The relationship between alexithymia and circulating cytokine levels in subjects undergoing upper endoscopy

Objective: Despite emerging evidence suggesting a link between alexithymia and immune function, previous studies yielded contrasting results. The proposed link between alexithymia and immune function remains controversial as does the role, in this relationship, of anxiety, depression and subjective stress. The aim of the study is to investigate the possible association between alexithymia and circulating levels of cytokines in subjects awaiting an upper endoscopy, a stressful procedure, controlling for anxiety levels, depression and subjective stress. Methods: Participants were recruited from among consecutive patients referred for routine diagnostic upper endoscopy. All participants completed the Toronto Alexithymia Scale (TAS-20), the Hospital Anxiety and Depression Scale, and the Stress-related Vulnerability Scale. Serum levels of IL-1β, IL-4, IL-6, IL-10, TNF-α and IFN-γ were measured by ELISA. Results: Of the 90 subjects initially approached, 68 completed the study. The TAS-20 identified 22 alexithymic and 36 non-alexithymic patients. ELISA detected significantly lower IL-4 and IL-6 concentrations in alexithymic than in non-alexithymic patients. According to multiple linear regression analysis, alexithymia predicted low IL-4 and IL-6 levels in the sample overall, independently of stress, anxiety, depression and other possible confounders. No between-group differences were found in serum levels of IFN-γ, IL-1β, and TNF-α. Conclusion: These findings argue against an isolated shift towards pro-inflammatory or anti-inflammatory mediators and suggest that circulating cytokine profiles differ in alexithymic and non-alexithymic subjects.