Rheumatology Advance Access published online on September 13, 2005
Rheumatology, doi:10.1093/rheumatology/kei109
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Department of Internal Medicine, Innsbruck Medical University, Innsbruck, Austria
* To whom correspondence should be addressed. Objectives. Diagnosis of ankylosing spondylitis (AS) can be difficult, and a specific laboratory test has not yet been introduced as a routine diagnostic tool. Our aim was to evaluate the diagnostic value of antibodies specifically binding to a recombinant 28-kDa antigen for the diagnosis of AS. Methods. Blinded sera were tested for antibodies binding to the procaryotically expressed 28-kDa protein using an enzyme-linked immunosorbent assay (ELISA). This purified 28-kDa protein is produced by a specific clone from an embryonic Drosophila hydei Xgtl I c-DNA library and is bound by human antibodies cross-reacting with both a 36-kDa protein of chromosomes from Drosophila melanogaster and a 69-Da HeLa S3 protein potentially involved in signal transduction pathways. Results. Serum concentrations of antibodies cross-reacting with this specific antigen were increased in 371 patients with AS compared with 37 healthy controls (39.5 vs 22.6 U/ml; P = 0.004). The positive predictive values of this ELISA test for AS were between 95.1% (95% confidence interval 90.6-97.9%) for a cut-off level of 50 U/ml and 97.4% (92.7-99.5%) for a cut-off level of 75 U/ml, and the sensitivities were between 42.1% (37.0-47.3%) for a cut-off level of 50 U/ml and 30.7% (26.1-35.7%) for a cut-off level of 75 U/ml. Conclusions. Serum ELISA tests for antibodies cross-reacting with the 28-kDa antigen show a high positive predictive value for AS of more than 95%.
Received May 2, 2005
Accepted August 9, 2005
Original Papers
High positive predictive value of specific antibodies cross-reacting with a 28-kDa Drosophila antigen for diagnosis of ankylosing spondylitis
2 Department of Radiology, Innsbruck Medical University, Innsbruck, Austria
3 Rehabilitationszentrum-Sonderkrankenanstalt Bad-Ischl der Pensionsversicherungsanstalt, Bad Ischl, and Gastein Research Institute, Bad Gastein, Austria
4 Clinic of Rheumatology and Physical Medicine, Minden, Germany
M. Schirmer*, E-mail: michael.schirmer{at}uibk.ac.at
Abstract
*These authors contributed equally to the design and performance of the study, and thus both have to be considered as last authors.
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  C. Duftner, C. Dejaco, and M. Schirmer Positive and negative predictive values from published studies can be misleading for decision-making in clinical practice: reply Rheumatology, June 1, 2006; 45(6): 780 - 781. [Full Text] [PDF]
|
|
|
|
|
|
M. Rudwaleit and J. Sieper Positive and negative predictive values from published studies can be misleading for decision-making in clinical practice Rheumatology, June 1, 2006; 45(6): 779 - 780. [Full Text] [PDF]
|
|