Researchers are trying to develop widely available blood tests to show how much AIDS virus people have in their bodies.
Such tests not only could help doctors monitor the effects of AIDS treatment but perhaps provide earlier diagnosis of AIDS infections, particularly in newborns.The tests now in wide use, available since the mid-1980s, reveal only the presence of AIDS antibodies, which are the body's reaction to an AIDS infection, but not the virus itself.
Two new generations of tests are under development, both based on greatly streamlined versions of polymerase chain reaction, or PCR, a sophisticated lab technique that expands tiny amounts of genetic material so it can be easily detected. The PCR technique has been used in sophisticated research to search for the HIV virus itself in humans.
The AIDS virus, unlike most other forms of life, carries its genes as RNA rather than DNA, both of which are acids found inside cells and help produce the proteins that build and regulate the body.
To make new copies of itself, the AIDS virus must first convert its genes from RNA into DNA and then stitch them into the genetic material of infected blood cells.
Furthest along are tests that will spot viral genes that have become part of blood cells this way. These tests, which look for viral DNA, will reveal whether or not someone is infected with the AIDS virus. But they do not show how much virus actually dwells within the cells.
The latest innovation, outlined at a scientific meeting Tuesday, are tests that reveal viral RNA. The tests will spot genes that are inside the virus but are not part of cells' genetic machinery.
Developers say this gives them a way to assess the quantity of individual viruses inside the body.