Proinflammatory immune markers in pregnant women living with HIV (WLWH) on antiretroviral treatment (ART) by maternal body mass index (BMI), in Cape Town, South Africa: cohort study

Pregnancy requires tightly regulated immune adaptation, which may be altered by maternal adiposity and HIV infection. In high HIV prevalence settings with rising obesity rates, overlapping metabolic and infectious inflammation may shape gestational immune trajectories. We examined patterns of C-reactive (CRP), serum amyloid A (SAA), and interferon-gamma inducible protein-10 (IP-10) among 527 pregnant women living with HIV in Cape Town, South Africa. Immune markers were measured at up to four antenatal visits. Maternal body mass index (BMI) was categorised as normal, overweight or obese. Antiretroviral therapy (ART) exposure was classified as initiation before conception or during pregnancy. Mixed-effects models assessed associations, adjusting for baseline CD4 cell count and viral load. CRP concentrations remained elevated across pregnancy and were significantly higher among obese women independent of ART timing. In contrast, IP-10 concentrations were strongly associated with ART timing, with higher levels observed prior to ART initiation and declining thereafter; no independent association with BMI was observed. SAA concentrations were modestly lower among obese women and among those on preconception ART. These divergent patterns persisted after adjustment for HIV disease severity. These findings suggest that metabolic and HIV-related inflammatory pathways operate in parallel during pregnancy, with adiposity predominantly influencing acute-phase responses and HIV-related immune activation shaping interferon-associated chemokines trajectories.