ABSTRACT
This chapter describes the effects of malnutrition on the thymus gland, T lymphocytes, and cell-mediated immunity in humans. The size of the thymus gland relative to body weight is greatest at birth, and although total thymus mass increases slightly during the first year of life, its size stabilizes even as the progressive process of physiological involution begins. A study of thymus pathology in malnourished children from Senegal used microscopic examination with an image analyzer to quantify the fibrous tissue invading the gland and employed this criterion, in addition to descriptions of architecture and density of lymphoid cells and Hassal’s corpuscles, to classify the degree of involution in malnourished subjects. Available human data demonstrate that protein-energy malnutrition causes major changes in thymus gland structure, with marked decreases in the number of cortical lymphocytes, fatty infiltration, fibrosis, and diminution and alteration of Hassal’s corpuscles.
