Early adversity, immunity and infectious disease

Complex interactions between biological, behavioral and environmental factors are involved in mediating individual differences in health and disease. In this review, we present evidence suggesting that increased vulnerability to infectious disease may be at least, in part, due to long-lasting effects of early life psychosocial adversities. Studies have shown that maternal psychosocial stress during pregnancy is associated with long lasting changes in immune function and disease resistance in the offspring. Studies further indicated that harsh environmental conditions during the neonatal period may also cause lasting changes in host response to infectious disease. Although the mechanisms involved in these effects have not been fully examined, several potential mediators have been described, including changes in the development of the offspring hypothalamic-pituitary-adrenal axis, alterations in epigenetic pathways, stress-related maternal health risk behavior and infection during pregnancy. Although there are ample literature indicating that perinatal psychosocial stress increases vulnerability to disease, other reports suggest that mild predictable stressors may benefit the organism and allow better coping with future stressors. Thus, understanding the possible consequences of perinatal adversities and the mechanisms that are involved in immune regulation is important for increasing awareness to the potential outcomes of early negative life events and providing insight into potential therapies to combat infection in vulnerable individuals.