[Antibodies to phospholipids and the vascular endothelium in nodular polyarteritis]

Clinical significance of antibodies to phospholipids (aPL) and vascular endothelium (aVE) was evaluated in 20 patients (9 women and 11 men aged 36 +/- 10.8 years) with nodular polyarteritis (NP) corresponding to classification criteria of the USA Rheumatology College. Antibodies to cardiolipin (aCL) (IgG and IgM) and to beta 2-glycoprotein (beta 2-GP1) (IgG) were titered by solid-phase enzyme immunoassay. Total serum level of aVE (IgG + IgM + IgA) was measured by solid-phase enzyme immunoassay using Eahy. 926 endothelial hybrydoma cell culture. Anticardiolipin antibodies were detected in 11 (55%) of 20 patients, 3 of these had IgG aCL, 4 IgM aCL, and 4 both antibody isotypes. Serum titers of all aCL were moderate in all cases. No antibodies to beta 2-GP1 were detected in any of the patients. Total serum endothelial activity varied from 0 to 89.7% in patients with NP. Mean aVE level was 24.45 +/- 21.2%, which was significantly higher than in donors (p < 0.001). In 4 (26.7%) of 15 patients with NP total level of aVE surpassed the upper threshold normal value. The presence of aCL directly correlated with the presence of reticular livedo (r = 0.54, p < 0.05), but not with any other clinical laboratory manifestations of the disease, including thrombotic complications (deep thrombosis of lower limb veins, stroke, myocardial infarction), renal involvement, increased erythrocyte sedimentation rate, increased concentrations of von Willebrand factor antigen and C-reactive protein, or angiitis activity. Vascular endothelial antibodies directly correlated with renal involvement (r = 1.00, p < 0.01), distal gangrene of the limb (r = 0.83, p < 0.01), and angiitis activity (r = 0.78, p < 0.001), with high level of von Willebrand factor antigen and increased erythrocyte sedimentation rate (r = 0.66 and r = 0.64, respectively; p < 0.01), but not with aCL (r = 0.43, p > 0.05) of any isotype (aCL IgG r = -0.01; r = 0.34; p < 0.05). All patients with aVE had aCL in the serum (aCL IgG in 1, aCL IgG and IgM in 1, and aCL IgM in 2 patients). The results indicate different significance of a CL and aVE in NP; the mechanisms of realization of their pathogenetic potential are still to be investigated.