Inflammation and cytomegalovirus viremia during pregnancy drive sex-differentiated differences in mortality and immune development in HIV-exposed infants.

Children who are HIV-exposed but uninfected have increased infectious mortality compared to HIV-unexposed children, raising the possibility of immune abnormalities following exposure to maternal viraemia, immune dysfunction, and co-infections during pregnancy. In a secondary analysis of the SHINE trial in rural Zimbabwe we explored biological pathways underlying infant mortality, and maternal factors shaping immune development in HIV-exposed uninfected infants. Maternal inflammation and cytomegalovirus viraemia were independently associated with infant deaths: mortality doubled for each log10 rise in maternal C-reactive protein (adjusted hazard ratio (aHR) 2.09; 95% CI 1.33-3.27), and increased 1.6-fold for each log10 rise in maternal cytomegalovirus viral load (aHR 1.62; 95% CI 1.11-2.36). In girls, mortality was more strongly associated with maternal C-reactive protein than cytomegalovirus; in boys, mortality was more strongly associated with cytomegalovirus than C-reactive protein. At age one month, HIV-exposed uninfected infants had a distinct immune milieu, characterised by raised soluble CD14 and an altered CD8 + T-cell compartment. Alterations in immunophenotype and systemic inflammation were generally greater in boys than girls. Collectively, these findings show how the pregnancy immune environment in women with HIV underlies mortality and immune development in their offspring in a sex-differentiated manner, and highlights potential new intervention strategies to transform outcomes of HIV-exposed children. ClinicalTrials.gov/NCT01824940

Stunting status and exposure to infection and inflammation in early life shape anti-bacterial immune cell function among Zimbabwean children

Background: Children who are stunted (length–for-age Z-score<-2) are at greater risk of infectious morbidity and mortality. Previous studies suggest that stunted children have elevated inflammatory biomarkers but no studies have characterised their capacity to respond to new infections (i.e. their immune function). We hypothesised that anti-bacterial immune function would differ between stunted and non-stunted children and relate to their health and environment during early life. Methods: We enrolled a cross-sectional cohort of 113 HIV-negative children nested within a longitudinal cluster-randomised controlled trial of household-level infant and young child feeding (IYCF) and water, sanitation and hygiene (WASH) interventions in rural Zimbabwe (SHINE; Clinical trials registration: NCT01824940). Venous blood was collected at 18 months of age and cultured for 24h without antigen or with bacterial antigens: heat-killed Salmonella typhimurium (HKST) or Escherichia coli lipopolysaccharide (LPS). TNFα, IL-6, IL-8, IL-12p70, hepcidin, soluble (s)CD163, myeloperoxidase (MPO) and IFNβ were quantified in culture supernatants by ELISA to determine antigen-specific immune function. The effect of stunting status and early life exposures (anthropometry, inflammation at 18 months, maternal health during pregnancy, household WASH) on immune function was tested in logit and censored log-normal (tobit) regression models. Results: Children who were stunted (n=44) had higher proportions (86.4% vs 65.2%; 88.6% vs 73.4%) and concentrations of LPS-specific IL-6 (geometric mean difference (95%CI): 3.46pg/mL (1.09, 10.80), p=0.035) and IL-8 (3.52pg/mL (1.20, 10.38), p=0.022) than non-stunted children (n=69). Bacterial antigen-specific pro-inflammatory cytokine concentrations were associated with biomarkers of child enteropathy at 18 months and biomarkers of systemic inflammation and enteropathy in their mothers during pregnancy. Children exposed to the WASH intervention (n=33) produced higher LPS- (GMD (95%CI): 10.48pg/mL (1.84, 60.31), p=0.008) and HKST-specific MPO (5.10pg/mL (1.77, 14.88), p=0.003) than children in the no WASH group (n=80). There was no difference in antigen-specific immune function between the IYCF (n=55) and no IYCF groups (n=58). Conclusions: Anti-bacterial immune function among 18 month old children in a low-income setting was shaped by their stunting status and prior exposure to maternal inflammation and household WASH. Heterogeneity in immune function due to adverse exposures in early life could plausibly contribute to infection susceptibility