Effect of DGKKO on HIT thrombosis in a microfluidic system. (A) Representative images over a 15-minute window of flow through the channels from 1 of 3 independent studies showing platelet accumulation (white aggregates) on the endothelial lining. Scale bar is included, and arrows at the bottom indicate direction of flow. In this assay, optimal platelet adhesion occurs using human umbilical vein endothelial cell–lined channels subjected to photochemical injury by hematoporphyrin, followed by perfusion of whole blood supplemented with PF4 and HIT monoclonal (KKO and 5B9) or polyclonal (patient-derived) antibodies. The effect of DGKKO added 15 minutes after HIT antibody–induced activation is shown for each monoclonal or polyclonal antibody used. Note that KKO by itself led to platelet accumulation on injured endothelium, as previously noted,21 likely because of the presence of hPF4 released from the platelets. (B) Quantitative analysis of platelet adhesion showing mean ± 1 SEM of 3 independent experiments. P values were determined using 2-way Student t test comparing platelet accumulation in the absence of DGKKO with that in the presence of DGKKO.
