PF4 and familial hypercholesterolemia: A total of 22 HDL proteins significantly and positively correlated with lesion area in the hypercholesterolemia study (50), among which PLG, the immunoglobin chain C region (IGHM), and platelet factor 4 (PF4) were strongest (r = 0.469, P = 0.00026; r = 0.461, P = 0.00034; r = 0.37, P = 0.0049, respectively).