Serum growth arrest specific protein 6 and its receptor (Axl) in SLE patients

Aim of the workGrowth arrest-specific protein 6 (Gas6) and its soluble tyrosine kinase receptor sAxl are known to have antiapoptotic function which may be implicated in systemic lupus erythematosus (SLE) pathogenesis. We aimed to assess serum levels of GAS6 and its receptor sAxl in SLE patients and to correlate these levels with disease activity index and renal involvement.Patients and methodsGas6 and sAxl were measured by enzyme linked immunosorbent assay (ELISA) in sera obtained from 50 female patients with SLE and 40 healthy age-matched females serving as controls. Disease activity was calculated according to the SLE disease activity index (SLEDAI).ResultsSerum levels of Gas6 and sAxl were significantly increased in patients with SLE in comparison to controls (p < 0.001). Serum Gas6 levels increased significantly in active SLE patients and lupus nephritis patients (p < 0.001). Serum levels of Gas6 correlated positively with SLEDAI, double-stranded DNA titers and proteinuria. In addition, there was a significant negative correlation between Gas6 serum levels and both C3 and C4; while, serum sAxl levels did not show these correlations.ConclusionsGas6 and sAxl may have a role in the pathogenesis of SLE. Increased serum Gas6 level may be an important risk factor for the development and severity of lupus nephritis. So, Gas6 may have a potential role to serve as a disease activity marker and may have a role as a therapeutic target for SLE.