Soluble and membranous endothelial protein C receptor in systemic lupus erythematosus patients: Relation to nephritis

Aim of the work: To investigate the role of endothelial protein C receptor (EPCR) (membrane and soluble forms) as a biomarker of lupus nephritis (LN) in systemic lupus erythematosus (SLE) patients and to study its relation to the prognosis and response to treatment. Patients and methods: The study included 30 SLE patients and 30 matched healthy volunteers as well as 10 renal biopsies from surgical nephrectomy as a control for membranous (mEPCR) examination. SLE disease activity index-2000 and damage index were assessed. Serum sEPCR was measured. Renal expression of mEPCR was analyzed. All patients were reassessed after 3 months. Results: Patients were 26 females and 4 males with a mean age of 29.6 +/- 10.04 years and disease duration of 4.4 +/- 3.5 years. Their mean SLEDAI was 13.9 +/- 9.9 and damage index 1 +/- 1.5. Serum levels of sEPCR were significantly higher in patients with LN (19.9 +/- 5.7 ng/ml) than those without (8.95 +/- 4.2 ng/ml) and controls (5.3 +/- 2.6 ng/ml)(p < 0.001). SLE patients with cutaneous vasculitis (n = 9) had significantly higher sEPCR levels than those without (18.1 +/- 7.8 vs 10.2 +/- 5.2 ng/ml)(p = 0.02). There was a significant correlation between sEPCR percentage of change and of SLEDAI-2k with and without LN (p < 0.01 and p < 0.05). A significant difference was observed in sEPCR according to the prognosis and treatment response after 3 months. mEPCR stained positively in glomeruli and tubules of LN patients with no relation to histopathological grading. Conclusion: sEPCR plays a role in the pathogenesis, is related to a bad prognosis and poor response to treatment in LN. mEPCR was not related to LN grading. (C) 2018 Egyptian Society of Rheumatic Diseases. Publishing services provided by Elsevier B.V.