CHAPTER 3 Immune System^145
since they produce an antigen-specific antibody. T-cells provide a cellular immune
response. Mature T-cells are composed of CD4 and CD8 cells. CD8 cells are re-
sponsible for destroying foreign and viral inhabited cells, and suppress immuno-
logical functions. CD4 cells, also known as helper T-cells, stimulate immune
functions, such as B-cells and macrophages. A macrophage is a cell whose func-
tions include ingesting foreign or invading cells.
Just the Facts
Acquired Immunodeficiency Syndrome (AIDS)
WHAT WENT WRONG?
The human immunodeficiency virus (HIV) causes malfunction of T-cells which
protect the body from invading microorganisms. When it enters a cell, HIV repli-
cates, causing the cell to reproduce more infected cells. It also frequently causes
cell death. The CD4 lymphocyte is most often affected, followed by B-lymphocytes
and macrophages. Immunodeficiency results.
PROGNOSIS
Prognosis has improved since HIV was discovered in 1981. Fewer patients are
progressing from HIV to AIDS, and both classes are living longer. New drugs and
therapies are decreasing the number of deaths. Patients are living with fewer dis-
abilities and comorbidities.
HALLMARK SIGNS AND SYMPTOMS
- Anorexia—secondary to GI manifestations, oral disease, and side effects of
medications. - Fatigue—cells dying at an abnormal rate; opportunistic infections due to a
poorly functioning immune system.
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