In which of the following conditions would you be LEAST likely to see a robust delayed-type hypersensitivity (DTH) response to a Candida antigen skin challenge?

Question

A. X-linked agammaglobulinemia
B. DiGeorge syndrome
C. Selective IgA deficiency
D. Common variable immunodeficiency
E. Chronic granulomatous disease

Answer 1

ANS: B.  A delayed-type hypersensitivity (DTH) response is an immune reaction in which T cell-dependent macrophage activation and inflammation cause tissue injury. The severity of the reaction to the subcutaneous injection of antigen is used as an assay for cell-mediated immunity. A deficient cutaneous DTH response to common microbial antigens, such as Candida antigens, suggests a T cell immunodeficiency. DiGeorge syndrome is a selective T cell deficiency caused by a congenital malformation that results in defective development of the thymus and other embryologically associated structures. In contrast, X-linked agammaglobulinemia, selective IgA deficiency, and common variable immunodeficiency are B cell immunodeficiencies. Chronic granulomatous disease is a congenital disorder in which phagocytes cannot generate free radicals and kill ingested microbes.