Flow cytometric identification of myeloid disorders by asynchronous expression of the CD14 and CD66 antigens

Using a multiparameter flow cytometry assay enumerating cells positive for CD13, CD14 and CD66 antigens, we determined the asynchronous CD14/CD66 co-e xpression in unselected bone marrow and peripheral blood samples with suspe cted malignant blood disorders. CD14/ CD66 co-expression greater than or eq ual to 5% were found in 131/691 bone marrow samples. Only 55 of these exhib ited an identifiable population in 2-parameter flow cytometry histograms. O f the 55 samples 43 (78%) came from patients with myeloid disorders; e.g. 1 1 with myelodysplastic syndromes, 15 with chronic myeloproliferative disord ers and 17 with acute myeloid leukaemia. Only one of these 17 cases was a d e novo case, while 8 were secondary to another malignant haematological dis ease and 8 were from the period after cytoreductive therapy. Notably, CD14/ CD66 co-expression patterns were related to disease categories; e.g. in chr onic myelomonocytic leukaemia and acute myeloid leukaemia following a dyspl astic phase the co-expression displayed two subsets in peripheral blood, lo w-avidity CD14 and low-avidity CD66, respectively. The latter disease categ ory also exhibited these 2 subsets in bone marrow. In all other cases, the CD14/CD66 co-expression in bone marrow was heterogeneous. In conclusion, ab normal CD14/CD66 coexpression might be a valuable parameter in defining asy nchronous myelopoiesis in malignant myeloid disorders, especially myeloprol iferative disorders and secondary acute myeloid leukemias.