Which virus causes progressive loss of CD4+ T cells leading to AIDS?

Which virus causes progressive loss of CD4+ T cells leading to AIDS?

• A. Human immunodeficiency virus (HIV)
• B. Hepatitis B virus
• C. Epstein-Barr virus
• D. Cytomegalovirus

Answer: (A)

HIV stands out because it directly targets and progressively depletes CD4+ T helper cells, the central coordinators of the immune response. As HIV replicates and destroys these cells, the immune system loses its ability to mount effective responses, paving the way for opportunistic infections and certain cancers that define AIDS. Over time, the CD4+ T cell count falls, and AIDS develops when it becomes severely low or when characteristic opportunistic infections appear. The other viruses don’t cause AIDS through CD4+ T cell depletion. Hepatitis B virus infects liver cells and leads to hepatitis, not immune failure. Epstein-Barr virus mainly affects B cells and can cause mononucleosis or B-cell–related cancers, not a progressive loss of CD4+ T cells. Cytomegalovirus can cause disease in people with weakened immunity but is typically a complication rather than the primary cause of AIDS.

HIV stands out because it directly targets and progressively depletes CD4+ T helper cells, the central coordinators of the immune response. As HIV replicates and destroys these cells, the immune system loses its ability to mount effective responses, paving the way for opportunistic infections and certain cancers that define AIDS. Over time, the CD4+ T cell count falls, and AIDS develops when it becomes severely low or when characteristic opportunistic infections appear.

The other viruses don’t cause AIDS through CD4+ T cell depletion. Hepatitis B virus infects liver cells and leads to hepatitis, not immune failure. Epstein-Barr virus mainly affects B cells and can cause mononucleosis or B-cell–related cancers, not a progressive loss of CD4+ T cells. Cytomegalovirus can cause disease in people with weakened immunity but is typically a complication rather than the primary cause of AIDS.