PF4 and Thrombocytosis: PPBP (pro-platelet basic protein, aka CXCL7 and low affinity platelet factor IV (PF4)), in a module positively correlated with ICH and aPHE volumes and negatively with rPHE, is a platelet-derived growth factor and a platelet-specific chemokine implicated in thrombosis, thrombocytosis, and heparin-induced thrombocytopenia [88].