Anti-DNA antibodies cross-reacting with laminin inhibit trophoblast attachment and migration: implications for recurrent pregnancy loss in SLE patients.

PROBLEM: Systemic lupus erythematosus (SLE), an autoimmune disease, is associated with reduced fetal survival, recurrent abortions, and other pregnancy complications. Some of the autoantibodies found in SLE bind to laminins (LNs), which play an important role in the implantation of the fertilized ovum in humans. METHOD OF STUDY: To elucidate the role of these specific autoantibodies, chorionic villous explants from 6 7-week-old human placentas were established as organ cultures on laminin-1 (LN-1), collagen IV (CN-IV) or uncoated culture dishes. The cultures were then exposed to a mouse monoclonal anti-DNA/anti-LN-1 antibody, to human polyclonal lupus antibodies cross-reacting with LN-1, a function-blocking polyclonal antibody to LN-1, polyclonal antibodies to CN-IV, or IgG control.
RESULTS: The explants attached to LN-1 and CN-IV, but not to uncoated culture dishes. LN-1 promoted migration of trophoblast, whereas CN-IV promoted migration of fibroblast-like cells. Trophoblast attachment and migration were abolished in a dose-dependent manner by all three antibodies to LN-1, but not by antibodies to CN-IV or IgG control. Furthermore, the effect of anti-LN antibodies was abolished by preincubating them with LN-1.
CONCLUSIONS: These studies suggest that anti-DNA antibodies cross-reacting with LNs may play a role in early pregnancy failure in SLE patients by interfering with placental implantation.