Purified IgG from Patients with Obstetric but not IgG from Non-obstetric Antiphospholipid Syndrome Inhibit Trophoblast Invasion

PROBLEM: Some patients with antiphospholipid syndrome (APS) suffer pregnancy morbidity (PM) but not vascular thrombosis (VT), whilst others suffer VT only. Therefore, we compared the effects of IgG from VT+/PM− and VT−/PM+ subjects on human first-trimester trophoblast (HTR8) cells. METHOD OF STUDY: HTR-8 cells were incubated with APS VT+/PM−, APS VT−/PM+ or healthy control (HC) IgG. We measured trophoblast invasion by cell invasion assay; mRNA expression of TLR4 and adaptor proteins; phosphorylation of p38 MAPK, NFκB and ERK; and expression of interleukin (IL)-8 and IL-6. RESULTS: VT−/PM+ IgG, but not VT+/PM− IgG significantly reduced HTR-8 invasion. The effects on invasion were blocked by TLR-4 inhibition. Neither VT+/PM− nor VT−/PM+ IgG altered MyD88 mRNA expression, phosphorylation of signalling molecules or cytokine expression. CONCLUSIONS: VT−/PM+ IgG exert functionally relevant effects on human trophoblast cells but VT+/PM− IgG do not.