SSB and systemic lupus erythematosus: The numbers of white blood cells, neutrophils, lymphocytes, and monocytes, 24-h proteinuria levels, Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) score, anti-ds-DNA antibodies, U1-nuclear ribonucleoprotein (anti-U1RNP) antibodies, anti-histone antibodies, anti-Ro (anti-SS-A) antibodies, anti-La (anti-SS-B) antibodies, and other clinical indicators showed no significantly different in the US31-positive and US31-nagtive SLE patients.