Levels of Tumour Necrosis Factor-Alpha and Interleukin-6 in Severely Ill Patients with Eating Disorders

Abstract

Background: The underlying pathophysiology of eating disorders (ED) is dependent on complex interactions between psychological, biological and social factors. The purpose of the present study was to examine a possible increase in cytokines indicating inflammation, as measured by tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in ED patients, and to explore possible relationships between cytokines and self-reported personality traits. Methods: Female patients with severe ED (n = 26) were recruited consecutively from an inpatient clinic and were compared to age-matched healthy females (n = 12). Commercial ELISA tests developed for the measurement of serum levels of TNF-α and IL-6 were employed. Personality traits were measured using Karolinska Scales of Personality. Results: The patient group displayed increased levels of the cytokine TNF-α and a tendency towards increased IL-6 levels. Spearman’s rank correlation coefficient was used to examine possible relationships between levels of cytokines and personality traits. The results showed that IL-6 levels were positively related to both somatic and psychic anxiety and to aggression scales, such as irritability and suspicion. Increased levels of TNF-α, in turn, were significantly correlated with high scores on the depression-related anxiety scale Inhibition of Aggression. However, increased levels of cytokines in the ED group did not seem to be mainly associated with symptoms of depression. Conclusion: We cannot rule out the possibility that comorbid conditions in the group contribute to the higher cytokine values. Further studies need to explore the possible influence of cytokines on the severity of ED and whether this might be mediated or moderated by specific personality traits.