HIV Disease and AIDS
Keys to Understanding and Coping
The Target: Your Immune System
The immune system is where a basic understanding of Human Immunodeficiency Virus (HIV) disease and Acquired Immunodeficiency Syndrome (AIDS) begins.
Although the immune system is highly complex, the role it plays in our health is clear and essential: to protect the body from diseases such as HIV.
To perform its job effectively, the immune system enlists an army of different cells, each with a specialized function. Together, they create a powerful force against infection.
Imagine a football team and the players on it. Some attack and some defend. In many ways, the immune system works the same way, with white blood cells called CD4 cells acting as the quarterback in charge.
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CD4 cells (also known as T cells) are key to immune system response and success. They organize and rally the other immune system cells to action -- including B cells and CD8 cells.
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B cells defend against the invading microbes by making substances called antibodies, helping to protect healthy cells from infection.
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At the same time, CD8 cells act as killers, destroying those cells already infected by the microbes.
Questions & Answers
"What is the normal number for CD4 cells?"
The immune system is always producing CD4 cells. In healthy people, they can number anywhere from 425 to 1600 in 5 millilitres (or about a teaspoonful) of blood, with about 1000 the norm.
"Will one blood test tell me exactly how my immune system is doing?"
CD4 cell counts vary widely in the same person, so do not rely on any one test as a sure sign of how your immune system is doing. Look for trends in your CD4 counts over a period of time.
"Are my CD4 cell counts a measure of how sick or healthy I am?"
CD4 cell counts indicate only how likely you may be to get certain kinds of infection.
