| BACKGROUD:Polycythemia vera (PV) is a malignant clonal hemotopoietic disorder resulted from the mutation of multipotent hematopoietic stem cells. PV was characterized by erythrocytosis, but in most cases, there were erythrocytosis, guanulocytosis and thrombocytosis in bone marrow. It has been confirmed that the red blood cell, platelet, granulocyte, monocyte, B lymphocyte of PV patients had been derived from the same abnormal mutated stem cell colone used the glucose-6-phosphate dehydrogenase(G6PD) gene and polymorphic X-linked gene analyzing methods. Erythropoietin inhibited apoptosis and improved the proliferation of erythroid progenitors, so it was essential for the formation of colony forming unit-erythroid(CFU-E). The erythroid progenitors of 97 %~100% PV patients could form endogenous erythroid colonies(EEC) without the addition of erythropoietin. The PV megakaryocyte precursors(CFU-MK) were hypersensitive to thrombopoietin. The stem/progenitor cells of PV cases were also hypersensitive to various growth factors(IL-3, GM-CSF, IGF-1). So we conside the hematopoietic function of PV patients hematopoitic stem cells is at higher level, the stem/progenitor cells of PV cases may be abnormal in proliferation and apoptosis. It was been reported that the expression of BCL-XL gene was higher in mononuclear cells and erythroid progenitors of PV patient. But there is no report about the proliferation and apoptosis of CD34 positive bone marrow cells of PV patients in the world.PV is characterized by increases of circulating blood cells, blood viscosity ,thrombotic event, high incidence of myelofibrosis and leukemia evolution. PV was diagnosed by symptoms, blood cell count, bleed viscosity and excluding the secondary erythrocytosis. But these parameters were not specific, EEC can be the index of malignant colones of PV. It can be used for very important for diagnosing the PV.Untreated PV patients are at particularly higher risk of both thrombotic and hemorrhagic events. Thrombosis was the main cause of death in PV patients. Several investigators suggested that MF occured in 5~50% of the patients with PV. The transition to this stage of the disease occured, on average, at 10 years after initial diagnosis. 15 years or more after initial diagnosis, this complication was a major clinical problem which affected almost 50% of patients. The basic questions to be resolved regarding PV is the identification of efficient therapy to inhibit the malignant clone. The aim of our study is to prove if IFN and Hu were effective and safe in the treatment for PV patients. Hydroxyurea (HU) was widely used in PV treatment in 20 century. But it was reported having increased the incidence of leukemic transformation and myelofibrosis. The mutagenic effect of HU was debated. IFN has been extensively used as a myelosuppressive agent in chronic myeloid leukaemia. IFN was reported to suppress the abnormal hematopoietic clones and reduce the myelofibrosis and leukemic transformation in recent decades. But there was no report about the efficiency and safety of HU plusing IFN for PV patients in our country.Study on these questions will be very significant for understanding the pathogeneisis... |
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