The Usefulness of Endothelial Cell Adhesion Molecules and Anti-C1q Antibody in Monitoring Systemic Lupus Erythematosus Disease Activity

Objectives. The study was conducted to determine the correlation of ICAM-1, VCAM-1, and anti-C1q antibody levels with SLE disease activity index (SLEDAI) and standard SLE disease activity immunological markers (anti-dsDNA and sera C3 and C4). Study Design. This was a cross-sectional study. Materials and Methods. Blood samples were obtained from 95 SLE patients (45 active SLE and 50 nonactive SLE) and 50 controls. The subjects were assessed using SLEDAI and score of more than five is determined as having active SLE. The sera were tested for serum ICAM-1, VCAM-1, and anti-C1q (ELISA), anti-dsDNA (CLIFT), serum C3, and serum C4 (immunonephelometry). Results. Anti-dsDNA and anti-C1q antibody showed good positive correlations with SLEDAI (r=0.529, P<0.001 and r=0.559, P<0.001, resp.). VCAM-1 and sera C3 and C4 showed fair correlation with SLEDAI (r=0.294, P=0.004; r=-0.312, P=0.002; and r=-0.382, P<0.001, resp.). ICAM-1 level showed no significant correlation with SLEDAI (P=0.062). There were significant correlations of VCAM-1 and anti-C1q antibody with anti-dsDNA (r=0.226, P=0.006 and r=0.511, P<0.001, resp.). VCAM-1 showed poor inverse correlation with serum C3 (r=-0.183, P=0.028) and fair inverse correlation with serum C4 (r=-0.251, P=0.002). Anti-C1q antibody demonstrated fair inverse correlation with both sera C3 and C4 (r=-0.420, P≤0.001 and r=-0.398, P<0.001, resp.). However, ICAM-1 showed no significant correlation with anti-dsDNA and sera C3 and C4 (P=0.259, P=0.626 and P=0.338, resp.). Conclusions. The serum levels of anti-C1q antibody in SLE patients showed the best correlation with the SLEDAI and standard immunological tests for SLE disease activity. These data support that anti-C1q antibody is a useful marker for monitoring SLE global disease activity. The potential of VCAM-1 needs further confirmation.