Aberrant expressions of haemostatic genes in granulocytes of chronic myeloproliferative disorders-polycythaemia vera [PV] and essential thrombocythaemia [ET]

Objective: A pilot study to test the hypothesis that dysregulated expression of haemostasis genes in clonal granulocytes of MPD patients contributes to the genesis of haemostatic complications. In this study of 36 patients with MPD and 18 healthy controls, specific target genes Procoagulant Tissue Factor [TF], prothrombotic cytokines Interlukin1 β [IL1β], Tumor Necrosis Factor α [TNFα],Vascular Endothelial Growth Factor[VEGF] and Heparanase in clonal granulocytes were analyzed by qualitative methods, for disease associated aberrant gene expression, as proof of concept. Context: Granulocytes especially PMN leukocytes are well known mediators of thrombosis in inflammatory states and leukocytosis, a defining feature of MPD, correlates well with thrombosis, the risk falling with cytoreduction. Further, in vivo activation of leukocytes and enhanced plateletleukocyte interactions have been documented in MPD. Further research is needed to explore the links between leukocytes and the haemostatic complications of MPDs. Design: This observational study has compared patterns of gene expressions in granulocytes of patients with PV and ET by qualitative RT-PCR. Patients and Measurements: We studied 14 patients diagnosed with PV, 22 with ET at the Haematology department, and 18 healthy controls. Granulocytes were purified by Ficoll gradient centrifugation, RNA isolated and RT PCR performed using cDNA under optimized conditions. Finally PCR products were separated by Agarose gel electrophoresis and identified by UV transillumination. Results: TF was expressed by none of the controls but 42% of PV and 27% of ET patients granulocytes revealed TF expression. Conclusion: Upregulation of TF and other haemostasis related genes in granulocytes genes as suggested by this qualitative method of RTPCR suggests altered gene expression in granulocytes of MPD patients. This could be further explored by quantitative studies.