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Polycythemia vera (PV) is a chronic myeloproliferative disorder due to a haematopoietic stem cell's clonal proliferation. PV is also characterized by independency or hyper sensibility of haematopoietic progenitors to several cytokine as erythropoietin. This acquired disorder is often associated with thrombocytosis, leukocytosis and splenomegaly. Generally, diagnosis remains easy, based on basic clinical and biological abnormalities. Sometimes, positive diagnosis required more sophisticated tests as assay of endogenous erythroid colony, erythropoietin blood level and bone marrow biopsy. Usually natural history of disease remains long with a good quality of life. In some cases complications occur: mainly thrombosis and late myeloid metaplasia with myelofibrosis and acute leukemia. Therapeutic approachs remain complex and difficult to optimize based up on age and disease severity. Treatment searchs for reducing hyper viscosity complications and for avoiding therapeutic induced leukemia.

Polycythemia vera is a myeloproliferative syndrome. This clonal disorder involves a pluripotent stem cell capable of differentiating into red blood cells, granulocytes, and platelets. Polycythemia vera is characterized by the overproduction of mature red blood cells in the bone marrow. Myeloid and megakaryocytic elements are also often increased. Polycythemia vera (PV) is rarely associated with pregnancy. About 20 cases have been reported. Prognosis of PV is not influenced by pregnancy. Conversely, pregnancy outcome is poor, due to the occurrence of gestational hypertension, stillbirth and induced prematurity. During pregnancy, clinical management needs to be close including a collaborative approach between obstetricians, hematologists and anesthesists. The risk of poor outcome may be reduced by the association of antiaggregant and anticoagulant therapy. Phlebotomy can be provided in order to maintain hemoglobin level under 42%.

Aims: To compare by a prospective study in high risk polycythemia vera (PV) patients 33P alone and 32P followed by low-dose hydroxyurea (HU) maintenance therapy. Toxicity, efficiency, and leukemogenic potential were studied., Patients: 483 patients with a documented PV, aged more than 65 years at diagnosis, were included between 1980 and 1996 in a prospective study comparing 32P alone and 32P followed by low-dose HU maintenance therapy. Blood cell counts were performed every two months and a clinical evaluation by a specialist was obtained every four or six months., Results: Treatments were well tolerated, but chronic leg ulcers were observed in the maintenance therapy arm. The risk of leukemia was about 15% at the 15th year in the group of patients treated by 32P alone, but reached 30% in the group receiving maintenance therapy. In both arms, there was no significant correlation between occurrence of leukemia and the total dose of 32P. There was a correlation between the leukemic risk and disease severity, estimated on the frequency of relapse. Cancer occurrence was slightly higher than expected in the maintenance arm. HU treatment did not protect against progression to myelofibrosis, probably due to the lack of maintenance of an efficient myeloid or megakaryocytic suppression. Median life-span was slightly shorter in the group receiving HU maintenance. In all cases, life-span was only one year lower than that observed in the reference population., Conclusion: For all these reasons, we suggest the us of 32P alone in elderly patients; complementary chemotherapy should only be prescribed in the cases with short-term relapse, and late resistance to 32P.

A review is presented of the clinical, physiopathological and therapeutic aspects of four varieties of chronic myeloproliferative syndrome: polycythemia vera, idiopathic thrombocythemia, chronic myelocytic leukemia and idiopathic myeloid metaplasia. Routine and experimental therapeutic approaches are discussed.

During the last 12 years, 86 apparently primary polycythemias have been observed in subjects less than 40 years old. In twelve of them a non-suspected cause has been found (seven abnormalities of the hemoglobin function). In 43 cases, all males, the erythrocytosis (red cell volume more than 36 ml/kg) was pure and stable, without any complication; this "benign erythrocytosis" probably depicts extreme values of the normal distribution of the red cell mass. In 31 cases, the disease had criteria similar to those of polycythemia vera observed in older patients; in 12 of these cases, severe thrombo-embolic complications have been observed at the very beginning of the disease; however no further complication has been seen, when the patients were actively treated (phlebotomies or 32P); at the present time, no one of these cases did show transformation into acute leukemia, but the long-term prognosis (beyond 15 years) cannot yet been precisely drawn.

The authors report the results of phlebotomy for polyglobulia vera in a series of 73 patients eligible for inclusion in an international co-operative study. Previous studies usually gave actuarial survival curves but failed to mention the complications and discomfort associated with phlebotomy, although these are of importance in clinical practice. Most of the 73 patients were excluded on account of discomfort (20%), vascular thrombosis (almost 50%) or transformation into myelofibrosis within a mean period of 4 years (20%). Only 10% were treated with long-term phlebotomy. Although phlebotomies avoid the long-term risk of leukaemia attached to radiophosphorus or chemotherapy (20% on average after a mean delay of 12 years), they have practical limitations and their own, important risks. In patients over 65 and in those at high vascular risk, the best treatment is myelosuppression. However, younger subjects with polyglobulia vera but no vascular risk and/or thrombocytosis may benefit, at least temporarily, from phlebotomy.

Recent studies from this department have suggested that the level of 2,3-DPG may be determined in part by the volume of the erythrocyte; this conclusion was reached on the basis of the finding of significantly elevated values of 2,3-DPG in heterozygous beta-thalassemia, even in the absence of anemia. In order to test the role of microcytosis in the formation of 2,3-DPG levels, a study was undertaken on a different patient material characterized by microcytosis without anemia or hypoxia, namely on cases of polycythemia vera (PV) rendered microcytic through therapeutic venesection (or blood loss) and on appropriate controls. Five cases of untreated PV (mean HB 18.36 +/- 1.53 g/dl, mean MCV 94.4 +/- 3.9 fl) had 2,3-DPG levels slightly lower than normal controls (13.67 +/- 0,75 mumoles/g Hb vs 14.18 +/- 1.41 mumoles/g Hb). Six microcytic iron deficient PV's (mean Hb 17.42 +/- 2.34 g/dl, mean MCV 74.5 +/- 6.2 fl) had very significantly increased 2,3-DPG levels (17.73 +/- 1.75 mumoles/g Hb). Similar high levels were obtained in five cases venesected in the past and maintained with cytostasis (mean Hb 15.22 +/- 0.67 g/dl, MCV 82.5 +/- 7.5 fl, 2,3-DPG 17.04 +/- 2.44 mumoles/g Hb). A strong linear negative correlation was obtained between 2,3-DPG values and the MCV (r = -0.736, P less than 0.001). It is concluded that microcytosis of other etiology and not only of beta-thalassemia may also lead, per se, to increased levels of 2,3-DPG. The different levels of 2,3-DPG in PV undergoing venesection vs untreated patients may explain some discrepant reports on the behavior of this metabolite in PV.