title: Hippocampal volume and depressive symptoms are linked to serum IL-18 in schizophrenia.
abstract: OBJECTIVE
  Since schizophrenia (SCZ) is often accompanied by hippocampal abnormalities and dysregulation of cytokine production, this study aimed to investigate the impact of the cytokine interleukin (IL)-18, whose biological system appears to be perturbed in SCZ, on brain structure and clinical severity in patients with chronic SCZ.
  
  
  METHODS
  The serum levels of IL-18, including its free bioactive form (i.e., the cytokine fraction not bound to its specific endogenous inhibitor IL-18 binding protein), were evaluated in a case-control study involving 71 individuals with SCZ diagnosis and 29 healthy controls. All participants underwent brain MRI automatic evaluation for hippocampal volume estimation. The Positive and Negative Syndrome Scale (PANSS) was administered to measure severity of symptoms in patients with SCZ.
  
  
  RESULTS
  Lower amounts of free IL-18 were related to smaller hippocampal volume measures in patients with SCZ. Furthermore, in line with a possible neuroprotective effect of the cytokine, higher levels of free IL-18 corresponded to lower subscores of PANSS depression in patients with SCZ.
  
  
  CONCLUSIONS
  These findings demonstrate that the levels of circulating bioactive IL-18 are related to both hippocampal volume and severity of psychopathologic symptoms in patients with SCZ, confirming the involvement of the cytokine in SCZ pathophysiology and suggesting hippocampal-dependent and neuroprotective functions of IL-18 in this clinical context.
authors.affiliation: Department of Clinical and Behavioral Neurology (P.B., F.P., I.P., M.I., F.S., A.C., C. Chiapponi, C. Caltagirone, G.S.), IRCCS Santa Lucia Foundation, Rome, Italy; Department of Neuroscience (C. Caltagirone), University "Tor Vergata," Rome, Italy; and Menninger Department of Psychiatry and Behavioral Sciences (G.S.), Baylor College of Medicine, Houston, TX.
authors.forename: Paola
authors.initials: P
authors.lastname: Bossù
authors.affiliation: Department of Clinical and Behavioral Neurology (P.B., F.P., I.P., M.I., F.S., A.C., C. Chiapponi, C. Caltagirone, G.S.), IRCCS Santa Lucia Foundation, Rome, Italy; Department of Neuroscience (C. Caltagirone), University "Tor Vergata," Rome, Italy; and Menninger Department of Psychiatry and Behavioral Sciences (G.S.), Baylor College of Medicine, Houston, TX.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Piras
authors.affiliation: Department of Clinical and Behavioral Neurology (P.B., F.P., I.P., M.I., F.S., A.C., C. Chiapponi, C. Caltagirone, G.S.), IRCCS Santa Lucia Foundation, Rome, Italy; Department of Neuroscience (C. Caltagirone), University "Tor Vergata," Rome, Italy; and Menninger Department of Psychiatry and Behavioral Sciences (G.S.), Baylor College of Medicine, Houston, TX.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Palladino
authors.affiliation: Department of Clinical and Behavioral Neurology (P.B., F.P., I.P., M.I., F.S., A.C., C. Chiapponi, C. Caltagirone, G.S.), IRCCS Santa Lucia Foundation, Rome, Italy; Department of Neuroscience (C. Caltagirone), University "Tor Vergata," Rome, Italy; and Menninger Department of Psychiatry and Behavioral Sciences (G.S.), Baylor College of Medicine, Houston, TX.
authors.forename: Mariangela
authors.initials: M
authors.lastname: Iorio
authors.affiliation: Department of Clinical and Behavioral Neurology (P.B., F.P., I.P., M.I., F.S., A.C., C. Chiapponi, C. Caltagirone, G.S.), IRCCS Santa Lucia Foundation, Rome, Italy; Department of Neuroscience (C. Caltagirone), University "Tor Vergata," Rome, Italy; and Menninger Department of Psychiatry and Behavioral Sciences (G.S.), Baylor College of Medicine, Houston, TX.
authors.forename: Francesca
authors.initials: F
authors.lastname: Salani
authors.affiliation: Department of Clinical and Behavioral Neurology (P.B., F.P., I.P., M.I., F.S., A.C., C. Chiapponi, C. Caltagirone, G.S.), IRCCS Santa Lucia Foundation, Rome, Italy; Department of Neuroscience (C. Caltagirone), University "Tor Vergata," Rome, Italy; and Menninger Department of Psychiatry and Behavioral Sciences (G.S.), Baylor College of Medicine, Houston, TX.
authors.forename: Antonio
authors.initials: A
authors.lastname: Ciaramella
authors.affiliation: Department of Clinical and Behavioral Neurology (P.B., F.P., I.P., M.I., F.S., A.C., C. Chiapponi, C. Caltagirone, G.S.), IRCCS Santa Lucia Foundation, Rome, Italy; Department of Neuroscience (C. Caltagirone), University "Tor Vergata," Rome, Italy; and Menninger Department of Psychiatry and Behavioral Sciences (G.S.), Baylor College of Medicine, Houston, TX.
authors.forename: Chiara
authors.initials: C
authors.lastname: Chiapponi
authors.affiliation: Department of Clinical and Behavioral Neurology (P.B., F.P., I.P., M.I., F.S., A.C., C. Chiapponi, C. Caltagirone, G.S.), IRCCS Santa Lucia Foundation, Rome, Italy; Department of Neuroscience (C. Caltagirone), University "Tor Vergata," Rome, Italy; and Menninger Department of Psychiatry and Behavioral Sciences (G.S.), Baylor College of Medicine, Houston, TX.
authors.forename: Carlo
authors.initials: C
authors.lastname: Caltagirone
authors.affiliation: Department of Clinical and Behavioral Neurology (P.B., F.P., I.P., M.I., F.S., A.C., C. Chiapponi, C. Caltagirone, G.S.), IRCCS Santa Lucia Foundation, Rome, Italy; Department of Neuroscience (C. Caltagirone), University "Tor Vergata," Rome, Italy; and Menninger Department of Psychiatry and Behavioral Sciences (G.S.), Baylor College of Medicine, Houston, TX.
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Spalletta