Effects of retinoic acid, 1,25-dihydroxyvitamin D3, cytosine arabinoside and α-interferon on bone marrow cells from patients with myelodysplastic syndromes

Abstract Bone marrow cells from 15 patients with myelodysplastic syndromes and 2 with acute myeloid leukemia were incubated in vitro with all- trans -retinoic acid (RA), 1,25-dihydroxy vitamin D3 (D3), cytosine arabinoside (ara-C) and α-interferon (IFN). 3 H-thymidine incorporation ( 3 H-TdR), differentiation and clonal growth were studied. D3 was found to be the most effective inducer of differentiation and differentiation was correlated with a decreased 3 H-TdR. Differentiation with one of the inducers was significantly correlated to differentiation with any of the other inducers. Patterns of differentiation and spontaneous and D3-induced 3 H-TdR were used to divide the patients into 3 different groups. In the first group, 5 patients with extremely low spontaneous 3 H-TdR and differentiation in combination with a slightly increased 3 H-TdR after induction differed from all other patients by a higher percentage of bone marrow blast and a more pronounced pancytopenia. The two other groups had a high spontaneous 3 H-TdR but differed with respect to the D3-induced differentiation which was absent in one group ( n = 6) and present in the other ( n = 5). The two groups showed no difference in the clinical features.