Relation between JAK2 (V617F) mutation status, granulocyte activation, and constitutive mobilization of CD34+ cells into peripheral blood in myeloproliferative disorders

Francesco Passamonti, Elisa Rumi, Daniela Pietra, Matteo G. Della Porta, Emanuela Boveri, Cristiana Pascutto, Laura Vanelli, Luca Arcaini, Sara Burcheri, Luca Malcovati, Mario Lazzarino, Mario Cazzola

Research output: Contribution to journalArticle


We studied the relationship between granulocyte JAK2 (V617F) mutation status, circulating CD34+ cells, and granulocyte activation in myeloproliferative disorders. Quantitative allele-specific polymerase chain reaction (PCR) showed significant differences between various disorders with respect to either the proportion of positive patients (53%-100%) or that of mutant alleles, which overall ranged from 1% to 100%. In polycythemia vera, JAK2 (V617F) was detected in 23 of 25 subjects at diagnosis and in 16 of 16 patients whose disease had evolved into myelofibrosis; median percentages of mutant alleles in these subgroups were significantly different (32% versus 95%, P <.001). Circulating CD34+ cell counts were variably elevated and associated with disease category and JAK2 (V617F) mutation status. Most patients had granulocyte activation patterns similar to those induced by administration of granulocyte colony-stimulating factor. A JAK2 (V617F) gene dosage effect on both CD34+ cell counts and granulocyte activation was clearly demonstrated in polycythemia vera, where abnormal patterns were mainly found in patients carrying more than 50% mutant alleles. These observations suggest that JAK2 (V617F) may constitutively activate granulocytes and by this means mobilize CD34+ cells. This exemplifies a novel paradigm in which a somatic gain-of-function mutation is initially responsible for clonal expansion of hematopoietic cells and later for their abnormal trafficking via an activated cell progeny.

Original languageEnglish
Pages (from-to)3676-3682
Number of pages7
Issue number9
Publication statusPublished - May 1 2006


ASJC Scopus subject areas

  • Hematology

Cite this