What can cause acquired combined B and T cell immunodeficiencies?

• A. Genetic mutations only
• B. Radiation and chemotherapy
• C. Both A and B
• D. Only advanced age

Answer: (B)

Acquired combined B and T cell immunodeficiencies can arise from environmental factors like radiation and chemotherapy. These treatments are known to damage the bone marrow and lymphoid tissues where B and T cells are produced and mature, leading to a decrease in the overall immune function.

Radiation can cause direct damage to the DNA within the cells, and chemotherapy, while used to treat cancer, can indiscriminately affect rapidly dividing cells, including those involved in the immune response. This results in a compromised ability to produce both types of lymphocytes, which are crucial for mounting an effective immune response to infections.

Genetic mutations generally refer to primary immunodeficiencies that are present from birth, which differ fundamentally from acquired immunodeficiencies caused by external environmental factors. Similarly, while advanced age can impact immune function, it does not typically lead to combined immunodeficiencies in the same direct manner as radiation or chemotherapy, which cause specific damage to the immune system.