Sphingosine-1-phosphate in anti-neutrophil cytoplasmic antibody-associated vasculitis: coagulation-related clinical indicators and complications

Background: Sphingosine-1-phosphate (S1P) plays a significant role in anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). Methods: We collected the plasma samples from 40 patients with AAV and 10 healthy volunteers. The plasma levels of S1P were tested by enzyme-linked immunosorbent assay (ELISA). The levels of serum creatinine (Scr) were tested by rate method, and then the estimated glomerular filtration rate (eGFR) of the patients was calculated from the Scr, age, and gender. Prothrombin time (PT), partial thromboplastin time (APTT), thrombin time (TT), fibrinogen (FIB), fibrinogen reduction product (FDP), D-dimer and C-reactive protein (CRP) were tested by turbidimetric inhibition immunoassays. Platelets (PLTs) were tested by fluorescently labeled electrical impedance method. Results: The plasma levels of S1P were significantly higher in AAV patients than in healthy volunteers. Correlation analysis showed that plasma levels of S1P were negatively correlated with glomerular filtration (P=0.022, r = −0.306), and positively correlated with circulating levels of Birmingham vasculitis activity score (BVAS), PLT and D-dimer, (P=0.004, r = 0.443; P Conclusions: Plasma levels of S1P were associated with circulating levels of D-dimer, PLT and BVAS in the patients with AAV. Hence, plasma S1P level can be used as a biomarker to predict coagulation-related complications in AAV.