When HIV infection destroys lymphocytes (T-Helper Cells), it weakens the body's immune system, which protects against many infections and cancers.Acquired immunodeficiency syndrome (AIDS) is a chronic, potentially life-threatening condition caused by the human immunodeficiency virus (HIV). By damaging your immune system, HIV interferes with your body's ability to fight infection, and disease weakening is part of the reason that the body is unable to eliminate HIV infection once it has started.HIV (human immunodeficiency virus) is a retrovirus that attacks the immune system.Most people who are diagnosed early and take medicines for HIV can live long, healthy lives.HIV destroys T lymphocytes (helper T cells).Helper T cells are crucial for immune system function and activate after encountering antigens from disease-causing microorganisms