RESUMO
To evaluate hydroxyurea [HU] induced changes in the expression of phosphatidylserine as well as various cell surface adhesion molecules in red cells of sickle cell anemia patients. The red cell membrane expression of CD36, CD49d. CD71 and annexin V were tested using flow cytometry and results were correlated with percent of HbF, as measured by 1-IPLC, as well as other hematological variables. The present study included 60 patients with sickle cell anemia [SCA], 40 of them underwent treatment with HU for a period of 12-18 months and the other 20 patients were newly diagnosed as [SCA], beside 20 healthy subjects as controls. Hydroxyurea caused a significant increase in Hb concentration, MCV values and HbF percentage. HU effectively decreased total teaeocyc count, total platelet counts. reticulocytes percentage and expression of CD36, CD71, CD49d and annexin V from pretreatment values. However, these values continued to be significantly higher in treated patients than those of controls. A significant positive correlation was found between Hb concentration and percent of HbF and also between reticulocyte counts and CD49d expression. A significant negative correlation was found between Hb concentration and percent of reticulocytes, CD36, CD49d, Annexin and CD71 expressions. A significant negative correlation was also found between reticulocyte percent and percent of HbF, CD36, Annexin and CD7I expressions. Treatment of sickle cell anemia with hydroxyurea causes a significant increase in HbF together with a significant reduction of CD36, CD7I and CD49d adhesion molecules and annexinV expressions on the surface of erythrocytes. These findings could have clinical relevance, as inhibition of adhesion receptor expression or activity may explain part of the beneficial effects of HU