Stress and the Immune System: Insights From Psychoneuroimmunology

Stress profoundly impacts the immune system, functioning as both an enhancer and suppressor of immune responses. The ultimate outcome depends on a combination of individual characteristics, genetic, epigenetic, and environmental factors, and the nature of the stressor. Stress hormones influence leukocyte trafficking, activity, cytokine production, and the overall immune function, leading to immune dysregulation. This review offers a comprehensive perspective on the physiology of the stress response and its effects on immunity, particularly stress-induced alterations in immune cell function. It explores how stress contributes to immunodeficiencies, allergies, and autoimmune diseases, thereby impacting vaccine efficacy, increasing susceptibility to infections, and promoting cancer development. Stress is implicated in the onset and exacerbation of specific autoimmune disorders and contributes to allergic conditions, intensifying allergic responses in both adults and children, particularly in the context of parenting stress and domestic violence. This review also investigates immune changes associated with specific stressors, including bereavement, intimate partner violence, childhood maltreatment, caregiving stress, and post-traumatic stress disorder. This work addresses the multifaceted dimensions of psychoneuroimmunology, shedding light on the significant health consequences of stress-induced immune dysfunction, and emphasizes the need for integrative therapeutic approaches. Key words Fight and flight " Cortisol " T cells " Antibodies " PTSD.