tam receptor ligands in lupus protein s but not gas6 levels reflect disease activity in systemic lupus erythematosustam受体配体在狼疮蛋白s但不是gas6水平反映在系统性红斑狼疮疾病活动.pdf

Suh et al. Arthritis Research Therapy 2010, 12:R146 /content/12/4/R146 RESEARCH ARTICLE Open Access TAM receptor ligands in lupus: Protein S but not Gas6 levels reflect disease activity in systemic lupus erythematosus 1,2 1 1 3 1* Chang-Hee Suh , Brendan Hilliard , Sophia Li , Joan T Merrill , Philip L Cohen Abstract Introduction: The TAM (tyro 3, axl, mer) kinases are key regulators of innate immunity and are important in the phagocytosis of apoptotic cells. Gas6 and protein S are ligands for these TAM kinases and bind to phosphatidyl serine residues exposed during apoptosis. In animal models, absence of TAM kinases is associated with lupus-like disease. To test whether human systemic lupus erythematosus (SLE) patients might have deficient levels of TAM ligands, we measured Gas 6 and protein S levels in SLE. Methods: 107 SLE patients were recruited. Of these, 45 SLE patients were matched age, gender and ethnicity with normal controls (NC). Gas6 and free protein S were measured with sandwich enzyme linked immunosorbent assays (ELISAs). Results: Overall, the plasma concentrations of Gas6 and free protein S were not different between 45 SLE patients and 45 NC. In SLE patients, the levels of free protein S were positively correlated with age (r = 0.2405, P = 0.0126), however those of Gas6 were not. There was no correlation between the concentrations of Gas6 and free protein S in individuals. Levels of free protein S were significantly lower in SLE patients with a history of serositis, neurologic disorder, hematologic disorder and immunologic disorder. Gas6 levels were elevated in patients with a history of neurologic disorder. The SLE patients with anti-Sm or anti-cardiolipin IgG showed lower free protein S levels. Cir