Selective inflammatory propensities in adopted adolescents institutionalized as infants

This study examined whether early life adversity (ELA) limited to infancy was associated with an increase in circulating levels of proinflammatory cytokines and cellular cytokine responses to three stimulants [lipopolysaccharide (LPS), phytohemagglutinin (PHA), and phorbol myristate acetate plus ionomycin (PMA/IO)]. Participants were previously institutionalized (PI) youth (N = 45, 56 % female) who had spent their first years in institutional care (e.g., orphanages, baby homes) before being adopted into well-resourced homes (median age at adoption = 13 mos) and non-adopted comparisons (NA; N = 38, 55 % female). Their age range was 13.3-21.2 years (M = 16.3 years). This analysis followed up an earlier report on these youth (Reid et al., 2019a) that identified an increase in terminally differentiated CD8 + CD57 T cells among the PI relative to the NA youth. Cytokine levels in circulation were not highly correlated and thus examined separately. PI youth had higher circulating levels of Tumor Necrosis Factor-alpha (TNF alpha), but not Interleukin-1 beta (IL-1 beta) or Interleukin-6 (IL-6). Cytokine responses to in vitro activation within each stimulant condition were highly correlated and were thus combined to generate an index of the inflammatory reaction to each stimulant. Using Multivariate Analysis of Covariance, there was a highly significant multivariate effect of group, which was carried primarily by the PMA/IO condition, with PI youth exhibiting a larger inflammatory response than NA youth. Tests of mediation showed that both the early rearing effects on circulating TNF alpha and the composite inflammatory index of PMA/IO responsiveness were mediated in the statistical model by the percentage of CD8 + CD57+ TEMRA cells in circulation, a marker of replicative senescence in T cells. Sex differences were also found in circulating levels of IL-6 and TNF alpha, with males having higher levels than females.

Automated summary

This study examined the impact of early life adversity on levels of proinflammatory cytokines and cellular cytokine responses in youth. It found that PI youth showed a larger inflammatory response than NA youth under stimulation with PMA/IO. Sex differences were also observed in circulating levels of IL-6 and TNF alpha.