Elsevier

Physiology & Behavior

Volume 129, 22 April 2014, Pages 194-198
Physiology & Behavior

Peripheral interleukin-2 level is associated with negative symptoms and cognitive performance in schizophrenia

https://doi.org/10.1016/j.physbeh.2014.02.032Get rights and content
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Highlights

  • Peripheral IL-2 levels correlated positively with performance in tests of working memory and intelligence in patients with schizophrenia.

  • IL-2 levels correlated negatively with scores in the negative subscale of PANSS.

  • These associations pose IL-2 as a possible marker of cognitive and affective preservation in schizophrenia.

Abstract

Although several studies have pointed to a possible role of interleukin 2 (IL-2) in schizophrenia (SZ), association between IL-2 and the different groups of symptoms has not been explored. The objective of this study was to investigate a possible correlation of peripheral IL-2 levels with symptoms and cognitive performance in patients with SZ. In addition, we compared the plasma levels of IL-2 between patients with SZ and healthy controls. Twenty-nine chronically medicated outpatients with SZ according to DSM-IV were compared with twenty-six healthy controls. The patients were evaluated with the Positive and Negative Syndrome Scale (PANSS), the Calgary Depression Scale for Schizophrenia (CDSS), the Clinical Global Impression (CGI) and the Global Assessment of Functioning (GAF). All the participants had blood collected into EDTA tubes by venipuncture between 9:00 and 10:00 AM. Plasma concentrations of IL-2 were determined by cytometric bead array. A computerized neuropsychological battery assessed verbal learning, verbal fluency, working memory, set shifting, executive function, inhibition and intelligence. Patients with SZ had lower levels of IL-2 than healthy controls (p < 0.001). In the SZ group, IL-2 levels were positively correlated with scores in the digit span test (rho = 0.416, P = 0.025) and intelligence (rho = 0.464, P = 0.011). We also found a negative correlation between IL-2 and total score in the negative subscale of PANSS (rho =  0.447, p = 0.015). Our findings suggest that IL-2 may be involved in the mechanisms related to cognitive deterioration and negative symptomatology in schizophrenia.

Keywords

Schizophrenia
Interleukin-2
Biological markers
Cognition
Behavioral symptoms

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