Annual Research Review: Social relationships and the immune system during development

Abstract

A child’s social relationships serve critical functions during development. The interface between a child’s social world and their immune system, particularly innate immunity, which helped children survive in the face of infections, nutritional scarcity, and violence throughout human history, is the focus of this Annual Research Review. This article reviews the state of research on social relationships and innate immune inflammation during childhood. Warmth and rejection in childhood social relationships, as well as physical trauma and unpredictable social environments, were not consistently related to circulating inflammatory markers such as interleukin‐6 and C‐reactive protein during childhood. Instead, links between social environments and inflammation were observed in studies that focus on children with greater background risk factors, such as low family socioeconomic status, family history of mood disorders, or presence of chronic interpersonal stressors combined with acute episodic stressors. In addition, studies on worse childhood social environments and greater inflammation in adulthood were more consistent. Warmth and rejection in the social environment may be related to sensitivity of immune cells to the anti‐inflammatory actions of glucocorticoids, though this is primarily observed in adolescent women at risk for depression. Additional mechanistic evidence suggests that greater warmth and less rejection are related to processes that regulate inflammation, including greater expression of the glucocorticoid receptor gene and lower expression of genes that are responsive to the pro‐inflammatory transcription factor NF‐kappa B. The article concludes by discussing implications of the interface between a child’s social relationships and inflammation for mental health and other recent (on evolutionary timescales) health threats, as well as recommendations for future research, and recommendations for researchers interested in integrating inflammatory measures in developmental research.

Commentary: Social Immune Processes as Pathways to Psychopathology: a commentary on Robles (2020)

“…As well, family routines reflect only a small slice of potential social disruptions. Nevertheless, this work provides initial support for the fact that the social and inflammatory processes reviewed by Robles (2020) may mediate the intergenerational transmission of certain psychopathology symptoms.…”

“…As Robles (2020) discusses, connections between inflammation and social conditions are strongest in samples in which children are at elevated psychosocial risk. For example, he notes that interpersonal stressors are more strongly associated with markers of immune processes, such as glucocorticoid sensitivity, among children who have a family history of depression than among children without a family history of depression.…”

“…Of course, it is also possible that nonrelational factors account for these links, such as inherited cognitive biases that lead to distorted perceptions of interpersonal rejection. In light of these possibilities, an important question remains unanswered: To what extent does risk conferred by parental psychopathology overlap with disruptions in dimensions of social relationships reviewed by Robles (2020)?…”

“…Indeed, many of the relationship dimensions captured by Robles (2020) are separately implicated in depression (and other forms of psychopathology). As just one example, in a study of adults with diagnosed depression, backward dating of targeted social rejection experiences versus other life stressors found that individuals experiencing social rejection became depressed three times faster than did individuals encountering other stressors (Slavich, Thornton, & Monroe, 2009).…”

“…In this Annual Research Review, Robles (2020) discusses and synthesizes a growing literature on immune correlates of social relationships during childhood and adolescence. As he notes, the capacity for our social experiences to shape innate immune processes holds tremendous medical and psychiatric import.…”