The overexpression of PRV-1 seems to be a useful tool for discriminating ET and PV from ST and SE, thus offering an innovative diagnostic approach on the basis of the detection of positive diagnostic criteria instead of exclusion criteria.
These preliminary observations indicate that the Jak2(V617F) mutation in particular and PRV-1 overexpression appear to be suitable markers for monitoring treatment efficiency in prospective randomised clinical studies comparing pegylated interferon and hydroxyurea in well defined PV patients with a clear indication for cytoreductive therapy.
We concluded that, rather than an upregulation of the PRV-1 gene in the clonal haematopoiesis of polycythaemia vera, a failure to downregulate PRV-1 in granulocytes emigrating from the bone marrow might be responsible for the increase of transcripts in peripheral cells.
Levels of the mutation were significantly higher in polycythemia vera compared with essential thrombocythemia (P=0.0005) and correlated with the following jointly significant variables at diagnosis: PRV-1, hemoglobin, white cell count, neutrophil count, and red cell count, using multiple regression analyses (P=0.015).
Within this context, elevated CD177 expression is not only a specific feature of PV but may be an indicator of increased erythropoietic activity in thalassaemia syndromes.
Because there is no overlap between the PRV-1 expression in PV patients versus healthy controls or SE patients, the assay has a very high sensitivity and specificity for the diagnosis of PV in our population.
EECs were observed in 14 of 14 patients with PV and 4 of 12 with ET, and increased granulocyte PRV-1 mRNA levels were found in 9 of 13 patients with PV and 2 of 12 with ET.
In polycythemia vera (PV) and essential thrombocythemia (ET) specific JAK2 mutations constitutively activate the JAK-STAT pathway, explaining biologic findings such as endogenous erythroid colony (EECs) growth or PRV-1 RNA overexpression.
In 58 ET patients, a possible association between polycythaemia rubra vera-1 (PRV-1) overexpression and subnormal plasma EPO was investigated, which was always measured prior to the institution of platelet lowering agents.
We isolated a novel gene, subsequently named PRV-1, which is highly expressed in granulocytes from patients with PV (n = 19), but not detectable in normal control granulocytes (n = 21).
The function of the CD177 is not known, but the CD177 gene is highly homologous to a gene overexpressed in neutrophils from patients with polycythemia rubra vera called PRV-1.
We observed concordance between EECs and PRV-1 in MPD patients across all diagnostic subclasses, but our results indicate that EECs remain the most reliable auxiliary test for polycythemia vera (PV).