الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
B-cell lymphoproliferative neoplasm are heterogeneous malignant neoplasm. they are clonal expansion of various stages of B-lymphocytes in bone marrow, peripheral blood and lymph nodes, B-cell lymphomas represent one of the major health problem all over the world. Clinical presentation is variable from indolent clinical course to aggressive fatal disease. Diagnosis depend on many aspects as clinical presentation, morphology molecular cytogenatic and flow cytometry.
The differentiation and activation of B cells involve multiple processes that regulate gene rearrangement, proliferation, and apoptosis. When these are disrupted, malignancies often occur, including lymphomas and CLL. Complete cure of both diseases with conventional chemotherapy remains extremely rare. Although T cell-mediated anti-tumor immune responses have the potential to eliminate tumor cells, CLL and lymphoma cells are inherently poorly immunogenic, rendering T cell-based immunotherapy ineffective.
Immunoregulatory molecules are known to play critical roles in regulating T cell-mediated immunotherapy, and manipulation of immunoregulatory pathways may be an important alternative method to improve the efficacy of such treatments.
A number of different negative immune regulators expressed on the surface of tumor cells have been identified, such as CD200.
CD200 is a type 1a transmembrane protein, is encoded by a gene residing at chromosome 3q12, related to the B7 family of co stimulatory receptors, with two extracellular domains, a single transmembrane region, and a cytoplasmic tail with no known signaling motifs.