Role of Regulatory Immune Cells in Psychiatric Disorders

The etiology of psychiatric disorders is widely acknowledged to involve immune-inflammatory abnormalities, whereas there has been a growing emphasis on investigating the cellular basis of immune functions within these disorders in recent years. Pathogen- and damage-associated molecular patterns can be activated by either internal or external stimuli. This activation process is regulated by immune regulatory cellsB regulatory cell, specifically regulatory T and B cells (Treg and Breg). Dysregulation of the functions of these cells, which are integral components of the adaptive immune system, is acknowledged to contribute to various diseases, including malignancies and graft-versus-host disease, whereas, these dysfunctions have piqued researchers' interest in recent years, prompting investigations into their potential roles in the etiopathogenesis of psychiatric disorders. Treg cells have distinct functions in maintaining tissue equilibrium and restructuring. Yet, their involvement in brain homeostasisHomeostasis and remodeling remains insufficiently understood, partly due to their limited presence in the brain during normal physiological states. However, there are indications that Tregs intertwined with neurotransmitterNeurotransmitter systems, notably through cytokine pathways. Among psychiatric disorders, schizophreniaSchizophrenia and mood disordersMood disorder are undoubtedly the most extensively researched disorders concerning Treg proportion and function. Studies have indicated that an imbalance in Tregs could potentially result in neuronal damage due to compromised neuroprotective mechanisms, which is a postulated factor in the etiopathogenesis of psychotic and mood disordersMood disorder. Less number of studies in anxietyAnxiety, eating disordersEating disorder, and autism spectrum disordersAutism spectrum disorder revealed considerable variations in Treg cell subsets. Overall, despite the noteworthy insights garnered from recent research, there is a need for longitudinal studies with larger sample sizes and subgroup analyses to comprehensively grasp the role of immune regulatory cells and their potential therapeutic applications in the management of psychiatric disorders.