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Background: Symptoms of allergy are largely attributed to an IgE-mediated hypersensitivity response. However, a considerable number of patients also exhibit clinical features of allergy without detectable systemic IgE. Previous work showed that Ig-free light chains (IgLC) may act as an alternate mechanism to induce allergic responses. CD4+CD25+ T cells are crucial in the initiation and regulation of allergic responses and compromised function might affect the response to allergens., Objective: To examine the contribution of CD4+CD25+ T cells and IgLC towards the whey-allergic response., Methods: Mice were sensitized orally with whey using cholera toxin as an adjuvant. CD25+ T cells were depleted in vivo using a CD25 mAb. The acute allergic skin response to whey and ex vivo colon reactivity was measured in the presence or absence of F991, a specific inhibitor of IgLC. Serum whey-specific antibodies and IgLC in serum and mesenteric lymph node (MLN) supernatants were measured. Depletion of CD4+CD25+ T cells was confirmed in the spleen., Results: Anti-CD25 treatment strongly reduced whey-specific antibody levels and resulted in a partial depletion of effector T cells and a major depletion of Foxp3(+) regulatory T cells. Surprisingly, despite the abolished specific IgE response, the acute allergic skin response to whey was not affected. IgLC levels were enhanced in the serum and MLN supernatants of CD25-depleted sensitized mice. F991 inhibited the acute skin response and colon hyperreactivity in anti-CD25-treated mice, indicating that these responses were mainly IgLC dependent., Conclusions: Depletion of CD4+CD25+ T cells resulted in a switch from an IgE- to an IgLC-dependent acute skin response and functional hyperresponsiveness of the colon. Our data suggest that CD25+ T cells play a crucial role in balancing cow's milk allergy between IgE and IgE-independent responses and both mechanisms might play a role in allergic responses to the same allergen.

Cow's milk protein allergy is a condition commonly managed by general practitioners and paediatricians. The diagnosis is usually made in the first 12 months of life. Management of immediate allergic reactions and anaphylaxis includes the prevention of accidental food ingestion and provision of an adrenaline autoinjector, if appropriate. By contrast, the clinical course of delayed food-allergic manifestations is characterised by chronicity, and is often associated with nutritional or behavioural sequelae. Correct diagnosis of these non-IgE-mediated conditions may be delayed due to a lack of reliable diagnostic markers. This review aims to guide clinicians in the: (i) diagnostic evaluation (skin prick testing or measurement of food-specific serum IgE levels; indications for diagnostic challenges for suspected IgE- and non-IgE-mediated food allergy), (ii) dietary treatment, (iii) assessment of response to treatment, (iv) differential diagnosis and further diagnostic work-up in non-responders, (v) follow-up assessment of tolerance development and (vi) recommendations for further referral.

Background: Studies on cow's milk allergy (CMA) in adults are scarce. Little is known about the clinical symptoms, eliciting doses (ED), and allergens involved., Objective: The aim of this study was to analyse the clinical symptoms, ED and allergen recognition in adult CMA patients, compared with cow's milk (CM)-sensitized, but tolerant controls., Methods: Adult CMA patients were evaluated by standardized questionnaires (n=30), skin prick tests (SPTs) and specific IgE for CM allergens (n=18), and a double-blind placebo-controlled food challenge (DBPCFC, n=10). A control group (n=25) of CM-sensitized, but tolerant adults was included., Results: The majority of CMA patients (20/30, 67%) reported severe symptoms. In all patients participating in DBPCFC, CMA was confirmed. ED for subjective symptoms (0.3-300 mg CM protein) were significantly lower than that for objective symptoms (300-9000 mg CM protein). The severity of CMA by history and ED was not correlated with SPT or IgE. Patients had higher SPT reactivity than controls for CM, alpha-lactalbumin and beta-lactoglobulin (P=0.002, P=0.014 and P=0.004) but not for casein. Specific IgE to CM tended to be higher (P=0.068) and IgE to casein was higher in patients than that in controls (P=0.016). No difference was observed for IgE to alpha-lactalbumin and beta-lactoglobulin., Conclusion: Adult CMA is severe in nature. ED are low, starting from 0.3 mg CM protein. Patients with CMA recognize the same major allergens (casein and whey proteins) as controls, but display a stronger SPT and IgE reactivity.

Introduction: Patients with primary Sjögren's syndrome (pSS) are reported to have a variety of gastrointestinal symptoms partly attributed to an overrepresentation of celiac disease. We have observed that irritable bowel syndrome (IBS)-like symptoms are frequent complaints in this patient group. Allergic manifestations to various drugs are also common in pSS. A role of food allergy in IBS has been proposed., Objective: This study is aimed at evaluating the mucosal response to rectal challenge with cow's milk protein (CM) in patients with pSS and relates possible CM reactivity to their intestinal symptoms., Methods: A rectal challenge with CM was performed in 21 patients with pSS and 18 healthy controls. Fifteen hours after challenge the mucosal production of nitric oxide (NO) and the release of myeloperoxidase (MPO) as signs of mucosal inflammatory reaction were measured using the mucosal patch technique., Results: Eight out of 21 patients with pSS had a definite increase of mucosal NO synthesis and the luminal release of MPO after rectal CM challenge. This sign of milk sensitivity was not linked to IgG/IgA antibodies to milk proteins. The symptoms for IBS according to Rome III criteria were fulfilled in 13 patients. All patients who were CM sensitive suffered from IBS. In a small open study, patients reactive to CM reported an improvement of intestinal symptoms on a CM-free diet., Conclusion: A rectal mucosal inflammatory response after CM challenge is seen in 38% of patients with pSS as a sign of CM sensitivity. IBS-like symptoms were common in pSS, linked to CM sensitivity.

Background: The central role of specific IgE in cow's milk allergy (CMA) is well documented. However, less is known about the function of other immunoglobulin isotypes in allergy and tolerance to cow's milk proteins (CMPs)., Objective: To determine differences in the antibody responses that are associated with allergy and tolerance to cow's milk in allergic, atopic and non-atopic individuals of different age groups., Methods: Nineteen infants (<1 year), 18 children (6-14 years) and 41 adults (21-68 years) were included. Each age group was comprised of subjects with CMA, atopic individuals without a history of CMA and non-atopic subjects. Levels of specific IgE, IgG4, IgG1 and IgA to whole cow's milk and the six most abundant individual CMPs were determined in plasma by ELISA. For comparison, specific IgE and IgG4 were measured to ovomucoid and house dust mite (HDM) in individuals allergic for the respective allergens, and in atopic and non-atopic subjects without allergy., Results: In infants and children with CMA, alphas1-casein and beta-lactoglobulin induced the highest specific IgE response, whereas alphas1-casein was the most allergenic CMP in adult patients. Specific IgG4 and IgG1 responses were the highest to alphas1-casein and beta-lactoglobulin in all age groups, while kappa-casein and alpha-lactalbumin induced the highest levels of IgA. CMP-specific IgG4 was higher in atopic children and adults without CMA, as compared with non-atopic individuals. A similar difference between tolerant atopic and non-atopic subjects was observed for IgG4 specific to ovomucoid, whereas HDM-specific IgG4 was not detectable in these subjects., Conclusion: Maintenance of tolerance to cow's milk in atopic children and adults without CMA is associated with elevated levels of specific IgG4, in combination with low specific IgE. The up-regulation of specific IgG4 in tolerant atopic individuals may be related to the type of allergen and its regular dose of exposure.

Background: Multiple food intolerance in infants, including intolerance to extensively hydrolysed proteins (HP), is often difficult to treat. However, few data have been reported on clinical outcome and dietary treatment of these patients., Aims: To evaluate the clinical characteristics of patients with HP-intolerance and the long-term outcome of treatment with ass' milk., Patients and Methods: This study included 21 HP-intolerant infants (15 males, median age at diagnosis 2 months) treated with an ass' milk-based diet and 70 cow's milk (CM) intolerant infants (40 males, median age at diagnosis 3 months) treated with casein hydrolysate milk-based diet. All patients were followed-up for a median period of 4 years. Both HP-intolerance and intolerance to other foods were diagnosed according to the double-blind placebo-controlled procedure. Formal CM-challenges were conducted at yearly intervals until tolerance was demonstrated. At diagnosis and after one year of the respective diets, the following growth parameters were determined: relative weight for sex and age, relative weight for height and height z-score., Results: During the study period, multiple food intolerance was documented in 21/21 HP-intolerant infants (ass' milk group) and in 20/70 infants with CM-intolerance but tolerating HP (casein hydrolysate group) (P < 0.0001). In the ass' milk group, the more frequent food intolerances were toward soya, oranges, tomatoes and fish; goat's milk intolerance was demonstrated in five out of six patients receiving this food, and sheep's milk derivatives intolerance in four out of seven; these patients tolerated ass' milk. During the study period 3/21 patients in the ass' milk group became ass' milk intolerant; they showed vomiting (one cases) or diarrhoea (two cases). A lower percentage (52%) of patients in the ass' milk group became CM-tolerant during the study period than in the casein hydrolysate group (78%) (P < 0.01) and the age of the children at CM-tolerance was higher in the ass' milk than in the casein hydrolysate-treated children (P < 0.05). At diagnosis, a higher frequency of cases with elevated serum total IgE and specific IgE to CM antigens (P < 0.01) was observed in the ass' milk group. No difference was recorded between the two treatment groups in any of the growth parameters considered either at diagnosis or during the follow-up., Conclusions: HP-intolerant patients showed a higher frequency of persistent food intolerance and of multiple food intolerance than patients tolerating casein hydrolysate. Ass' milk feeding was confirmed as a safe and valid treatment of the most complicated cases of multiple food intolerance.

Background: Milk hydrolysates, although frequently used as substitutes in cases of cow's milk allergy, show a reduced but never a complete abolishment of antigenicity and allergenicity., Objective: Our purpose was to determine the lower molecular weight limit of peptides to elicit skin reactions and to bind IgE antibodies in vitro., Methods: Using FPLC, an ultrafiltrated whey hydrolysate, was fractionated in different molecular weight fractions. Skin-prick tests were performed with the hydrolysate and its fractions in five cow's milk allergic children, and RAST inhibition tests were done using the serum of these children., Results: On the basis of the lowest extinction values between two peaks of the chromatogram, seven fractions with molecular weights between 15000 and 125 Da were obtained. Peptides of > 2600 Da elicited a clearly positive skin reaction and inhibited IgE-binding, while peptides of < 1400 Da did not give any positive skin reaction but were still able to inhibit to a small extent IgE-binding to the hydrolysate., Conclusion: Our findings suggest that for skin reactivity peptides of > 1400 Da are needed. The minimal molecular mass for IgE binding in vitro appears to be situated between 1400 and 970 Da. Such peptides might be used to develop a safe formula for patients reacting to milk hydrolysates or even for tolerance induction.

Background: We demonstrated recently that mite-allergic patients differed from healthy controls in the specificity of their IgG antibodies towards mite antigens., Objective: The present study investigates whether these discriminatory IgG responses could be associated with the expression and the evolution of clinical manifestations in allergy to cow's milk proteins., Methods: Antibody specificity was evaluated by comparing IgG-binding to native bovine beta-lactoglobulin (nBLG) and its products of pepsin hydrolysis (dBLG) using a solid-phase enzyme-linked immunosorbent assay (ELISA). Antibody specificity was further investigated in competitive ELISA using streptavidin-biotin technology with purified IgG fractions from selected subjects and specific mouse monoclonals raised against BLG., Results: IgG antibodies from CM-intolerant or allergic sera (n=222) showed a higher degree of binding to nBLG than to dBLG, while control sera showed similar levels to both nBLG and dBLG (n=99 children/65 adults). Sera from symptomatic patients, wether or not they contained IgE antibodies, demonstrated group-segregating capacities to compete with pooled purified IgG from each clinical class, and with selected murine anti-nBLG monoclonal antibodies for binding to n- and dBLG. Furthermore, this inhibitory capacity shifted dramatically in a small subset (n=14) of children as they developed CM-tolerance., Conclusions: The IgG responses to BLG of CM-intolerant or allergic patients are very different from those of healthy controls, being characterized not only by increased titres but also similar patterns of modified specificity, including a marked preference for conformational epitopes. Cross-competition experiments confirmed that the restricted specificity was clinically associated, appearing as an immunological signature, which allowed almost complete discrimination between patient groups. This phenomenon is a particularly promising diagnostic feature in this category of young patients where conventional tests usually only document the status of sensitization.

Background: Recent research has shown that cow's milk protein intolerance (CMPI) often persists beyond 4 years of age., Aims: To evaluate the clinical and immunological characteristics of a group of infants with persistent CMPI., Patients and Methods: Twelve infants (6 m, 6f) with persistent CMPI were followed up from birth until a median age of 5 years. The patients underwent CMP challenge each year to evaluate CMP-tolerance. As controls we followed 26 infants (12 m, 14 f) with CMPI that resolved within 1-2 years., Results: A family history of atopic disease was found in 10/12 patients with persistent CMPI and in 10/26 controls (P<0.01). Clinical presentation changed over time: at onset symptoms were prevalently gastrointestinal, while at the end of the study there was an increased frequency of wheezing and constipation and a higher frequency of delayed reactions to CMP-challenge than at study commencement (9/12 vs 2/12; P<0.007). 11/12 infants with persistent CMPI and 3/26 controls (P<0.0001) presented multiple food intolerance. During the observation period 9/12 infants with persistent CMPI and 2/26 controls showed atopic disease: asthma, rhinitis, eczema (P < 0.0001)., Conclusions: Persistent CMPI forms are characterized by: (a) considerable importance of familial atopic disease; (b) change in CMPI manifestations over time and more prolonged delay between CMP consumption and manifestation of symptoms; (c) very high frequency of multiple food intolerance and allergic diseases.

Background: Partial and extensive hydrolysed protein formulae have been developed to lower or eliminate the antigenicity of milk proteins. Although normally well tolerated, extensive hydrolysates have been reported to induce serious allergic reactions in very sensitive children. Moreover, clinical practice has often raised concern about the role of partial hydrolysates in cow's milk allergy prevention., Objective: Starting from these considerations, we used anti-casein monoclonal antibodies to evaluate the presence of residual antigenic activity in both partially and extensively protein hydrolysates., Methods: Electrophoretic analyses associated with immunoblotting technique were performed using nine protein-enriched commercial formulae., Results: The presence of different amounts of residual intact cow's milk proteins and/or polypeptidic material with conserved antigenic activity (according to the extensive or partial hydrolysis) was verified in most milk-based samples considered., Conclusion: The use of monoclonal antibodies and immunoblotting could be useful for the quality of commercial 'hypoallergenic' formulae.

To test the hypothesis that cow's milk protein intolerance (CMPI) might cause or contribute to gastro-oesophageal reflux (GOR), 10 of 14 infants with abnormal GOR on prolonged oesophageal pH monitoring who had failed to respond to conventional antireflux therapy were placed on a hypo-allergenic diet for 1 month. In no child was there significant improvement in pH monitoring indices, and only two showed any symptomatic improvement. Therefore, in these children, CMPI did not appear to contribute to GOR. It is probable that CMPI is rare as a cause of passive GOR, although our results do not exclude CMPI as a cause of active vomiting.

The clinical and immunologic findings of two breast-fed babies who experienced anaphylaxis after a feeding with a partially whey hydrolysate formula (PWHF) are reported. Sensitization to this formula seems to have occurred in the first days of life in the Maternity Hospital where the babies were fed the same formula. These two case reports suggest that PWHF may be immunogenic in the IgE system. This data is in agreement with previous studies which showed intact fragments of cow's milk (CM) proteins in PWHF.

In a comparative study six different protein hydrolysates, marketed as 'hypoallergenic' infant formulae were investigated by skin prick tests, RAST, RAST inhibition and titrated provocation tests. When hydrolysates containing a high percentage of larger peptides were found to have the highest capacity to induce positive skin tests, provocation tests and to bind to human serum IgE antibodies of cow's milk allergic children. Casein hydrolysates appeared to have the least residual allergenic activity. We recommend that 'hypoallergenic' formulae should be tested in each case, before being prescribed to cow's milk sensitive children.

Some infants intolerant to cow's milk protein (CMP) are often also intolerant to other food proteins including soy protein (SP). The effect of CMP and SP in infants recovering from diarrhoeal disease was studied in 22 infants who were maintained on an hypo-allergenic formula for 4-6 weeks. The infants were then challenged successively, initially with SP, followed 24 h later with CMP and then rechallenged with SP 24 h after CMP provocation. Three groups were recognized on the basis of clinical symptoms and mucosal changes following SP challenge. Group 1 comprised four infants who developed clinical and histological reactions on SP challenge. The subsequent CMP challenge, 24 h after the initial SP challenge, resulted in clinical symptoms in three of the four infants, and they developed increased mucosal injury. Rechallenge with SP in the three infants caused development of severe clinical symptoms. Group 2 comprised 12 infants who developed histological reaction but had no clinical symptoms to initial SP challenge. The subsequent CMP challenge caused further progression in mucosal pathology in 11 of the 12 infants and six also had associated clinical symptoms. Rechallenge with SP in the latter six infants resulted in development of clinical symptoms in three and tolerance to SP in three infants. Group 3 comprised six infants who tolerated SP and CMP but one of these infants developed mild histological changes to CMP. The progression of mucosal injury following SP and CMP challenge was associated with a significant decrease in mucosal disaccharidases, alkaline phosphatase levels and presence of reducing sugar in the stools. The 1 h blood xylose level continued to decrease significantly following the pre-SP, post-SP, and post-CMP challenge. It appears that the small bowel mucosa of young infants recovering from diarrhoeal disease remains sensitive not only to CMP but also to SP. The feeding of these proteins in rapid successive sequence to infants with mucosal damage might result in further progression of the mucosal injury. Thus, the exclusion for a variable period of time of antigenic food proteins like CMP and SP from the diet of young infants recovering from diarrhoea might reduce the risk of inducing mucosal sensitivity to these proteins in susceptible infants.