[Autoantibodies in systemic lupus erythematosus: spectrum and clinical associations]

We have analysed the clinical features and autoantibody profile of 84 tunisian patients with newly diagnosed systemic lupus erythematosus (SLE). Antinuclear antibodies (ANA) were detected by an immunofluorescence method, anti-dsDNA and anti-cardiolipin (aCL) antibodies by ELISA, antinucleosome and anti-extractible nuclear antigens (or anti-ENA: anti-Sm, anti-RNP, anti-SSA and anti-SSB) by immunodot. The mean age of the patients was 29,9 years and the sex-ratio F/M was 6. The most common initial features were haematological (80%), rheumatological (78%) and cutaneous (75%) disorders. 59% of the patients had glomerular nephropathy. ANA were detected in 97.6%, antinucleosome in 78.6%, anti-dsDNA in 75%, anti-histones in 44%, anti-Sm in 36.9%, anti-RNP in 32.1%, anti-SSA in 54.8% and anti-SSB in 14.3% of patients. IgG and IgM aCL were detected in 45 and 40% of the patients respectively. The significant clinical associations were those of nephropathy and disease activity with anti-dsDNA and antinucleosome antibodies. Our results confirm the clinical polymorphism of SLE, the high frequency of antinucleosome antibodies at time of diagnosis and the predominance of anti-SSA among anti-ENA antibodies.