[Cellular composition of tracheal lymphoid tissue in children in their first year of life]

By means of morphometrical methods in histological preparations the quantitative relations of various cell types of lymphoid formations has been studied in newborns and in suckling children. The trachea in the newborns practically does not possess any morphological substrate in the form of lymphoid accumulations, responsible for immune defense of the organ from any external influence. Development of the lymphoid tissue begins in the suckling age and its cytoarchitectonics depends on their localization in the organ's wall. A special place among the accumulations of the lymphoid cells occupy connective tissue spaces of the tracheal glands, where besides lymphocytes and fibroblasts a great amount of plasma cells is situated. Under epithelium these cells are in the least amount, in the prenoduli they are of an intermediate amount. In all the lymphoid structures investigated reproductive function is absent; this is proved by absence of blasts and mitotically dividing cells. Increase in amount of the tracheal lymphoid formations in all age groups studied takes place at the expense of cells migration across blood vessels.