John Libbey Eurotext

Hématologie

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The WHO revised diagnostic criteria for myeloprolative disorders Volume 14, issue 3, Juillet 2008

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Hôpital Beaujon, 100 boulevard du Général Leclerc, 92118 Clichy

Criteria for the diagnosis of Ph negative MPDs (Polycythemia Vera, Primary myelofibrosis and Essential Trombocythemia) where first settled more than 30 years ago by the Polycythemia Vera Study Group (PVSG). The world health organisation (WHO) proposed a new version of these criteria in 2001. Except for the elimination of Ph or BCR/ABL positive patients both sets of criteria where based on a phenotypic characterisation of the patients as initially proposed by the PVSG. The recent description of the V617F mutation of JAK2 in exon 14 and of the less frequent mutations of JAK2 in exon 12 and of the W515L/K mutation of MPL (thrombopoietin receptor), offer new opportunities for a diagnosis of Ph negative MPDs according to genotypic markers. However, as none of these mutations is presently specific of one of these disorders, focusing on the heterogeneous characteristics of ET and PMF patients, the approach proposed by WHO experts in 2007 for their identification combines the search for mutations, as the best marker for the presence of a clonal disorder of myeloid cells, and a classification according to previous phenotypic criteria. The value of this approach is presently limited by the occurence of progression among MPDs, as suggested by the description of prefibrotic or prepolyglobulic forms of PMF and PV, and by the inadequacy of some phenotypic criteria in children.