OBJECTIVETo analyze the number of myeloid-derived suppressor cells(MDSC) and the level of prostaglandin E2(PGE2) in the bone marrow of adult ITP patients, and to explore their possible mechanisms involved in the pathogenesis of this disease.

METHODSTwenty-five patients of newly diagnosed ITP, 25 patients of complete remission group and 15 patients of control group were selected. The number of MDSC in the bone marrow between 3 groups was detect by flow cytometry (FCM). The serum level of prostaglandin E2 (PGE2) in 3 groups was determined by enzyme linked immunosorbent assay (ELISA). The relative expression of IFN-γ mRNA in bone marrow mononuclear cells was measured by real time fluorescence quantitative polymerase chain reaction (RT-qPCR) in each groups.

RESULTSThe number of MDSC in the complete remission group was significantly higher than that in the control group (P<0.05); the number of MDSC in the newly diagnosed group was higher than that in the control group; the number of MDSC in the complete remission group was higher than that in the newly diagnosed group. The serum level of PGE2 in bone marrow of ITP patients in the newly diagnosed group was higher than that of the control group（P<0.05）. The serum level of PGE2 in the bone marrow of ITP patients of the complete remission group was higher than that of the control group (P<0.05）. The level of PGE2 in bone marrow serum of ITP patients of the newly diagnosed group was lower than that in the complete remission group(P<0.05）. The relative expression level of IFN-gamma in bone marrow mononuclear cells of the ITP patients in newly diagnosed group was higher than that in the control group and the complete remission group（P<0.001）. The relative quantification (RQ) of IFN-γ in bone marrow mononuclear cells was 2.60 between the newly diagnosed group and the complete remission group.

CONCLUSIONWhen adult ITP disease is remitted, the number of MDSC rises and correlates with the therapeutic response and PGE2 level in the bone marrow.