A
sufficient level of healthy Lactobacillus bacteria in the vagina is associated
with lower HIV viral load in the female genital tract, which may reduce the risk
of sexual and perinatal transmission, according to a study presented at the recent
15th Conference on Retroviruses and Opportunistic Infections
(CROI 2008) in Boston.
Hydrogen peroxide-producing (H202+)
Lactobacillus is normally present in the vagina and is a key regulator of the
vaginal ecosystem. It may have a direct effect in suppressing HIV, and also suppresses
unhealthy, pathogenic bacteria.
Researchers evaluated the effects of H202+
Lactobacillus on HIV concentrations in cervicovaginal lavage (CVL) specimens over
time to test the hypothesis that the acquisition of H202+
Lactobacillus would lead to decreased HIV levels in the female genital tract.
This
observational cohort study included 57 HIV positive women from Seattle, WA, and
Rochester, NY. At study entry, about half were on antiretroviral therapy and about
40% had undetectable plasma HIV RNA (< 30 copies/mL).
In total, they
had 390 study visits, done every 3-4 months (median 6 visits; range 1 to 15).
Data collection was completed at the end of November 2007. Visits included collection
and HIV RNA testing of blood plasma (using an assay with a lower limit of quantitation
of 30 copies/mL) and CVL (lower limit 1500 copies/mL) samples. Vaginal cultures
were performed to identify the presence of H202+
Lactobacillus. The 390 study visits yielded 270 paired samples with complete data.
Results
•
About half the women had H202+
Lactobacillus present at any given time.
•
HIV RNA was detected in CVL samples at 17%
of the visits, and was highly associated with plasma HIV RNA, which was detected
at 64% of the visits (P < 0.001).
•
Presence of Lactobacillus was associated with
a 3-fold lower CVL HIV viral load (P = < 0.01).
•
H202+
Lactobacillus colonization appeared to be dynamic over time:
•
121 paired samples (47%) showed stable colonization
between visits;
•
62 pairs (24%) showed no evidence of Lactobacillus
at either visit.
•
Acquisition of H202+
Lactobacillus resulted in about a 5-fold (0.7 log10) decrease in CVL HIV RNA level
compared with stable colonization, after adjusting for plasma HIV RNA and antiretroviral
therapy status (P = 0.015).
•
Loss of Lactobacillus resulted in
about a 3-fold (0.5 log10) increase in CVL HIV viral load compared with stable
colonization (P = 0.029).
Conclusion
"These
prospective, longitudinal data demonstrate that acquisition of H202+
Lactobacillus is associated with a significant reduction in vaginal HIV
load, while loss of H202+
Lactobacillus results in an increase in vaginal HIV load," the investigator
concluded.
They added that, "These findings may have relevance for
secondary prevention strategies."
2/19/08
Reference J
Hitti, K Paul, K Agnew, and others. Protective Effect of Vaginal Lactobacillus
on Genital HIV-1 RNA Concentrations: Longitudinal Data from a US Cohort Study.
15th Conference on Retroviruses and Opportunistic Infections (CROI 2008). Boston,
MA. February 3-6, 2008. Abstract 27LB.
Vaginal
Lactobacillus Lowers Genital Viral Load in Women with HIV
Results
