Inclusion Criteria

DISEASE CHARACTERISTICS:

- Diagnosis of 1 of the following:

- Severe or very severe aplastic anemia, as defined by the following criteria:

- Meets ≥ 2 of the following criteria:

- Absolute neutrophil count < 0.5 x 10^9/L (severe) or < 0.2 x 10^9/L
(very severe)

- Platelet count < 20 x 10^9/L

- Reticulocyte count < 20 x 10^9/L

- Hypocellular bone marrow (< 30% cellularity) without evidence of fibrosis
or malignant cells

- Single lineage acquired marrow failure (e.g., pure red cell aplasia,
agranulocytosis, amegakaryocytic thrombocytopenia)

- Paroxysmal nocturnal hemoglobinuria clone allowed

- Failed first-line therapy with antithymocyte globulin (ATG) and cyclosporine OR not
eligible for ATG-based studies

- Failure is defined as lack of hematological response, requirement for chronic
immunosuppressive treatment to sustain response, or relapse

- Not eligible for a low-risk stem cell transplantation

- No evidence of risky myelodysplastic syndromes (i.e., IPSS 3-4), as defined by the
presence of marrow blast excess or karyotypic abnormalities, or other primitive
marrow disease

- No history of constitutional aplastic anemia (e.g., Fanconi anemia or dyskeratosis
congenita)

PATIENT CHARACTERISTICS:

- WHO performance status 0-2

- Not pregnant or nursing

- No active malignant tumor within the past 5 years

- Transaminases ≤ 3 times upper limit of normal (ULN)

- Albumin ≥ 1.5 g/L

- Creatinine ≤ 3 times ULN

- No CMV viremia, as defined by positive PCR or pp65 test

- No cardiac failure (i.e., ejection fraction < 35%)

- No other concurrent life-threatening disease (including HIV infection)

PRIOR CONCURRENT THERAPY:

- No prior allogeneic stem cell transplantation

- At least 2 weeks since prior cyclosporine or filgrastim (G-CSF)