CFU‐gm assay, cytochemical and electron microscopic studies in agar in patients with preleukemic syndrome and aplastic anemia

Thirty‐seven patients with chronic cytopenia were studied using a CFU‐gm assay in agar. Cell proliferation was evaluated on days 2, 3, 5,7, and 10 of incubation. Growth patterns were different in cultures of hematologically healthy persons versus patients with preleukemic syndrome (PL) and aplastic anemia (AA). Three types of PL syndrome and two types of AA (C₁ and C₂) were distinguished. Bone marrow dysfunction was evaluated further using cytochemistry and electron microscopy to morphologically study cell proliferation in vitro. Cytochemical staining performed in agar demonstrated well‐defined maturation defects in myelopoietic precursor cells from the bone marrow of PL patients. Electron microscopic findings of Auer‐body‐like inclusions in “statu nascendi” in the vacuoles of preleukemic cells supported our results. PL patient groups at high risk for development of overt leukemia and patients with grave prognosis in AA were distinguished. Our results are relevant for the clinical diagnosis and prognosis of patients with cytopenia.