The plasma TNFα concentration and platelet mitochondrial mass (expressed as number seen in 50 platelets by TEM) were higher in MPN patients than in healthy controls, and TNFα concentration was inversely correlated with mitochondrial mass in MPN platelets regardless of mutation (Fig. 2), which was also significant when this analysis was confined to JAK2 V617F MPN (n = 15; r = − 0.75; P = 0.03). This evidence concerns the gene JAK2 and myeloproliferative disorder.