What term is used to identify a serious condition characterized by a defect in the body's natural immunity?

AIDS, or Acquired Immunodeficiency Syndrome, is characterized by a significant weakening of the immune system due to infection with the Human Immunodeficiency Virus (HIV). This virus attacks and destroys key cells in the immune system, making individuals more vulnerable to infections and diseases that a healthy immune system would typically be able to combat. The severe defect in the body's natural immunity is the hallmark of AIDS, which is why it is recognized as a serious condition associated with immunodeficiency. Other options may refer to medical conditions that affect the body, but they do not specifically relate to a deficiency in the immune system like AIDS does.