The nurse practitioner is initiating treatment for a 29-year-old man with human immunodeficiency virus (HIV). What is the pathogenesis of HIV?

Choice A reason: HIV is not an autoimmune disorder. Autoimmune diseases involve the immune system attacking the body's own tissues, whereas HIV is a viral infection that targets and destroys immune cells, specifically CD4+ T lymphocytes. Choice B reason: HIV infects CD4+ T cells and macrophages, leading to progressive depletion of these cells. This impairs both cell-mediated and humoral immunity, rendering the host susceptible to opportunistic infections and certain malignancies. The virus integrates into host DNA and replicates, gradually weakening the immune system. Choice C reason: Tickborne illnesses such as Lyme disease or babesiosis are unrelated to HIV. They are caused by different pathogens and have distinct transmission routes and pathophysiology. Choice D reason: HIV is not a nosocomial infection. It is primarily transmitted through blood, sexual contact, and vertical transmission from mother to child. Nosocomial infections are acquired in healthcare settings and typically involve bacteria like MRSA or Pseudomonas.