Développement du système immunitaire

Je souhaitais partager avec celles que ça intéresse l'impact majeur du lait maternel sur le système de défense de nos tout-petits. Ce n'est pas toujours facile à comprendre, mais voici des passages importants:
Being delivered next to the mother's anus the newborn is subsequently colonized by the mother's microbial flora. This microflora is the least threatening, since the mother provides defence against these microbes primarily via breastfeeding, but also to some extent via her trans-placentally-transferred IgG antibodies. These antibodies provide tissue defence that is pro-inflammatory by activating the complement system and phagocytes. This form of defence is costly, because the inflammation will consume energy and will cause the common symptoms of disease, such as pain, tiredness, fever and loss of appetite, via the increase in leptin caused by the cytokines IL-1b, TNFa and IL-6 produced by the leucocytes that are activated by exposure to infectious agents. Furthermore, this form of defence, although necessary and vital, is clearly undesirable in the young infant because it can interfere with growth and development. The link between frequent infections in early life and impaired growth is commonly observed in poor socio-economic regions. In contrast, the host defence provided via the milk protects without inducing inflammation; it can even counteract inflammation ...
Early breastfeeding promotes the establishment of an optimal microbial gut flora in the infant from delivery onwards, counteracting potential pathogens. Certain harmless strains, such as Lactobacillus rhamnosus and other lactobacilli, are promoted by human milk. Some bifidobacteria also seem to be favoured by breast-feeding... (Des probiotiques quotidiens à peu de frais!!!)
These oligosaccharides seem to affect the composition of the gut microflora and may partly explain why breastfed children carry potentially pathogenic E. coli, Klebsiella and other Enterobacteriacae strains less often than non-breastfed children ...
It has been proposed that the presence of IL-7 in milk is linked to the fact that the central organ in the immune system, the thymus, is twice as large in breastfed infants compared with non-breastfed infants . Studies in Africa have shown that a smaller thymus at birth predicts a higher infant mortality from infections , independent of other factors known to reduce the size of the thymus such as birth weight and malnutrition...
Based on the evident protective capacity of breastfeeding, it has been suggested that not breastfeeding may be the most common immunodeficiency in infancy ...
Some studies have shown that breastfeeding may enhance vaccine responses ...
...so many defence strategies have developed in the mammary glands and the milk, all defending without inducing inflammation in the offspring; some components, like lactoferrin, even actively counteract inflammation. Thus, appetite is not disturbed, as it is when tissue defence is initiated; a process that always induces inflammation, which is consistently costly, particularly for a growing individual, and also affects appetite, i.e. via pro-inflammatory cytokines increasing leptin levels.
http://journals.cambridge.org/download.php?file=%2FPNS%2FPNS66_03%2FS0029665107005654a.pdf&code=6690d7605f7834c1a22b52fd9ff5084a
En français:
http://www.lllfrance.org/Dossiers-de-l-allaitement/DA-Hors-serie-JIA-2003.-Allaitement-laits-industriels-et-systeme-immunitaire.html
EN RÉSUMÉ, L'IMPORTANT C'EST QUE LE CORPS SE DÉFENDE, MAIS SI CELUI-CI PEUT LE FAIRE SANS ANTIBIOTIQUES ET ENCORE MIEUX SANS INFLAMMATION, COMME GRÂCE AU LAIT MATERNEL, C'EST L'IDÉAL. C'est fou comme la nature est bien faite!