Relevant laboratory findings in patients with sickle cell disease living at high altitude

In an attempt to assess the physiological changes that occur in a patient suffering from the sickle cell disease (SCD) and living permanently at a high altitude, hematological parameters (hemoglobin concentration, RBC count, reticulocyte count, MCH, MCHC, MCV, Hb S, F and A₂ levels) and biochemical parameters (serum bilirubin, erythrocyte 2,3-DPG, serum iron, TIBC and haptoglobin levels) were measured in patients with two sickle cell syndromes (homozygous Hb SS and heterozygous Hb S/β°-thalassemia) matched with Hb AA normal controls living at an altitude of 3000m. These parameters were compared with values obtained in similar groups of subjects residing at sea level.

Our results confirm that normal controls permanently residing at altitude have higher hemoglobin concentrations and erythrocyte 2,3-DPG levels than do normal counterparts living at sea level. Patients with SCD living permanently at high altitude show a marked increase in 2,3-DPG levels with little or no change in hemoglobin concentration. Normal serum iron and total iron binding capacity (TIBC) levels in our patients exclude iron deficiency as a possible reason for the poor expected erythropoietic response to altitude. We suggest that the marked rise in 2,3-DPG may be an important aid to oxygen delivery to tissues of SCD patients living at high altitude.