|Inclusion Criteria:||1) Patients up to 65 years of age at time of registration with a diagnosis of severe aplastic anemia (SAA). SAA is defined as follows: Bone marrow cellularity < 25%, or marrow cellularity < 50% but with < 30% residual hematopoietic cells. Two out of three of the following (in peripheral blood): neutrophils < 0.5 x 10^9/L; platelets < 20 x 10^9/L; reticulocytes < 20 x 10^9/L. SAA diagnostic criteria may be applied to assessment at initial diagnosis or to the follow-up assessments.|
2) Patient must have an available unrelated donor with a 7/8 or 8/8 match for HLA-A, B, C and DRB1 antigen. Typing is by DNA techniques: intermediate resolution for A, B and C, and high resolution for DRB1. HLA-DQ typing is recommended but will not count in the match
3) Patient and/or legal guardian able to provide signed informed consent.
4) Matched unrelated donor must consent to provide marrow allograft.
5) Patients with adequate organ function as measured by: a) cardiac: left ventricular ejection fraction at rest must be > 40% or shortening fraction > 20% b) hepatic: serum total bilirubin < 2x upper limit of normal for age as per local laboratory; ALT and AST < 4x upper limit of normal for age as per local laboratory; c) renal: serum creatinine < 2x upper limit of normal for age (as per local laboratory). d) pulmonary FEV1, FVC and DLCO (corrected for Hb) > 50% predicted. For pts where pulse oxymetry is perfomed, O2 saturation > 92%
6) The diagnosis of Fanconi anemia must be excluded in patients younger than 18 years of age by diepoxybutane (DEB) testing on peripheral blood or comparable testing or marrow.