A conditioned cell culture medium of CD11blow human macrophages or a biologically active fraction thereof can be prepared by a method that includes (i) culturing a population of human mononuclear cells of the monocyte/macrophage lineage for 5-7 days, so as to induce differentiation of the mononuclear cells to macrophages； (ii) incubating the macrophages obtained in (i) with apoptotic cells or in the presence of a pro-resolving lipid mediator to reduce the CD11b expression, thus obtaining a culture of CD11blow macrophages； and (iii) collecting the conditioned cell culture medium of CD11blow macrophages. Pharmaceutical compositions containing the CD11blow macrophages conditioned medium or a culture of CD11blow macrophages can be used in the treatment of cancer or fibrosis.
