Changes in immune activation markers during pregnancy and postpartum

Changes in CD4+ cell levels and other immune parameters have been reported to occur during pregnancy but the timing of these alterations and their relationship to changes in immune function have not been well characterized. In addition, the influence of sociodemographic, obstetric, and other covariates on these relationships is largely unknown. We measured three immune activation markers, soluble interleukin-2 receptor (sIL-2R(α)), soluble CD8 antigen (sCD8), and neopterin during pregnancy and postpartum in 170 HIV-1-seronegative women enrolled in the Mothers and Infants Cohort Study. Ante-partum and postpartum changes in these markers were examined using multivariable longitudinal random effects models. Neopterin levels began to rise well before delivery and were in decline by 2 months postpartum. sIL-2R(α) and sCD8 levels increased at or near delivery and peaked by 2 months postpartum. After adjustment for other variables, the peak in sIL-2R(α) was greater among women with pre-term than full-term deliveries (P = 0.05). All three markers were higher in whites than non-whites and in 'hard' drug users than non-users (P ≤ 0.001 for each). After adjustment for these and other variables, hepatitis C virus (HCV) seropositivity was associated with higher levels of sCD8 and neopterin (P ≤ 0.001 for each) but not sIL-2R(α) (P = 0.27). These longitudinal data indicate that a state of broad immune activation develops at or near delivery. A number of maternal variables appear to influence the magnitude of these changes.