US researchers have found that women injecting drug users
have substantially lower viral
load than men even when both groups have similar href="../atu/ATU_Glossary.htm#cd4">CD4
A review of viral load measurements using three different techniques (Chiron
bDNA, Roche PCR and cell-associated infectious viral load) found that levels in
women were between 38% and 65% lower than those found in male IDUs at similar
CD4 counts.
Women also developed AIDS-defining illnesses at a similar speed to men in the
cohort, despite having lower average viral load at baseline.
The authors of the study suggest that current viral load thresholds for
starting treatment may not be appropriate for women, and that it might be
prudent to revise the US threshold for starting therapy down to 5,000 copies for
women.
The reason for the sex difference in the relationship between viral load and
disease progression risk is unknown, say the authors, and more research needs to
be done, but it’s not a new observation. Two other studies published in 1996
(Katzenstein; Bush) also found that HIV RNA levels were 50% lower in women when
controlling for CD4 count.
The full text of the report is available from The Lancet On-line, October 7
at http://www.thelancet.com . Free
one-off registration is required for non-subscribers.
H Farzadegan et al. Sex differences in HIV-1 viral load and progression to
AIDS. The Lancet vol 352:9139, November 7, 1998