cause of the demise of the immune system, which then leads to the body being unable to fight off opportunistic diseases; the person gets AIDS and dies. Part and parcel of that definition of AIDS is a broken immune system. So for years – and still today, as a matter of fact – an HIV-Positive’s CD4 cell count was thought to be an indication of progression to AIDS. But a major study in 1991 – I think the researcher’s name was Hill – found that CD4 counts were not really a reliable marker to predict progression to AIDS in HIV-Positive subjects. What Dr. Hill said exactly was that ‘variance in CD4 from… non-HIV related longitudinal fluctuations needs to be accounted for in analysis of the prognostic power of CD4 in HIV infection.’ Since then other studies have found HIV-Negative people to have low CD4 cell counts as well.”
“When you say ‘a low CD4 count,’ what constitutes a normal CD4 cell count?”
“The normal range is usually considered to be between 500 and 1500.”
“500 and 1500 what?”
“Sorry. 500 to 1500 CD4 cells in a cubic millimeter of blood.”
“That’s a fairly wide range, isn’t it?”
“Yes, and a person’s CD4 cell count can vary widely within that range, depending on a lot of factors, even in the course of 24 hours. Just go out and lie on a beach for a while and your CD4 cell count will go down. Any time we don’t need our immune system to be actively fighting some perceived threat, it will rest – take a nap, if you will, and fade into the background.”
It was a really good example that Campbell had never thought about. He’s glad Fowler had.
“What other factors will impact a CD4 cell count, Dr. Fowler?”
“Well, it’s now been well documented that malnutrition is one of the biggest things that can lower a CD4 cell count. Malnutrition, chronic stress and fatigue. On the other hand, infections, and even vaccinations, will make the CD4 count go up as the immune system responds to a foreign invader and builds up its armies. Generally speaking, if you have high CD4 cell counts, your immune system is considered to be doing pretty well; and if you have very low CD4 cell counts, you're considered to be in trouble.”
“But you said that healthy people who were HIV-Negative could also have low CD4 cell counts.”
“Yes, they can. Another recent study in Africa found HIV-Negative people with lower than normal CD4 cell counts – around 350. That’s why there is so much controversy about using CD4 cell counts to diagnose AIDS or to begin HIV drug therapy.”
“But
“When you say ‘a low CD4 count,’ what constitutes a normal CD4 cell count?”
“The normal range is usually considered to be between 500 and 1500.”
“500 and 1500 what?”
“Sorry. 500 to 1500 CD4 cells in a cubic millimeter of blood.”
“That’s a fairly wide range, isn’t it?”
“Yes, and a person’s CD4 cell count can vary widely within that range, depending on a lot of factors, even in the course of 24 hours. Just go out and lie on a beach for a while and your CD4 cell count will go down. Any time we don’t need our immune system to be actively fighting some perceived threat, it will rest – take a nap, if you will, and fade into the background.”
It was a really good example that Campbell had never thought about. He’s glad Fowler had.
“What other factors will impact a CD4 cell count, Dr. Fowler?”
“Well, it’s now been well documented that malnutrition is one of the biggest things that can lower a CD4 cell count. Malnutrition, chronic stress and fatigue. On the other hand, infections, and even vaccinations, will make the CD4 count go up as the immune system responds to a foreign invader and builds up its armies. Generally speaking, if you have high CD4 cell counts, your immune system is considered to be doing pretty well; and if you have very low CD4 cell counts, you're considered to be in trouble.”
“But you said that healthy people who were HIV-Negative could also have low CD4 cell counts.”
“Yes, they can. Another recent study in Africa found HIV-Negative people with lower than normal CD4 cell counts – around 350. That’s why there is so much controversy about using CD4 cell counts to diagnose AIDS or to begin HIV drug therapy.”
“But