| dc.description.abstract | Background:
Commercial sex workers are at high risk of HIV acquisition
especially in countries
with high HIV prevalence.
In Kenya, over 10% of all new HIV infections have been attributed to sex
workers and their clients.
Unprotected sex results in
exposure of the female genital tract to
sex-
derived antigens present in semen. Studies have reported a post-coital inflammatory response to these
antigens in animals
and humans.In vivo, such inflammatory response leads
to recruitment of
activated leukocytes including T cells from the peripheral circulation to the genital mucosa where
they can be infected by HIV.
There is need to explore the impact of sex work on the activation of the
immune system and its role in the transmission
of HIV.HIV-exposed seronegative (HESN)
female
sex workers
have been shown to have lower peripheral and mucosal immune activation than their
HIV-
positive counterparts
or
HIV-
uninfected low risk women. This reduced immune activation state
is thought to be protective against HI
V infection. It is,
therefore,
thought that HESN sex workers are
able to down regulate sex-
work-
induced immune activation by a yet unknown mechanism.
Hypothesis:
This study
hypothesized that sex work results in exposure to very strong immune
stimulants
which can drive systemic immune activation
and that HESN women are able to down
regulate this sex work-
driven immune activation more efficiently than HIV susceptible controls.
Objective:
The study was
designed to
characterize the impact of sex work on activation
and
phenotype
of peripheral T cells, among female sex workers at the Pumwani
Clinic, Nairobi.
Methods:
Thirty
female sex workers were recruited; 10 in each arm of HESN, HIV-
positive, and
New Negatives.
Blood samples were obtained from
them
when in active sex work, during a sex
break
and upon return to sex work. PBMCs were extracted from the blood and stained with a 10-colour monoclonal antibody panel for phenotypic
(CD3, CD4, CD8, CD45RA,
CD161), trafficking
(CCR7, CCR5)
and activation markers
(CD69, HLA-DR, CD95)
of T cells. Expression
of
these
markers was then evaluated by flow cytometry. Statistical
analyses were done to compare the
expression
of T cell activation markers and memory phenotypes within each group
during sex work,
sex break
and upon return to sex work. The difference in response
to interruption of sex work was
also assessed across groups.
Results:
A reduction in CCR5 expression on CD8+ T cells in HIV-
positive
sex workers
was
observed
upon taking
a break from sex work.
A trend
toward
increase
dexpression
of CD161 on
10
CD4+ T cells
was also observed in the HIV-positive.
In New Negatives, we observed a trend towards
decreased
naïve CD8+ T cells
during the sex break and upon return to sex work.
It was also observed
that there
is no difference in the pattern of response to the interruption of sex work between HESN
female sex workers and their HIV-
positive and New Negative counterparts.
Overall,
HIV-
positive
women had
higher frequency of effector memory T cells and CD95 express in
g CD8+ T cells and a
lower frequency of naïve
CD8+ T cells than HESN and New Negatives.
Conclusion:
Sex work
had
a
subtle effect
on the
expression of T cell activation markers
and memory
phenotypes
in the peripheral compartment. Interruption of commercial
sexual activity
had a greater
impact on T cell activation in HIV-positives.
In
HESN and New Negatives, sex work
had no
discernible effect on peripheral immune activation.
No
apparent difference in the way HESN, HIV-
positive and New Negative sex workers
respond to
interruption of sex work
was observed, which
may be due to various limitations of this study.
Therefore, the impact of sex work could be confined
to the FGT mucosa and not
be reflected
in the peripheral compartment | en_US |
