SNRPD1 and systemic lupus erythematosus: It is worth to note that in our study, the positive rates of anti-SmD1 in naive, non-naive and unselected total SLE patients were 68.00%, 56.80% and 60.97% respectively, which indicate that the positive rate of anti-SmD1 in patients with SLE was fluctuated with the different patients recruited.