title: Interleukin-6 in cerebrospinal fluid as a biomarker of acute meningitis.
abstract: BACKGROUND
  Microbiological culture of cerebrospinal fluid is the gold standard to differentiate between aseptic and bacterial meningitis, but this method has low sensitivity. A fast and reliable new marker would be of interest in clinical practice.
  
  
  OBJECTIVE
  Interleukin-6, secreted by T cells in response to meningeal pathogens and quickly delivered into cerebrospinal fluid, was evaluated as a marker of acute meningitis.
  
  
  METHODS
  A total of 150 cerebrospinal fluid samples were analysed by an electrochemiluminescence method, selected according to patient diagnosis: (a) bacterial meningitis confirmed by positive culture (n = 26); (b) bacterial meningitis with negative culture or not performed (n = 15); (c) viral meningitis confirmed by polymerase chain reaction or immunoglobulin G determination (n = 23); (d) viral meningitis with polymerase chain reaction negative or not performed (n = 42); and (e) controls (n = 44).
  
  
  RESULTS
  Cerebrospinal fluid interleukin-6 concentration showed significant differences between all pathologic groups and the control group (P < 0.001). As a diagnostic tool for bacterial meningitis, interleukin-6 showed an area under the curve of 0.937 (95% confidence intervals: 0.895-0.978), significantly higher than those of classical biomarkers. An interleukin-6 cutoff of 1418 pg/mL showed 95.5% sensitivity and 77.5% specificity, whereas a value of 15,060 pg/mL showed 63.6% sensitivity and 96.7% specificity, for diagnosis of bacterial meningitis.
  
  
  CONCLUSIONS
  Interleukin-6 measured by electrochemiluminescence method is a promising marker for early differentiation between aseptic and bacterial meningitis. More studies are needed to validate clinical implications for future practice in an emergency laboratory.
authors.affiliation: Clinical Biochemistry, Laboratory of Medicine, Hospital Universitario Central de Asturias, Oviedo, Spain pabgaher@gmail.com.
authors.forename: Pablo
authors.initials: P
authors.lastname: García-Hernández
authors.affiliation: Clinical Biochemistry, Laboratory of Medicine, Hospital Universitario Central de Asturias, Oviedo, Spain.
authors.forename: Belén
authors.initials: B
authors.lastname: Prieto
authors.affiliation: Clinical Biochemistry, Laboratory of Medicine, Hospital Universitario Central de Asturias, Oviedo, Spain.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Martínez-Morillo
authors.affiliation: Clinical Biochemistry, Laboratory of Medicine, Hospital Universitario Central de Asturias, Oviedo, Spain.
authors.forename: Verónica
authors.initials: V
authors.lastname: Rodríguez
authors.affiliation: Clinical Biochemistry, Laboratory of Medicine, Hospital Universitario Central de Asturias, Oviedo, Spain Biochemistry and Molecular Biology Department, University of Oviedo, Oviedo, Spain.
authors.forename: Francisco V
authors.initials: FV
authors.lastname: Álvarez
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000134:cerebrospinal fluid; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D015850:Interleukin-6 / Q000134:cerebrospinal fluid*; D008297:Male; D008581:Meningitis / Q000134:cerebrospinal fluid* / Q000175:diagnosis / Q000382:microbiology / Q000821:virology; D008875:Middle Aged; D055815:Young Adult
chemical_list: D015415:Biomarkers; C508600:IL6 protein, human; D015850:Interleukin-6
keywords: Meningitis; cerebrospinal fluid; interleukin-6; sensitivity; specificity