Figure 2.

(A) Heparin-induced platelet activation assay was used to detect of HIT antibodies. CD61 (glycoprotein IIIa) and CD62p (p-selectin) served as markers of platelet identification and activation, respectively. Adenosine diphosphate was used to confirm normal platelet activation. The proportion of activated platelets was at least >11% in the presence of heparin (0.1 or 0.3 IU/ml) compared with baseline (no heparin), and the activation could be suppressed by a high dose of heparin (100 IU/ml). There was obvious platelet activation in the presence of the patient's plasma and low concentration (0.1 and 0.3 U/ml) of heparin, which was suppressed by the high concentration of heparin (100 U/ml). (B) PF4-induced flow cytometry-based platelet activation (PIFPA) revealed that the percentage of activated platelets increased from 12.28% baseline, no PF4 addition) to 29.95% with addition of 5 μg/ml PF4.