OBJECTIVETo investigate the effect of decitabine and plasma of ITP patients on in vitro cultrue of megakaryocytes in bone marrow of steroid-resistant ITP patients.

METHODSBone marrow mononuclear cells were isolated from 20 steroid-resistant ITP patients, both methyl cellulose semisolid culture system (to observe and count the number of megakaryocytes colony-forming unit) and liquid culture system (to analysis the expression rate of CD41a(+) cells) were used for megakaryocyte cultrue. The experiments were divided into 4 groups according to the different components of the culture system, group A was control, group B was added with decitabine, group C with ITP plasma, group D with both decitabine and ITP plasma, and the rest of the culture components were the same in the 4 groups except the above-mentioned materials. Morphology of megakaryocytes was observed by inverted and light microscopy. The expression rate of CD41a⁺ cells in culture was analysed by flow cytometric.

RESULTSDifferent concentration of decitabine showed different effect on megakaryocyte growth of steroid-resistant ITP patients and the optimal concentration to differentiate into megakaryocyte for bone marrow mononuclear cells is 3.0 µmol/L. Compared with group A, both megakaryocyte colony forming units (CFU) and expression rate of CD41a⁺ cells in group B were statistically significantly higher (P < 0.05). As compared with group A, the megakaryocyte colony-forming units in group C decreased with statistically significant difference, while compared with group C, the megakaryocyte colony-forming units in group D obviously increased with statistically significant difference.

CONCLUSIONSDecitabine is able to induce bone marrow mononuclear cells of steroid-resistant ITP patients to differentiate into megakaryocyte and the optimal concentration is 3.0 µmol/L; ITP plasma is able to inhibit the megakaryocyte growth of steroid-resistant ITP patients.