Pregnant women are at greater risk both of HIV acquisition and transmission to their negative partners than non-pregnant women. This is independent to behavioural factors and is likely to have biological causes.
Jan Walters and colleagues from University of California, University of Southern California and Children's Hospital Los Angeles hypothesised that pregnancy may cause shifts of the cerviovaginal cytokine profile that may increase the risk of infection.
Using a multiplex assay, the investigators compared concentrations of 39 immunodulatory factors in cervicovaginal lavage from 21 pregnant and 24 non-pregnant HIV negative women attending ob/gyn clinic. They measured cervical ectopy (an independent risk for HIV transmission) by planimetry. They used the same multiplex assay to determine plasma CCL22 concentrations.
They found 26/39 (66%) measured immunomodulatory factors were detectable in at least half of the tested samples. Concentrations of CCL22 were 3-fold lower in cervicovaginal lavage in pregnant women than non-pregnant women (geometric mean 30 pg/mL vs 90 pg/mL, p=0.001).
They observed a strong negative correlation of the cervicovaginal lavage CCL22 concentration with gestational age (Spearman's rank correlation coefficient -0.49), p=0.0006. Non-pregnant women were assigned a gestational age of zero.
No other tested factors were associated in adjusted analysis.
The investigators concluded that pregnancy appears to result in reduced concentrations of the HIV suppressive cytochine CCL22 in cervicovaginal secretions, which could contribute to the increased susceptibility to HIV during pregnancy. They suggested that their hypothesis should be tested in prospective studies.
- Walter J et al. Reduced concentration of the HIV suppressive cytokine CCL22 in cervicovaginal secretions from pregnant women. 18th CROI, Boston. February 2011. Poster abstract 734.
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