GPVI-deficient patients are unresponsive to fibrin. Glass coverslips were coated with collagen or fibrin as described in "Materials and methods." (Ai) Human platelets (ptl; 20 × 109/L) were allowed to spread on coated coverslips, followed by staining of actin with Alexa-488 phalloidin. The pictures are representative results of a control and 2 GPVI-deficient patients. Scale bar, 5 μm. (Aii) The histograms illustrate the quantification of the surface area of platelets and the number of platelets calculated per millimeter squared. In each independent experiment, 5 random pictures were analyzed (100 platelets in total). The results are shown as mean ± standard deviation. ***P < .001. (B) Representative aggregation traces form a GPVI-deficient patient are shown (the control aggregation trace is representative of >20 donors).
