What is an example of an acquired cell-mediated (T-cell) immunodeficiency?

• A. DiGeorge's Syndrome
• B. HIV and AIDS
• C. X-linked hypogammaglobulinemia
• D. Severe combined immunodeficiency syndrome

Answer: (B)

An acquired cell-mediated (T-cell) immunodeficiency is characterized by the loss of T-cell function which can lead to a compromised immune response. HIV (Human Immunodeficiency Virus) specifically attacks the CD4+ T-helper cells, which are crucial for orchestrating the immune response. As the disease progresses to AIDS (Acquired Immunodeficiency Syndrome), the body's ability to mount an effective immune response against infections is severely diminished. This results in increased susceptibility to opportunistic infections, some of which may not typically cause disease in individuals with a fully functioning immune system.

In contrast, DiGeorge's Syndrome is a congenital disorder characterized by the absence or underdevelopment of the thymus gland, affecting T-cell development, but it is not acquired; it is present from birth. X-linked hypogammaglobulinemia primarily affects B-cell function, leading to reduced antibody production rather than a direct T-cell deficiency. Severe combined immunodeficiency syndrome involves both T-cell and B-cell deficiencies and is also a genetic disorder rather than an acquired condition.

Therefore, the identification of HIV and AIDS as an acquired cell-mediated immunodeficiency reflects the nature of the disease—where T-cell function is directly impacted due to viral infection.