Aplastic Anemia (AA) Zhongshan Hospital ,Fudan UniversityZou Shanhua 。Outline Bone marrow hematopoiesis failure led by chemicals, radiation, biological factors and unknown etiology. The common clinical presentation is mild to severe pancytopenia. Epidemiology The incidence rate of AA :0.74 per 100,000 ，AAA : 0.14 per 100,000,  CAA : 0.60 per 100,000. Distribution ：most AA patients are young and middle-aged people, male more than female Etiology  Primary AA ：unknown causes ，about 60~70% Secondary AA Etiology of Secondary AA Chemicals  Drug: antibiotics, antineoplastic agent, NSAIDs  Other chemicals: benzene and benzene derivatives, arsenic, heavy metals,insecticides Etiology of Secondary AA Radiation Viral infection ：Hepatitis virus, EBV Mechanism  Hematopoietic stem cell defect Stem cells count decrease Stem cells proliferation capacity decrease Mechanism Hematopoietic microenviroment defect  　stromal cells  hematopoietic growth factor  microcirculation  Mechanism Immunologic derangement CD4/CD8 （↓,inversion)  γ-IFN, TNFα, IL-2↑immunosuppressive therapy Clinical Features Clinical features:  anemia, infection, hemorrhage Differences:  AAA(SAA-Ⅰ), CAA , SAA-ⅡLaboratory study—complete blood count Common feature ：anemia, reticulocyte count ↓granulocytopenia thrombocytopenia percent of lymphocyte increase relatively Laboratory study—complete blood count SAA:  Ret < 1%  Granulocyte count <0.5×109/L BPC<20×109/L CAA:  Ret > 1% Granulocyte count >0.5×109/ L  BPC>20×109/L Laboratory study －bone marrow Common feature ：Naked eye ：bone marrow is  plenty of oil drops Microscope ：hypoplasia or polar hypoplasia; hematopoietic cells decrease ，nonhematopoietic cells increase Laboratory study －bone marrow  SAA:polar hypoplasia, progenitor  cell can hardly be seen,no  megakaryocyte CAA: hypoplasia , megakaryocytes decrease or disappear Laboratory study －bone marrow biopsy More valuable than marrow aspiration Ratio of hematopoietic tissue/fatty tissue Megakaryocyte proliferation can be evaluated accurately; Laboratory study CFU-GM↓NAP ↑EPO ↑Criteria of diagnosis Pancytopenia, reticulocyte absolute count↓Without splenomegaly Hypoplasia or polar hypoplasia of bone marrow; if not, megakaryocyte should disappear; Biopsy: hematopoietic tissue↓fatty tissue↑Excluding other diseases with pancytopenia For anemia,ordinary treatment is ineffective  Criteria of diagnosis AAA(SAA-Ⅰ) CAA SAA-ⅡDifferential diagnosis PNH ：there is CD55 and CD59-depleted cell clone MDS: essence ：clonal disease, dyshaematopoiesis , chromosal aberration Aleaukemic leukemia Differential diagnosis malignant histocytosis myelofibrosis treatment Support treatment: Enviroment protection and self-protection Transfusion Infection and hemorrhage of prenvention or treatment treatment Androgen ：Testosterone Propionate, Stanozolol , Testosterone Undecanoate Immunosuppression ：ALG,ATG, cyclosporine High-dose immunoglobulin or methyprednisolone Marrow transplantation Hematopoietic growth factors: G-CSF,GM-CSF,EPO  prognosis SAA ：CAA ：* *