0000000000700742
AUTHOR
Natascha Clemens
Human antiphospholipid antibodies induce TNFα in monocytes via Toll-like receptor 8
The antiphospholipid syndrome (APS) is characterized by recurrent arterial and/or venous thromboses, pregnancy loss and the presence of antiphospholipid antibodies (aPL). One of the discussed mechanisms of this thrombotic activity in APS patients is attributed to TNFalpha secretion in monocytes after aPL stimulation. To investigate this mechanism in detail, we employed a monoclonal aPL and IgG fractions of APS patients for stimulation of human peripheral monocytes. Stimulation with this monoclonal aPL resulted in an increased expression and secretion of TNFalpha, caused by specific upregulation of TLR8 mRNA and protein expression levels. To confirm the specificity of this finding we could d…
In Vitro Effects of Antiphospholipid Syndrome-IgG Fractions and Human Monoclonal Antiphospholipid IgG Antibody on Human Umbilical Vein Endothelial Cells and Monocytes
It has been shown that stimulation of endothelial cells and monocytes by antiphospholipid antibodies leads to a prothrombotic state involving upregulation of tissue factor (TF). We examined the in vitro effects of IgG fractions from patients with antiphospholipid syndrome (APS) and of a β-2-glycoprotein 1-independent human monoclonal antiphospholipid antibody (HL-5B) on human umbilical vein endothelial cells (HUVEC) in comparison to untreated cell controls and to exposure to monoclonal IgG control antibody. We also examined the effect of recombinant monocyte chemoattractant protein-1 (MCP-1) on peripheral blood monocytes. Stimulation of endothelial cells with APS IgG fractions or HL-5B resu…