While the SL E (Systemic Lupus Erythematosus) specificity of ANA is low, that of anti-dsDNA autoantibodies is high. The DNA used in the assay must be double stranded: autoantibodies to single –stranded (ss) DNA exist in many diseases and specific to none. The prevalence (70%) of antidsDNA autoantibodies is much higher in SL E, giving a higher diagnostic sensitivity than the similarly disease-specific anti-Sm autoantibodies (30%). Anti-dsDNA autoantibodies are usually detected by very analytically sensitive techniques, such as ELISA (Enzyme Linked Immunosorbent Assay). Within SLE, ds-DNA autoantibodies tend to associate with the presence of glomerulonephritis. Their levels are used to monitor disease activity. We suggest the use of ds-DNA to find the difference between SL E patients with benign variants and classical syndrome of severe skin and renal disease.
Key words: SLE , systemic lupus erythematosus, ANA, anti-nuclear antibodies, ds-DNA, doublestranded DNA antibodies, IFA, immunoflourescence assay, ELISA , enzyme linked immunosorbent assay
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