MERTK and systemic lupus erythematosus: As showed in Figures 1(a) and 1(b), there was no significant difference in MerTK mRNA levels in PBMC or CD14+ monocytes/macrophages between patients with SLE and healthy controls (n = 35, 8.69 ± 2.28 versus n = 26, 9.16 ± 1.6, P = 0.876; n = 8, 0.20 ± 0.02 versus n = 5, 0.23 ± 0.04, P = 0.497, resp).