What is a primary effect of HIV/AIDS on the body?

The primary effect of HIV/AIDS on the body is damage to cell-mediated immunity. HIV, or Human Immunodeficiency Virus, specifically targets and attacks the immune system, particularly the CD4+ T cells, which are vital for the immune response. As the virus progresses and the number of these immunocompetent cells declines, the body's ability to fight infections and certain diseases becomes severely compromised. This loss of cell-mediated immunity leads to an increased vulnerability to opportunistic infections and can result in various complications associated with AIDS (Acquired Immunodeficiency Syndrome).

The other options may describe different conditions or effects, but they do not encapsulate the fundamental impact of HIV/AIDS on the immune system. Decreased lung function is not a direct consequence of HIV infection itself but may result from opportunistic infections or other complications. Increased blood pressure can occur for various reasons but is not a specific consequence of HIV/AIDS. Lastly, growth of muscle mass is not associated with HIV/AIDS; in fact, some individuals may experience muscle wasting due to the disease's progression and the effects of chronic illness.