ABSTRACT
Thymic hypoplasia (DiGeorge syndrome) occurs when the immune system in infants is deprived of thymic influence. T cells are absent or deficient in the blood and thymusdependent areas of lymph nodes and spleen. Infants with this condition are highly susceptible to infection by viruses, fungi, protozoa, or intracellular bacteria due to defective intracellular microbial killing by phagocytic cells with interferon. By contrast, B cells and immunoglobulins are not affected.
