Elevated concentrations of salivary secretory immunoglobulin A anti-cow's milk protein in newborns at risk of allergy

Secretory immunoglobulin A (SIgA) anti-casein and SIgA anti-beta-lactoglobulin (BLG) were determined in the saliva of 158 healthy mature infants at birth and in breast milk samples using a direct Elisa technique. IgG anti-casein and anti-BLG were measured in serum samples from mothers and newborns (cord blood). A high risk of allergy was defined in 66 infants who had cord blood (CB)-IgE levels greater than or equal to 0.9 IU/ml and/or parents with atopic diseases. Thirty infants had CB levels less than 0.9 IU/ml and parents without clinical symptoms of atopy but with elevated serum IgE concentrations or type I skin reactions to common allergens (low risk). Sixty-two infants had CB-IgE levels less than 0.9 IU/ml and healthy parents (no risk). The groups were matched for social status, smoking and dietary habits. SIgA anti-casein and anti-BLG were detected in all newborns. SIgA anti-casein was significantly higher (p less than 0.05) in high risk infants (medium 157; 50% confidence limits 45-270) than in no risk (48; 25-150) or low risk infants (43; 21-130). SIgA anti-casein values correlated with maternal allergy, maternal allergy plus CB-IgE, but not with paternal allergy. Breast milk SIgA anti-BLG was depressed (p less than 0.05) in mothers with manifest allergy compared to healthy mothers. Determination of salivary SIgA anti-casein may represent an additional screening method for early detection of infants with atopic disposition.     

Significance of IgE level in amniotic fluid and cord blood for the prediction of allergy

Intrauterine sensitization has been reported in animal and clinical studies. One study suggests that the amniotic fluid (AF) IgE level might be useful in predicting infant allergy. We followed for 1 year 83 newborns on whom we had 78 samples of AF, 82 of cord serum (CS), and 83 of maternal serum (MS). All infants were delivered by C-section at term. Amniotic fluid samples were aspirated through the exposed myometrium. Sanguineous specimens were excluded. Amniotic fluid, CS, and MS were tested for total IgE level and IgE RAST to three foods: cow's milk, egg white, and peanut. Data on family medical history, feeding history, and allergy symptoms were collected for 12 months. By 1 year 23% had probable allergy: recurrent wheezing = 8, food related G.I. symptoms = 7, and atopic dermatitis = 4. Allergy in formula-fed infants occurred more often than in those breast-fed for greater than 6 months. IgE in AF was greater than or equal to 0.5 IU/mL in 21/78 (27%); range = 0.5 to 5.9 and geometric mean = 0.76. No correlation was noted between AF total IgE and the appearance of allergy. RAST was equivocally positive in 1.2% AF. Cord serum total IgE was greater than or equal to 0.5 IU/mL in 6/82 (7%); range = 0.5 to 2.6 and geometric mean = 0.72. Allergy appeared in 67% of infants with CS total IgE greater than or equal to 0.5 IU/mL. RAST was negative in all CS samples. In this limited series, AF IgE did not seem to have predictive value of allergy in infancy.     

The standard level of IgE RIST and eosinophil counts in 0-year old allergic children according to multiple factor analysis type II

We specified three standard levels of IgE RIST (10, 20, 60 IU/ml) for the ninety-four (94) allergic clients of 0-year infants, who classified with three groups. Each group was furthermore divided in two groups such as a group under the standard level and a group exceeding the level respectively. Next, using the Multiple Factor Analysis Type II, we examined quantitative analysis that each of three classified groups was influenced on 12 allergic factors of sex, existence and inexistence of wheezing and atopic dermatitis, family history of allergic diseases, eosinophil counts. IgE RAST scores and antibody titers against egg white, milk and soybean, IgE RAST scores to Dermatophagoides farinae, while the we discussed how the standard levels were adequately reacted to the analysis. As a results, strong allergic factors which influenced the three groups commonly were two factors of IgE RAST scores to egg white and D.f. In particular, the factor which influenced the group of 10 IU/ml standard level was eosinophil counts and family history of allergic diseases. Furthermore, the strong factors which influenced the group classified on 60 IU/ml standard outstandingly appeared in IgE RAST scores to soybean, however, we did not find any difference between three groups. On the other hand, when we specified the standard level at 100/mm3, 200/mm3, 400/mm3 in regard to the eosinophil counts under the same method and examined results, we found strong allergic factors which influenced family history of allergic diseases. IgE RAST scores to egg white and soybean. However, the study scarcely recognize any difference between the three groups.     

The patch test, skin prick test, and serum milk‐specific IgE as diagnostic tools in cow's milk allergy in infants

We evaluated the value of the patch test, skin prick test, and milk‐specific IgE by CAP RAST in 301 infants with suspected hypersensitivity to cow's milk. The patch test was carried out with milk powder, and the skin prick test with cow's milk‐based formula. Hypersensitivity to cow's milk was determined with double‐blind, placebo‐controlled challenge. An immediate reaction to cow's milk challenge was observed in 100 infants (33%), a delayed reaction in 76 (25%), and a negative result in 125 (42%). Skin prick test wheals were significantly greater in infants with immediate reactions than in infants with delayed or negative reactions. Milk‐specific IgE was correlated with the skin prick test ( r =0.78, P <0.001, n =268) but did not contribute to further discrimination of immediate reactions from delayed or negative reactions compared to skin prick test alone. In our study population, the skin prick test (diameter ≥3 mm) showed a specificity and sensitivity of 91% and 69%; the results for milk‐specific IgE (≥0.7 kU/l) were 88% and 58%, respectively. The patch test did not distinguish subjects with immediate or delayed reactions from those with negative reactions.     

Cow's milk allergy: diagnostic accuracy of skin prick and patch tests and specific IgE

BACKGROUND: The objective of the present study was to evaluate the relevance of skin tests and the concentration of cow's milk-specific IgE antibodies in correlation with oral cow's milk challenge in infants with suspected cow's milk allergy. METHODS: The study material comprised 143 infants under the age of 2 years who had undergone a diagnostic elimination challenge because of suspected cow's milk allergy in 1996. Cow's milk-specific IgE was measured, and skin prick and patch tests were performed. RESULTS: Of the 143 oral cow's milk challenges performed, 72 (50%) were positive. Of the positive reactions, 22 involved immediate-type reactions. In 50 patients, delayed-onset reactions of eczematous or gastrointestinal type appeared. Of the infants with challenge-proven cow's milk allergy, 26% showed elevated IgE concentrations to cow's milk, 14% had a positive skin prick test, and 44% had a positive patch test for cow's milk. Interestingly, in most patch test-positive patients, the prick test for cow's milk was negative. CONCLUSIONS: Our study demonstrated that many patients with a negative prick test result had a positive patch test to cow's milk. The patch test was a more sensitive method than the prick test or RAST to detect cow's milk allergy in this study population. Our results indicate that patch testing will significantly increase the probability of early detection of cow's milk allergy. Confirmation of the diagnosis is essential in patients with negative test results but a clinical suspicion of food allergy, and in patch test-positive patients. For this purpose, the most reliable method is the elimination-challenge procedure.     

Specific antibodies in infants with gastrointestinal intolerance to cow's milk protein

Antibodies of various immunoglobulin classes against cow's milk proteins were studied in infants and children with cow's milk protein intolerance, gluten-sensitive enteropathy and acute gastroenteritis. Their IgE, IgG, IgM and IgA antibody levels determined with the enzyme-linked immunosorbent assay (ELISA) and the IgE antibodies also determined with RAST, were compared with reference groups of children and adults. IgE, IgT or IgA antibodies against unseparated cow's milk proteins, alpha-lactalbumin, beta-lactoglobulin, alpha-casein and beta-casein were present in many of the studied samples, but did not discriminate between the individuals with and without intolerance symptoms. As a group, the infants with late reactions to cow's milk showed increased levels of IgE and IgG antibodies detected with the ELISA, while patients with gluten-sensitive enteropathy had significantly increased levels of IgG and IgA antibodies of cow's milk proteins compared to the reference group. By combining the findings of antibody increases in various immunoglobulin classes, an individual discrimination could be reached. Thus, 8 of 9 of the patients with late reactions to cow's milk had increased levels of IgE or IgG + IgA antibodies as compared to 3 of 22 in the reference group. Serodiagnosis with the ELISA may, therefore, be of some use in patients with a suspicion of cow's milk protein intolerance.     

Prenatal exposure to household pets influences fetal immunoglobulin E production

Background Early life pet exposure may protect against allergic sensitization during childhood. Few studies have evaluated the effect of prenatal pet exposure on potential neonatal markers of allergic risk. Objective The aim of this study was to investigate whether maternal exposure to pets affects cord blood IgE levels in a population‐based, general risk, ethnically mixed birth cohort. Methods Pet keeping during pregnancy was ascertained from women residing in a defined area of Wayne County Michigan and recruited from five staff model obstetric clinics. Maternal venous blood was analysed for total and allergen‐specific IgE along with cord blood total IgE from 1049 infants. Results Compared with infants from households with no cats or dogs kept indoors during pregnancy, infants whose homes had either cats or dogs had significantly reduced mean cord IgE levels [0.34 IU/mL (95% CI 0.30–0.38) vs. 0.24 IU/mL (0.20–0.27), P=0.025]. Similar effects were apparent in cat‐only households [0.21 IU/mL (0.16–0.27), P=0.020] and dog‐only households [0.24 IU/mL (0.19–0.29), P=0.045]. There was no effect on results when excluding mothers who reported avoiding pets due to allergy‐related concerns. Conclusion Mothers with either cats or dogs in their home during pregnancy deliver children with lower cord blood IgE levels compared with mothers who do not live with these pets, supporting the hypothesis that pet exposure influences immune development in a manner that is protective for atopy and is operant even before birth.     

Total serum IgE and specific IgE antibodies in children with bronchial asthma

Correlation between total serum IgE levels and RAST scores in a total of 342 asthmatic children were evaluated. The median and range of serum IgE were 1,050 IU/mL and 20 to 10,000 IU/mL respectively. Positive rates of RAST were highest for mites and house dust (87% to 91%) and lowest for milk, dogs, buckwheat, and eggs (2% to 8%). In general, patients with higher RAST scores had higher serum IgE (P less than .05, Mann-Whitney test). In individual cases, however, serum IgE levels did not significantly correlate with RAST scores and RAST was mandatory to estimate the levels of specific IgE antibodies.     

An enzyme-linked immunosorbent assay for cow's milk protein-specific IgE using biotinylated antigen Avoidance of interference by specific IgG

Detection of specific IgE by the radioallergosorbent test (RAST) which uses labelled antibody can be hampered by the presence of antibodies other than IgE but with the same specificity and may limit usefulness of the RAST for diagnosis of IgE-mediated milk allergy in infancy when high titres of cow's milk protein-specific IgG antibodies are known to be present. This can be avoided by using a system employing labelled antigen, such as the enzyme-linked immunosorbent assay (ELISA) described here, where IgE in the test serum is immunoadsorbed to anti-human IgE coated to microtitre plates. Biotinylated antigen, in this case cow's milk proteins, binds to specific IgE and the reaction is revealed colorimetrically by adding horseradish peroxidase (HRP)-avidin conjugate.     

Whey hydrolysate compared with cow's milk-based formula for weaning at about 6 months of age in high allergy-risk infants: effects on atopic disease and sensitization

Ninety-one high atopy-risk infants were prospectively followed up to 18 months of age with regard to the development of allergic/atopic manifestations and sensitization. They were randomized into one of two feeding groups, i.e., a hydrolyzed, ultrafiltered cow's milk whey formula, Profylac® ( n = 32), or an ordinary cow's milk formula ( n = 39), for 12 months, started after exclusive breast-feeding for 0–9 (median 6.0) months. Lactating mothers avoided milk, egg, and fish, as did the infants up to 12 months of age. Twenty of the 91 infants were breast-fed exclusively for more than 9 months and regarded as a control group. All infants were followed-up by questionnaires, physical examinations, skin prick tests, and determination of serum total IgE and cow's milk-specific IgE. The frequency of allergic/atopic disease was similar in the three groups. However, all three infants who developed cow's milk allergy with skin symptoms belonged to the cow's milk formula group. The skin prick test with whey hydrolysate was negative in all, while with cow's milk it was positive in eight infants. Growth was similar in the three groups. The study comprises too few infants to allow us to make statistically based statements. However, the difficulties encountered and the limited effects obtained by the use of whey hydrolysate at weaning at about 6 months of age made us conclude that we can spare high atopy-risk families this extra burden.     

Immunoglobulin E and immunoglobulin G4 antibodies to cow''s milk in children with cow''s milk allergy

The presence of cow's milk specific antibodies of immunoglobulin E and G4 classes were studied in 47 children with a positive clinical history of cow's milk allergy. The children were challenged with cow's milk orally. The clinical diagnosis was verified by immediate reactions in 25 patients while 22 had late reactions or were provocation test negative in spite of the clinical history. There was no relation between levels of cow's milk specific IgG4 antibodies and provocation test result, i.e. neither with immediate or late reactions. Total IgF. Was elevated above + 1 SD for age in 31 41 tested patients. Of these, 29 had immediate type reactions to cow's milk wheat flour and/or egg white, while only two of 10 children with IgE of less than +1 SD had a demonstrable allergy to any of these foods. The sensitivity was 80%. Specific IgE antibodies to cow's milk were demonstrated in 11 of 14 children with immediate reactions and in three of 15 who were provocation test negative or had only late reactions. This means a sensitivity of 79% and a specificity of 80%. At least had only late reactions. This means a sensitivity of 79% and a specificity of 80%. At least one of the four patients with specific IgE but negative provocation test result had earlier shown an immediate reaction when challenged with cow's milk indicating that the specific IgE antibodies were not truly "false" positive reactions but a consequence of previous allergy. Our results confirm an association between elevated total serum IgE and food allergy and an association between positive RAST to cow's milk and positive provocations in young children. We did not find any evidence for specific IgE-1 antibodies playing a role in these patients.     

Diagnostic value of skin-prick and patch tests and serum eosinophil cationic protein and cow''s milk-specific IgE in infants with cow''s milk allergy

The diagnosis of cow's milk allergy is based on a clinical response to an elimination-challenge test with cow's milk. We studied the usefulness of the skin-prick and patch tests and measurement of cow's milk-specific IgE and eosinophil cationic protein in serum as diagnostic tools for cow's milk allergy in a cohort of 6209 unselected infants followed from birth for the development of cow's milk allergy. Of the 239 infants challenged with cow's milk, 118 showed a positive and 121 a negative response at a mean age of 6.9 months. A positive reaction to a skin-prick test with cow's milk (> or = 3 mm) was seen in 72 (61%) and 29 (24%) infants with positive and negative challenges, elevated serum cow's milk-specific IgE (> or = 0.7 kU/L) in 52 (45%) and 15 (13%) infants, a positive reaction to patch test with cow's milk protein fractions in 26 (26%) and eight (8%) infants, and elevated serum eosinophil cationic protein (> or = 20 microg/L) in 22 (21%) and seven (13%) infants, respectively. Parallel use of the four tests with the above-mentioned cut-off values correctly classified 73% of the infants with a sensitivity of 0.76 and a specificity of 0.67. An immediate reaction to cow's milk challenge correlated with skin prick test positivity and elevated serum milk-specific IgE, and tended to correlate with patch test positivity. No single test or parallel use of the four tests could predict the challenge outcome acceptably in this prospectively followed, unselected cohort of 6209 infants. A positive reaction to one or more tests needs to be confirmed by a challenge test and a negative response to all four tests does not rule out the possibility of cow's milk allergy.     

The oral Prausnitz-Küstner reaction in food allergies

The oral Prausnitz-Küstner (P-K) reaction was examined in 41 children suspected of IgE-mediated food allergy. The recipients were served by their mothers in this study. A positive reaction was observed in 9 children when used hen's egg, cow's milk, chicken, buckwheat, red-bean, salmon or common-dolphin. Among them, seven have had an anaphylactic skin reaction (systemic urticaria and/or angioedema) to the foods. The other two were babies who were fed only by the breast milk. Therefore, the oral P-K test may be useful for the diagnosis and the prediction of food-anaphylaxis. The sera that had the radioallergosorbent test (RAST) scores of 3 or greater were negative in the oral P-K reaction in 26 out of 36 tests, and the sera that showed the positive oral P-K reaction to buckwheat or chicken were zero in the RAST scores. These results suggest that a soluble substance (e.g., histamine-releasing factor) in addition to the IgE antibody might be involved in the oral P-K reaction, and that the RAST technique does not always detect the IgE antibody that recognizes the food antigens degenerated during the absorption in vivo.     

Asthma in Tanta, Egypt: serologic analysis of total and specific IgE antibody levels and their relationship to parasite infection.

The relationship between asthma, IgE and parasite infection was compared in 68 randomly selected patients with asthma and 37 nonasthmatic controls living in Tanta, Egypt. Sera were assayed for total IgE and for IgE antibodies to inhaled allergens (mite, cat, cockroach, ryegrass, ragweed and 3 fungi) and to parasite antigens (Schistosoma mansoni and Brugia malayi). Parasite infection was determined by microscopic examination of stool specimens. Total IgE levels were significantly higher in patients with asthma (geometric mean 909 IU/ml), than in controls (geometric mean 145 IU/ml, p less than 0.001). The high IgE levels correlated with parasite infection and the presence of IgE antibodies to S. mansoni antigens, which were also elevated compared to controls. The prevalence of allergen-specific IgE antibodies among Egyptian asthmatics was low by comparison with 'Western' asthmatics, but nonetheless higher than among Egyptian controls. A radioallergosorbent test (RAST) values of greater than 40 U/ml to any allergen was found in 19/68 (28%) sera from the asthma group, as compared to only 1/37 (3%) sera from controls (p less than 0.001). The highest RAST values were to dust mite (Dermatophagoides pteronyssinus and D. farinae) allergens, followed by rye grass and ragweed allergens. The results suggest that in this area of Egypt, several factors may influence the development of asthma, including nonspecific activation of IgE and/or inflammatory mechanisms by helminth parasites and sensitisation to environmental allergens.     

Cow's milk hypersensitivity in an elderly woman: clinical and immunologic findings

We report a case of allergy to cow's milk diagnosed in a 79-year-old woman, who had the habit of drinking large amounts of milk and other dairy products for several years. She had been an asthmatic since the age of 40. At age 65, she noticed a correlation between cheese and milk intake and onset of asthma and two episodes of shock, and she has been avoiding milk for the past 15 years. Positive skin prick tests for cow's milk proteins, grass pollens, and house dust mite were observed. Serum IgE levels were above 3,000 U/mL, with high molecular weight IgE detected by gel chromatography. RAST results confirmed the presence of sensitizations detected by skin prick tests. The patient never suffered from atopic eczema. This unusual case of food allergy with onset after the age of 40 may indicate that prolonged exposure to food antigens in predisposed individuals may lead to the development of allergy even in adult age, lasting for decades after partial elimination of the allergen from the diet.     

人奶、牛奶和新生儿配方奶中表皮生长因子含量

目的:比较不同来源新生儿用奶中表皮生长因子(EGF)含量以及母乳EGF含量与新生儿成熟度的相关性。方法:应用放射免疫分析法测定了57份人初乳、4种新鲜牛奶和8种基于牛奶的新生儿配方奶的EGF含量。结果:早产儿乳中EGF含量最高,其次是足月儿乳,母乳EGF含量与新生儿胎龄和出生体重呈负相关;新鲜牛奶的EGF水平(16.6±3.8) nmol/L与足月儿乳相当;非水解蛋白质配方奶中EGF含量较低,水解蛋白质配方奶的EGF浓度在可测范围之下。结论:早产儿乳中EGF的高含量可能代表着一种与早产儿加速生长发育相适应的代偿机制。配方奶中的EGF不足甚至缺乏,不宜应用于消化系统发育不完善或胃肠道受损的新生儿。     

In utero exposure to parental smoking, cotinine measurements, and cord blood IgE

The relationship between parental smoking and cord blood IgE has been studied in a survey conducted in 99 unselected newborn infants with a sensitive tests for IgE and cotinine as a biologic marker to validate smoking data. For both cord blood cotinine and maternal urine continine creatinine ratio (CCR), significantly higher levels were observed for smokers compared to nonsmokers. Furthermore, among nonsmokers, passive smokers had significantly higher cotinine levels than true nonsmokers, which demonstrates that cord blood may be used to assess active as well as passive maternal smoking. No association was observed in this study between cord blood IgE and maternal smoking assessed by questionnaire (geometric means of cord blood IgE levels were 0.11 IU/ml for newborn infants of smoking mothers and 0.12 IU/ml for newborn infants of nonsmoking mothers). The same observations were drawn from the analysis of cord blood IgE and cotinine levels, with correlation coefficients of -0.005 for cord blood CCR and 0.003 for maternal CCR. Additional studies are needed to determine whether maternal smoking is causally related to cord blood IgE and by which mechanisms.     

Reducing the need for food allergen challenges in young children: a comparison of in vitro with in vivo tests

BACKGROUND: Double-blind placebo-controlled food challenges (DBPCFC), the gold standard for the diagnosis of food hypersensitivity, are time-consuming and not without risk. We have recently reported skin prick test (SPT) weal diameters to cow's milk, egg and peanut above which infants and young children referred for investigation of suspected food allergy showed an adverse reaction on food challenge. We have termed these the "100% diagnostic SPT levels". In this study, we compare in vivo with in vitro measurement of IgE antibody levels to three common food allergens--cow's milk, egg and peanut--in infants and young children with suspected food allergy, in order to reduce the need for food challenges. METHODS: SPT and Enzyme Allergo-sorbent Test (EAST) (from 1992 to 1998) and CAP values (from 1999 to 2000) were performed in 820 children < 2 years of age with suspected allergy to cow's milk and/or egg and/or peanut. SPT levels previously shown to be diagnostic of challenge-proven allergy to cow's milk, egg and peanut were used as the "100% diagnostic SPT levels" and compared with EAST and CAP values associated with IgE food allergy according to the manufacturer's definition. RESULTS: McNemar's test showed a significant difference between the "100% diagnostic SPT levels" and positive EAST in identifying patients who did not require food challenge for cow's milk (P = 0.01), egg (P < 10-6) and peanut (P < 10-6), and a significant difference between the "100% diagnostic SPT levels" and positive CAP (P < 10-6) for egg and peanut but not cow's milk. Twenty-three per cent of food challenges which, based on the results of EAST and CAP, would have been necessary to confirm the diagnosis of food allergy were avoided by the use of the "100% diagnostic SPT levels" . CONCLUSION: The use of the "100% diagnostic SPT levels" compared with in vitro measurement of IgE antibody to cow's milk, egg and peanut reduces the need for food challenge in young children with suspected food allergy.     

Allergenicity of major cow's milk and peanut proteins determined by IgE and IgG immunoblotting

BACKGROUND: Specific IgG antibodies are frequently observed in food-allergic patients. However, the allergen-fraction specificity of IgG antibodies in relation to IgE antibodies is not well defined. Our aim was to determine the IgE and IgG antibody profile to major cow's milk and peanut-antigen fractions in food-allergic patients and tolerant individuals. METHODS: Sera were collected from 10 patients allergic to cow's milk and 10 patients allergic to peanuts, as well as from 20 control subjects. Cow's milk and peanut proteins were migrated on SDS-PAGE and immunoblotted for IgE, IgG, and IgG4 antibodies. Food-specific IgE concentrations were measured by CAP System FEIA, and IgG and IgG4 concentrations by ELISA. RESULTS: In food-allergic children, similar fraction-specific IgE, IgG, and IgG4 antibody-binding profiles to the major cow's milk or peanut antigens were found. In nonallergics, the presence of fraction-specific IgG antibodies was mostly dependent on regular ingestion of the food. The presence of specific antibody on immunoblots correlated with their quantitative measurement. The mean value for specific IgE in cow's milk-allergic patients was 450 +/- 1,326 IU/ml, and 337 +/- 423 IU/ml in peanut-allergic patients. Specific IgG antibody values in milk-allergic patients were not different (median OD 1.5, range 0.3-2.3) from controls (median OD 1, range 0.2-1.8). However, in peanut-allergic patients, IgG concentrations were significantly higher than in controls (OD 1.2 [0.5-1.3] vs 0.5 [0.3-0.7]; P< 0.01). CONCLUSIONS: Similar fraction-specific IgE and IgG antibody profiles in allergic individuals suggest a common switching trigger involving both isotypes. Intrinsic allergenicity might explain identical IgG antibody fraction specificity in nonallergics and in allergics. The presence of IgG antibodies in nonallergics was related to regular ingestion of the food.     

Effect of combined maternal and infant food-allergen avoidance on development of atopy in early infancy: a randomized study

The effect of maternal and infant avoidance of allergenic foods on food allergy was examined in a prenatally randomized, controlled trial of infants of atopic parents. The diet of the prophylactic-treated group (N = 103) included (1) maternal avoidance of cow's milk, egg, and peanut during the third trimester of pregnancy and lactation and (2) infant use of casein hydrolysate (Nutramigen) for supplementation or weaning, and avoidance of solid foods for 6 months; cow's milk, corn, soy, citrus, and wheat, for 12 months; and egg, peanut, and fish, for 24 months. In the control group (N = 185), mothers had unrestricted diets, and infants followed American Academy of Pediatrics feeding guidelines. The cumulative prevalence of atopy was lower at 12 months in the prophylactic-treated (16.2%) compared to the control (27.1%) group (p = 0.039), resulting from reduced food-associated atopic dermatitis, urticaria and/or gastrointestinal disease by 12 months (5.1% versus 16.4%; p = 0.007), and any positive food skin test by 24 months (16.5% versus 29.4%; p = 0.019), caused primarily by fewer positive milk skin tests (1% versus 12.4%; p = 0.001). The prevalences of allergic rhinitis, asthma, and inhalant skin tests were unaffected. Serum IgE levels in the prophylactic-treated group were marginally lower only at 4 months. Thus, reduced exposure of infants to allergenic foods appeared to reduce food sensitization and allergy primarily during the first year of life.