Clinical and serological correlates of anti-Sm autoantibodies in Chinese patients with systemic lupus erythematosus: 1,584 cases

To investigate the association of anti-Sm antibodies with clinical and serological features in systemic lupus erythematosus. A group of 1,584 patients with SLE was recruited. Clinical and laboratory data were compared between patients with and without anti-Sm antibodies. There were 1,424 females and 160 males, the mean age of the patients was 33.2 ± 12.3 years, and the mean duration of disease was 32.5 ± 59.4 months. A total of 469 (29.6%) were anti-Sm antibodies positive. The presence of anti-Sm antibodies was associated with arthritis, renal involvement, malar rash, vasculitis and low serum complement C3. The positive rate of anti-nuclear, anti-dsDNA, anti-La/SSB and anti-U1RNP antibodies were significant higher in anti-Sm positive group when compared with anti-Sm negative group. A trend towards a higher presence of anti-Sm antibodies related to an early disease onset was observed. In conclusion, Anti-Sm antibodies are associated with lupus related clinical and laboratory profiles and correlated significantly with disease activity.