title: Comparison of type I, type III and type VI collagen binding assays in diagnosis of von Willebrand disease.
abstract: BACKGROUND
  von Willebrand factor (VWF) plays a key role in coagulation by tethering platelets to injured subendothelium through binding sites for collagen and platelet GPIb. Collagen binding assays (VWF:CB), however, are not part of the routine work-up for von Willebrand disease (VWD).
  
  
  OBJECTIVE
  This study presents data on collagen binding for healthy controls and VWD subjects to compare three different collagens.
  
  
  METHODS
  VWF antigen (VWF:Ag), VWF ristocetin cofactor activity and VWF:CB with types I, III and VI collagen were examined for samples obtained from the Zimmerman Program.
  
  
  RESULTS
  Mean VWF:CB in healthy controls was similar and highly correlated for types I, III and VI collagen. The mean VWF:CB/VWF:Ag ratios for types I, III and VI collagen were 1.31, 1.19 and 1.21, respectively. In type 1 VWD subjects, VWF:CB was similar to VWF:Ag with mean VWF:CB/VWF:Ag ratios for types I, III and VI collagen of 1.32, 1.08 and 1.1, respectively. For type 2A and 2B subjects, VWF:CB was uniformly low, with mean ratios of 0.62 and 0.7 for type I collagen, 0.38 and 0.4 for type III collagen, and 0.5 and 0.47 for type VI collagen.
  
  
  CONCLUSIONS
  Normal ranges for type I, III and VI collagen are correlated, but higher values were obtained with type I collagen as compared with types III and VI. The low VWF:CB in type 2A and 2B subjects suggests that VWF:CB may also supplement analysis of multimer distribution. However, these results reflect only one set of assay conditions per collagen type and therefore may not be generalizable to all collagen assays.
authors.affiliation: Department of Pediatrics, Division of Hematology/Oncology, Medical College of Wisconsin, Milwaukee, WI, USA. vflood@mcw.edu
authors.forename: V H
authors.initials: VH
authors.lastname: Flood
authors.forename: J C
authors.initials: JC
authors.lastname: Gill
authors.forename: P A
authors.initials: PA
authors.lastname: Christopherson
authors.forename: J S
authors.initials: JS
authors.lastname: Wren
authors.forename: K D
authors.initials: KD
authors.lastname: Friedman
authors.forename: S L
authors.initials: SL
authors.lastname: Haberichter
authors.forename: R G
authors.initials: RG
authors.lastname: Hoffmann
authors.forename: R R
authors.initials: RR
authors.lastname: Montgomery
mesh_terms: D016022:Case-Control Studies; D003094:Collagen / Q000737:chemistry / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D011485:Protein Binding; D020033:Protein Isoforms / Q000737:chemistry / Q000378:metabolism*; D014842:von Willebrand Diseases / Q000175:diagnosis* / Q000378:metabolism
chemical_list: D020033:Protein Isoforms; D003094:Collagen