Natural history of IgE antibodies in children at risk for atopy

BACKGROUND

The relationship between atopic diseases and high serum IgE levels has been emphasized since the mid-sixties, when IgE antibodies were discovered. A number of environmental factors, such as the type of feeding, passive smoking, viral infections, early mold, house dust mite and pet fur exposure modulate IgE synthesis and affect the development of atopic diseases.

OBJECTIVE

The aim of the present study was to investigate the natural history of total and specific IgE antibodies in babies at risk for atopy, enrolled in a prospective study for the prevention of atopic disease, and follow-up from birth to 4 years of age.

METHODS

One hundred seventy-four babies (90 boys and 84 girls) at risk for atopy were enrolled in this study. At the last follow-up the children had a median age of 52 months (range 43 to 74 months), dietary and environmental manipulations for the prevention of atopic diseases were recommended. All the infants were examined at the ages of 1, 3, 6, 9, and 12 months and twice each year subsequently when detailed histories were taken and signs and symptoms of atopic disease were sought. Total and specific IgE to cow milk, egg, soy, wheat, and Dermatophagoides pteronyssinus (Dpt) were measured at 6 and 12 months of life and then every year.

RESULTS

During the first 24 months of life, the number of children with specific IgE to foods (n = 30) was significantly higher in comparison to the number of children with specific IgE to Dpt (n = 12) (P = .0006). Cow milk and egg were the most common offending foods. The number of children with IgE to cow milk (n = 14) was significantly higher than that with IgE to soy (n = 9) (P = .0011). Total serum IgE levels were significantly higher in the group of children who developed atopic disease in comparison with the group that did not (P < .01).

CONCLUSION

Dietary and environmental measures may influence the IgE response in atopy-prone children, thus confirming the role of environmental factors in the modulation of the phenotypic expression of atopy.

[The primary and secondary prevention of allergic diseases in the child "at risk" for atopy: a review of the literature and the authors' personal experience]

The increasing prevalence of the atopic diseases in the industrialized countries is closely linked together the numerous efforts to attempt to prevent them. Several Authors have suggested environmental and/or dietetic measures in the "at risk" babies in the first months of life, more critical for the atopy development. The environmental measures are directed to the avoidance of the major inhalant allergens (house dust mite, pet allergens, cigarette smoking, etc.). The employment of the acaricides can be useful to this purpose. The dietetic measures include: prolonged and exclusive breast feeding in the first six months of life, delayed and gradual weaning, avoidance of the major food allergens (cow's milk proteins, egg, fish, etc.) for the breast-feeding mother, choice of an adequate cow's milk substitute when the breast-feeding is not sufficient. For long time soya milk has been employed. In the last decade partially or highly hydrolyzed formulae were introduced, but in some cases they can be more allergenic of cow's milk. In this paper we reviewed the various environmental and dietetic measures and the different prevention programs that the several Authors have adopted in "at risk" babies.

Systemic reactions to specific immunotherapy in children with respiratory allergy: a prospective study

The aim of this multi-centre prospective study was to evaluate the prevalence of systemic reactions to specific immunotherapy in children with allergic asthma and or rhinitis. One thousand and fifty-six children (653 boys and 403 girls), median age 8.5 years, were enrolled in this three-year prospective study. All the children were treated with injections of the following allergenic extracts: 689 of house dust mite, 291 of grass, 109 of Parietaria, 13 of Alternaria, 6 of Artemisia and 11 of Olea. Among 1056 treated children, 41 (3.7%) had systemic reactions: 40 children (3.7%) experienced mild symptoms such as asthma and/or urticaria, and only one shock (0.08%). A total of 47,247 injections were administered, and the rate of systemic reactions, according to the number of total injections was only 0.08%. According to the allergenic extract, systemic reactions occurred in 29/689 children (4.2%) treated with house dust mites extract (0.09% of the injections), in 9/291 children (3.1%) treated with grass extract (0.07% of the injections) and in 3/109 children (2.8%) treated with Parietaria extract (0.06% of the injections). The prevalence of systemic reactions was significantly higher (p < 0.0001) in the children treated with house dust mite extract in comparison with those treated with pollen extracts. All the systemic reactions appeared within 30 minutes following the administration of the extract and occurred in 37/41 cases (90.2%) with the same dose, previously tolerated. Most reactions were mild, and were readily controlled by immediate emergency treatment. There was no need for hospitalization.(ABSTRACT TRUNCATED AT 250 WORDS)

Food allergy and asthma

Food allergy (FA) is one of the causes of atopic dermatitis (AD), of acute urticaria, of reactions of the gastrointestinal tract, and of acute systemic anaphylaxis, but its role in asthma appears to be less clear. The prevalence and incidence of subjects with food-induced wheezing have not been well studied. In addition, the number of subjects with proven food-induced wheezing by double-blind, placebo-controlled oral food challenge (DBPCOFC) has been small. At the moment wheezing is considered unusual in food-hypersensitive subjects, and wheezing as the unique symptom of FA is rare. Furthermore, most cases of food-induced asthma have been observed in children. Food allergy may trigger allergic respiratory symptoms through two main routes: ingestion or inhalation. Children with asthma, who are allergic to foods, present some particular features such as AD and a related significantly elevated total serum IgE level. Alternatively, FA may occur in patients who are "high IgE responder" and more prone to become sensitive to many allergens, including foods. Therefore, children with asthma and a history of AD and/or elevated total serum IgE level should be carefully assessed for FA. We have shown that a significant proportion of children with IgE-mediated cow's milk allergy experienced asthma following DBPCOFC with cow's milk.

Cord blood mononuclear leukocytes of neonates at risk of atopy have a deficiency of arachidonic acid

Essential fatty acids and their delta-6-desaturated derivatives are major components of cellular membrane phospholipids, contributing to their stability and functions. They are also precursors of inflammation mediators such as prostaglandins and leukotrienes, and are involved in cellular immunoregulation. Recent studies have stressed the importance of essential fatty acids in various diseases. Patients with atopic dermatitis have altered essential fatty acids levels in plasma and a clinical improvement has been shown after oral administration of essential fatty acids. The aim of our study was to investigate the distribution of essential fatty acids in the membranes of cord blood mononuclear leukocytes of newborns at risk of atopy, and to correlate the levels of essential fatty acids at birth with total IgE values and with the onset of atopic disease. Newborns at risk of atopic disease have a significant reduction in arachidonic acid in the membranes of cord blood mononuclear leukocytes. Our data show a significant decrease in arachidonic acid in neonates at risk of atopy, suggesting that the abnormality of essential fatty acids is a primary phenomenon associated with atopic status.

Atopic sensitization in children of Somali immigrants in Italy

Children of immigrants are known to be at greater risk for developing allergic manifestations than the population in general. In this study we observed children of Somali origin living in Italy in order to find plausible explanations for the high risk of allergic disease in immigrants. Fifty-two children aged 0-14 years (mean = 6.7 years) were examined during the spring season. The mothers of the children were asked to fill in a questionnaire on symptoms and signs of atopic diseases and the family history of atopy. In addition, a physical examination and skin tests were performed. All families used mattresses, pillows and/or blankets made of wool, known to favor the growth of mites. In the majority of these children's families we found at least five people cohabitating in the same room. Skin prick tests were most frequently positive for Dermatophagoides pteronyssinus. Seventy-four percent (14/19) of those with symptoms were positive to D. pteronyssinus. Only 14% (2/14) of those positive to D. pteronyssinus were positive to Lolium perenne. Thirty-seven percent (19/52) had atopic symptoms and 15% (5/33) of those without symptoms were positive to D. pteronyssinus (p < 0.0001 compared to those with symptoms). Sensitization to food allergens occurred less frequently as compared to common inhalant allergens (p < 0.0001). A high prevalence of atopic diseases among children of Somali immigrants in Italy might be attributed to contact with the new environment and poor socioeconomic conditions that promote, for example, the growth of mites. However, further studies are needed to document these differences.

Immunogenicity of a so-called hypoallergenic formula in at-risk babies: two case reports

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.

Allergenicity of milk protein hydrolysate formulae in children with cow's milk allergy

Cow's milk protein hydrolysate formulae have been developed to lower or eliminate the allergenicity of cow's milk proteins, and to reduce the antigenic load and the risk of sensitization. Cross-reactivity between different hydrolysate formulae and cow's milk proteins has been demonstrated. We have studied 20 children (median age 31 months, range 15-76 months) with a history of IgE-mediated cow's milk allergy. All the children had immediate allergic respiratory and/or cutaneous and/or gastro-intestinal reactions to cow's milk ingestion. In addition, the children had positive prick skin tests and positive RAST to cow's milk. Prick skin test, RAST, and double-blind placebo controlled food challenges were performed with three different hydrolysate formulae: a casein hydrolysate formula and two whey formulae, one partially and one extensively hydrolyzed. All 20 children had immediate allergic reactions after the challenge test with cow's milk. Only 2/20 children had a positive challenge test with a casein hydrolysate formula (Alimentum): one developed asthma and one urticaria. Two of the 15 children challenged with an extensively hydrolysed whey formula (Profylac) developed perioral erythema. Nine out of 20 children had a positive challenge test with a partially hydrolysed whey formula (Nidina H.A.): four developed asthma, three urticaria and two lip oedema. All children had positive prick skin tests to cow's milk proteins (casein and/or lactalbumin); 9 to Nidina H.A.; 3 to Profylac, and 3 to Alimentum. Specific IgE antibodies to cow's milk were present in all children; in 13 to Nidina H.A., in 4 to Profylac, and in 3 to Alimentum.

Is prevention of food allergy worthwhile?

Several studies performed in high-risk babies have demonstrated a significant reduction in the prevalence and severity of atopic diseases with dietary and environmental manipulations. It has been demonstrated that prolonged breast-feeding and the avoidance of cow's milk, eggs and fish during the first three months of lactation significantly decrease both the prevalence and the severity of atopic disease up to the age of 5 years. We have shown a significant reduction in both the prevalence and the incidence of atopic dermatitis, food allergy and asthma in high-risk children followed up to the age of 5 years who received preventive dietary (prolonged breast-feeding, cow's milk- and egg-free diet to the nursing mothers, supplementation with a soya formula containing sucrose when breast milk was not available, delayed weaning) and environmental measures (no smoking and no pets in the house, measures for the elimination of mites, etc.). However, occasionally, breast-fed infants may experience allergic sensitization to food antigens ingested by the mother during lactation. The factors that determine which infants will develop sensitization to food antigens in breast milk are not fully understood. The genetic predisposition to IgE-mediated hypersensitivity reactions is certainly a prerequisite; however, properties of human milk, such as immune characteristics, may play a role in the phenotypic expression of sensitization. Our studies suggest that the abnormally low levels of the long-chain polyunsaturated derivatives found in infants at risk of atopy are unlikely to be corrected by breast-feeding and may explain the contradictory results from studies on the effectiveness of breast milk against the development of atopic dermatitis.

Breast milk from mothers of children with newly developed atopic eczema has low levels of long chain polyunsaturated fatty acids

BACKGROUND

Infants at risk of atopic dermatitis have lower than normal levels of long chain polyunsaturated fatty acids. These fatty acids are normally present in substantial quantities in human breast milk.

METHODS

Because of the equivocal evidence concerning the ability of breastfeeding to delay the onset or reduce the severity of atopic dermatitis, we have analyzed the fatty acid composition of breast milk from the mothers of children with newly developed disease with the use of gas chromatography.

RESULTS

Breast milk lipids from mothers of children with newly developed atopic dermatitis had increased proportions of linoleic acid and significantly decreased proportions of its long chain polyunsaturated derivatives compared with a control group. The ratio of linoleic acid to the sum of its metabolites, gamma-linolenic acid, dihomo-gamma-linolenic acid, and arachidonic acid was 11.78 in the atopic group and 9.02 in the control group (p < 0.01).

CONCLUSIONS

These results are consistent with previous findings of an abnormal fatty acid status in atopic subjects and may account for some of the inconsistent results from studies of the effect of breastfeeding on the subsequent development of atopic dermatitis. We conclude that further studies to examine the effects of supplementation of the diet of breastfeeding mothers with long chain polyunsaturates should be done.

Prevention of atopic diseases in high risk babies (long-term follow-up)

Several studies have demonstrated that dietary and environmental manipulations in the first months of life have a protective effect on the development of allergic diseases in babies "at risk" of atopy. We have prospectively followed up 174 "high risk" infants who underwent dietary and environmental manipulations, such as exclusive breast-feeding for the first 6 months of life, supplemented if necessary with soy-protein formula (Isomil, Abbott), delayed weaning beyond the 6th month of life, and rigorous environmental manipulations for the elimination of house-dust mite and passive smoking. The low prevalence of atopic disease (10%) and the trivial course of the allergic manifestations in this "at risk" population confirm the effectiveness of this preventive program. Moreover, this study demonstrates that the incidence of atopic dermatitis peaks at 6 months, and decreases until it disappears. Food allergy appears only at 6 months and may disappear later. The incidence of asthma peaks at 6 and 36 months and decreases at low levels in the intervals. Allergic rhinitis develops not sooner than 36 months.

Allergenicity and nutritional adequacy of soy protein formulas

Soy protein formulas are used for different conditions, including cow milk protein allergy, lactose and galactose intolerance, and severe gastroenteritis. Feeding soy protein formulas to normal term infants is associated with normal growth, normal protein nutritional status, and normal bone mineralization. Recent studies of infants fed soy protein formulas exclusively during the first months of life revealed no immunologic abnormality; however, the use of such formulas for management of cow milk protein allergy and for prevention of atopy is controversial. Although in the past decade many studies have stressed soy allergenicity, soy allergenicity has been confirmed by the challenge test in only a few studies. In this article we review the studies dealing with the allergenicity of soy protein formulas. We also present our own data on their use in the prevention and management of cow milk protein allergy.

New strategies for the prevention and treatment of allergic rhinitis in children

Allergic rhinitis (AR) is a very common disease in children, often underdiagnosed and with underestimated complications. Its prevalence has increased during the last years, due to changes in environmental factors. The therapeutic strategy will include prevention by identification and eviction of the main allergens, associated to pharmacological therapy. Among antirhinitic drugs, the new generation of non-sedative specific antihistamines represent the main choice. We report our own experience with astemizole, one of these new antihistamines which confirms that astemizole is an effective and safe drug for the management of AR in children.

Soy hypersensitivity in children with food allergy

To evaluate humoral (IgE antibodies) and clinical (positive challenge test) soy hypersensitivity prevalence, we studied 317 children (271 boys and 100 girls) with a median age of 5 months (range 1-120) who visited the Division of Allergy and Clinical Immunology of the Pediatric Department of the University of Roma "La Sapienza" because of histories and symptoms suggestive of food allergy. Atopic dermatitis (AD) was present in 247/317 children (78%), diarrhea in 19 (6%), urticaria in 22 (7%), and rhinitis and/or asthma in 29 (9%). All children underwent diagnostic procedures including family and personal history, physical examination, PRIST, and RAST to cows milk (CM), egg, wheat, soy, and Dermatophagoides pteronyssinus (Dpt). Open challenge tests to soy were performed in the hospital under observation and with emergency equipment at hand. The prevalence of humoral sensitization to CM was 54%, to egg 46%, to Dpt 35%, to wheat 24%, and to soy 22%. Only five children had IgE only to soy; six to soy and egg; and 58 to soy, CM, and egg. Only ten children (3%) had positive challenge to soy and only five of them had IgE to soy. RAST had a sensitivity of 0.69, a specificity of 0.83, a negative predictive value of 0.77, and a positive predictive value of only 0.06.

Effect of flunisolide on nasal eosinophils and IgE, and symptom score in children with allergic rhinitis

We evaluated the effect of treatment with flunisolide nasal spray (100 micrograms/day for 3 months) in 24 children with allergic rhinitis on the following parameters: clinical symptoms, absolute number of peripheral and nasal eosinophils, and total IgE levels in nasal secretion. Therapy with flunisolide induced a significant reduction of clinical symptoms (p < 0.001), nasal eosinophils (p < 0.001) and nasal IgE concentration (p < 0.02), while it did not affect the number of peripheral eosinophils. These results indicate that flunisolide can reduce the allergic inflammation of the nasal mucosa.

Prevention of atopic disease in at risk newborns

At least 15% of children have at least one atopic disease and genetic factors play an important role in the development. Screening of family history and high serum cord IgE permits introduction of dietary and environmental measures to prevent atopy. Environmental, prenatal, perinatal factors, exposure to household allergens, infections, cigarette smoking, dietary factors, including those during pregnancy, duration of breast feeding, dietary measures during lactation, all have effects in modifying the atopic response.