Background: Soluble Fas (sFas) is a marker of apoptosis that appears to increase in the serum of systemic lupus erythematosus patients and may have a correlation with disease activity. The exact role of sFas in apoptosis is not clear. The purpose of this study is to assess the correlation between serum levels of soluble Fas (Apo/1-CD95) and the activity of systemic lupus erythematosus.
Methods: Our study was performed on 114 systemic lupus erythematosus patients who were compared with 50 randomly selected sex, age and race-matched healthy controls. Disease activity was defined according to the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI-2K). All physical exams and laboratory parameters were collected to determine the SLEDAI. sFas levels were determined using a commercially available ELISA kit.
Results: There was a significant difference between serum levels of sFas in the case and control groups (P=0.001). A significant correlation coefficient existed between the sFas and SLEDAI2K variables (P=0.001, r=0.494). Significant statistical difference was found between serum levels of sFas in the active and inactive phases of disease according to SLEDAI< or =9 or > or =10, (P=0.002). The sFas levels were 270 - 300 pg/mL for SLEDAI< or =9 and 355-502 pg/mL for SLEDAI> or =10, with a confidence interval of 95 percent.
Conclusion: This study shows a significant elevation of sFas levels in the sera of systemic lupus erythematosus patients with active disease; therefore it can be used as an appropriate marker for evaluation of disease activity.