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Biomedical subjects

R van Ree

Publications and source records attributed to R van Ree.

At least 55 records · Page 3Linked to original sources
PubMed1998

Standardization of in vivo and in vitro diagnostic procedures in food allergy.

For most foods, true standardization is not yet feasible because there is insufficient information on the relative importance of individual allergens and their variants. Standardization without sufficient information may easily be counterproductive because improvements are less likely to be implemented. In the analysis of natural test material, the following principles apply: 1) RAST inhibition is usually inferior to other means of allergen quantitation. 2) Immunoblot is inefficient for some "important" allergens and overefficient for some "unimportant" allergens and may therefore be deceptive. 3) Single-component assays are the only satisfactory way to describe complex mixtures. Improving the actual food-testing procedure is important, but will not alone result in a reliable diagnostic procedure. Tests for measuring "effect modifiers" will have to be developed in order to predict in vivo reactions to foods.

Allergens↗
PubMed1998

Involvement of the N-terminus of Der p 2 in IgE and monoclonal antibody binding.

The major house dust mite allergen Der p 2 was expressed as a recombinant fusion protein in Escherichia coli either with glutathione-S-transferase as fusion partner or with a poly-histidine tag. Both recombinant fusion proteins failed to react with 3/14 Der p 2-specific monoclonal antibodies (mAbs). When Der p 2 was expressed in yeast with one alanine linked N-terminally to the allergen, no reactivity was observed. When expressed without any fusion partner, all 14 mAbs showed reactivity. The addition of a single N-terminal alanine also disrupted an important epitope for IgE. In RAST inhibitions, an average decrease in inhibitory potency of 72+/-32% was observed (n = 16) with a maximum decrease of 91%. These observations suggest that the N-terminus of Der p 2 is involved in an important epitope for IgE that is disrupted by the addition of one single amino-acid. Recombinant Der p 2 molecules should therefore preferably lack any fusion peptide.

Alanine↗
PubMed1997

Poor biologic activity of cross-reactive IgE directed to carbohydrate determinants of glycoproteins.

BACKGROUND: In our outpatient population, approximately one third of patients sensitized to grass pollen were found to have significant serum levels of anti-peanut IgE in the RAST, without positive peanut skin prick test (SPT) response and without peanut-related allergic symptoms. It was suggested earlier that poor biologic activity of IgE antibodies directed to cross-reactive carbohydrate determinants (CCD) of glycoproteins might explain these discrepancies. OBJECTIVE: In this study we investigated the biologic activity of IgE directed to CCD. METHODS: Sera of 32 patients allergic to grass pollen with significant levels of anti-peanut IgE, a negative response on peanut SPT, and no symptoms of peanut allergy were tested for the presence of anti-CCD IgE. Eleven of these patients with greater than 3.0 IU/ml anti-peanut IgE (patients 1 to 11) were selected together with four control patients allergic to peanut, on the basis of a positive response on peanut SPT and a history of peanut allergy (patients 12 to 15). Inhibition of the peanut RAST was performed by using proteinase K-treated grass pollen extract as a CCD source. Basophil histamine release assays (BHRAs) were performed with peanut extract and the isolated peanut major allergens Ara h 1 and Ara h 2. In addition, intracutaneous tests with peanut extract were performed. RESULTS: In 29 (91%) of 32 patients with discrepant peanut RAST and SPT responses, anti-CCD IgE (> or =0.1 IU/ml) was detected. In patients 1 to 11 almost complete inhibition of the peanut RAST with CCD was found (94.3% +/- 5.5%; mean +/- SD). In contrast, in the patients allergic to peanut only partial inhibition (59%) was found in one subject (p = 0.002, Mann-Whitney test). In the BHRAs and the intracutaneous tests of patients with discrepant peanut RAST and SPT results, reactivity was found only at high concentrations of peanut allergens. When related to specific IgE levels, reactivity to peanut allergens in the BHRAs of these patients was found to be at least a factor of 1000 less when compared with reactivity to control inhalant allergens. CONCLUSION: We conclude that cross-reactive IgE directed to carbohydrate determinants of glycoproteins, as found in grass pollen-sensitized patients, has poor biologic activity. It can therefore cause positive RAST results without apparent clinical significance.

2S Albumins, Plant↗
PubMed1997

Allergy to Rosaceae fruits without related pollinosis.

BACKGROUND: Rosaceae fruit allergy is frequently associated with birch pollinosis in Central and Northern Europe and with grass pollen allergy in Central Spain. The main cross-reactive structures involved for birch pollinosis are Bet v 1 and profilin, and for grass pollinosis they are profilin and carbohydrate determinants. Rosaceae fruit allergy can occasionally be observed in patients without pollinosis. OBJECTIVE: We investigated the clinical presentation and the allergens involved in allergy to Rosaceae fruit without pollinosis. METHODS: Eleven patients from Central Spain allergic to apples, peaches, and/or pears but not to pollens were compared with 22 control subjects with combined grass pollen and fruit allergy. Skin prick tests and RASTs to apple, peach, and pear were performed. Cross-allergenicity was studied by RAST inhibition. Bet v 1 was tested with an indirect RAST, and profilin was tested in skin prick tests, histamine release, and RAST. RESULTS: Rosaceae fruit allergy without pollinosis is severe with 82% of patients reporting systemic symptoms, mainly anaphylaxis (73%), whereas oral symptoms are less frequent (64%). Anaphylactic shock was observed in 36% of patients. The fruit allergens involved showed cross-reactivity among Rosaceae species but were not related to profilin or Bet v 1. Ninety-one percent of patients with combined grass pollinosis and fruit allergy reported oral allergy, 45% reported systemic symptoms, 18% reported anaphylaxis, and 9% reported anaphylactic shock. CONCLUSION: Allergy to Rosaceae fruits in patients without a related pollen allergy is a severe clinical entity. Profilin- and Bet v 1-related structures are not involved in Rosaceae fruit allergy without pollinosis.

Adolescent↗
PubMed1997

Lack of lysozyme activity of natural and yeast-derived recombinant Der p 2.

For Dermatophagoides pteronyssinus a number of allergens have been reported. Although the function of several allergens is known, that of the house dust mite allergen Der p 2 is unknown. A role as lysozyme has been suggested. We tested a yeast-derived recombinant Der p 2 for its lysozymatic activity. This recombinant allergen and affinity-purified natural Der p 2 lacked this enzymatic activity. Whole-body mite extract retained its lysozymatic activity after removal of the group 2 allergen by monoclonal antibody depletion. Analysis of spent medium revealed the reciprocal: it contained group 2 allergen, but lacked lysozymatic activity. Together, these data demonstrate that mite lysozyme and Der p 2 are different components of mite extract.

Allergens↗
PubMed1996

False-positive skin prick test responses to commercially available dog dander extracts caused by contamination with house dust mite (Dermatophagoides pteronyssinus) allergens.

BACKGROUND: In an outpatient population, a high frequency of positive skin prick test responses to dog dander was found in the absence of detectable IgE to dog dander in the RAST. The majority of these patients were sensitized to house dust mites (Dermatophagoides pteronyssinus) and had no obvious dog-related allergic symptoms. These findings prompted us to investigate whether dog dander skin test preparations are contaminated with house dust mite allergens in amounts sufficient to cause false-positive skin prick test responses in patients sensitized to house dust mites. METHODS: Antigen detection assays with monoclonal and polyclonal antibodies were used to determine concentrations of the major allergen Can f 1 from dog dander and the major allergens Der p 1 and Der p 2 from house dust mites in five commercially available dog dander skin prick test preparations (A to E). RESULTS: Can f 1 concentrations varied for the different extracts (A: 170 micrograms/ml, B: 11.1 micrograms/ml, C: 13.3 micrograms/ml, D: 3.8 micrograms/ml, and E: 59.4 micrograms/ml). Der p 1 was detectable in all extracts (A: 33.4 ng/ml, B:5.1 ng/ml, C:29.6 ng/ml, D: 0.4 ng/ml, and E: 1.9 ng/ml), and Der p 2 was detectable in some of the commercially available dog dander skin prick test preparations tested (A: 31.3 ng/ml, B: 3.0 ng/ml, and C: 7.5 ng/ml). The median house dust mite threshold in the skin prick test was found to be 5.8 ng/ml, of Der p 1 (range, 3.5 to 20.8 ng/ml) in nine patients tested. CONCLUSION: Contamination of commercially available dog dander skin prick test preparations with the major allergens (Der p 1 and Der p 2) of the house dust mite (D. pteronyssinus) was demonstrated. These contaminations cause false-positive responses to skin prick tests with dog dander in patients sensitized to house dust mite.

Allergens↗
PubMed1996

Specific IgE and IgG4 immune responses to tetanus and diphtheria toxoid in atopic and nonatopic children during the first two years of life.

BACKGROUND: In order to investigate, whether atopic and nonatopic children show differences in their specific IgE and IgG4 immune responses to tetanus (T) and diphtheria (D) antigens, we studied 538 children who had been followed from birth on and from whom records had been kept of all immunizations. METHODS: The prevalence of eczema and asthma was registered at regular intervals and the cumulative incidence of symptoms was determined at 24 months of age. Total serum IgE and specific IgE to a panel of nine allergens as well as T- and D-specific IgE and IgG4 were determined from the 24-months blood samples. RESULTS: Our results show that both atopic and nonatopic children are capable of mounting high levels of toxoid-specific IgE antibody responses. Children with cord blood IgE > 0.9 kU/1, serum IgE 10-100 kU/1 and > 100 kU/1 and at least one sensitization to an allergen at 24 months of age have significantly higher IgE responses to T and D (p < 0.001). In contrast, specific IgG4 antibody concentrations to T and D were not significantly different in children with elevated total IgE levels at 24 months. No differences in subgroups of children with or without early symptoms of atopy were observed. CONCLUSIONS: Our data indicate that IgE responses to toxoids such as T and D are not limited to infants with clinical manifestations of atopy in the first 2 years of life but are related to immunological parameters of atopy.

Asthma↗
PubMed1996

Possible induction of food allergy during mite immunotherapy.

Sera of 17 patients receiving immunotherapy for house-dust mite allergy were tested for IgE antibodies against snail and shrimp. Serum samples were taken at the start of immunotherapy and 14-20 months later. While the average IgE response to mite, Der p 1, and Der p 2 did not alter significantly, the average response to snail showed a significant increase. This included two conversions from negative to strongly positive. These novel IgE antibodies against snail were shown to be cross-reactive with mite. Three patients had a positive RAST for shrimp. For one of them, a strong increase of IgE against shrimp (and snail) was observed. In 2/3 snail/shrimp-positive sera, IgE antibodies against the cross-reactive allergen tropomyosin from mite, snail, and shrimp were demonstrated. A clear IgE response to snail (> 10% binding in a snail RAST) was confirmed by a positive skin prick test (SPT) for 6/10 patients. The two patients with antitropomyosin IgE also had a positive SPT for shrimp, and demonstrated the oral allergy syndrome (OAS) after eating shrimp. The observations in this study indicate that house-dust mite immunotherapy is accompanied by the induction of IgE against foods, including tropomyosin-reactive IgE. Food allergy (OAS) was observed in patients that had IgE antibodies against this cross-reactive allergen. In conclusion, induction of IgE during mite immunotherapy might occasionally cause allergy to foods of invertebrate animal origin.

Allergens↗
PubMed1996

Asthma after consumption of snails in house-dust-mite-allergic patients: a case of IgE cross-reactivity.

A group of 28 patients from Italy was studied who had asthma after consumption of snail. All patients also had asthma and/or rhinitis caused by house-dust mite. RAST analyses confirmed the combined sensitization to snail and mite. In a few sera, IgE antibodies reactive with other foods of invertebrate origin (mussel and shrimp) were detected. RAST inhibition showed that most IgE antibodies against snail were cross-reactive with house-dust mite. In contrast, the mite RAST was not significantly inhibited by snail. This indicates that house-dust mite was the sensitizing agent. Immunoblot analyses revealed multiple bands in snail extract recognized by IgE. In contrast to what has been described for cross-reactivity between shrimp and mite, tropomyosin played only a minor role as a cross-reactive allergen in these patients. The observations in this study indicate that snail consumption can cause severe asthmatic symptoms in house-dust-mite-allergic patients. It might, therefore, be advisable to screen mite-allergic asthma patients for allergy to snail and other invertebrate animal foods.

Adult↗
PubMed1995

Lol p XI, a new major grass pollen allergen, is a member of a family of soybean trypsin inhibitor-related proteins.

BACKGROUND: Monoclonal antibodies were obtained against an unknown allergen from Lolium perenne grass pollen. The allergen had an apparent molecular mass of 18 kd on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Earlier immunoblotting studies had shown that carbohydrate-specific IgG antibodies recognize an antigen of similar size. OBJECTIVE: We sought to characterize the allergen biochemically and immunologically. METHODS: The amino acid sequence of the allergen was determined by automated Edman degradation, and its monosaccharide composition was determined by gas chromatographic analysis. A panel of 270 grass pollen-positive sera was assessed in a RAST with the purified allergen. Protease digestion (proteinase K) and chemical deglycosylation (trifluoromethane sulfonic acid) were used to distinguish between carbohydrate and peptide epitopes for IgE antibodies. RESULTS: The allergen was shown to be a glycoprotein with a molecular mass of 16 kd, of which 8% is carbohydrate. Its amino acid sequence shares 32% homology with soybean trypsin inhibitor (Kunitz) but lacks its active site. No homology was found with known grass pollen allergens, hence it was designated Lol p XI. A high degree of homology (44%) was found with a tree pollen allergen, Ole e I, the major allergen of olive pollen. More than 65% of grass pollen-positive sera had IgE against Lol p XI. IgE reactivity was demonstrated both with the carbohydrate moiety and the peptide backbone. CONCLUSIONS: Lol p XI is a new major grass pollen allergen carrying an IgE-binding carbohydrate determinant. Lol p XI is structurally related to the major allergen from olive pollen.

Allergens↗
PubMed1995

Pollen-related allergy to peach and apple: an important role for profilin.

BACKGROUND: Birch pollinosis is often accompanied by allergy to fruits such as peach and apple. Bet v I is of major importance as cross-reactive allergen for this combined allergy. We studied a group of patients with combined grass pollinosis and fruit allergy from an area virtually without birch trees. OBJECTIVE: The aim of this study was to investigate the possible involvement of profilin and carbohydrate groups as cross-reactive structures in pollen and fruits. METHODS: RAST inhibition was performed to measure cross-reactive IgE to pollen and fruits. The presence of IgE against profilin was determined in a RAST with purified grass profilin, and IgE against carbohydrate structures was determined in a RAST with proteinase K-digested grass pollen extract. The biologic activity of IgE in response to profilin was tested by in vitro histamine release and skin prick tests. RESULTS: IgE against fruits was shown to be largely cross-reactive with grass pollen. The majority of the patients had IgE against profilin (12 of 16) and carbohydrate structures (9 of 10). Profilin was shown to have biologic activity, in both histamine release and skin prick tests. CONCLUSION: Profilin is an important allergen for patients with combined grass pollen/fruit allergy in areas without birch trees.

Adolescent↗
PubMed1995

Multiplicity of cross-reactive epitopes on Bet v I as detected with monoclonal antibodies and human IgE.

Six monoclonal antibodies against Bet v I, the major cross-reactive allergen of birch pollen (Betula verrucosa), were obtained. Four did not react with fruits, but two monoclonal antibodies (mAbs) (5H8 and 9C11) were reactive with apple and other fruits. These two cross-reactive antibodies reacted with identical or overlapping sites, but differed in their relative degree of cross-reactivity toward various fruits and hazelnut. Cross-reactive human IgE antibodies reacted with a nonoverlapping epitope, as indicated by results of a two-site radioimmunoassay (RIA) with the fruit-reactive mAb 9C11. By isoelectric focusing (IEF) in conjunction with immunoblotting, a maximum of seven isoforms could be distinguished. Depletion of birch-pollen extract for Bet v I with the most reactive mAb (7F7) removed approximately 95% of the IgE cross-reactivity between birch pollen and apple extract. The remaining 5% cross-reactive material was still capable of inhibiting the binding of IgE to apple allergen completely, and was reactive with mAbs 5H8 and 3C4. By means of IEF/immunoblot, it was shown that these mAbs recognize an isoform of Bet v I that is poorly, if at all, recognized by mAb 7F7. These results illustrate the heterogeneity of Bet v I, both with respect to the cross-reactive sites as well as to the backbone structure. This type of heterogeneity has possible implications for the use of monoclonal antibodies in allergen standardization.

Adult↗