From Mechanism Discovery to Intervention: Mast Cell Overactivation and Histamine Dysregulation in ASD and PTSD—Implications for Therapy, Environmental Design, and Support in War-Affected Populations.

Abstract

This paper explores the role of mast cell overactivation and histamine dysregulation as potential pathophysiological mechanisms underlying symptoms observed in ASD and PTSD. Evidence from reviews, meta-analyses, and observational studies suggests a significant association between MCAS, HIT, environmental triggers, and a broad spectrum of those symptoms. Mast cells, as key components of the immune system, play a central role in inflammatory signaling and neuroimmune communication. When over activated, they release also histamine acting through H1–H4 receptors, influencing multiple systems, including immune, gastrointestinal, cardiovascular, respiratory, and central nervous system functions, affecting GABAergic and glutamatergic signaling, blood–brain barrier integrity, and neuroinflammatory pathways. Histamine degradation is primarily regulated by DAO and HNMT; genetic polymorphisms or acquired deficiencies in these enzymes may impair histamine clearance, leading to systemic accumulation and exacerbation of neurological and behavioral symptoms. A notable clinical overlap exists between MCAS, HIT, ASD, and PTSD, including gastrointestinal disturbances, sensory hypersensitivity, cognitive impairment, emotional dysregulation, sleep disturbances, and chronic neuroinflammation. Environmental and physiological triggers—such as infections, allergens, mold exposure, toxins, dietary histamine, and sensory stressors (light, noise, vibration, temperature, and humidity)—may further contribute to mast cell activation and symptom severity. Preliminary evidence indicates that interventions targeting mast cells regulation by design of low-trigger, supportive indoor environments, may help reduce symptom burden. These findings underscore the importance of interdisciplinary approaches and highlight the need for controlled clinical trials to evaluate the efficacy of integrated therapeutic dietary, supplementation and environmental strategies, particularly in vulnerable populations, including individuals affected by war-related trauma stress