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Session 112 Poster Presentations
The Effects of Antiretroviral Therapy during Pregnancy
Session Day and Time: Thursday 1:30 - 3:30 pm
Room: Hall B


890
Immune Activation During Late Pregnancy and Postpartum as Measured by Elevated Serum Beta2-microglobulin Correlates with Increases in HIV RNA and CD4/CD8 T-cells
H. M. Truong*1, M. S. Sim1, M. Dillon1, C. Uittenbogaart1, R. Dickover1, S. Plaeger2, Y. Bryson1
1Univ of California at Los Angeles and 2Natl Inst of Hlth, Bethesda, MD

Background: Previously observed rise in HIV RNA postpartum in both treated and untreated women remain unexplained. However, immune activation may play a role. We evaluated b2-microglobulin (b2m), HIV RNA, and CD4/CD8 T-cells in HIV-infected pregnant women receiving various regimens of HAART or zidovudine (ZDV) monotherapy prenatal (PN)/ postpartum (PP) compared to HIV negative (HIV-) controls.

Methods: HIV-infected (n = 96) and HIV- (n = 28) pregnant women were enrolled (1989–2002) in a prospective cohort study of maternal-fetal HIV transmission. HIV infected women were divided into groups based on maternal antiretroviral treatment: I – none (n = 11), II – ZDV PN only (n = 12), III – ZDV PN & PP (n = 37) and IV – HAART PN & PP (n = 36). Serum b2m, plasma HIV RNA, and CD4/CD8 T cells were sequentially measured. Longitudinal analysis utilized the Proc Mixed (SAS) method.

Results: Mean maternal plasma HIV RNA increased from delivery to 2–8 weeks PP within each group (p = 0.003). Groups III and IV had PP increases in HIV RNA (p < 0.05) despite continued treatment. Mean CD4 T cells increased within each group from 3rd trimester (3rd tri) through PP (p = 0.002). Increases PP in mean CD4 T-cells occurred in HIV- controls and in each group (p=0.01) despite concurrent rise in HIV RNA. Mean CD8 T-cells increased from 3rd tri through PP in Groups I, II and III (p < 0.05) but remained stable in the HAART group and HIV- controls. b2m increased within each group from 3rd tri through PP (p < 0.0001), but there was no difference across groups. Observed increases in b2m correlated within individuals with HIV RNA (p = 0.01). At all time points, b2m was higher in HIV infected groups than HIV- controls (p < 0.01). b2m increased PP in groups I, II, and III but remained stable in the HAART group and HIV- controls.

Conclusions: HIV-infected pregnant women showed PP increases in HIV RNA, CD4 T-cells, and b2m regardless of treatment. Since the rise in CD4 T-cells and b2m was also seen in HIV- pregnant women, this suggests hormonal changes and/or labor-induced cytokines may contribute to immune activation. The immune activation correlates with increased plasma HIV RNA in PP women despite treatment, although HAART appears to blunt the effect. With new guidelines recommending optional treatment of PP women with > 350 CD4 T-cells/ml, the observed rise in HIV RNA PP may have implications for enhanced transmission to infants by early breastfeeding and to sexual partners.