Antiphospholipid antibodies in pediatric lupus nephritis

Antiphospholipid antibodies (aPL) of various isotypes are known to occur in systemic lupus erythematosus (SLE), but the significance of this finding in the pediatric population remains unclear. Our aim was to determine whether children with lupus nephritis have an increased risk of thrombosis and whether antiphosphatidylserine (APS) or antiphosphatidylinositol (API) antibodies were predictive of thrombotic complications. Thirty-six children (27 girls/9 boys; 44% black) with SLE nephritis (WHO II, 1; WHO III, 7; WHO IV, 21; WHO V, 7) were evaluated for antiphosphatidylserine, antiphosphatidylinositol, and anticardiolipin immunoglobulin (Ig) G and IgM isotypes, using a modified solid-phase enzyme-linked immunoassay (ELISA). Twenty-four patients (67%) had at least one positive aPL. Longitudinal data on 26 patients showed fluctuations in the degree of positivity. Eight patients experienced thrombotic complications, with equal distribution between arterial and venous events. Other clinical manifestations included thrombocytopenia in seven patients (19%), hemolytic anemia (44%), lupus anticoagulant (6%) and false-positive Venereal Disease Research Laboratory (VDRL) test results (11%). Comparisons between those with and without a thrombotic event showed no detectable difference in the incidence of aPL positivity between the two groups. We conclude that neither APS, API, nor anticardiolipin (ACL) activity was predictive of thrombotic complications in our subset of patients with lupus nephritis.