Human milk factors and atopy in early childhood

Sammanfattning: Background: The protective effect of breast milk against atopic manifestations in infancy, i. e. atopic eczema and food allergy, has been controversial for the last decades. Differences in the composition of human milk could explain these controversies.Aims: To investigate the composition of milk antibodies, such as lgE, total S-IgA and S-IgA antibodies against food and inhalant allergens (B-lactoglobulin, ovalbumin and cat allergen) in milk from atopic and non atopic mothers. To study human milk nucleotide, polyamine and polyunsaturated fatty acid (PUFA) composition. Furthermore, the composition of these factors in maternal milk were related to the development of allergic disease in the children during the first 18 months of life.Methods: One hundred and twenty (120) children were followed at 3, 6, 12 and 18 months of age. Blood samples were obtained at birth and at 3 months. Skin prick tests were petformed 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 dming the lactation period. Total IgE antibodies were measured by RIA and S-IgA antibodies by ELISA. Milk nucleotides and polyamines were measured by HPLC and PUFA by gas chromatography.Results: Total IgE and total S-IgA levels were similar in colostrum from atopic and non atopic mothers, Total S-IgA levels were, however, lower in mature milk from atopic than from non atopic mothers. Levels of S-IgA antibodies against foods and cat, were similar in the two groups during the lactation period, except for low levels of anti-OVA S-lgA in colostrum of atopic mothers. Nucleotide composition was similar in milk from atopic and non atopic mothers. Low levels of putrescine and spermine were, however, found in mature milk from atopic mothers.Low levels of LA, LNA, n-6 LCP and n-3 LCP and particularly higher LAILNA and AA!EPA ratios were found in milk from atopic mothers at one month of lactation. Correlations between individual LCP levels were observed in milk from non atopic mothers. These correlations were absent in milk from atopic individuals, indicating a disturbed PUFA metabolism. The differences were less obvious in serum phospholipids from newboms.Total lgE, total S-IgA and S-IgA antibodies against foods and cat, as well as nucleotide and polyamine levels were similar in milk from mothers of allergic children. Lower levels of EPA in transitional milk and lower levels of EPA, DPA and DHA (p<0.05 for all) in mature milk were found in mothers of allergic as compared to mothers of non allergic children. Total n-6/total n-3 and AA/EPA ratios were low in both transitional and mature milk from mothers of allergic children. The disturbed correlations within the n-6 fatty acids in milk from atopic mothers were not related to the development of atopy in the children. In contrast, C20:4 n-3 correlated well to most of the n-6 fatty acid levels only in milk from non atopic mothers of non atopic children.The PUP A levels in serum from allergic and non allergic children were similar, except higher levels of C22:4 n-6 and C22:5 n-6 (p<0.05 for both) and higher AA!EPA ratio in serum phospho1ipids from the former group (p<0.05). Changes in levels of milk PUFA were reflected in changes in PUFA serum phospholipids, particularly for the n-6 PUPA. 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.Conclusion: Low levels of anti-QV A S-IgA antibodies in colostrum and low levels of total S-IgA, putrescine and spermine in mature milk. were related to maternal atopy. Human milk IgE antibody and nucleotide composition were not related to maternal atopy. Neither of these milk factors were, however, related to development of anergic disease in children. Low levels of n-6 and n-3 PUFA in transitional milk were related to maternal atopy, particularly low levels of n-3 PUP A and high AA/EPA ratio in maternal milk and serum phospholipids in the infants were related to the development of allergy in the children. The milk PUPA composition influenced the composition of PUPA in serum phospholipids of the children. The findings are suggested to be partly related to a 8-6 desaturase dysfunction in atopic individuals.