rosaceae foods. Methods: In peach-, cherry- or hazelnut-allergic patients, prevalence of sensitization, IgE-binding capacity, cross-reactivity and allergenic potency of Pru p 3 was compared with Pru av 3 (cherry) and Cor a 8 (hazelnut). Results: Frequency of sensitization to corresponding nsLTPs was 88, 85, and 77% in peach-, hazelnut- and cherry-allergic patients, respectively. Concomitant allergic reactions to cherry and hazelnut were reported in 51 and 44% of peach-allergic patients, respectively. In contrast to cherry allergy, hazelnut allergy was not strictly associated to peach allergy. Sensitization to Cor a 8 or Pru av 3 was strongly correlated with IgE reactivity to Pru p 3, even when subjects tolerated peach. Specific IgE was highest for Rosaceae LTPs, and cross-inhibition experiments confirmed a stronger IgE-binding capacity of Pru p 3 than Cor a 8. The biological potency of Pru p 3 and Pru av 3 was similar but stronger for both nsLTPs than that of Cor a 8. Conclusion: Clinical cross-reactivity of food-allergic patients in the Mediterranean area is likely attributed to a primary sensitization to Pru p 3 and serological cross-reactivity with homologous food nsLTPs. In comparison to Cor a 8, Rosaceae nsLTPs showed a stronger IgE-binding capacity and allergenic potency indicating a different epitope pattern.

An Observational Study on Outgrowing Food Allergy during Non-Birch Pollen-Specific, Subcutaneous Immunotherapy

Background: Birch pollen-specific immunotherapy (SIT) decreases allergy to foods containing birch pollen-homologous allergens. Cross-reactivity was also observed between plane tree pollen and some vegetable foods. Objective: The aim of this study was to evaluate the outgrowing of food allergy by patients suffering from vegetable food allergy associated with plane tree pollinosis (rhinoconjunctivitis and/or asthma) during plane tree pollen SIT. Methods: An observational and prospective study was conducted in 16 adult patients suffering from vegetable food allergy (hazelnut, walnut, lettuce, peach and cherry) and from plane tree pollinosis receiving plane tree pollen SIT for 1 year. Open oral challenges with the implicated food were performed before and after SIT. Blood samples were drawn for measurement of pollen- and food-specific IgE and IgG4 before and after treatment. Results: Plane tree SIT resulted in a significant decrease in food allergy, since the mean food quantity provoking objective symptoms increased from 2.19 to 13.74 g (p < 0.05), and 6 of the 11 patients tolerated the highest level (25 g) of the challenged food after plane tree SIT. Laboratory data also showed a decrease in IgE levels and an increase in IgG4 levels after immunotherapy. Conclusion: SIT with plane tree pollen has a positive impact on food allergy in plane tree pollen-allergic subjects.

Relevance of the recombinant lipid transfer protein of Hevea brasiliensis: IgE-binding reactivity in fruit-allergic adults.

BACKGROUND Lipid transfer proteins (LTPs) are relevant allergens in certain plants. The role of the LTP of Hevea brasiliensis in the latex-fruit syndrome is widely unknown. OBJECTIVE To study IgE reactivity with recombinant Hevea LTP in sera of fruit-allergic adults with and without natural rubber latex (NRL) allergy. METHODS An LTP-specific complementary DNA of H brasiliensis leaves was amplified, subcloned into the pMAL expression system, and analyzed. The recombinant protein was coupled to ImmunoCAP, and the IgE-binding properties were studied in sera of 10 NRL-allergic patients without symptoms to fruit and 48 atopic patients with fruit allergy. Eleven of these 48 patients were also allergic to NRL, 14 displayed sensitization to NRL without symptoms on NRL exposure so far, and 23 had neither symptoms nor IgE antibodies to NRL. RESULTS After expression in Escherichia coli, a soluble maltose-binding protein-rHev b 12 fusion protein was isolated and coupled to ImmunoCAP to determine rHev b 12 specific IgE reactivity. rHev b 12 specific IgE binding was found in 3 fruit-allergic patients with NRL sensitization (0.68, 0.88, and 0.96 kU/L) and in 3 fruit-allergic patients without NRL sensitization (1.58, 2.25, and 2.27 kU/L). The remaining 52 serum samples and all maltose-binding protein control test results were negative (< 0.35 kU/L). CONCLUSIONS In these patients, rHev b 12 specific IgE reactivity seems to result from common cross-reactive epitopes with some of the fruit LTPs tested and underscores only an involvement in co-recognition. No clinical relevance of IgE binding to the LTP of H brasiliensis in association with NRL allergy was detected.

Molecular cloning and immunological characterisation of potential allergens from the mould Fusarium culmorum.

BACKGROUND High quality and stability are essential requirements of commercial allergen preparations. Recently we have demonstrated the very low stability of protein allergens in an extract of the ubiquitous mould Fusarium culmorum. OBJECTIVE The present study was performed to identify, isolate and characterise allergens of F. culmorum as a basis for a stable allergenic reference material. In addition, the significance of IgE binding to carbohydrate structures in the natural allergen source was investigated. METHODS Sera of 52 subjects with suspected mould allergy were used to determine the IgE binding capacity of a commercial F. culmorum extract and an in-house extract by immunoblotting and enzyme allergo sorbent test (EAST). Binding of IgE-antibodies to putative carbohydrate structures located on glycoproteins was verified by periodate treatment of blot strips prior to immunodetection. A complementary (c)DNA expression library of F. culmorum was prepared and screened for IgE-binding clones using sera from F. culmorum-sensitive individuals. Positive clones were isolated, and the open reading frames were subcloned into expression vectors to produce recombinant proteins in E. coli. The recombinant proteins were tested for their IgE reactivity by immunoblotting and EAST. RESULTS Using the in-house extract for EAST and immunoblot experiments 44% (23/52) of the sera were found to contain F. culmorum-specific IgE antibodies. Compared to the in-house extract, nearly all IgE-reactivties in the range of 15-30kD were lacking in the commercial preparation as examined by immunoblot analysis and only 10% (5/52) of the sera were found to contain F. culmorum-specific IgE by EAST. IgE binding to putative carbohydrate structures was observed in the high molecular weight range in approximately 50% (12/23) of the IgE-positive sera by both extracts. Three IgE binding clones were isolated from the cDNA-library. One clone (Fus c 1) is homologous to the highly conserved 60S acidic ribosomal protein P2 described as minor allergen in other moulds. The second (Fus c 2) shows high similarity (64%) to a respiratory allergen from the basidiomycete Coprinus comatus (Cop c 2). The third clone (Fus c 3) was not related to known proteins. With sera from 26 individuals sensitised to F. culmorum the IgE prevalence of recombinant proteins rFus c 1, rFus c 2 and rFus c 3 was found to be 35, 50, and 15%, respectively. CONCLUSIONS F. culmorum may represent an underestimated source of aeroallergens. In contrast to highly labile and poorly standardised F. culmorum extracts, the new recombinant allergens may serve as stable allergenic reference material. A combination of rFus c 1 and rFus c 2 is suitable to diagnose 81% of F. culmorum-sensitised subjects. IgE reactivity to putative carbohydrate structures is relatively frequent, and can not be detected by these allergens.

Aspirin desensitization in the treatment of antiphospholipid syndrome during pregnancy in ASA-sensitive patients

Problem  Antiphospholipid syndrome (APS) is associated with thrombosis and poor pregnancy outcome in the presence of antiphospholipid antibodies (aPL). Patients with aPL have a high risk of foetal loss. However, with low‐dose aspirin (acetylsalicylic acid; ASA) in combination with subcutaneous heparin, the chances of full‐term delivery increase. Nevertheless, ASA treatment is avoided in pregnant, ASA‐sensitive women with APS.