Serum and Urinary Cell–free MiR-146a and MiR-155 in Patients with Systemic Lupus Erythematosus

OBJECTIVE: Recent studies showed that micro-RNA play important roles in the pathogenesis of autoimmune diseases. We studied the levels of miR-146a and miR-155 in the serum and urinary supernatant of patients with systemic lupus erythematosus (SLE). METHODS: The serum and urinary supernatant levels of miR-146a and miR-155 were determined by real-time quantitative polymerase chain reaction in 40 patients with SLE and 30 healthy controls. RESULTS: Compared to controls, serum miR-146a and miR-155 levels were lower, and the urinary level of miR-146a was higher, in SLE. Estimated glomerular filtration rate (eGFR) correlated with both serum miR-146a (r = 0.519, p = 0.001) and miR-155 (r = 0.384, p = 0.014). Serum miR-146a inversely correlated with proteinuria (r = -0.341, p = 0.031) and the SLE Disease Activity Index (r = -0.465, p = 0.003). Serum miR-146a and miR-155 levels also correlated with red blood cell count, platelet count, and lymphocyte count. After treatment with calcitriol for 6 months, serum miR-146a level of SLE patients increased significantly (p < 0.001), and its change inversely correlated with the level of calcium-phosphate product (r = -0.466, p = 0.003). CONCLUSION: The results suggested that serum miR-146a and miR-155 participate in the pathophysiology of SLE and might be used as biomarkers of SLE.