title: Peripheral interleukin-2 level is associated with negative symptoms and cognitive performance 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 10:00AM. 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.
authors.affiliation: Schizophrenia Program (PROESQ), Department of Psychiatry, Federal University of São Paulo, Rua Machado Bittencourt, 222, São Paulo, SP, CEP 04044-000, Brazil; Interdisciplinary Laboratory of Clinical Neurosciences (LINC), Department of Psychiatry, Federal University of São Paulo, Rua Pedro de Toledo, 669, Edifício de Pesquisas II, third floor, São Paulo SP, CEP 04039-032, Brazil. Electronic address: elsonmed@gmail.com.
authors.forename: Elson
authors.initials: E
authors.lastname: Asevedo
authors.affiliation: Interdisciplinary Laboratory of Clinical Neurosciences (LINC), Department of Psychiatry, Federal University of São Paulo, Rua Pedro de Toledo, 669, Edifício de Pesquisas II, third floor, São Paulo SP, CEP 04039-032, Brazil. Electronic address: lucas-rizzo@hotmail.com.
authors.forename: Lucas B
authors.initials: LB
authors.lastname: Rizzo
authors.affiliation: Schizophrenia Program (PROESQ), Department of Psychiatry, Federal University of São Paulo, Rua Machado Bittencourt, 222, São Paulo, SP, CEP 04044-000, Brazil; Interdisciplinary Laboratory of Clinical Neurosciences (LINC), Department of Psychiatry, Federal University of São Paulo, Rua Pedro de Toledo, 669, Edifício de Pesquisas II, third floor, São Paulo SP, CEP 04039-032, Brazil. Electronic address: aryararipe@gmail.com.
authors.forename: Ary
authors.initials: A
authors.lastname: Gadelha
authors.affiliation: Interdisciplinary Laboratory of Clinical Neurosciences (LINC), Department of Psychiatry, Federal University of São Paulo, Rua Pedro de Toledo, 669, Edifício de Pesquisas II, third floor, São Paulo SP, CEP 04039-032, Brazil. Electronic address: rodrigomansur71@uol.com.br.
authors.forename: Rodrigo B
authors.initials: RB
authors.lastname: Mansur
authors.affiliation: Interdisciplinary Laboratory of Clinical Neurosciences (LINC), Department of Psychiatry, Federal University of São Paulo, Rua Pedro de Toledo, 669, Edifício de Pesquisas II, third floor, São Paulo SP, CEP 04039-032, Brazil. Electronic address: vanessakota@gmail.com.
authors.forename: Vanessa K
authors.initials: VK
authors.lastname: Ota
authors.affiliation: Schizophrenia Program (PROESQ), Department of Psychiatry, Federal University of São Paulo, Rua Machado Bittencourt, 222, São Paulo, SP, CEP 04044-000, Brazil; Interdisciplinary Laboratory of Clinical Neurosciences (LINC), Department of Psychiatry, Federal University of São Paulo, Rua Pedro de Toledo, 669, Edifício de Pesquisas II, third floor, São Paulo SP, CEP 04039-032, Brazil. Electronic address: arthur.berberian@gmail.com.
authors.forename: Arthur A
authors.initials: AA
authors.lastname: Berberian
authors.affiliation: Interdisciplinary Laboratory of Clinical Neurosciences (LINC), Department of Psychiatry, Federal University of São Paulo, Rua Pedro de Toledo, 669, Edifício de Pesquisas II, third floor, São Paulo SP, CEP 04039-032, Brazil. Electronic address: brunosini@yahoo.com.br.
authors.forename: Bruno S
authors.initials: BS
authors.lastname: Scarpato
authors.affiliation: Translational Psychoneuroimmunology Group, Federal University of Minas Gerais, Avenida Antonio Carlos, 6627, Pampulha, Belo Horizonte MG, CEP 31270-901, Brazil. Electronic address: altexr@gmail.com.
authors.forename: Antônio L
authors.initials: AL
authors.lastname: Teixeira
authors.affiliation: Schizophrenia Program (PROESQ), Department of Psychiatry, Federal University of São Paulo, Rua Machado Bittencourt, 222, São Paulo, SP, CEP 04044-000, Brazil; Interdisciplinary Laboratory of Clinical Neurosciences (LINC), Department of Psychiatry, Federal University of São Paulo, Rua Pedro de Toledo, 669, Edifício de Pesquisas II, third floor, São Paulo SP, CEP 04039-032, Brazil. Electronic address: rodrigoabressan@gmail.com.
authors.forename: Rodrigo A
authors.initials: RA
authors.lastname: Bressan
authors.affiliation: Interdisciplinary Laboratory of Clinical Neurosciences (LINC), Department of Psychiatry, Federal University of São Paulo, Rua Pedro de Toledo, 669, Edifício de Pesquisas II, third floor, São Paulo SP, CEP 04039-032, Brazil. Electronic address: elisabrietzke@hotmail.com.
authors.forename: Elisa
authors.initials: E
authors.lastname: Brietzke
mesh_terms: D000328:Adult; D001774:Blood Chemical Analysis; D003071:Cognition; D056344:Executive Function; D005260:Female; D006801:Humans; D007361:Intelligence Tests; D007376:Interleukin-2 / Q000097:blood*; D007802:Language; D007858:Learning; D008297:Male; D008570:Memory, Short-Term; D009483:Neuropsychological Tests; D011569:Psychiatric Status Rating Scales; D012559:Schizophrenia / Q000097:blood*; D012565:Schizophrenic Psychology
chemical_list: C508594:IL2 protein, human; D007376:Interleukin-2
keywords: Behavioral symptoms; Biological markers; Cognition; Interleukin-2; Schizophrenia