C Fourgeaud1, W El Nemer2, U Michon Pasturel3, S Bonhomme3, A Brignier4, I Lazareth3, P Priollet3. 1. Service de médecine vasculaire, groupe hospitalier Paris-Saint-Joseph, 185, rue Raymond-Losserand, 75674 Paris cedex 14, France. Electronic address: caroline.fourgeaud@gmail.com. 2. Institut national de la transfusion sanguine, Inserm U1134, 6, rue Alexandre-Cabanel, 75739 Paris cedex 15, France. 3. Service de médecine vasculaire, groupe hospitalier Paris-Saint-Joseph, 185, rue Raymond-Losserand, 75674 Paris cedex 14, France. 4. Service d'hématologie A, hôpital Necker, 149, rue de Sèvres, 75015 Paris, France.
Abstract
UNLABELLED: Negative BCR ABL myeloproliferative neoplasm (MPN) such as polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (MFP) are clonal hematological malignancies and may lead to a high risk of venous, arterial or microcirculatory thrombosis. Atypical sites of thrombosis can sometimes reveal the neoplasm disorder. Their diagnoses are a major issue because of the propensity to develop acute myeloid leukemia and/or myelofibrosis. The acquired JAK2V617F variant (Janus kinase 2; 9p24) is a prevalent MPN and also a sensitive marker for PV diagnosis (95% positive mutation), but not specific since found in approximately 50% of patients with ET and MFP. PATIENT AND METHODS: We present a diagnostic and a therapeutic approach based on one patient with microcirculatory ischemic manifestations in the toes, and who had strictly normal cell blood counts and was positive for JAK2V617F mutation: thrombotic risk factor evaluation; bone marrow biopsy; red cell adhesion assays. These experimental assays are promising for the development of new therapeutics in MPN; they assess red cell adherence to the vascular endothelium after the phosphorylation of Lu/BCAM subsequent to a positive JAK2V617F mutation. RESULTS: Compared with controls, our patient exhibited increased Lu/BCAM receptor phosphorylation and red blood cell adhesion. CONCLUSION: This development may lead to improved care for patients with thrombotic manifestations, normal blood cell counts, and a positive JAK2V617F mutation: multidisciplinary management, including regular hematological monitoring, could lead to the introduction of a cytoreductive treatment.
UNLABELLED: Negative BCR ABL myeloproliferative neoplasm (MPN) such as polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (MFP) are clonal hematological malignancies and may lead to a high risk of venous, arterial or microcirculatory thrombosis. Atypical sites of thrombosis can sometimes reveal the neoplasm disorder. Their diagnoses are a major issue because of the propensity to develop acute myeloid leukemia and/or myelofibrosis. The acquired JAK2V617F variant (Janus kinase 2; 9p24) is a prevalent MPN and also a sensitive marker for PV diagnosis (95% positive mutation), but not specific since found in approximately 50% of patients with ET and MFP. PATIENT AND METHODS: We present a diagnostic and a therapeutic approach based on one patient with microcirculatory ischemic manifestations in the toes, and who had strictly normal cell blood counts and was positive for JAK2V617F mutation: thrombotic risk factor evaluation; bone marrow biopsy; red cell adhesion assays. These experimental assays are promising for the development of new therapeutics in MPN; they assess red cell adherence to the vascular endothelium after the phosphorylation of Lu/BCAM subsequent to a positive JAK2V617F mutation. RESULTS: Compared with controls, our patient exhibited increased Lu/BCAM receptor phosphorylation and red blood cell adhesion. CONCLUSION: This development may lead to improved care for patients with thrombotic manifestations, normal blood cell counts, and a positive JAK2V617F mutation: multidisciplinary management, including regular hematological monitoring, could lead to the introduction of a cytoreductive treatment.