الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
In humans, the major histocompatibility complex (MHC), known as human leukocyte antigens (HLA), are separated into HLA-I and HLA-II, and HLA III based on their structure, tissue distribution and function. The genes that encode HLA-I (HLA-A, B, C) and HLA-II (HLA-DR, DP, DQ) molecules are the most polymorphic genetic system in the human genome, so much that some loci (e.g. HLA-B or DR) have more than 300 alleles. This group of genes resides on chromosome 6, and encodes cell-surface antigen-presenting proteins and has many other functions.
Class II molecules consist of two trans membrane polypeptides, Alpha Chain and Beta Chain. The Beta chain is much more polymorphic compared to the Alpha chain for this reason HLA typing is currently done on Beta chain (HLA-DRB1, HLA-DRB3, HLA-DRB4, HLA-DRB5, HLA-DQB1, and HLADPB1). As for HLA-DR; it consists of one α chain encoded by HLA DRA locus and 4 β chains (only 3 possible per person), encoded by HLA DRB1, DRB3, DRB4, DRB5 loci.
Leukemia is blood cell cancer occuring in the bone marrow. The cell undergoes mutation and becomes a form of leukemia. The leukemia cells will develop and thrive better than normal cells once the marrow cell undergoes a leukemic switch. It is the most common type of cancer in the blood and affects adults 10 times more than children. Most people with leukemia are over the age of 50 years.
AML is the most common acute leukemia in adults, and in patients over 50 years, it accounts for > 80% of all leukemias. Although its etiology is unknown it may evolve after being exposed to some risk factors as previous cytotoxic chemotherapy, benzene, ionizing radiation, genotoxic agents, chromosomal abnormalities, or after a previous hematologic disorder. The disorder occurs in a malignantly transformed multipotential hematopoietic stem cell that undergoes multiple genomic alteration until an overt disease arises. chronic Myeloid Leukemia (25, 32) represents 15% of cancer in adults. The median age of onset of disease is 67 years; however, all ages are at risk of developing CML.