2.1 Patients
AA cases and myelodysplastic syndrome (MDS) cases were all from Shanghai
Children’s Hospital between. According to the severity, AA patients were
classified into non-severe AA, severe AA and very severe
AA7. MDS was diagnosed based on WHO classification
criteria8. Twenty children with solid tumors without
bone marrow infiltration and any hematological complications were used
as normal controls. Bone marrow biopsy specimens from AA, MDS and normal
controls were used for immunohistochemistry. The bone marrow fluid of
the first suction and peripheral blood from AA and controls were
detected by flow cytometry.