Severe hypocellular marrow failure classification criteria
| Marrow cellularity . |
|---|
| <25% or 25%-50% with <30% residual hematopoietic cells |
| AND cytopenias (at least 2 of 3) |
| Absolute neutrophil count <500 × 109/L Platelets <20 × 109/L Absolute reticulocyte count <60 × 109/L |
| Marrow cellularity . |
|---|
| <25% or 25%-50% with <30% residual hematopoietic cells |
| AND cytopenias (at least 2 of 3) |
| Absolute neutrophil count <500 × 109/L Platelets <20 × 109/L Absolute reticulocyte count <60 × 109/L |
The immunologically mediated disease, severe aAA, accounts for the majority of severe hypocellular marrow failure.