Does breast-feeding prevent the development of allergy?

Prevalence, severity and risk factors of asthma, rhinitis and eczema in a large group of Chinese schoolchildren

BACKGROUND

There is a lack of information on the prevalence, severity and risk factors of asthma, rhinitis and eczema in Chinese children.

OBJECTIVE

To establish baseline data for a major longitudinal study of factors affecting asthma, rhinitis and eczema in a large group of children from the industrialized city of Shijiazhuang, China.

METHODS

We used the International Study of Asthma and Allergies in Childhood questionnaire and studied 10 338 children, ages 6-18, from Shijiazhuang.

RESULTS

The prevalence of childhood asthma, rhinitis and eczema is 1.2%, 13.5% and 11.8%, respectively. Boys had higher prevalence of these conditions than girls and younger children had higher prevalence of asthma and eczema but lower prevalence of rhinitis than older children. Breastfed children had lower prevalence of asthma and rhinitis, but not eczema, than non-breastfed children. Overweight children had higher prevalence of asthma and rhinitis than those who were not overweight. Children exposed to paternal smoking had higher prevalence of rhinitis and eczema than those not exposed; children exposed to pets had higher prevalence of asthma and rhinitis than those not exposed.

CONCLUSIONS

The prevalence of asthma in this study group is low, but the prevalence of rhinitis is high, and could be considered a major public health problem. The prevalence of asthma, rhinitis and eczema is generally higher in boys and younger children generally have higher prevalence of asthma and eczema but lower prevalence of rhinitis. Exposure to pets is a risk factor for rhinitis, being overweight is a risk factor for asthma and rhinitis, and exposure to parental smoking is a risk factor for asthma, rhinitis and eczema in these children.

Global analysis of breast feeding and risk of symptoms of asthma, rhinoconjunctivitis and eczema in 6-7 year old children: ISAAC Phase Three

BACKGROUND

In Phase Three of the International Study of Asthma and Allergies in Childhood (ISAAC), we investigated the relationship between breast feeding in infancy and symptoms of asthma, rhinoconjunctivitis and eczema in 6-7 year old children.

METHODS

Parents or guardians of 6-7 year old children completed written questionnaires on current symptoms of asthma, rhinoconjunctivitis and eczema, and on a range of possible asthma risk factors including a history of breast feeding ever. Prevalence odds ratios were estimated using logistic regression, adjusted for gender, region of the world, language, per capita gross national income, and other risk factors.

RESULTS

In all 206,453 children from 72 centres in 31 countries participated in the study. Reported breast feeding ever was not associated with current wheeze, with an odds ratio (adjusted for gender, region of the world, language, per capita gross national income, and factors encountered in infancy) of 0.99 (95% CI 0.92-1.05), current rhinoconjunctivitis (OR 1.00, 95% CI 0.93-1.08), current eczema (OR 1.05, 95% CI 0.97-1.12), or symptoms of severe asthma (OR 0.95, 95% CI 0.87-1.05). Breast feeding was however associated with a reduced risk of severe rhinoconjunctivitis (OR 0.74, 95% CI 0.59-0.94) and severe eczema (OR 0.79, 95% CI 0.66-0.95).

CONCLUSIONS

There was no consistent association between breast feeding use in the first year of life and either a history or current symptoms of wheezing, rhinoconjunctivitis or eczema in 6-7 year old children, but possibly an effect on severe symptoms of the latter two conditions.

Changes in salivary and fecal secretory IgA in infants under different feeding regimens

BACKGROUND

One of the causes of food allergy in infancy is assumed to be immunological immaturity of the intestinal tract. The purpose of the present study was to examine changes in salivary and fecal secretory IgA (sIgA) levels in infants under different feeding regimens to evaluate the immunological maturity of the intestinal tract.

METHODS

Thirty-four infants were enrolled at the beginning of the study, and 28 of them were followed up to 12 months of age. sIgA was measured on enzyme-linked immunosorbent assay. Changes in the levels of salivary and fecal sIgA during the first 12 months of life were compared among formula-fed infants (F group), breast-formula-fed infants (BF group) and breast-fed infants (B group).

RESULTS

Salivary sIgA was detected in almost all neonates on the day of birth. Salivary sIgA was significantly higher in the F group than in the BF group at the age of 2 months (P < 0.05). Fecal sIgA appeared from day 2 and rapidly increased at 1 month of age in all groups. B group infants had significantly higher level of fecal sIgA than F group infants at 1 month of age (P < 0.05).

CONCLUSIONS

The level of salivary sIgA hardly changed, whereas fecal sIgA was significantly influenced by intake of breast milk.

Effects of intestinal microflora and the environment on the development of asthma and allergy

The aim of previous research into the causes of allergic diseases, including asthma was mostly to identify potential risk factors in the environment. No major risk factors have been identified, however. Over the past 10 years, focus has, therefore, more been directed towards protective factors that could enhance the development of tolerance to allergens which were previously encountered early in life, but are now lost in modern affluent societies. In particular, the role of childhood infections has been discussed, but so far these studies have not been conclusive. Recent epidemiological studies and experimental research suggest that the microbial environment and exposure to microbial products in infancy modifies immune responses and enhances the development of tolerance to ubiquitous allergens. The intestinal microflora may play a particular role in this respect, as it is the major external driving force in the maturation of the immune system after birth, and animal experiments have shown it to be a prerequisite for normal development of oral tolerance. Recent studies have shown differences in the composition of the microflora between healthy and allergic infants in countries with a high and low prevalence of allergies and between healthy and allergic infants within such countries. These differences are apparent within the first week of life and thus precede clinical symptoms. The use of live microorganisms that might be beneficial to health has a long tradition and the safety is well documented. Very recently, several prospective intervention studies, modifying the gut flora from birth have yielded encouraging results and may suggest a new mode of primary prevention of allergy in the future.

Cytokine, chemokine and secretory IgA levels in human milk in relation to atopic disease and IgA production in infants

The relationship between breast-feeding, IgA production and development of atopic disease in children is a matter of controversy. Some of this controversy might be due to individual differences in the composition of breast milk. The aim of this study was to relate the levels of cytokines, chemokines and secretory (S)-IgA antibodies in breast milk to the development of atopic manifestation and salivary IgA production in infants. Cytokine, chemokine and SIgA levels, as measured with enzyme-linked immunosorbent assay (ELISA), in colostrum and mature milk were analyzed in relation to the development of positive skin-prick tests (SPT), allergic symptoms and salivary IgA antibody production during the first 2 years of life in 53 infants. There was no association between levels of IL-4, -5, -6, -8, -10, -13, -16, IFN-gamma, TGF-beta1, -beta2, RANTES, eotaxin or SIgA levels in the breast milk with either SPT-positivity, development of allergic symptoms or salivary IgA levels during the first 2 years of life in the infants. Thus, differences in the composition of cytokines, chemokines and SIgA in breast milk did not, to any major degree, affect the development of a positive SPT, atopic symptoms, nor salivary IgA antibody production during the first 2 years of life.

Effects of breast milk from allergic and non-allergic mothers on mitogen- and allergen-induced cytokine production

Breast milk contains several components that provide specific immunity and affect the maturation of the infant's immune system. The aim of this study was to analyze the effects of breast milk, on mitogen- and allergen-induced cytokine production from cord blood mononuclear cells (CBMC), and if those effects differ between allergic and non-allergic mothers. The cells were incubated for 96 h with phytohemagglutinin (PHA), ovalbumin or cat dander in the presence of various dilutions of colostrum. Colostrum inhibited both mitogen- and cat-induced IFN-gamma and mitogen-induced interleukin-4 (IL-4) production. The inhibition on IFN-gamma production was to some extent caused by TGF-beta, as the effect was modified when an anti-TGF-beta antibody was added to the cultures. In contrast, colostrum enhanced allergen-induced production of the Th2-like cytokines IL-5 and IL-13, and this was accompanied with increased production of IL-10. No differences were found between allergic and non-allergic mothers. The inhibitory effect of breast milk on IFN-gamma production, which was partly due to the high levels of TGF-beta, together with the enhancing effect on IL-10 secretion, confirm that breast milk is anti-inflammatory. Although the production of IL-5 and IL-13 was enhanced by colostrum, this was accompanied with an increased production of IL-10. Together with the high levels of TGF-beta in breast milk and inhibitory effect of colostrum on IL-4 production, this suggests a possible mechanism whereby breast-feeding may protect against the development of allergy. Despite differences in the composition of breast milk between allergic and non-allergic mothers, the effects of breast milk on cytokine production from CBMC were independent of the atopic status of the mothers.

Does low IgA in human milk predispose the infant to development of cow's milk allergy?

We sought a relationship between total and cow's milk-specific IgA levels in colostrum and human milk and subsequent development of cow's milk allergy (CMA) in the breast-fed infant. The study included 87 nursing mothers and their infants (age, 2 d to 7 mo), followed prospectively up to 1 y. At 1 y, 48 mothers (69% with an atopic constitution) had an infant with CMA, verified by clinical cow's milk challenge, eight (38% with an atopic constitution) had a baby who had had protracted infantile colic but no CMA (disease control group), and 31 (23% with an atopic constitution) had a healthy infant. Total breast-milk IgA was measured by radial immunodiffusion, and IgA antibodies to cow's milk were measured by ELISA during the breast-feeding period. The levels of total and cow's milk-specific IgA antibodies in colostrum and human milk were significantly lower in the mothers whose baby later developed CMA [estimated third day value, 0.38 g/L (95% confidence interval, 0. 24-0.82)] than in the ones whose infant remained healthy or had had infantile colic but not CMA [0.82 g/L (95% confidence interval, 0. 99-1.51); p < 0.05]. The infants developed CMA significantly more often if the concentration of total IgA antibodies in milk was <0.25 g/L, when measured between 6 d and 4 wk postpartum [sensitivity, 0. 55; specificity, 0.92; odds ratio, 14.7 (95% confidence interval, 3. 1-70.2); p < 0.001]. The levels of cow's milk-specific IgA positively correlated with the levels of total IgA but not with the development of CMA in the infant. The levels of total or cow's milk-specific IgA did not correlate with maternal atopy. IgA antibodies in colostrum and human milk may prevent antigen entry at the intestinal surface of the breast-fed infant. A low IgA content in human milk may lead to defective exclusion of food antigens and thus predispose an offspring to develop food allergies.

Human milk polyunsaturated long-chain fatty acids and secretory immunoglobulin A antibodies and early childhood allergy

The possible protective effect of breast milk against atopic manifestations in infancy, i.e. atopic eczema and food allergy, has been controversial for the last decades. Besides the methodological problems, differences in the composition of human milk could explain these controversies. The aim of this study was to investigate the composition of polyunsaturated fatty acids (PUFA) and secretory immunoglobulin A (S-IgA) levels to food proteins (ovalbumin and beta-lactoglobulin) and an inhalant allergen (cat) in milk from mothers of allergic and non-allergic children. Blood samples were obtained at birth and at 3 months from 120 children. Skin prick tests were performed at 6, 12 and 18 months, and the development of atopic diseases was assessed in the children. Breast milk samples were collected from their mothers at birth and monthly during the lactation period. Milk PUFA composition was measured by gas chromatography, and enzyme-linked immunosorbent assay (ELISA) was used to measure total S-IgA, anti-cat S-IgA, anti-ovalbumin S-IgA, and anti-beta-lactoglobulin S-IgA. Allergic disease developed in 44/120 children (22/63 children of allergic mothers and 22/57 children of non-allergic mothers). Lower levels of eicosapentaenoic acid, C20:5 n-3 (EPA), docosapentaenoic acid C22:5 n-3 (DPA), and docosatetraenoic acid C22:4 n-6 (DHA) (p < 0.05 for all) were found in mature milk from mothers of allergic as compared to milk from mothers of non-allergic children. The total n-6:total n-3 and the arachidonic acid, C20:4 n-6 (AA):EPA ratios were significantly lower in transitional and mature milk from mothers of allergic children, as compared to milk from mothers of non-allergic children. The PUFA levels in serum of allergic and non-allergic children were largely similar, except for higher levels of C22:4 n-6 and C22:5 n-6 (p < 0.05 for both) and a higher AA:EPA ratio in serum phospholipids in the former group (p < 0.05). Changes in the levels of milk PUFA were reflected in changes in PUFA serum phospholipids, particularly for the n-6 PUFA. The AA: EPA ratio in maternal milk was related, however, to the AA:EPA only in serum from non-allergic children, while this was not the case in allergic children. The levels of total S-IgA, anti-cat S-IgA, anti-ovalbumin S-IgA, and anti-beta-lactoglobulin S-IgA in milk from mothers of allergic, as compared to non-allergic, children were similar through the first 3 months of lactation. Low levels of n-3 PUFA in human milk, and particularly a high AA:EPA ratio in maternal milk and serum phospholipids in the infants, were related to the development of symptoms of allergic disease at 18 months of age. The milk PUFA composition influenced the composition of PUFA in serum phospholipids of the children. We also showed that the lower levels of colostral anti-ovalbumin S-IgA and lower total S-IgA in mature milk from atopic mothers did not influence the development of allergic disease in the children up to 18 months of age. The findings indicate that low alpha-linolenic acid, C18:3 n-3 (LNA) and n-3 long-chain polyunsaturated fatty acids (LCP) 20-22 carbon chains, but not the levels of S-IgA antibodies to allergens, are related to the development of atopy in children.

Cytokines in breast milk from allergic and nonallergic mothers

The allergy-preventing effect of breast-feeding remains controversial, possibly because of individual variations in the composition of the breast milk. The aim of this study was to investigate the concentrations of cytokines involved in allergic reactions and IgA antibody production in breast milk from allergic and nonallergic mothers. The cytokine concentrations were determined in colostrum and 1-mo. milk samples from 24 mothers with, and 25 mothers without, atopic symptoms, using commercial ELISA kits. The immunosuppressive cytokine transforming growth factor-beta was predominant and was detectable in all milk samples. IL-6 was detected in the majority of colostral and mature milk samples, whereas the other cytokines were less commonly detected. The concentrations of IL-6, IL-10, and transforming growth factor-beta, which are all involved in IgA synthesis, correlated with each other and with total IgA concentrations in colostrum. The concentrations of IL-4 were higher in colostrum from allergic than nonallergic mothers, and similar trends were seen for IL-5 and IL-13. In conclusion, transforming growth factor-beta and IL-6 were the predominant cytokines in human milk. The correlation between the concentrations of cytokines involved in IgA synthesis, i.e. IL-10, IL-6, and transforming growth factor-beta, may explain the stimulatory effect on IgA production in breast-fed babies. Varying concentrations of IL-4, IL-5, and IL-13 may explain some of the controversy regarding the possible allergy-preventive effect of breast-feeding.

Atopic sensitization during the first year of life in relation to long chain polyunsaturated fatty acid levels in human milk

The levels of the long chain polyunsaturated n-6 and n-3 fatty acids (PUFA) were studied in colostrum and mature milk of 29 atopic and 29 nonatopic mothers and related to sensitization in their babies during the first 12 mo of life. The levels of alpha-linolenic acid (LNA) were lower (0.96 versus 1.23 weight percentage, p < 0.01) and the levels of dihomo-gamma-linoleic acid were higher (0.36 versus 0.31 weight percentage, p < 0.05) in mature milk from mothers of atopic babies (n = 24) compared with mothers of nonatopic babies (n = 34). The total n-3 levels and the ratio of n-6 PUFA/n-3 PUFA were similar in colostrum of all mothers and then decreased significantly in mature milk (p < 0.001), particularly in milk given to atopic babies. The levels of the n-6 fatty acids arachidonic acid, C22:4, and C22:5 n-6 correlated in milk samples from nonatopic mothers (r = 0.61-0.97, p < 0.05 to p < 0.001) but were largely absent in colostrum and mature milk from atopic mothers. In contrast, LNA and eicosapentaenoic levels correlated in colostrum from the atopic mothers (r = 0.61-0.88) regardless of atopic sensitization in the infants, whereas LNA correlated to C20:4 n-3 in colostrum from nonatopic mothers of nonatopic infants. Furthermore, the levels of the n-3 fatty acid C20:4 n-3 correlated significantly to all n-6 fatty acids, except linoleic acid (r = 0.64-0.79, all p < 0.01) in mature milk from nonatopic mothers of nonsensitized children. Low levels of LNA and total n-3 long chain polyunsaturated fatty acids, in mature milk from the mothers, appear to be associated with atopic sensitization early in life, as well as disturbed relationships between the n-3 fatty acid 20:4 and the n-6 fatty acids particularly in mature milk. On the other hand, disturbed relationships within the individual fatty acids in the n-6 series in human milk reflected the atopic status in the mothers. The variations in the lipid composition of human milk could in part explain some of the controversies regarding the protective effects of breast-feeding against allergy.

Strategies for prevention

Allergy prevention is antigen specific. Elimination of native CMP from the diet in at-risk infants decreases the incidence of CMPA, but evidence for a decreased incidence of other atopic diseases is lacking. Clinical trials comparing the efficacy of different types of hydrolysates are needed.

The long-term effect of a partial whey hydrolysate formula on the prophylaxis of atopic disease

At the age of 5 years, the prevalence of atopic manifestations was analysed in 58 formula-fed "at risk" infants because of a history of atopic disease in at least two first degree relatives. Infants were randomly assigned to receive either a partial whey-hydrolysate formula (n: 28) or a regular cow's milk formula (n: 30) during the first 6 months of life; thereafter, feeding was unrestricted. Only non-breastfed infants were included. The groups did not differ in risk factors or in known confounding factors possibly influencing the incidence of manifestations suggestive of atopic disease. At 6 months, the prevalence of cow's milk protein (CMP) sensitivity was significantly decreased in the hydrolysate group (7% versus 43%; P: 0.002). At the age of 12 (21% versus 53%; P: 0.029), 36 (25% versus 57%; P: 0.018) and 60 months (29% versus 60%; P: 0.016) there was still a significant difference in the number of atopic manifestations, if calculated cumulatively. There was no difference between the groups if only the new cases after the age of 6 months were considered. Eczema was less frequent in the whey-hydrolysate group, but only during the 1st year of life, suggesting a decreased prevalence of CMP sensitivity. During the first 6 months, diarrhoea of non-infectious origin occurred in 8/30 infants (27%) of the adapted formula group, and in no infant in the hydrolysate group. "Colic as single manifestation" was considered of "allergic" origin in 1/28 infants in the hydrolysate group, and in 4/30 infants in the adapted formula group.(ABSTRACT TRUNCATED AT 250 WORDS)

Fecal IgE levels in infants at 1 month of age as indicator of atopic disease

Fecal IgE levels were investigated in 165 asymptomatic infants at 1 month of age under two nutritional regimens, breast-feeding and formula feeding, and the possibility of predicting by fecal IgE levels the onset of atopic disease was studied in these infants. IgE levels were measured by time-resolved fluoroimmunometric assay. IgE antibodies are detectable in fecal extracts, and we have already reported that IgE levels are increased in food-allergy patients after administration of food allergens, and this increase in fecal IgE levels may be a specific consequence of the local immune response to food-allergen stimulation in the gut mucosa. The presence of atopic disease and the feeding method during the nursing period were surveyed by questionnaire in 89 of these 165 infants when they were 18 months old. In an analysis of the present results, IgE values above 0.015 U/ml, the lower limit of measurement, were considered to be high. Forty-eight (29%) of the 165 subjects showed a high fecal IgE level. Thirty-seven (35%) of 105 formula-fed infants had high fecal IgE levels, whereas only 11 (18%) of 60 breast-fed infants had high levels (P < 0.05). With respect to atopic family history, 30 (39%) of the 77 infants with atopic family history had high fecal IgE levels, as compared with 18 (20%) of the 88 infants without atopic family history (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Relationship between IgG1 and IgG4 antibodies to foods and the development of IgE antibodies to inhalant allergens. II. Increased levels of IgG antibodies to foods in children who subsequently develop IgE antibodies to inhalant allergens

In the present investigation we have tested the hypothesis that children with a high IgG antibody response to foods have an increased risk of developing IgE antibodies to inhalant allergens. Sera from 106 children with an increased risk of developing IgE-mediated allergy were analysed. During the follow-up, in 54 of these children IgE antibodies to inhalant allergens appeared. A positive/negative IgG1 and IgG4 anti-food score was determined as described previously: sera from age-clustered unselected children were tested for the levels of IgG1 and IgG4 antibodies to common foods. For each IgG RAST and each age group, the 75-percentile was chosen as cut-off value. Each antibody level was thus converted into a positive (higher than the 75-percentile of the age group) or negative value. The number of positive tests was used as the score. High-risk children with a high IgG1 anti-food score more often developed inhalant-specific IgE antibodies than high-risk children with low IgG1 titres: 50% of the children with a high IgG1 anti-food score developed IgE antibodies to grass pollen. Fifty per cent of the children with a high and 14% of the children with a low IgG1 anti-food score developed IgE antibodies to cat dander. For the prediction of the development of IgE anti-mite (house dust mite), the IgG4 anti-food scores appeared less useful than the IgG1 anti-food scores; 46% of the IgG4 high responders versus 22% of the IgG4 low responders acquired IgE anti-mite, whereas for IgG1 these percentages were 73 and 19, respectively.

Influence of maternal diet during lactation and use of formula feeds on development of atopic eczema in high risk infants

OBJECTIVE

To examine the effects of maternal diet during lactation and the use of formula feeds on the development of atopic eczema in infants at risk.

DESIGN

Mothers who planned to breast feed exclusively were randomly allocated to either a restricted diet (avoiding milk and other dairy products, eggs, fish, peanuts, and soybeans) or a diet without restrictions. Mothers who did not plan to breast feed were randomly allocated to using one of three formula feeds.

SETTING

Child health centre in Canada.

SUBJECTS

97 Mothers who chose to breast feed and 124 mothers who did not.

INTERVENTIONS

Restricted diet for 49 mothers who breast fed. Casein hydrolysate formula, soy milk formula, or cows' milk formula for infants not breast fed.

MAIN OUTCOME MEASURE

Development of eczema in babies.

RESULTS

Infants were followed up over 18 months and examined for eczema. Eczema was less common and milder in babies who were breast fed and whose mothers were on a restricted diet (11/49 (22%) v 21/48 (48%)). In infants fed casein hydrolysate, soy milk, or cows' milk 9/43 (21%), 26/41 (63%), and 28/40 (70%), respectively, developed atopic eczema.

CONCLUSIONS

In families with a history of atopic disease [corrected] mothers who breast feed should avoid common allergenic foods during lactation. If they choose not to breast feed a hydrolysate formula should be used.

Epidemiology of asthma in western Europe

Asthma deaths are uncommon, but have recently increased in some countries due to problems in the management of the disease. Morbidity rates show large variations, which can be attributed to differences in defining the disease, but also to genuine variations, with a trend towards less asthma in northern Europe. It has been suggested that allergic diseases as a whole, and asthma in particular, may exhibit an upward secular trend. Risk factors include a genetic background and environmental triggering factors. The importance of genetic factors is illustrated by family studies and by extreme prevalence rates observed in some communities. Environmental factors include rapid air pollution variations which act as a trigger for asthma attacks. However, at levels currently prevailing in western Europe, air pollutants do not induce a higher incidence of asthma. Altitude generates a gradual decrease in Dermatophagoides, thus explaining both the clinical improvement in asthmatics living in altitude and a lower prevalence of asthma in populations born and living there. Among the other aero-allergens, grass pollens plays a major role in spring, elicitating asthma attacks. Some natural allergens transformed by man (castor bean, soja) can be responsible for asthma epidemics.

Development of atopic disease after early administration of cow milk formula

We prospectively studied the incidence of atopic disease in healthy term infants with a birth weight between -1 and -2 SD who were fed a cow milk formula during the first few days of life. A total of 216 infants were randomized to receive either early feeding with formula before normal breastfeeding was started (n = 112) or "normal feeding" with breastmilk (n = 104). Symptoms of allergy developed in 18% of the infants before 18 months of age in the formula fed group, as compared to 33% in the breastfed group (P less than 0.05). The difference was confined to the group of infants with a history of allergy in two family members. Thus, 11% of the formula-fed infants developed allergy symptoms, as compared to 61% of the control infants (P less than 0.01). Our study implies that early feeding during the first days of life with a cow milk formula, before the introduction of breastmilk, may reduce the incidence of allergy symptoms before 18 months of age in infants with a family history of allergy.

Mucosal immunity: the immunology of breast milk

The mammary glands represent one part of the mucosal immune system, a definable, subunit of humoral and cellular immune functions in man that appears to have developed particular qualities well suited to guard our interface with the environment. As our understanding of secretory immunoglobulins and lymphocyte migration patterns continues to develop, the immunologic components found in breast milk appear increasingly likely to play a specific immunologic role in the protection of the nursing infant. The biologic basis for the observed protective effect of breast-feeding is reviewed with an emphasis on the mechanisms involved in the development and maintenance of mucosal immunity in general.

Effect of homogenization and pasteurization on the allergenicity of bovine milk analysed by a murine anaphylactic shock model

In a factorial design study a murine anaphylactic shock model was used to analyse the effect of homogenization, pasteurization, and fat content on the ability of bovine milk to induce anaphylactic reactions. Mice were sensitized by either oral or subcutaneous immunizations with various types of bovine milk. In spite of a significantly higher antibody titre in the mice sensitized subcutaneously, there was no difference in the sensitivity between orally and subcutaneously immunized mice with respect to anaphylactic reactions. Pasteurization did not seem to change the ability of milk to induce anaphylactic reactions. However, increasing fat contents in combinations with homogenization resulted in an increase of the ability of the milk to induce anaphylactic reactions.

Allergic dermatitis (sweet itch) of Icelandic horses in Sweden: an epidemiological study

A survey of allergic dermatitis (sweet itch) in Sweden contained information on 441 Icelandic horses. Results of a questionnaire indicated that approximately 15 per cent of the country's Icelandic horses suffered from the disease. The prevalence of allergic dermatitis was significantly higher among horses imported from Iceland (26.2 per cent) compared to that of Swedish-born animals (6.7 per cent). In addition, horses born in Iceland were significantly more severely affected than horses born in Sweden. The risk of allergic dermatitis in Sweden appeared to be more than six times higher for horses exported from Iceland to Sweden relative to that of horses originally born in Sweden. The prevalence of disease for horses of seven years or older was 30 per cent for Icelandic-born individuals as compared to 7.3 per cent for horses born in Sweden. Similarly, the risk of allergic dermatitis in Sweden for horses of seven years or older appeared to be nearly 10 times higher for horses imported from Iceland relative to that of horses born in Sweden. Allergic dermatitis usually appeared during the third grazing season for imported horses and during the fourth season for horses born in Sweden. Furthermore, the course of the disease tended to become worse with time. Analysis of the prevalence of allergic dermatitis relative to gender revealed no significant differences. Certain geographical variations in the prevalence of the disease was also found.

Cord blood IgE and month of birth

If cord blood IgE is used to detect those predisposed to become allergic it is important to define appropriately the normal values for this measurement. A commonly cited cut off point is 1.0 IU/ml. We analysed 5353 cord blood samples for IgE by means of an enzyme linked immunosorbent assay. Descriptive statistics of the distribution curve of cord blood IgE concentrations showed that most normal values were well below the cut off value of 1.0 IU/ml and that most abnormal values were in the neighbourhood of 1.0 IU/ml. It seems advantageous, therefore, to lower the cut off value for cord blood IgE. When cord blood IgE was analysed according to the child's month of birth a significantly uneven distribution of abnormal cases of cord blood IgE concentrations over the year was found. The occurrence of an abnormal cord blood IgE concentration showed a significant cyclic trend, with a peak near the end of April and a trough in late October.

Influences of neonatal serum IgE concentration, family history and diet on the incidence of cow's milk allergy

Serum IgE concentration was measured on the 5th day of life in 943 infants. All infants were included in a 3 month follow-up study. The frequency of cow's milk allergy was studied according to either family history, IgE level, or both. Feeding (mother's milk or formula feeding) was taken into account. Manifestations suggestive of food allergy were hardly observed in breast-fed babies. In the formula-fed group a positive family history correlated with a 40% incidence of allergic manifestations, compared to a 13% incidence (P less than 0.001) in the group with negative family history. A high IgE level (IgE greater than 1.3 U/ml) indicated a 43% risk of developing allergic manifestations in formula-fed babies as compared to 15% (P less than 0.001) in the group with normal results of a screening test. Frequency of allergic manifestations in a subgroup with a negative family history and a high IgE level (38%) was equal to the frequency in the subgroup with a positive family history and negative screening test results (IgE less than 1.3 U/ml)(36%). The incidence in the subgroup with both positive screening test results and a positive family history was 49%. None of these differences were significant. The frequency in the subgroup with both parameters negative was 8% (P less than 0.001 to 3 other subgroups). Our results indicate that the family history seems to correlate as well with the incidence of allergic manifestations as the neonatal serum IgE concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of maternal food antigen avoidance during pregnancy and lactation on incidence of atopic eczema in infants

One hundred and twenty-one women with history of a previous child with atopic disease were randomly allocated during the next pregnancy to antigen avoidance or control groups. Dietary advice consisted of almost complete exclusion of milk and dairy products, egg, fish, beef and peanut throughout pregnancy and lactation. A total of 109 completed the study. Maternal antigen avoidance was associated with reduced occurrence of atopic eczema and the skin involvement was less extensive and milder. The beneficial effect was observed mainly in the breast-fed group. Among the fifty-five who completed the trial of antigen avoidance, seventeen infants developed atopic eczema, five out of thirty-five who were breast-fed and twelve out of twenty who were formula-fed. Among the offspring of fifty-four control mothers given no dietary restriction, eczema was observed in twenty-four infants, eleven out of thirty-six breast-fed and thirteen of eighteen formula-fed. Avoidance of common dietary allergens during pregnancy and lactation enhanced the preventive beneficial effect of exclusive breast feeding on the incidence of atopic eczema among infants at high risk.

IgG subclass deficiencies

IgG subclasses differ not only in their biochemical and biologic properties, but also in their occurrence as selective deficiencies, alone and in combination. The normal range of IgG subclass concentrations in children and adults is compared with deficiencies found in individuals with repeated respiratory tract infections. Concomitant IgA deficiency is often noted. It is suggested that decreased IgG2 and IgG3 levels in IgA-deficient individuals may increase the risk of recurrent respiratory infection and lung damage. Finally, the efficacy immunoglobulin. prophylaxis in reducing of infection is anecdotally related.

Presence of IgE suppressor factors in human colostrum

In spite of intensive investigations, the ability of breast feeding to delay and to attenuate atopic diseases in children remains debatable. This study documents a mechanism whereby breast feeding might interfere with the synthesis of IgE by breast-fed infants. Indeed, we show that colostrum contains IgE-binding factors (IgE-BF) capable of suppressing the in vitro synthesis of human IgE. Colostrum obtained from 15 donors was successively depleted of lipids and casein, filtered through Amicon XM50 membrane (mol. mass cut-off 50 kDa) and lyophilized. IgE-BF was demonstrated in such preparations by two different approaches, i.e. a classical rosette inhibition assay and Western blot analysis. In the first instance, lyophilized preparations of colostrum inhibited the binding of IgE-coated bovine erythrocytes to IgE recovered on the surface of RPMI 8866 lymphoblastoid cells. The rosette-inhibiting activity could be absorbed on IgE- but not on IgG-Sepharose 4B and it could be recovered in the eluate of IgE-Sepharose 4B. The molecular mass of IgE-BF was comprised between 10 to 20 kDa as estimated by gel filtration through a calibrated Sephadex G-75 column. After fractionation on 12% sodium dodecyl sulfate-polyacrylamide gel electrophoresis and transfer to nitrocellulose membrane, colostrum displayed one band of 14 kDa and reacted with radiolabeled IgE but not with IgG nor IgM. This 14-kDa band could be removed by absorbing colostrum with IgE- but not with IgG-Sepharose 4B. Most importantly, the colostrum IgE-BF suppressed the spontaneous in vitro synthesis of IgE by B lymphocytes derived from allergic donors without altering the production of IgM.