Correlation of Immune Activation during Late Pregnancy and Early Postpartum with Increases in Plasma HIV RNA, CD4/CD8 T Cells, and Serum Activation Markers

A previously observed rise in the plasma viral load postpartum in both treated and untreated HIV-positive women remains unexplained. Virological and immunological markers were evaluated in HIV-negative controls and HIV-positive pregnant women with and without antiretroviral treatment. Plasma HIV RNA, CD4/CD8 T cells, and serum activation markers were sequentially measured during the third trimester, at delivery, and 2 to 8 weeks postpartum in a cohort of HIV-positive pregnant women (n 96) enrolled in a maternal-fetal HIV transmission study and a control group of HIV-negative pregnant women (n 28). Mean plasma HIV RNA (P 0.003) increased from delivery to postpartum, and mean CD4 T cells (P 0.002) and serum 2-microglobulin (P < 0.0001) increased from the third trimester through postpartum among the HIV-positive women. Mean CD8 T cells increased from the third trimester through postpartum in women receiving zidovudine (ZDV) and in those not treated (P < 0.05) but remained stable in those on highly active antiret-roviral therapy (HAART) and the HIV-negative controls. Increases in serum 2-microglobulin were correlated with increases in HIV RNA (P 0.01). HIV-positive pregnant women showed postpartum increases in plasma HIV RNA, CD4 T cells, and serum 2-microglobulin regardless of the treatment regimen. The rise in CD4 T cells and 2-microglobulin was also observed in HIV-negative pregnant women, suggesting hormonal changes and/or labor-induced cytokines may contribute to immune activation. Immune activation correlated wit