early maturation of the immune system

Family photo of the Cibersam researchers.

states of acute psychosocial stress stimulate the secretion of an antibody-like protein key in the first immune defense against infections, but only after puberty. However, boys and girls with history of abuse exhibit a response similar to that of adolescents, suggesting a early maturation of the immune system in these subjects, according to an international study with the participation of various groups from the Mental Health Cyber ​​(Cibersam) coordinated by Professor Lourdes Fañanás, from the Faculty of Biology and the Institute of Biomedicine of the University of Barcelona (Ibub).

In this study, published in Brain Behavior and Immunity, Researchers from the Cibersam groups at the Hospital Clinic/Idibaps, Hospital Gregorio Marañón and Hospital Puerta de Hierro in Madrid and the Hospital Universitario de Álava have also participated. In addition, it has had the collaboration of researchers from the Adolescent Crisis Unit (UCA) of the Sisters Hospitallers of Sant Boi and the Day Hospital for adolescents of Orienta-Gavà.

In this study, we have investigated the behavior of secretory immunoglobulin A (s-IgA) in saliva against acute psychosocial stress in children and adolescents, exploring its variations according to the stage of development, infantile or post_pubertal, and the existence of history of child abuse.

For this, they investigated 94 children and adolescents from 7 to 17 yearss (54 with psychiatric diagnosis) belonging to a large state-wide multicenter study (EPI-Young Stress Project). To evaluate their biological reactivity against stress, five saliva samples were obtained for each subject during the Trier Social Stress Test (TSST-C), a standardized protocol that allows evaluating the biological response coping with acute psychosocial stress in a controlled and reliable way; s-IgA and cortisol levels were analyzed in these samples.

A relationship between childhood maltreatment and the “fight or flight” immune response

According to the Principal Investigator of the Cibersam group G08 at the UB, Lourdes Fañanás, “it has been possible to associate increased secretion of s-IgA against acute psychosocial stress in adolescents, but not in children. This data was already partially known and has been ratified in this new sample of the young population. However, this possible marker had not been investigated in children and adolescents with a history of child abuse, a condition of great psychological stress and in which affected children usually live chronically.”

Exposure to stress leads to the activation of various biological processes that aim to prepare an effective response to a threatening situation and then restore homeostasis once the stressor has ended. The changes involved in the stress response depend on the sympathetic nervous system (SNS) and the hypothalamic-pituitary-adrenal (HPA) axis, and each of them involves a rapid adaptive response known as “fight or flight response”. In parallel, the SNS activates the immune system, characterized by the activation of inflammatory processes and that could be altered after long periods of chronic stress (such as abuse).

Symptoms of accelerated biological aging

This study, therefore, has shown that the s-IgA in saliva could be a feasible biomarker to explore the peripheral immune response to stress in young populations. In particular, it has been observed that, although children and adolescents showed similar basal levels of s-IgA, their reactivity to stress seemed to differ, because the former showed an increase after the stressor and a rapid recovery, while children and girls prepubertal children did not show an s-IgA response.

“However, we observe that children exposed to abuse exhibited a pattern of response to stress similar to that of adolescentsindicates Laia Marqués, Cibersam researcher at the UB and first author of the work.

Consequently, adds Águeda Castro, co-author of this work, “this phenomenon would be in line with generalized theories that defend that individuals exposed to a wide range of harmful exposures, whether of a psychosocial or chemical nature, experience what is known as accelerated biological aging. But more studies are required to elucidate the role of abuse history in the regulation of the immune system in the earliest stages of development.”

In addition, indicates Laia Marqués, “these alterations in the immune system associated with abuse can have a strong impact, since the deregulation of this system globally affects the body and it has been related to different physical and mental pathologies in the short and long term”.

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