Serum Levels of Soluble Fractalkine in Active Systemic Lupus Erythematosus and its Relation to Disease Activity and Renal Impairment

Background: Fractalkine (Fkn, CX3CL1) is a membrane-bound chemokine with a domain which can induce both adhesion and migration of leukocytes and is involved in the recruitment of cells into tissues undergoing inflammatory responses. Since Fkn is expressed in many tissues, we suggest that it may be implicated in the pathogenesis of systemic lupus erythematosus (SLE). The aim of this study is to determine soluble Fkn (sFKN) levels in SLE and to assess their relationship with disease activity and renal impairment. Method: Levels of sFkn in serum were measured in 20 SLE patients who divided into active and inactive according to SLE Disease Activity Index (SLEDAI) and 10 healthy individuals as a control group using enzyme-linked immunosorbent assay. Expression of Fkn CX3CL1 mRNA was quantified using real-time polymerase chain reaction. Results: There was a highly significant increase in serum sFkn levels in active SLE patients when compared to inactive patients and control group, while there was a significant increase in sFkn levels in inactive patients when compared to control group. Also, there were highly significant increases in Fkn (CX3CL1) mRNA expression in active SLE patients when compared to inactive SLE patients and control group, while there were no significant differences in (CX3CL1) mRNA expression in inactive SLE patients when compared to control group. The serum sFkn levels in active SLE show highly significant positive correlation with SLE disease activity index (SLEDAI), urea and createnin, while a significant positive correlations were found between sFkn , dsDNA, ESR and CRP. Conclusion: Soluble Fkn may play key role in the pathogenesis of SLE, including the renal involvement. Soluble Fkn is also a serologic marker of disease activity and renal impairment in patients with SLE