CD4 count and Viral Load

Viral Load, CD4 levels and HIV/AIDS
by Josh
CD4 T helper lymphocyte levels are depleted by HIV/AIDS. CD4 T helper cell depletion weakens the immune system opening it up to infections whih the body cannot combat. It also opens the body up to opportunistic infection. The normal DC4 count in a male is usually above 400 or 500 (Viral Load).
Sometimes a person can be affected with HIV and not get sypmtomes for many years. However CD4 count goes down within the first few weeks of infection. HIV targets helper T cells with the co-receptor CCR5. These cells are abundant in the intestinal mucosa. (Viral Load)
Viral load meaures the content of virus per ml of blood. This measurement indicates the severity of the virus. Obviosuly a higher viral load inidcated a more sever viral infection. In the US the FDA has approved 3 different viral load tests for HIV(viral load)
• Amplicor HIV-1 Monitor test (Hoffman-La Roche), better known as the PCR test
• NucliSens HIV-1 QT, or NASBA (bioMerieux)
• Versant/Quantiplex HIV-1 RNA, or bDNA (Chiron/Bayer)
Viral Load is how many viral particles per ML of blood
Viral Load in eq/ml Classification Remarks
below 200.000 very low below detection limit of bDNA test
200,000-1,000,000 low
1,000,000-5,000,000 medium average viral load at 3,200,000 eq/ml
5,000,000-25,000,000 high
above 25,000,000 very high

(table taken from http://www.janis7hepc.com/Viral_Loads.htmViral Load )

Recently, Logs have been used to express viral load.
log(1730000)=6.24
6.24^10 = 1730000
Bibliography
Viral Loads
http://www.janis7hepc.com/Viral_Loads.htmViral Load
http://en.wikipedia.org/wiki/Viral_load