[Diagnosis of latent polycythemia vera: A clinician's opinion]. / Diagnostika latentnoi istinnoi politsitemii (vzglyad klinitsista).

AIM: to identify the clinical features of latent polycythemia vera (PV) as an independent nosological entity. SUBJECTS AND METHODS: The investigation enrolled 81 patients (50 with extensive (manifest) PV and 31 with latent PV) who had visited the Outpatient Department, Hematology Research Center, Ministry of Health of Russia, in 2014 to October 2015. RESULTS: The gender distribution of the patients was statistically comparable in the analyzed groups. The patients with manifest PV were slightly older than those with latent PV: the median age in the compared groups was 56 and 44 years, respectively. Red blood cell counts, hemoglobin concentrations, and packed cell volume were higher in the patients with manifest PV. Blood platelet counts were higher in the latent PV group. There were no differences in the number of white blood cells in the compared groups. All the patients were JAK2 V617F mutation carriers. The JAK2 allele load was significantly higher in the manifest PV group than in the latent PV group. The compared patient groups differed in the rate of thromboses in the history or at diagnosis. In the patients with latent PV, thromboses were detected in 38% of cases versus 16% in those with manifest PV. In latent PV, there were mainly venous thromboses; abdominal vascular thromboses were diagnosed with a high frequency. Arterial thromboses were revealed in only 2 cases. CONCLUSION: Chronic myeloproliferative disease that is characterized by the JAK2 V617F mutation, borderline hemoglobin counts, and morphological features of a bone marrow trephine biopsy specimen, which are specific for PV, is an independent PV variant, namely: latent PV.

Gene Expression upon Proliferation and Differentiation of Hematopoietic Cells with Ph Chromosome ex vivo.

The genesp53, mdm2, p21, c-myc,bcr/abl, bcr, bcl2, bax, and gapdh participate in the regulation of cell proliferation and differentiation, apoptosis and cell distribution for the cell cycle ex vivo in the Ph(+)cells of chronic myeloid leukemia containing the Ph chromosome andbcr/abloncogene. Expression of these genes correlates with regulation of cell proliferation and differentiation by alternating proliferation and maturation stages for three main Ph+cell types that occur under chronic myeloid leukemia. Thep53, p21, mdm2, and gapdh genes overexpress in active proliferating myeloid cells in the cell cycle S+ G2/M phases and when the phases are coincident with the proliferation stage. Expression of these genes decreases to a considerable level under alternation of the Ph(+)cell proliferation and maturation stages and whenever the expression is greatly diminished under significant neutrophil accumulation and especially under repeated alternation of the stages. In the course of neutrophil maturation, gene expression levels decrease in the range of gapdh > actin > c-myc, bcr/abl,p21 > p53 > bcl2 > bax.The expression levels of these genes in neutrophils are lower than those in myelocytes and lower by an order of magnitude than that in the cells with a prolonged proliferation stage. TheBcr/ablexpression gene under prolonged maturation and neutrophil accumulation is inhibited; however it is enhanced by 2-3 times for the proliferation stage with myelocyte accumulation. Minimalbcr/ablexpression is observed under overexpression ofp53, mdm2, p21, c-myc,as well as under cell maximum at the S and G2/M phases. Bcr/abloverexpression is observed under low expression of thep53, p21, mdm2genes. In the Ph(+ )cells with a high P/D efficiency index (5-20), overexpression of the genes in the range ofbcr> gapdh>bcr/abl, as well as a decreased expression of thep53, bcl2, mdm2, p21<< gapdh genes is observed for Ph(+)cells from the CML blast crisis and CML acceleration phase. Low control of cell proliferation and cell cycle by gene-regulators presumably promotesbcr/abloverexpression and activаtes the production ofbcr/abl+ cells. Apoptosis in the Ph(+ )cells is induced by expression of thebax > bcl2, р53, p21, c-myc andgapdhgenes. The blocking of Ph(+)cell apoptosis, neutrophil accumulation, and decrease in the expression of the p53, mdm2 and p21, c-myc,bcr/abl genes occur at the maturation stage.

Cell Regulation of Proliferation and Differentiation ex vivo for Cells Containing Ph Chromosome in Chronic Myeloid Leukemia.

Cell regulation of Ph(+)cell proliferation and differentiation has been studied ex vivo in various chronic myeloid leukemia (CML) patients. The regulation is provided by alternation of effective stages of proliferation and maturation with inhibition of Ph(+) cell proliferation by accumulating neutrophils under apoptosis blockage. The alternation of stages consists of switching stage 1 (effective proliferation) to stage 2 (effective maturation) and proceeds according to the 1/2 -1/2/1 or 2/1-2/1/2/1 schemes. The kinetic plots of alternations pass through control points of crossing plots, where the parameters of proliferation and maturation are equal. The indices of P/D efficiency (ratio of proliferation and maturation rates) are 1.06±0.23 and don't depend on time, alternation order, or sources of Ph(+) cells - CML patients. During stages alternation, conversely, the parameters of Ph+ cell proliferation and maturation vary. The proliferation stages are characterized by increased proliferating cells content, a decreased number of neutrophils, and apoptosis induction. At the maturation stages, conversely, apoptosis is inhibited, the number of mature neutrophils increases, while immature Ph(+) cells decrease. High content neutrophils inhibit the proliferation of Ph(+) cells and impair their own maturation by inversion of maturation order, probably through a feedback mechanism. The regulation differences ex vivo reveal three types of Ph(+) cells from various individual CML patients, distinguished by the number and duration of alternating stages of proliferation and maturation. Ph(+) cells types 1 and 2 have one prolonged stage of effective proliferation or effective maturation with efficiency indices P/D(1) = 1-20 or P/D(2) ⇐ 1. At the same time period, the proliferation and differentiation of the Ph(+) cells type 3 proceeds with repeated alternations of stages with P/D(1) = 1-4 or P/D(2) ⇐ 1. Type 1 Ph(+) cells (~20%) were isolated from patients in advanced stages of CML, while Ph(+) cells types 2 and 3 (30 and 50% correspondingly) were isolated from CML chronic phase patients sensitive to chemotherapy.