Anti-Telomere Antibodies in Lupus Glomerulonephritis

Background. Differentiating Systemic lupus erythematosus (SLE) from other autoimmune rheumatic diseases and undifferentiated connective tissue diseases may be difficult. Diagnosing SLE early and more accurately is important for patient education and for the institution of appropriate treatment to reduce morbidity. The aim of this study is to investigate the prevalence and diagnostic significance of antibodies against telomeric DNA in SLE and other autoimmune rheumatic diseases, and to make comparisons with five conventional anti-DNA or anti-nuclear antibody (ANA) assays. Methods. Antibodies to telomeres, which are highly repetitive sequences of DNA (TTAGGG/CCCTAA) at the end of eukaryotic chromosomes, were measured by an enzyme linked immunosorbent assay (ELISA) in 225 patients with SLE and 108 with other autoimmune rheumatic diseases (96 rheumatoid arthritis, 12 mixed connective tissue disease). Other assays used were two commercial ELISA assays for anti-dsDNA using calf thymus as antigen, Crithidia luciliae immunofluorescence and immunofluorescence using Hep-2 cells for ANA. Results. The prevalence of anti-telomere in SLE was 58,67 %, versus 5,21 % in rheumatoid arthritis and 25 % in mixed connective tissue disease. Specificity of anti-telomere for SLE was 90,6 %, positive and negative predictive value were 94,2 % and 45,8 %, respectively. Other anti-dsDNA assays had low sensitivities. The association of antitelomere with a history of nephritis in patients with SLE was stronger (P=0,005) than the other assay. The correlations between the different assays were good (P<0,001 for all comparisons). Conclusions. We found that the ELISA assay for antitelomeric DNA antibodies was a sensitive and highly specific test for SLE. The most sensitive test was ANA by immunofluorescence, followed by anti-dsDNA and antitelomere. Anti-telomere was clearly more specific than the first two tests.