A small case-control study determined that aging HIV-infected people (median 56 years) with a good CD4 count (median 724 cells/mm (3)) and long-term viral suppression with antiretroviral therapy have CD4 and CD8 cells
similar to those of a substantially older HIV-negative comparison group (median 88 years) and utterly unlike those of a younger HIV-negative group (median 27 years).
Both groups had similar concentrations of CD8 cells
. These cells destroy damaged or infected cells by releasing a torrent of chemicals that take apart target cells.
According to our results patients with more severe form of disease had the lowest number of both CD4 and CD8 cells
which can be a sign of suppressed cellular immunity in these patients.
The team also found that SIV creates such mutants in response to the assault by CD8 cells
at about the same rate as HIV does.
These are CD4 cell factors that are necessary to turn on the CD8 cells
(cytotoxic T lymphocytes).
Three research groups now challenge that dogma with evidence showing that under certain conditions, CD8 cells
can make the CD4 protein and consequently become infected by the AIDS virus.
The engineered stem cells developed into a large population of mature, multifunctional HIV-specific CD8 cells
that could specifically target cells containing HIV proteins.
Levy and others quickly established that CD8 cells
can secrete one or more soluble molecules that hinder HIV.
They treated the CD8 T-cells with TAT2 and combined them with the CD4 T-cells in the dish-and found that the treated CD8 cells
inhibited production of HIV by the CD4 cells.
To identify what was inhibiting HIV production in asymptomatic patients, the team separated the T cells into CD4 cells, which help trigger immune responses and which form the target of HIV infection, and CD8 cells
, which destroy infected cells.
The Stanford team found similar numbers of CD8 cells
in the two groups.
Normally, these CD8 cells
kill other cells and make interferon gamma, a TH1 messenger.