Abstract: Objective: To investigate the correlation of phosphatidylserine-specific phospholipase A1 (PS-PLA1) and the disease activity in the patients with systemic lupus erythematosus (SLE). Methods: The expression level of PS-PLA1 in serum of SLE patients and healthy controls was detected by enzyme-linked immunosorbent assay (ELISA). Disease activity was assessed using SLEDAI score. The correlation between PS-PLA1 level and SLE activity was analyzed. Results: A total of 101 SLE patients (31 in activity group and 70 in stability group) and 80 healthy controls were enrolled. The expression level of PS-PLA1 in SLE patients (35.555±10.098) ng/mL was significantly higher than that in healthy controls (26.416±9.785) ng/mL (P<0.001), and the expression level of PS-PLA1 in active group (38.222±9.752) ng/mL was significantly higher than that in stable group (29.532±8.194) ng/mL (P<0.001). The level of PS-PLA1 was positively correlated with SLEDAI score, anti-dsDNA antibody and C-reactive protein (P<0.05), and negatively correlated with C3 and C4 (P<0.05). The sensitivity and specificity of PS-PLA1 as a marker of SLE activity were 80.0% and 66.7% respectively. Conclusion: The serum level of PS-PLA1 in SLE patients is increased, which is positively correlated with disease activity.

Key words: systemic lupus erythematosus, PS-PLA1, SLEDAI score, disease activity