Effect of GM-CSF, 1, 25-Dihydroxycholecalciferol (Vit.D) and All-Trans-Retinoic Acid (ATRA) on the Proliferation and Differentiation of MDS-Bone Marrow (BM)-Cells In Vitro

Abstract

Myelodysplastic syndromes (MDS) are a heterogenous group of stem cell disorders characterized by an impaired differentiation of the pluripotent stem cell resulting in dysplastic changes of all three hemopoietic lineages. We studied the effect of vitamin D (Vit.D) or all-trans retinoic acid (ATRA; 10⁻⁶ and 10⁻⁸M) in combination with GM-CSF on the proliferation and differentiation of mononuclear bone marrow-cells (MNC) of 48 MDS-patients as compared to 9 normal bone marrow (BM)-controls in a special colony assay: 30,000 MNC were cultured in agar plugs for 7 days (d) and the resulting colonies immunophenotyped in situ by a panel of monoclonal antibodies.

In 14 of 48 cultured MDS-BM-samples hemopoietic clones could be grown which expressed myelomonocytic antigens (CD14 (21%*), CD15 (35%*)) as well as blast antigens (CD20 (9%*), CD34 (10%*), Glycophorin A (Glyco A, 18%*)) whereas all normal BM-colonies were negative for blast markers. Vit.D or ATRA in combination with GM-CSF could not induce an (immunologically measurable) increased differentiation (5 higher percentage of differentiated clones) as compared to GM-CSF alone. We conclude that Vit.D and ATRA have no sufficient differentiation effect on MDS-cells.

Our colony assay in combination with immunophenotyping enables an in vitro measurement of differentiation and proliferation in MDS. We suggest the use of this technique to measure effects of therapy in the course of the disease.

Keywords:

• MDS
• colony assay
• immunophenotyping
• differentiation