Which statement describes immunodeficiency diseases?

• A. Autoimmune reaction against self
• B. Allergic hypersensitivity
• C. Occurs when the immune system responds but is not strong enough to do the job
• D. Exaggerated immune response to pathogens

Answer: (C)

Immunodeficiency diseases occur when the immune system is weakened or not functioning well, so it can mount only a partial or ineffective defense. That means infections are more frequent, more severe, or caused by organisms that usually don’t cause trouble. This is why the statement describing immunodeficiency is the one that says the immune system Responds but isn’t strong enough to do the job.

This concept contrasts with autoimmune conditions, where the immune system attacks the body’s own tissues; with allergic hypersensitivity, where the immune system overreacts to harmless substances; and with situations where the immune response is exaggerated to pathogens, which is about an overactive, not a deficient, response. Immunodeficiencies can be genetic or acquired, and management focuses on preventing infections and supporting immunity.