Part 1 - The effects of nutritional deficiency on systemic and local immunity: implication for gastrointestinal disease

Abstract

This chapter discusses the effects of nutritional deficiency on systemic and local immunity and implication for gastrointestinal disease. The immunosuppressive effects of undernutrition, together with observations that infection is of greater severity, lasts longer and recurs more frequently in malnourished children, is well documented. Among the nutritional deficiencies, energy, protein, iron, folic acid, vitamin A, pyridoxine and zinc, both individually and collectively, have been examined in depth. Profound thymic atrophy was identified as one of the striking histopathological features of severe malnutrition more than 50 years ago. The thymus is small with ill-defined demarcations between the cortex and the medulla. There are fewer than normal lymphoid cells, and Hassal corpuscles are crowded, dilated, and degenerate and occasionally, even calcified. There is cellular depletion with involution of thymus-dependent areas in the spleen and lymph nodes. These morphological alterations are reflected in reduced activity of serum thymic factor. Defects in the ability of neutrophils to respond chemotactically are implied by the presence of mucocutaneous lesions and superficial necrotizing lesions with pyogenic bacteria during protein-energy malnutrition.