Reuters Health Information (2005-02-24): GBV-C infection does not protect against CD4+ cell loss or HIV progression
GBV-C infection does not protect against CD4+ cell loss or HIV progression
Last Updated: 2005-02-24 15:07:16 -0400 (Reuters Health)
NEW YORK (Reuters Health) - Despite earlier studies
suggesting that GB virus C (GBV-C) infection may protect against HIV-1
disease progression, a new study shows no such protection. However,
loss of GBV-C, as opposed to its continuous absence, appears to be
associated with accelerated progression of HIV-1 disease, investigators
report in the Journal of Infectious Diseases for March 1.
There are conflicting reports on what effect GBV-C co-infection has
on HIV-1 disease progression. Some research groups have observed a
strong association between GBV-C viremia and improved survival in
HIV-infected patients (See Reuters Health report Feb. 13), while others
have not (See Reuters Health report May 3, 2004).
Dr. Akke K. Van der Bij from the Municipal Health Service of
Amsterdam and colleagues studied this issue in 326 men with an
established date of HIV-1 seroconversion who were followed for a median
of 8 years in The Amsterdam Cohort Studies.
For each participant, researchers tested a first plasma sample
obtained at entry shortly after seroconversion and a last serum sample
obtained before 1996 for GBV-C RNA and envelope protein-2 antibodies
Tests on the first samples revealed GBV-C RNA in 137 men (42%) and
E2 antibodies, signifying resolved GBV-C viremia, in 134 men (41%).
Tests on the last sample revealed GBV-C RNA in 69 men (21%) and E2
antibodies in 126 (39%).
According to the investigators, "men who lost GBV-C RNA between
collection of the first sample and collection of the last sample had a
nearly 3-fold higher risk of HIV-1 disease progression than did men who
never had GBV-C RNA."
However, the negative effect of GBV-C RNA loss on disease
progression disappeared when the researchers adjusted for changes in
CD4+ cell count, they report. Therefore, it seems that "GBV-C RNA loss
is due to CD4+ cell loss, not vice versa," they hypothesize.
Because GBV-C can replicate in CD4+ cells, a drop in CD4+ cells
during the course of HIV-1 infection reduces the number of target cells
for GBV-C. "This might explain why GBV-C RNA loss is associated with an
increased risk of death in HIV-1-infected individuals," the
GBV-C infection has been "seriously considered as a potentially
protective agent in the fight against HIV-1 disease progression," the
authors point out. Based on the current study, they urge caution until
further studies are performed in large, well-defined cohorts of
J Infect Dis 2005;191:678-685.