Background: Fractalkine (Fkn)/CX3CL1 which is a unique member of the CX3C
chemokine subfamily, and expressed on inflamed endothelium appears to possess
immunoregulatory properties that affect inflammatory/immune cell interactions and
inflammatory responses at sites of inflammation. Objective: The purpose of the
present study was to determine the Fractalkine/CX3CL1 level in SLE patients and
correlates that level with indices of disease activity and damage, trying to disclose its
role in the pathogenesis of SLE. Methods: The study was carried on forty SLE
patients (classified into 15 active and 25 inactive by using clinical and the BILAG
disease activity index assessment), thirty patients with rheumatoid arthritis (RA) as
disease control group and twenty healthy as control group. Levels of soluble Fkn
were measured by enzyme-linked immunosorbent assay. Expression of Fkn /CX3CL1
was quantified by real-time polymerase chain reaction. Results: Both serum sFkn
levels and mRNA expression of Fkn /CX3CL1 were significantly higher in patients
with SLE compared with RA patients and healthy controls (P<0.05) and were
significantly higher in SLE patients with active disease than in those with inactive
disease. Also, serum levels of sFkn were positively correlated with disease activity,
organ damage, anti–double-stranded DNA (anti-dsDNA) antibody titers, anti-Sm
antibody titers, immune complex C1q levels, anti-phospholipid, anti-RNP and ESR
level and negatively correlated with total hemolytic complement activity (CH50).
Conclusion: sFkn and CX3CL1 mRNA expression play crucial roles in the
pathogenesis of SLE and that sFkn may serve as a serologic inflammatory marker of
disease activity and organ damage.