title: Plasma cytokine profiles in depressed patients who fail to respond to selective serotonin reuptake inhibitor therapy.
abstract: OBJECTIVE
  Approximately 30% of patients with depression fail to respond to a selective serotonin reuptake inhibitor (SSRI). Few studies have attempted to define these patients from a biological perspective. Studies suggest that overall patients with depression show increased production of proinflammatory cytokines. We examined pro- and anti-inflammatory cytokine levels in patients who were SSRI resistant.
  
  
  METHODS
  Plasma concentrations of IL-6, IL-8, IL-10, TNF-alpha and sIL-6R were measured with enzyme linked immunosorbent assays (ELISA) in DSM-1V major depressives who were SSRI resistant, in formerly SSRI resistant patients currently euthymic and in healthy controls.
  
  
  RESULTS
  Patients with SSRI-resistant depression had significantly higher production of the pro-inflammatory cytokines IL-6 (p=0.01) and TNF-alpha (p=0.004) compared to normal controls. Euthymic patients who were formerly SSRI resistant had proinflammatory cytokine levels which were similar to the healthy subject group. Anti-inflammatory cytokine levels did not differ across the 3 groups.
  
  
  CONCLUSIONS
  Suppression of proinflammatory cytokines does not occur in depressed patients who fail to respond to SSRIs and is necessary for clinical recovery.
authors.affiliation: Alimentary Pharmabiotic Centre and Department of Psychiatry, Cork University Hospital, Wilton, Cork, Ireland.
authors.forename: Sinead M
authors.initials: SM
authors.lastname: O'Brien
authors.forename: Paul
authors.initials: P
authors.lastname: Scully
authors.forename: Peter
authors.initials: P
authors.lastname: Fitzgerald
authors.forename: Lucinda V
authors.initials: LV
authors.lastname: Scott
authors.forename: Timothy G
authors.initials: TG
authors.lastname: Dinan
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D000928:Antidepressive Agents / Q000627:therapeutic use*; D016207:Cytokines / Q000097:blood*; D003865:Major Depressive Disorder / Q000097:blood* / Q000188:drug therapy; D004351:Drug Resistance / Q000502:physiology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D017367:Selective Serotonin Reuptake Inhibitors / Q000627:therapeutic use*
chemical_list: D000928:Antidepressive Agents; D016207:Cytokines; D017367:Selective Serotonin Reuptake Inhibitors