A method of changing the phenotype of monocytes and macrophages from a pro inflammatory MI phenotype to an anti-inflammatory M2 phenotype is disclosed. The method can comprises providing a composition comprising a recombinant adeno-associated virus (rAAV) vector comprising an exogenous gene encoding ApoA-1 Milano or a fragment thereof, and administering the composition to mammal in need thereof to change the phenotype of monocytes or macrophages from a pro inflammatory M1 phenotype to an anti inflammatory M2 phenotype. By changing the phenotype of monocytes or macrophages from a pro-inflammatory M1 phenotype to anti-inflammatory M2 phenotype, atherosclerosis can be treated. A method of monitoring macrophage phenotypic switching and a method of assessing the efficacy of the treatment of atherosclerosis are also described.
