Role of Osteopontin in Systemic Lupus Erythematosus

Background: Systemic lupus erythematosus (SLE) is a multisystemic disease, caused by a variety of factors, which lead to immunological abnormalities. Osteopontin (OPN) is a pleiotropic protein, important in bone remodeling and immune system signaling. It produced by various cells, including immune cells, and played a key role in regulating T-helper 1/T-helper 2 balances, stimulating B lymphocytes to produce antibodies, regulating macrophages, neutrophils and inducing dendritic cells. Over expression of OPN has been associated with the pathogenesis of immune-mediated diseases. Objectives: To investigate the role of osteopontin in SLE and to assess its relation to disease activity and subclinical atherosclerosis. Subjects and Methods: This cross sectional case control study was conducted on 30 SLE patients fulfilling  SLICCA /ACR criteria for SLE classification and 30 subjects sex- and age-matched apparently healthy as control group. All patients were assessed for SLE disease activity by the systemic lupus activity Index (SLEDAI). Serum OSP and Doppler ultrasound for carotid artery media thickness (CIMT) were measured in all patients and control. Results: Plasma OPN levels were significantly higher in SLE patients than in control group (P<0.001) and had significant positive correlation with disease activity (r  0,595,  P<0.05) and CIMT  (r = 0.400, P <0.001), but there was no significant correlation between CIMT and disease activity.  Conclusion: serum level of OPN was higher in SLE patients and correlated with disease activity and CIMT, and can be used as a marker of subclinical atherosclerosis.