title: Beta-2-microglobulin levels in the cerebrospinal fluid of normal dogs and dogs with neurological disease.
abstract: BACKGROUND
  Cerebrospinal fluid (CSF) analysis is the basis for establishing a diagnosis of central nervous system (CNS) inflammation. However, the information provided by routine CSF analysis is limited. Determination of CSF beta-2-microglobulin (beta2m) concentration has been used diagnostically in humans to identify inflammatory CNS disease; we hypothesized that it may have similar value in dogs.
  
  
  OBJECTIVE
  The objective of this study was to measure (beta2m concentration in the CSF of clinically healthy dogs and compare the values to those observed in dogs with inflammatory CNS disease and intervertebral disc disease (IVDD).
  
  
  METHODS
  CSF was collected from 10 clinically healthy laboratory dogs and 11 dogs each with inflammatory CNS disease and IVDD. Routine CSF analysis was performed, and (beta2m concentration was measured by ELISA. CSF (beta2m concentration and CSF:serum (beta2m ratio were compared between groups by ANOVA. Linear relationships between CSF total nucleated cell count (TNCC), RBC count, total protein concentration, and (beta2m concentration were assessed by regression analysis.
  
  
  RESULTS
  The mean (+/- SD) CSF (beta2m concentration in clinically healthy dogs was 0.36 (+/- 0.05 microg/mL (cisternal) and 0.40 (+/- 0.07 microg/mL (lumbar). Median CSF (beta2m concentration in dogs with IVDD (0.46 microg/mL) and inflammatory CNS disease (0.85 microg/mL) differed from that of controls (0.36 microg/mL; P=.002). The concentration also differed between the 2 disease groups (P=.01). Five dogs with inflammatory CNS disease had CSF:serum (beta2m ratios >1. A correlation was identified between TNCC and (beta2m concentration (r=0.69, P=.0003).
  
  
  CONCLUSIONS
  CSF (beta2m concentration is higher in dogs with IVDD and inflammatory CNS disease, with highest values seen with inflammatory disease. This may be attributed in part to the correlation between CSF (beta2m concentration and TNCC, but also may reflect intrathecal immune activation.
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA. karen_munana@ncsu.edu
authors.forename: Karen R
authors.initials: KR
authors.lastname: Muñana
authors.forename: Miyoko
authors.initials: M
authors.lastname: Saito
authors.forename: Fumio
authors.initials: F
authors.lastname: Hoshi
mesh_terms: D000818:Animals; D004283:Dog Diseases / Q000134:cerebrospinal fluid*; D004285:Dogs; D004660:Encephalitis / Q000134:cerebrospinal fluid / Q000662:veterinary*; D008581:Meningitis / Q000134:cerebrospinal fluid / Q000662:veterinary*; D009187:Myelitis / Q000134:cerebrospinal fluid / Q000662:veterinary*; D012016:Reference Values; D001613:beta 2-Microglobulin / Q000134:cerebrospinal fluid*
chemical_list: D001613:beta 2-Microglobulin