ab17_2

Multicenter validation of recombinant, natural and synthetic antigens used in a single multiparameter assay for the detection of specific anti-nuclear autoantibodies in connective tissue disorders

L. Meheus¹, W.J. van Venrooij², A. Wiik³, P.J. Charles⁴, A.G. Tzioufas⁵, O. Meyer⁶, G. Steiner⁷, D. Gianola⁸, S. Bombardieri⁸, A. Union¹, S. De Keyser¹, E. Veys⁹, F. De Keyser⁹

¹Innogenetics N.V., Ghent, Belgium; ²Department of Biochemistry, University of Nijmegen, Nijmegen, The Netherlands; ³Department of Autoimmunology, Statents Seruminstitut, Copenhagen, Denmark; ⁴Kennedy Institute of Rheumatology, London, England; ⁵Department of Pathophysiology, University of Athens Medical School, Athens, Greece; ⁶Service de Rhumatologie, Hôpital Bichat, Paris, France; ⁷Division of Rheumatology, University of Vienna, Vienna, Austria; ⁸Department of Internal Medicine, University of Pisa, Pisa, Italy; ⁹Department of Rheumatology, University Hospital, Ghent, Belgium.

ABSTRACT
Objectives
We investigated the feasibility of using a single multi-parameter test based mainly on recombinant autoantigens for the detection of anti-nuclear autoantibodies, and analyzed the agreement between this test format and conventional techniques.

Methods
The presence of autoantibodies was determined by a line immunoassay (LIA) in 755 sera derived from patients with different autoimmune connective tissue disorders. All sera were previously tested by standard assays that are routinely used at the 8 participating European centers.

Results
The overall sensitivity and specificity of autoantibody detection by LIA was similar or higher as compared to combined conventional techniques (CCT). In particular, the detection of anti-Ro52 in systemic lupus erythematosus (SLE) sera (P = 0.004) and anti-LA in both SLE (P < 0.0009) and in Sjögren’s syndrome (P < 0.0009) sera was significantly more sensitive when using LIA compared to CCT. By contrast, CCT was never more sensitive than LIA for any of the markers.

Conclusion
The LIA is a reliable alternative to a combination of conventional techniques for the detection of specific anti-nuclear autoantibodies. The multi-parameter test also reveals autoantibody reactivities that may not be detected when only a limited number of conventional techniques are applied.

Key words
Autoantibodies, recombinant autoantigens.

Please address correspondence and reprint requests to: Lydie Meheus, PhD, Innogenetics N.V., Industriepark 7, Box 4, B-9052 Zwijnaarde, Belgium.