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[Study of bone marrow microvessel density is one of the diagnostic approaches in patients with Ph-negative chronic myeloproliferative diseases].

AIM
To define an association of bone marrow microvessel density (MVD) with histological properties (the magnitude of fibrosis and quantification of megakaryocytes (MGKC)) in patients with Ph-negative chronic myeloproliferative diseases (CMPD).


SUBJECTS AND METHODS
MVD was analyzed in 93 patients with different forms of CMPD, by estimating histological parameters. True polycythemia (TP) was present in 28 patients; 20 patients had essential thrombocythemia (ET), 36 had subleukemic myelosis, out them 6 were in a prefibrotic stage, and 9 with diagnosed post-TP (ET) myelofibrosis. The grade of myelofibrosis was estimated from the degree of bone marrow fibrosis as 0, 1, 2, and 3 and the clusters of MGKC were in accordance with degrees: 0, 1, and 2. MVD was studied from the absolute number of CD34-positive vascular structures.


RESULTS
In patients with TP, fibrosis was defined as grade 0 and 1 in 23 (82%) and 5 (18%) cases, respectively. The content of reticulin fiber was in the normal range in 19 (95%) of the 20 patients with ET. The clusters of MGKC of grades 1 and 2 showed an even distribution among patients with ET and those with TP. Fibrosis was absent in all the patients (n = 6) with prefibrotic-stage primary myelofibrosis (PMF). The patients with PMF had high MVD values [6.5 (range 2.8-22)] than those with TP [4.0 (range 1.76-10.2)] or ET [3.7 (range 2-8.5)] and the controls [3.2 (range 2-4.1)] (p < 0.001) confirming that angiogenesis is uninvolved at the onset of disease in patients with ET and those with TP. The patients with prefibrotic-stage PMF had higher values [6.0 (range 4.8-10.6)] than those with ET [3. 7 (range 2-8.5)] (p < 0.001). This suggests that angiogenesis is an early sign preceding the development of fibrosis.


CONCLUSION
Bone marrow angiogenesis assessment (from MVD measurements) may be an additional criterion for the diagnosis of disease evolution and an additional criterion between ET and PMF in a prefibrotic stage.