Abstract: Objective To study the influence of culture supernatant of psoriatic peripheral blood mononuclear cells (PBMCs) on the colony-forming of bone marrow-derived hematopoietic stem cells and progenitor cells. Methods Bone marrow-derived mononuclear cells were separated by density gradient centrifugation. Methylcellulose semi-solid culture medium was used to culture the bone marrow mononuclear cells in culture systems. The PBMC culture supernatant from psoriatic patients or normal controls were added to the culture, to observe their influence on the marrow-derived high proliferative potential colony forming cells (HPP-CFCs), erythroid and granulocyte-macrophage colony forming units (CFUs-E and CFUs-GM) of bone marrow hematopoietic stem/progenitor cells from healthy individuals. Results The values of HPP-CFCs, CFUs-E and CFUs-GM were significantly lower in the bone marrow cells stimulated by the supernatant of cultured psoriatic PBMCs than those stimulated by the supernatant of cultured normal PBMCs and those in the spontaneous proliferation group (P<0.05, P<0.01); however, no significant difference of those values was found between the group stimulated by supernatant of cultured normal PBMCs and the spontaneous proliferation group (P > 0.05). Conclusions Psoriatic PBMCs have specific biological activity and can inhibit the colony forming of bone marrow hematopoietic cells from healthy individuals.

Key words: Psoriasis, Leukocytes,mononuclear, Colony-forming units assay