HLA-C and pulmonary arterial hypertension: In mouse models of MI and pulmonary arterial hypertension–induced right ventricular overload, PYR increased the numbers of M2 macrophages and Foxp3+ Treg cells and reduced CCL2/7 chemotactic signaling, leading to decreased infiltration of MHC-IIhiCCR2+ macrophages (19–21).