Identification of the major water/salt insoluble wheat proteins involved in cereal hypersensitivity

Background Several studies have investigated water/salt soluble proteins which comprise 50% of the proteins in wheat. The remaining 50% of wheat proteins, are water/salt insoluble proteins of which there is limited information on their role in cereal hypersensitivity. Objectives To investigate the allergenicity of the water/salt insoluble gliadin and glutenin proteins (prolamins). Methods RAST, electrophoresis and Western blotting were used to identify water/salt insoluble wheat allergens. Competitive RAST inhibition was conducted to investigate cross-reactivity between prolamins and water/salt soluble wheat proteins. Results Specific IgE to α-gliadin and to total glutenins were detected in all sera. IgE to β-, γ-, fast ω-, and slow ω-gliadin were present in lower numbers of sera. Prolamin allergens of 90–11 kDa were identified by immunoblotting. Water/salt soluble proteins crossreacted with a-gliadin and total glutenins. Conclusions Individuals who are hypersensitive to water/salt soluble wheat proteins produce specific IgE to water/salt insoluble wheat proteins. Western blotting has shown that gliadins, glutenins and proteins with similar molecular weights as the endogenous water/salt soluble wheat enzyme inhibitors are important allergens. Alpha and fast ω- are the most allergenic gliadins. The water/salt insoluble proteins share cross-reacting epitopes with water/salt soluble proteins. These data show that the numbers of proteins involved in the development of cereal hypersensitivity is greater than previously believed and that the development of specific IgE to α-gliadin may in part depend on the presence of cross-reacting antibodies to water/salt soluble flour allergens.     

Immunoglobulin‐E‐binding epitopes of wheat allergens in patients with food allergy to wheat and in mice experimentally sensitized to wheat proteins

Background At present, B cell epitopes involved in food allergy to wheat are known only for a few allergens and a few categories of patients. Objective To characterize the epitopes of different wheat kernel allergens: α‐, γ, ω2, and ω5‐gliadin, a low‐molecular‐weight (LMW) glutenin subunit, and a lipid transfer protein (LTP1) recognized by allergic patients and by sensitized mice and provide further understanding of the role of structure in determining allergic response. Methods Sera were obtained from 39 patients suffering from food allergy to wheat. BALB/c mice were sensitized to gliadins or LTP1 by intraperitoneal immunizations. Continuous epitopes bound by IgE were delineated by the Pepscan technique. The response to reduced, alkylated LTP1 was compared with that of the native form to evaluate the importance of protein folding on IgE reactivity. Results Few continuous epitopes of LTP1 reacted with IgE from allergic patients and mice, but one of them was common to several patients and sensitized mice. The unfolded protein was not recognized by either patient or mouse IgE, emphasizing the major role of LTP1 folding and discontinuous epitopes in IgE‐binding. In contrast, many continuous epitopes were detected by patient and mouse IgE especially for an ω5‐gliadin, which is an unstructured protein, and to a lesser extent, for the other gliadins and a LMW‐glutenin subunit. Conclusion and Clinical Relevance The conformation of LTP1 appeared to have a strong impact on the type of IgE‐binding epitopes elicited by this protein in both man and mouse. The responses in mice sensitized to gliadins or LTP1 were sufficiently comparable with the human response in terms of IgE‐binding epitopes to provide support for the use of the mouse model in further investigations. Cite this as: S. Denery‐Papini, M. Bodinier, F. Pineau, S. Triballeau, O. Tranquet, K. Adel‐Patient, D.A. Moneret‐Vautrin, B. Bakan, D. Marion, T. Mothes, H. Mameri and D. Kasarda, Clinical & Experimental Allergy, 2011 (41) 1478–1492.     

Study of IgE antigenic relationships in hypersensitivity to hydrolyzed wheat proteins and wheat-dependent exercise-induced anaphylaxis

BACKGROUND: Wheat is involved in different forms of respiratory, food and contact allergy. The IgE of patients generally reacts with various flour proteins. It is not known if antigenic relationships could explain some of these reactions and if proteins could be involved in different pathologies. METHODS: Two sera were selected as representative of patients with either wheat-dependent exercise-induced anaphylaxis (WDEIA) or hypersensitivity to hydrolyzed wheat proteins (HHWP). Their IgE specificity was studied with wheat, barley and rye proteins, using immunoblot, and immunoblot inhibition with recombinant gamma-3 hordein. This protein was chosen for its cross-reactivity with omega-5 gliadin, a major allergen in WDEIA. RESULTS: The IgE from both sera strongly reacted with natural and recombinant gamma-3 hordein but displayed different patterns of reactivity with wheat, barley and rye proteins. Those from the WDEIA patient showed expected reactions with omega-5 gliadin, gamma-35 and gamma-75 secalins, but also with wheat low-molecular-weight glutenin subunits (LMW-GS), and not with C hordeins. On the contrary, IgE from a HHWP patient reacted with C hordeins, various omega gliadins, and gamma-75 secalin, but very weakly with gamma-35 secalin and LMW-GS. Recombinant gamma-3 hordein inhibited strongly but not totally the WDEIA patient's IgE binding to prolamins. No such inhibition could be observed for the HHWP patient's IgE. CONCLUSIONS: At least part of the reactions of prolamins with the IgE from the WDEIA patient was due to antigenic homologies. The occurrence of cross-reacting carbohydrates was unlikely. These common IgE epitopes were not involved in the pathology of the HHWP patient.     

The use of transglutaminase in the reduction of immunoreactivity of wheat flour

The immune response of wheat flour modified by the treatment with transglutaminase under different conditions of temperature, incubation periods and the ratio of enzyme/wheat flour was investigated. The particular wheat protein fractions were examined for the immune reaction by the use of an indirect non-competitive ELISA. Commercially available antibodies, namely, monoclonal antihuman IgG and monoclonal antihuman IgE conjugates with alkaline phosphatase and human sera with elevated IgG as well as rabbit sera against QQQPP peptide were tested. The highest decrease in gliadins immunoreactivity was observed for wheat flour modified under following conditions: temperature 37°C, 18 h of incubation and the ratio enzyme/wheat flour 1:10 000. For all rabbit sera examined the residual immunoreactivity of glutenins was found to be below 30% of the level measured for the untreated protein. The large decrease in allergenicity of glutenins leads to the conclusion that wheat flour modified by treatment with transglutaminase may be used as a constituent of food products destined for people with a classic food allergy, i.e. the allergy elicited by that protein fraction.     

Genetic differences in omega-gliadins involved in two different immediate food hypersensitivities to wheat

BACKGROUND: Anti-gliadin IgE are expressed in patients with food allergy associated to skin immediate hypersensitivity to hydrolyzed wheat proteins (IHHWP). It is not known if they react with omega5-gliadins, the major allergens in wheat dependant exercise-induced food anaphylaxis (WDEIA), encoded on wheat chromosomes 1B. METHODS: Unmodified gliadins from 14 wheat varieties expressing most of the 1B omega-gliadin alleles, were immunoprobed after SDS-PAGE and blotting, with four sera from patients with IHHWP, and two with WDEIA. Gliadins reacting with IgE were visualized using chemiluminescence and identified according to their mobility and typical SDS-PAGE pattern. The resulting signal was also measured to compare their IgE reactivity. RESULTS: IHHWP and WDEIA sera exhibited distinct patterns of reactivity. IgE of patients with IHHWP reacted mainly with all omega-gliadins alleles and one gamma-gliadin encoded respectively on chromosomes 1D and 1B, but not with any omega5-gliadins alleles as for WDEIA. A few other reactive alleles of omega-gliadins were encoded on chromosomes 1A. Unassigned additional bands of the whole gliadin pattern were also reactive. The four patients with IHHWP exhibited almost the same pattern of reactivity. Main differences concerned band reactivity which modulated the overall reactivity of each wheat variety. CONCLUSIONS: The IgE epitopes involved in IHHWP and WDEIA are different. This suggests that the protein state and the route of exposure to very similar gluten structures, probably orientate the pattern of epitope reactivity and the wheat food allergy manifestations.     

Clinical research on specific IgE and IgG4 antibodies in allergic children. Correlation specific IgE and IgG4 antibodies to food allergens to other allergic factors

We examined the correlation specific IgE and IgG4 antibodies to food allergens to other allergic factors in 150 asthmatic children by Multiple Factor Analysis-Type II. The following results were obtained. 1) 3 explanation variables (IgE RIST, Eosinophil count, Family history of allergy) had the strong influence power to 8 objective variables of food allergens. 2) By calculating the category score of explanation variables, the high IgE RAST score to Dermatophagoides farinae group had the strong influence power to the high score groups of IgE RAST and IgG4 antibody titers to food allergens. The fact indicated the linkage between specific IgE and IgG4 antibodies to food allergens to specific IgE antibody to Dermatophagoides farinae. 3) In the same way, the severe group of asthma had the strong influence power to the high score groups of IgE RAST and IgG4 antibody titers to food allergens, and specific IgG4 antibody group had a same directivity of specific IgE antibody group to the other allergic factors. So specific IgG4 antibody may play a "role of reaginic antibody".     

Immunoglobulin E antibodies to ingested cereal flour components: studies with sera from subjects with asthma and eczema

The specificity of immunoglobulin E for different cereal grain proteins was investigated using sera from twenty paedialric patients with asthma and/or eczema. Close correlations were observed between radioallergosorbent test values for grain extracts of wheat, rye and barley, and, to a lesser extent, oats. Of the different wheat flour fractions tested, the globulins and glutenins consistently bound higher levels of IgE than the gliadins and albumins. This is in contrast both with bakers' asthma (an allergy to inhaled flour where the albumins are important allergens) and with coeliac disease (in which gliadin is the most toxic fraction). Partial digestion of the flour proteins largely removed their ability to bind IgE, An analytical technique of identifying allergens after gel isoelectric focusing demonstrated that many different flour proteins were involved.     

Western blot analysis of water-soluble wheat flour (Triticum vulgaris) allergens.

Water-soluble wheat flour allergens were analyzed using the western blot technique. The sera of 130 bakers (42 with wheat flour allergy, 88 without allergy) were analyzed for IgE, IgG, and IgG4 binding towards wheat flour allergens. Three major allergens with molecular weights of 47, 17, and 15 kD were identified (Tri v Bd 47, Tri v Bd 17, and Tri v Bd 15; IUIS allergen nomenclature) by their ability to bind IgE from approximately 50% of the allergic sera. The specificity of the IgG was mostly directed against three high molecular weight components (134, 122, and 98 kD). In contrast, IgE and IgG4 was found frequently against the major allergens. 40% of healthy donors versus 12% of the asthmatic bakers had no detectable IgG4 against wheat flour extract. The biological activity of the water-soluble wheat flour components has been shown by their ability to induce histamine release from basophil leukocytes obtained from patients with bakers' asthma. The release of histamine from basophil leukocytes significantly correlated with the presence of IgE antibodies against wheat flour components of 47, 17 and 15 kD. A regulatory role of wheat flour specific IgG4 in allergic diseases could not be evaluated by western blot analysis.     

The investigation of asthmatic children by multiple factor analysis. II. The influence of 17 allergic factors on atopic dermatitis and allergic rhinitis in asthmatic children

We investigated possible influence of 17 allergy-associated factors on atopic dermatitis and allergic rhinitis using Multiple factor analysis in 150 asthmatic children. Atopic dermatitis was complicated in ninety-seven cases and allergic rhinitis in ninety-seven cases. 17 allergy-associated factors were as follows: 1) sex, 2) age, 3) onset age of asthma, 4) family history of allergy, 5) peripheral eosinophil counts, 6) IgE RIST, 7) IgE RAST score to egg white, 8) IgE RAST score to milk, 9) IgE RAST score to soybean, 10) IgG4 antibody titers to egg white, 11) IgG4 antibody titers to milk, 12) IgG4 antibody titers to soybean, 13) IgE RAST score to house dust, 14) IgE RAST score to Dermatophagoides farinae, 15) severity of asthma, 16) exercise-induced asthma, 17) atopic dermatitis or allergic rhinitis. We concluded as follows: 1) Factors which more strongly influenced both atopic dermatitis and allergic rhinitis were IgE RAST score to D.f., positive family history of allergy, IgE RIST and eosinophil counts. 2) Combination with high levels of IgG4 antibody to 3 food allergens such as egg-white, milk and soybean and IgE RAST to egg-white has a strong influence on atopic dermatitis, but high levels of IgG4 antibody to 3 food allergens except high level of IgG4 antibody to soybean have a weak influence on allergic rhinitis.     

IgE antibodies to wheat flour components Studies with sera from subjects with bakers' asthma or coeliac condition

Sera from two subjects with bakers' asthma and six patients with coeliac condition were examined for the presence of IgE antibodies with specificities for wheat flour components. Sera were studied using the radioallergosorbent test (RAST) together with whole flour and thirteen purified and partially purified flour fractions. IgE antibodies to a number of flour components were demonstrated in the allergic bakers' sera, but the strongest reactivities were observed with wheat albumins and globulins. A more detailed examination of the flour water-soluble proteins using RAST inhibition methods demonstrated that albumins were more reactive with the allergic sera than the globulins. Apart from the results with the water-soluble proteins, the two sera showed a different pattern of reactivity with the other flour preparations. No IgE antibodies to whole flour or any of the flour components, including A gliadin, were found in the coeliac sera. Failure to detect wheat gluten- or gliadin-specific IgE antibodies indicates that IgE-mediated reactions are not important in the pathogenesis of coefiac condition. Levels of total IgE in the sera from the coeliac subjects were elevated and, with two of the sera, some success was achieved in identifying the allergens responsible for the elevation. We propose that elevation of serum IgE may frequently occur in coeliac condition and may arise due to an increased uptake of antigens via the damaged intestinal mucosa.     

Identification of IgE-binding epitopes on gliadins for patients with food allergy to wheat

BACKGROUND: Food allergy to wheat induces different symptoms as atopic eczema/dermatitis syndrome (AEDS), urticaria and more severe reactions as wheat-dependent exercise-induced anaphylaxis (WDEIA). Different gliadin classes are involved in this allergy but IgE-binding epitopes are known only on omega5-gliadins and for WDEIA cases. OBJECTIVES: The aim of the study was to identify IgE-binding epitopes on several gliadin classes and for several patients with different symptoms and ages. METHODS: Eleven sera were analysed by pepscan with overlapping synthetic peptides. RESULTS: Sera from five patients with anaphylaxis, urticaria or WDEIA, displayed strong IgE-binding to sequential epitopes of the repetitive domains of alphabeta, gamma, omega2 or omega5-gliadins with two immunodominant epitopes on omega5-gliadin and a consensus motif of the type QQX1PX2QQ (X1 being L, F, S or I and X2 Q, E or G). One patient allergic to deamidated wheat proteins also had IgE to a repetitive peptide of gamma and omega2-gliadins of the type QPQQPFP. Sera from four patients with AEDS detected no linear epitopes on gliadins, despite the fact that they contained specific IgE to alpha, beta, gamma or omega-gliadins. One child with AEDS recognized cysteine-containing sequences in the nonrepetitive domains of alphabeta and gamma-gliadins. CONCLUSION: B epitopes in wheat allergy were different from B epitopes of coeliac disease. Differences exist in IgE-binding epitopes between patients with food allergy to wheat. IgE from those suffering from WDEIA, anaphylaxis and urticaria detected sequential epitopes in the repetitive domain of gliadins whereas IgE from AEDS patients probably recognized conformational epitopes.     

IgE binding to soluble and insoluble wheat flour proteins in atopic and non-atopic patients suffering from gastrointestinal symptoms after wheat ingestion

BACKGROUND: The involvement of IgE-mediated hypersensitivity reactions in the genesis of gastrointestinal symptoms after ingestion of foods containing wheat has been rarely reported. OBJECTIVE: To detect IgE specifically binding to wheat proteins in the sera of atopic and non-atopic patients suffering from gastrointestinal symptoms after ingestion of wheat and to evaluate the reliability of skin prick test and CAP in the diagnosis of food allergy to wheat. METHODS: The sera of patients (10 atopic and 10 non-atopic) previously diagnosed as suffering from irritable bowel syndrome and complaining of symptoms after wheat ingestion were analysed by immunoblotting for IgE binding to water/salt-soluble and insoluble wheat flour proteins. RESULTS: All the atopic patients and only one of the non-atopic patients were positive to wheat CAP. For the patients tested, skin prick test was positive for all the atopic patients and for only one of the non-atopic patients. However, immunoblotting experiments showed the presence of specific IgE to wheat proteins in all the patients. Ten out of 11 of the wheat CAP-positive patients had IgE binding to a soluble 16-kDa band, but the same band was recognized, in a slighter way, by only two out of nine of the wheat CAP-negative patients. Moreover, although almost all of the patients were negative in CAP testing with gluten, 19 out of 20 recognized protein bands belonging to the prolamin fraction. CONCLUSIONS: For the atopic patients the positivity to skin prick test and CAP to wheat was in accordance with the immunoblotting results and a food allergy to wheat could be diagnosed. In these patients a major allergen was a 16-kDa band corresponding to members of the cereal alpha-amylase/trypsin inhibitors protein family, the major allergens involved in baker's asthma. In the non-atopic patients the positive immunoblotting results contrasted with the responses of the allergologic tests, indicating that the allergenic wheat protein preparations currently used are of limited value in detecting specific IgE to wheat and that the fraction of irritable bowel syndrome (IBS) patients with food allergy may be larger than believed.     

IgE.IgG4 antibody in eczema in infants between 5-7 months of age. I. Relationship to the degree of eczema involvement]

Assessments have been made of serum IgE and IgA value, specific IgE and IgG4 antibody titers to foods, house dust, mite and percent peripheral++ eosinophil count in 191 infants with and without eczema between 5-7 months of age. Eczema patients were divided into 4 groups according to the degree of eczema involvement and laboratory data were compared between these and not eczematous group. The results were as follows; 1) IgE antibody titers were higher as the degree of eczema involvement increased. 2) RAST positive rates to foods increased with the degree of eczema involvement. Positive rate was highest to egg white followed by milk, soybean, wheat and rice. 3) Only 9 cases were RAST-positive to rice or wheat and all of them had IgE antibodies to other allergens tested. 4) A value of 10 IU/ml, which is the lowest measurable value of IgE in infants was considered to be a little too high to speculate allergy to some foods. 5) Specific IgG4 antibodies were positive only to milk. 6) All the 18 cases with positive milk-specific IgG4 antibody were all negative in milk-specific IgE antibody, and conversely all the 14 cases with positive milk-specific IgE antibody were negative in milk-specific IgG4 antibody. From these results, it was concluded that food allergy is related to the degree of eczema involvement in infants between 5-7 months of age.     

Interference in ragweed pollen and honeybee venom radioallergosorbent tests

We studied sera from patients sensitive to short ragweed (SRW) and honeybee venom (HBV) to investigate serum factors able to interfere with the measurement of IgE antibody levels by the radioallergosorbent test (RAST). We heated sera to destroy IgE antibodies and tested them for interference in the RAST. Heating sera for 4 hr at 56 °C destroyed up to 98% of the IgE antibody activity. After immunotherapy sera from patients sensitive to SRW and HBV produced striking interference in the RAST. The interference was most marked in the RAST employing 50-μg quantities of microcrystalline cellulose—linked allergens, but it was also evident in the RAST employing 500-μg quantities of such allergens and in the commercial RAST in which allergen is linked to paper disks. The interfering substance eluted from diethylaminoethyl (DEAE) cellulose in the IgG fraction. The interference could be eliminated by increasing the relative quantity of solid-phase allergen; RAST interference was not detected when SRW extract was linked to Sepharose 4B. The results indicate that serum factors, presumably IgG antibodies, produce interference in the RAST. Thus immunotherapy studies that measure IgE antibody levels by the RAST must consider the possibility that IgG antibodies can appear to depress IgE antibody levels. Furthermore, because commercially available RAST disks are susceptible to RAST interference, they must be used with caution for the diagnosis of allergy in patients whose sera may contain significant quantities of IgG antibodies.     

Sensitivity to tomato and peanut allergens in children monosensitized to grass pollen

Possible associations between allergy to grass pollen and positive skin tests to food allergens were studied in 102 children monosensitized (as to inhalant allergens) to grass pollen, and in 117 children monosensitized (as to inhalant allergens) to Dermatophagoides. Thirty-two foods were tested by an epicutaneous method. Positive skin tests to food allergens were more frequent in children with allergy to grass pollen (59.8%) than in children with allergy to Dermatophagoides (9.4%). A considerably high frequency of positive reactions to tomato (39.2%), peanut (22,5%), green pea (13.7%), and wheat (11.7%) was observed in children with allergy to grass pollen. Positive skin tests to peanut closely correlated with positive RAST results and nasal provocation tests, whereas in children with skin test positivity to tomato a close correlation with nasal provocation tests but a 45% correlation with a positive RAST result were observed. RAST inhibition experiments were carried out, and the results may suggest the presence of cross-reacting IgE to grass pollen, tomato, and peanut antigens. Clinical implications of these findings are discussed in the light of histories of food hypersensitivity, urticaria-angioedema, and atopic dermatitis in children with allergy to grass pollen.     

Do levels of immunoglobulin G antibodies to foods predict the development of immunoglobulin E antibodies to cat,dog and/or mite?

BACKGROUND: In children at high risk of inhalation allergy, food sensitization is associated with an increased risk for sensitization to inhalant allergens. Furthermore, this association was also found in a cross-sectional study. OBJECTIVE: To examine in a prospective study, whether levels of IgG to foods (i.e. mixture of wheat and rice, mixture of soy bean and peanut, egg white, cow's milk, meat, orange and potato) indicate an increased risk for the future development of IgE antibodies to inhalant allergens in a low-risk population and whether they can be used as predictors of the subsequent development of IgE antibodies in young, initially IgE-negative children. METHODS: Coughing children, aged 1-5, visiting their GPs, were tested for IgE antibodies to mite, dog and cat (RAST) and IgG (ELISA) to foods. All IgE-negative children were retested for IgE antibodies after two years. The IgG results (66 percentiles) of the first blood sample were compared to the RAST-scores of the second blood sample. RESULTS: After two years, 51 out of 397 (12.8%) originally IgE-negative children, had become IgE-positive for cat, dog and/or mite. An increased IgG antibody level to wheat-rice (OR = 2.2) and to orange (OR = 2.0) indicated an increased risk of developing IgE to cat, dog or mite allergens. In addition to IgG to a mixture of wheat-rice and orange; total IgE, breastfeeding, eczema as a baby and age were the most important predictors for the subsequent development of IgE to inhalant allergens. DISCUSSION: An increased IgG antibody level to a mixture of wheat-rice or orange, indicates an increased risk of developing IgE to cat, dog or mite allergens. This indicates that excessive activity of the mucosal immune system is present before IgE antibodies to airborne allergens can be demonstrated. Nevertheless, IgG to foods is not very helpful (with a positive predictive value of 16.5%, and negative predictive value of 90.6%) in identifying individual children at risk in clinical practice. However, besides other risk factors, IgG to wheat-rice and to orange could be useful as a screening test for studies in the early identification, i.e. before IgE antibodies can be detected, of children with an increased risk of developing IgE antibodies in the future.     

Immunoglobulin E in feces from children with allergy. Evidence of local production of IgE in the gut

Immunoglobulin E (IgE) was found by a double antibody radioimmunoassay technique (PRIST) in extracts of feces from 21 of 40 children with different kinds of allergy. 15 of the 22 children with gastrointestinal allergy and atopic dermatitis, but only 6 of the 17 patients with hay fever and/or bronchial asthma had detectable IgE in the extracts. The patients with gastrointestinal allergy also had the highest concentrations of fecal IgE, and the concentrations in feces did not correlate with the corresponding serum IgE levels. Furthermore, the presence of IgE in feces correlated with specific IgE antibodies in serum, measured as the sum of RAST classes to the food allergens wheat, fish, cow's milk and egg-white. IgE may therefore have been produced locally in the gut as a result of stimulation by food allergens. Since the concentrations of IgA in feces were also high in many children with allergy, and since some possibility of a positive correlation with high IgE concentration seemed to exist, the stimuli for local production of IgE and IgA may be interrelated.     

Humoral and cellular responses to cow milk proteins in patients with milk-induced IgE-mediated and non-IgE-mediated disorders

BACKGROUND: Cow milk allergy (CMA) is one of the most common food allergies in childhood. Patients with CMA present with a wide range of immunoglobulin (Ig)E- and non-IgE-mediated clinical syndromes. Limited information is known about the specific humoral and cellular responses to cow milk proteins in these various forms of CMA. OBJECTIVE: The aim of the study was to determine IgE, IgA, IgG1 and IgG4 antibody levels and lymphocyte proliferative responses to the major cow milk allergens in patients with IgE- and non-IgE-mediated CMA. METHODS: One hundred and forty cow milk allergic patients, 6 months to 22 years of age, were included in the study. One hundred and thirteen patients had IgE-mediated CMA, 11 had milk protein-induced enterocolitis syndrome and 16 had allergic eosinophilic gastroenteritis. Twenty-one patients without food allergy, 8 months to 18 years of age, served as controls. Serum IgE, IgA, IgG1 and IgG4 antibodies to alpha-, beta-, and kappa-casein, alpha-lactalbumin and beta-lactoglobulin were measured using enzyme-linked immunosorbent assays. For a subset of these patients, we performed lymphocyte proliferation assays to the various milk allergens. RESULTS: Patients with IgE-mediated CMA had higher specific IgE concentrations to casein compared with whey proteins (P < 0.001). In this group of patients, there was a positive correlation between IgE levels and levels of the other isotypes for all four milk proteins (P < 0.001). In general, the caseins were the more allergenic and antigenic proteins in all groups of patients. Patients with enterocolitis syndrome produced less milk protein-specific IgG4 (P < 0.05) and had a trend for higher IgA antibody levels when compared to the control group. Lymphocyte proliferative responses in all groups with CMA were significantly higher than controls (P < 0.05), although this response was similar in patients with IgE- and non-IgE-mediated CMA. CONCLUSION: There is a distinct pattern of humoral antibody response in the different forms of CMA. Patients with IgE-mediated CMA have an elevated polyisotypic response to cow milk protein. The relative lack of specific IgG4 production in patients with enterocolitis syndrome may be involved in the pathogenesis of the disease. In general, caseins appear to be the predominant allergen in patients with CMA.     

Immunoglobulin E specific to wheat and rye flour proteins

We have used the radioallergosorbent test (RAST) to determine IgE antibodies specific to wheat flour proteins in the sera of seven groups of patients. In some cases rye-specific IgE was also determined. Wheat and rye RAST scores showed a good correlation, presumably due to cross-reactions. Among bakers with asthma, positive scores, 0.5–3, occurred with a prevalence of 43%, and among children with eczema, scores in the range 0.5–4 were found with a prevalence of 54%. A score of 0.5 was a marginal value which was also occasionally encountered with sera from patient groups with no history of immediate hypersensitivity to wheat or rye. These groups included adults and children with allergic rhinitis and asthma, children from the general population and children with coeliac disease. The RAST appeared useful in the diagnosis of allergy to inhaled flour dust among bakers. Among children with eczema, positive wheat and rye RAST results were a common finding, which only occasionally could be linked to strong and unequivocal reactions to the foods in question. Both in bakers and children with eczema, wheat and rye RAST results showed good agreement with intracutaneous skin test results.     

The critical role of allergen-specific IgE,IgG4 and IgA antibodies in the tolerance of IgE-mediated food sensitisation in primary school children

Primary objective. There are about 6% of children who are either intolerant to or lose their ability to tolerate food allergens, resulting in the development of food hypersensitivity. The hypothesis that increase in food allergen-specific IgE antibody level is associated with the decrease in the levels of food allergen-specific IgG4 and IgA antibodies was used as a biomarker of food tolerance. Methods & Procedures. The Modified International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire (added gastrointestinal allergy questions) and Phadiatop infant test were used to screen one hundred 6–8-year-old allergic school children. Food allergen-specific IgE, IgG and IgA antibodies were measured by using the Phadia ImmunoCAP system radioabsorbent test (RAST). Immunoglobin E antibodies to common aeroallergens, were also detected by enzyme-linked immunosorbent assay. Main outcome. The level of analysed food specific-IgE antibody was obviously higher in the study population. Sensitivity to dust mites among the children was nearly 90%, and that to cockroach was 47%. Egg white-, cow's milk-, α-lactoalbumin-, β-lactoglobulin- and casein-specific IgG4/IgE and IgA/IgE ratios were lower in the atopic school children but not in the tropomysin-, mango- and kiwi-sensitive participants. Conclusion. The level of cow's milk- and egg white-specific IgE antibody still remained high along with a decrease in the specific IgG4/IgE and IgA/IgE ratios in our study population. Therefore, allergen-specific IgG4 and IgA antibodies are important biomarkers of tolerance establishment, and failure to establish tolerance to food allergens may be related to the regulation of the inhalant allergens encountered in late childhood stages.