Polycythemia Vera

Polycythemia vera (PV) is a clonal chronic myeloproliferative disorder mainly characterized by erythrocytosis with leukocytosis and thrombocytosis, absolute increase in total blood volume, blood hyperviscosity; clinical presentation: red-purple skin, dizziness, lightheadedness, headache, hypertension, hepatosplenomegaly; severe patients may develop vascular/neuro complications, bleeding and infarction.

Common Symptoms

Bleeding tendency; gingival bleeding; fatigue; Yi-Yu products; epistaxis; cyanosis; diplopia; epistaxis

Causes and Pathogenesis

Etiology: 'Endogenous' erythroid clone formation: In in-vitro bone-marrow stem-cell culture, normal marrow cells require EPO in medium to form late erythroid colonies (CFU-E); PV marrow cells grow without added EPO, suggesting EPO-independent erythroid clones are 'neoplastic'. When EPO is added to PV cultures, CFU-E contains both PV and normal cells, indicating normal stem cells remain but are suppressed by the PV clone. PV abnormal clone originates from a single cell, continuously proliferates, suppresses normal clones, and is cytogenetically unstable; clinical transformation to acute leukemia occurs. Enhanced EPO sensitivity of erythroid progenitors: At equal EPO concentration, PV patients have significantly more early BFU-E and CFU-E than normals, and more than PV without EPO; adding EPO antibody reduces PV CFU-E — indicating enhanced EPO sensitivity, one cause of erythrocytosis. Abnormal pluripotent-stem-cell proliferation: Normal erythrocytes contain both A and B G-6-PD isoenzymes; PV red/granulocytic/platelet cells contain only type A, while fibroblasts/lymphocytes retain both A and B — proving this is a single clonal disease at the pluripotent stem-cell level. Abnormal apoptosis: PV nucleated-RBC survival is longer than normal; PV colonies are highly sensitive to IL-3 and SCF which delay erythroid-progenitor apoptosis; under cytokine-free culture both PV and control undergo apoptosis, but PV less so — possibly related to high bcl-2 expression. Other: Experiments suggest PV serum may contain a glycoprotein stimulating erythropoiesis and also granulocytes/platelets — 'marrow-stimulating factor'; antigenically different from EPO but requiring small EPO to act; nature needs further study.

Treatment

Drug therapy, supportive therapy

Preventive Measures

This is a myeloproliferative disease; no clear preventive measures yet.

Department to Visit

It is recommended to visit the Hematology department; an appointment can be booked on this platform before the visit.

Warm reminder: The above information is for health science reference only and cannot replace professional medical diagnosis. If you have related symptoms, please seek medical attention at a regular hospital promptly.