2022 Volume 71 Issue 3 Pages 397-403
Anti-phospholipid antibodies (aPLs) are a heterogeneous group of autoantibodies that are frequently found in the plasma of patients with systemic lupus erythematosus (SLE). Although the presence of aPLs is associated with arterial and/or venous thrombotic complications in SLE patients, the mechanisms leading to thrombus formation remain unclear. We previously showed that aPLs induced monocyte tissue factor (TF) expression and the production of inflammatory cytokines such as TNF-α from monocytes. These thrombus-forming effects are considered to be exerted by the binding of aPLs to the surface of peripheral blood cells such as monocytes; however, the receptors recognized by aPLs have not yet been clarified. We confirmed by flow cytometric analysis that the expression of monocyte surface CD14 decreased when monocytes were stimulated with aPLs. Therefore, assuming that CD14 is a receptor that recognizes aPLs, we stimulated healthy human peripheral blood mononuclear cells with IgG-aPLs and analyzed the expression level of CD14 on the monocyte surface. Results showed that the expression level of CD14 on the monocyte surface was significantly reduced in only one case. Furthermore, it was revealed that the expression of TF on the surface of monocytes was suppressed by the treatment of monocytes with a monoclonal anti-CD14 antibody before stimulation. These results suggest that a signal by aPLs was transmitted via CD14 and may induce various inflammatory reactions such as TF expression on monocytes.
