Les anticorps anti-ADN ne sont plus ce qu'ils étaient!… L'apport des nouvelles techniques de dépistag e au diagnostic du lupus érythémateux disséminé

The diagnosis of systemic lupus erythematosus relies on a combination of clinical and biological criteria. Anti-double stranded (ds) desoxyribonucleic acid (DNA) antibodies (Abs) constitute the prevailing hallmark of this disease. Several methods have, therefore, been set for their detection. Meanwhile, evidence has been accumulating that discrete autoAb populations endowed with differing prognostic significances are detected, depending on the assay. From the results of eight tests available for the detection of anti-double stranded (ds)DNA Abs on a routine basis, five conclusions could be drawn. (1) The indirect immunoflurescence test using Crithidia luciliae as the substrate and the Farrzyme™ assay select those Abs with the highest affinity for dsDNA. (2) The sensitivity of enzyme-linked immunosorbent assays and the cytofluorimetric analysis (FIDIS™) based on Luminex™ technology is better, compared with the C. luciliae assay, whilst the specificity is lower. (3) The way DNA is presented, rather than its source, is influential in the assay. (4) Contamination of the dsDNA preparation with single-stranded DNA and ribonucleic acid (RNA) favors the detection of low-affinity Abs which are assimilated with high-affinity anti-dsDNA Abs. (5) The titer of these Abs and their detection through several techniques reflects activity of the disease.