engleski

Evaluation of multiplexed fluorescent microspheres immunoassay for detection of autoantibodies to nuclear antigens

Anti-nuclear autoantibodies (ANA-ENA) directed against various cell nuclear autoantigens characterise systemic rheumatic diseases. Some of them have asigned in the classification for systemic lupus erythematosus (SLE), mixed connective tissue disease (MCTD), systemic sclerosis (ScS) and Sjogren syndrome (SS). Because ANA testing is a critical part of diagnosis in systemic rheumatic diseases, it is important to detect them very carefully. Indirect immunofluorescence (IIF) on HEp-2 cells, atigen specific enzyme-immunoassay (ELISA) and polystirene microsphere-based fluorescent assay have been used for this purpose. The aim of our study was to compare sensitivity and concordance of these tests for detection of ANA-ENA autoantibodies and determination of target autoantigens in 42 patients with SLE and 164 patients with suspicious systemic autoimmune diseases. The ANA and antibodies to nine different autoantigens (SS-A, SS-B, Sm, RNP, DNA topo I, ds-DNA, centromere B, Jo-1 and histone) were tested. Comparison of ANA screening results by IIF (HEp-2) with enzyme immunoassay and with microsphere-based fluorescent assay (AtheNa Multi-Lyte ANA test system) showed a high rate of concordaance (Kappa value from 0, 289 - 0, 793 and agreement from from 88-98%). Positive discrepant results were found for ds-DNA specifcity in 12, 5% ; 25/200) specimens by AtheNA technology, while all tested sera were negative for this antibody by ELISA. Negative discrepant results were observed by AtheNa system for anti-ds-DNA (1, 5% ; 3/200) In 7 serum samples (3, 5% ; 7/200) we found completely different target antigens by ELISA (ds-DNA) and by AtheNa technology (SS-A, RNP or SS-A, SS-B). Very good concordance in the detection of individuaal target autoantigens was observed between ELISA and microsphere-based assay (Kappa value from 0, 306-0, 782 and agreement from 90-98%). Our results suggest that the AtheNA Multi-Lyte ANA test system may be a useful diagnostic tool for ANA-ENA determination.

ANA; HEp-2; AtheNa-ANA; Luminex

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