[Formation of a local IgA system in the intestines of infants in the 1st weeks of life].

Formation of the IgA passive and active system in the gastrointestinal tract of children of the first weeks of life was studied on the basis of determining the IgA content in coprofiltrates and the level of immunoglobulins in the breast milk. The predominant class of immunoglobulins contained by the breast milk during the first lactation week involved IgA that was present in considerable concentrations. The IgA level in the milk declined by the end of the first week. Before giving babies the breast, their coprofiltrates did not show IgA. Afterwards its concentration grew intensively in infants fed native breast milk and lowered gradually by one month and a half to two months of age. IgA was not detectable in coprofiltrates of infants of the first two weeks of life fed pasteurized breast milk. With age the frequency of detection increased, however, even during the second month of life IgA was not detectable in all the cases, its concentration being three times less as compared to that in breast fed children of the same age.