Which statement about secondary immunodeficiencies is true?

• A. They are acquired conditions such as HIV infection or chemotherapy-induced immunosuppression
• B. They are always present from birth
• C. They are exclusively genetic
• D. They involve only antibody production and not cellular immunity

Answer: (A)

Secondary immunodeficiencies are acquired conditions caused by external factors or diseases after birth, such as HIV infection or chemotherapy-induced immunosuppression. This captures the essential idea that these deficiencies develop due to another process rather than being inherited. They differ from primary immunodeficiencies, which are present from birth because of genetic defects.

They're not limited to being present from birth, nor are they exclusively genetic. And they don't affect only antibody production; many forms impair cellular immunity as well. For instance, HIV targets CD4+ T cells, weakening cellular and humoral responses, while chemotherapy can suppress both B and T cell functions.