ABSTRACT
Tonsils contain four specialized lymphoid compartments that together are involved in immune functions. The capacity of tonsillar lymphocytes to counter infections may be altered during one's lifetime. The classification of lymphocytes by CD antigen expression is now widely used in clinical medicine and experimental immunology. The present work was designed to study the distribution of CD4 and CD8 antigen expression in T lymphocytes in human tonsils at different periods of life. Sixty-two tonsillar specimens were obtained from still birth infants and from children aged 1-9 years. Paraffin sections were prepared and stained with H and E and with immunohistochemical stains to demonstrate CD4 and CD8 T lymphocytes. The distribution of these cells in the different components of the tonsils was evaluated with an image analyzer. The obtained data were statistically analyzed using SPSS. There was a significant increase in the distribution of stained CD4 and CD8 T lymphocytes in the interfollicular areas, mantle zones of lymphoid follicles, and partially in the germinal centers of the examined tonsils with the advancement of age. Activated T lymphocytes differentiate into several subtypes, among which are CD4 and CD8 cells. These types of T lymphocytes express surface antigens, which can interact with different foreign pathogens