Julien Grenier, Wassim El Nemer, and Maria De Grandis
Polycythemia vera (PV) and essential thrombocythemia (ET) are myeloproliferative neoplasms (MPN) characterized by clonal erythrocytosis and thrombocytosis, respectively. The main goal of therapy in PV and ET is to prevent thrombohemorrhagic complications. Despite a debated notion that red blood cells (RBCs) play a passive and minor role in thrombosis, there has been increasing evidence over the past decades that RBCs may play a biological and clinical role in PV and ET pathophysiology. This review summarizes the main mechanisms that suggest the involvement of PV and ET RBCs in thrombosis, including quantitative and qualitative RBC abnormalities reported in these pathologies. Among these abnormalities, we discuss increased RBC counts and hematocrit, that modulate blood rheology by increasing viscosity, as well as qualitative changes, such as deformability, aggregation, expression of adhesion proteins and phosphatidylserine and release of extracellular microvesicles. While the direct relationship between a high red cell count and thrombosis is well-known, the intrinsic defects of RBCs from PV and ET patients are new contributors that need to be investigated in depth in order to elucidate their role and pave the way for new therapeutical strategies.
I was diagnosed with PV about 7 yrs. ago. The side effects were nil until about 6 mos. ago when I started with itching problems after a shower. It is a horrible predicament. The treatment for a short time about 4 yrs. ago was Jakafi. I took it for a short while and had side-effects that were really debilitating and affected my life worse than the JAK- 2-mutation. I quit taking it and my platelet count went down to normal! My hematocrit hovers around 45-47 so I have phlebotomies about every 4 or 5 weeks. It was very upsetting that I was on a drug that cost over $20,000 a month and it was doing nothing to my platelet count to speak of. Previously, I was given anagrelide and another drug that was also a very bad experience. Trying to find a doctor who is on top of things with regard to gene mutations has not been an easy task.
May we ask who is your MPN specialist? We would love to help direct you to someone you feel confident in and that will listen to you.