Concomitant neutrophil JAK2V617F mutation screening and PRV-1 expression analysis in myeloproliferative disorders and secondary polycythaemia.

Polycythaemia vera (PV) is closely associated with both an acquired activating mutation of the JAK2 tyrosine kinase ( JAK2 V617 F) in granulocyte-derived DNA and increased granulocyte polycythaemia rubra vera-1 ( PRV-1) expression. In order to explore the correlation between these two biological markers and compare their diagnostic utility, mutation analysis for JAK2 V617 F and quantitative measurement of granulocyte PRV-1 expression were performed on the same study sample from 100 participants: 38 with PV, 22 with essential thrombocythaemia (ET), 10 with agnogenic myeloid metaplasia (AMM), 19 with secondary polycythaemia (SP) and 11 healthy volunteers. The respective overall (homozygous) JAK2 V617 F mutational frequencies were 95% (26%), 55% (0%), 30% (0%), 0% and 0%. The corresponding figures for increased PRV-1 expression were 89%, 18%, 20%, 21% and 9%. In patients with either ET or AMM, the likelihood of detecting JAK2 V617 F was significantly higher in the presence of an increased PRV-1 expression (83% vs. 38%; P = 0·05). Similarly, in patients with PV, homozygous as compared with heterozygous JAK2 V617 F correlated with higher levels of PRV-1 expression ( P = 0·11). The present study suggests an allele dose-dependent effect of JAK2 V617 F on granulocyte PRV-1 expression. However, compared with the PRV-1 assay, mutation screening for JAK2 V617 F displayed greater accuracy in distinguishing PV from SP. [ABSTRACT FROM AUTHOR]