الفهرس 
Chapter I: Resume of thalassemia majorOnly 14 pages are availabe for public view
 |  | from | 101 |  |  |
| | | from | 101 | | |
Abstract
- thalassemia is a hereditary disease which is characterized by the deficiency in the β-globin synthesis, since human have only one set of β-globin gene, therefore, total or partial suppression of the expression of either or both β-globin gene will cause very low hemoglobin production (Baysal and Carver, 1995). This genetic disorder is considered as a common mediterranean blood disorder that affects thousands of infants each year, moreover, β -thalassemia occurs among individuals of East Indian descent, African and Southeast Asian (Lukens, 1999).
β- thalassemia is classified depending on the clinical severity into three forms: thalassemia minor, thalassemia intermedia and thalassemia major which is the most severe form and treated with blood transfusion. Severe anemia becomes apparent in the first two years of life when the switch from γ to β-chain should take place (Athanasios et al, 2005).
The most common treatment for patients who have beta thalassemia major is regular blood transfusion to maintain hemoglobin at normal or near normal level. The aim of transfusion is to suppress endogenous erythropoiesis to minimize complications such as hepatosplenomegaly, bone changes, and inhibit increased gastrointestinal absorption of iron (Cunningham et al, 2004).
Leucodepletion and washing of red cell concentrates, widely recommended for multiple transfused patients with problems of immunization, must be carried out exploiting the technological and performance improvements of the operative systems (Roberta et al, 2012).
Removal of leucocytes reduces the risk of development of anti-HLA and, therefore, the risk of Graft-versus-Host disease (Cardo et al, 2008), and lowers the risk of transmission of viruses such as cytomegalovirus, human immunodeficiency virus, Epstein-Barr virus, human herpes viruses 6 and 8, and parvovirus B19 if performed before storage; furthermore, it reduces the formation of microaggregates and the release of cytokines (Kavalleron et al, 2000), responsible for adverse effects of transfusion such as febrile, non-hemolytic transfusion reactions, and leads to a lower concentration of potassium in the supernatant (Mehdizadeh et al, 2008).