Immune and Endocrine Function in Patients With Burning Mouth Syndrome

Abstract

Research suggests that varied etiologic factors are responsible for burning mouth syndrome (BMS). We examined the role of immune and endocrine function in the pathology of BMS. We conducted a case-control study to evaluate immune (lymphocyte subpopulations) and endocrine (hypothalamus-pituitary-adrenal axis and sympathetic-adrenomedullary system) function in 47 female BMS patients and 47 age-matched female controls presenting at an university clinic. Psychological state was assessed with the Zung Self-Rating Depression Scale and Taylor Manifest Anxiety Scale. BMS patients were significantly more anxious than controls (P=0.011). Plasma adrenaline level was significantly lower (P=0.020) in BMS patients than in controls, and linear regression analysis of all patients combined revealed that depression level was significantly positively associated with plasma noradrenaline and cortisol levels (P=0.002 and 0.001, respectively). However, as compared with controls, BMS patients had a significantly lower CD8(+) cell count (P<0.001) and a significantly higher CD4/CD8 ratio (P=0.002). Discriminant analysis revealed that CD8(+) cell count and CD4/CD8 ratio were independent variables that distinguished BMS patients from controls. The immunoendocrine system is substantially involved, and may have a key role, in the mechanism of chronic pain in BMS patients. Immune function was significantly and specifically suppressed in BMS, although the hypothalamic-pituitary-adrenal axis and sympathetic nervous system were predominantly activated by psychological stress that was not specific to BMS.