Dr. Lisa Sammaritano joined Hospital for Special Surgery in 1988, when she began a fellowship in rheumatic diseases. She has since developed a clinical practice geared towards patients with Systemic Lupus Erythematosus (SLE) and Antiphospholipid Antibodies, and combines this with clinical and basic research in these areas.
Antiphospholipid antibodies (aPL) are associated with a clinical syndrome which includes recurrent arterial and venous thromboses, recurrent fetal loss, thrombocytopenia and other complications. The mechanism of action of these autoantibodies has not been well defined. It is clear that most aPL bind to a cryptic epitope on a normal plasma glycoprotein, Beta 2-glycoprotein I, when this glycoprotein is bound to phospholipid.
Our recent work has shown activation of cultured human vein endothelial cells (HUVEC) by IgG from patients with anticardiolipin antibodies (aCL). Incubation with aCL IgG produced a 7-fold increase in monocyte adhesion compared with incubation with IgG from normal controls. Immunofluorescent microscopy demonstrated increased expression of cell adhesion molecules including E selectin, VCAM-1, and I CAM - 1.
We have also investigated possible contributors to aPL risk, or "second hit" factors. We have identified presence of IgG2 subclass of aCL to be associated with clinical risk of thrombosis. Presence of factor V Leiden is more common in aCL patients with as compared to without thrombosis. Finally, we continue to investigate other potential genetic or environmental risk factors, including FcRIIa allelic variation and homcysteinemia.
The safety of exogenous estrogens in systemic lupus has been widely questioned, with several case reports and one retrospective study suggesting an increased risk of flare associated with oral contraceptive use. Because of the potential benefits of oral contraceptives and hormone replacement therapy, we are conducting a nationwide multicenter randomized placebo-controlled double blind study to evaluate the safety of these preparations in patients with stable or inactive SLE. Hospital for Special Surgery is one of 5 centers participating in this NIH funded project, which may change practice patterns if safety of estrogens is shown.