Differential diagnosis of erythrocytosis. Hemoglobins with high oxygen affinitty

Abstract

Erythrocytosis is defined as the increase in red cell mass above 25% of its normal value. This increase have a parallel increase of hematocrit level. It was known that in situations of tissue hypoxia erythropoietin was the largest ensurer for erythrocyte synthesis, but it was not known how cells detected these changes and contributed to oxygen availability. The research on oxygen changes of Gregg Semenza, Willian Kaelin and Peter Radcliffe have earned them the 2019 Nobel Price in Physiology and Medicine. They describe how regulations is carried out at the cellular level by identifying 3 proteins, the hypoxia-inductible factor (HIF), prolyl hidrolase domain (PHD) and tumor suppressor factor, Von Hippel-Lindau (VHL).These authors analyze the mechanism of oxygen homeostasis in situations under well-oxygenated conditions and in situations of hypoxia and therefore as erythropoietin synthesis is performed through the hypoxia-responder element (HRE) located in region promoter of the EPO gene in peritubular renal interstitial cells. Erythrocytosis can be classified either as primary or secondary and can be either congenital and acquired. Subsequently the differential diagnosis is established between the subtypes of erythrocytosis, initiating the description with the diagnostic criteria of plycythemia vera. The diagnostic test needed to perform their differentiation are evaluated along with the applicable flow chart to schedule the study of erythrocytosis. Finally we expose our experience in hemoglobinopathies with high affinity for oxygen studied at the Clinico San Carlos Hospital, belonging to 34 patients from 18 families with 11 different variants of hemoglobinophaties. Two of them have only been described in our country. Despite having high hematocrit and hemoglobin levels and in two of then associated with thalassemia and presenting null values of normal hemoglobin A, patients are asmptomatic