Aplastic_Anemia_BJ贫血.ppt

APLASTIC ANEMIA Dr. Bhavesh S. Jarwani APLASTIC ANAEMIAEmpty Marrow Syndrome Is a disorder characterized by marked reduction or absence of erythroid, granulocytic and megakaryocytic cells in the marrow with resultant pancytopenia and reduced number of CD34+ and colony forming cells. Immune Mechanics in Aplastic Anemia T cells: mononuclear cells from the ps or marrow suppressed the csf by the progenitor cells have elevated numbers of the cytotoxic T Lymphocytes Cytokines: peripheral blood from this patients had raised levels of the soluble cytokines as y-INF and TNF and also y-INF mRNA , evidence of the gene expression Incidence:5-10 cases per million persons per year Age: Bimodal distribution young adults (15-30 years) elderly (above 60 years) Same incidence in Male and Female Geographic distribution more common in Asia than in North America and Europe Etiology Acquired: Drugs: Antimetabolites, antimitotic agents, gold, chloramphenicol, phenylbutazone and sulfonamides Radiation Chemicals: benzenes, Solvents, insecticides Viruses : Hepatitis A,B,C, E, G, and Parvo B19, CMV PNH Misc: pregnancy, connective tissue disorders, Graft-vs-Host disease Hereditary: Fanconi’s Anemia Dyskeratosis congenita Shwachman Syndrome Idiopathic: 50-65 % of cases Etiology Drugs may be having direct dose dependent toxicity to the marrow or having Idiosyncrasy to the drugs: Antineoplastic and antimetabolites are having direct dose dependent toxicity Chloramphenicol having first immediate dose dependent toxicity and long term Idiosyncrasy after one to two weeks later Radiation: Chronic exposure to low-dose and localized exposure leading to development of aplastic anemia Benzene and insecticides: direct and also induction of the hapten leading to immune mediated bone marrow suppression Virus: Hepatitis A,B,C,E and G. Parvovirus B19, CMV Pregnancy: Etiology PNH: defect in PIG-A gene, so partial or complete inability to construct Glycosylphosphatidylinositol(GPI) anchor for the at