Analysis of human leukemias using extensive immunophenotypes from an antibody microarray

A12 A novel microarray containing 82 cluster of differentiation (CD) antibodies has been used to obtain extensive immunophenotypes of leukemia cells. Leukocytes are captured on antibody dots corresponding to particular cell surface molecules to give a dot pattern that is the immunophenotype. Samples from the peripheral blood and bone marrow of 733 leukemia patients were analyzed. Discriminant Function Analysis of the expression profiles from these 733 patients and 63 normal subjects were clustered and showed high levels of consistency with diagnoses obtained using conventional criteria. The overall levels of consensus for classification using the microarray compared with established criteria were 93.9% (495/527 patients) for peripheral blood and 97.6% (201/206 patients) for bone marrow aspirates, showing that the extensive phenotype alone was frequently able to classify the disease when the leukaemic clone was the dominant cell population. Immunophenotypes for neoplastic cells were distinguishable from normal cells when the leukaemic count was at least 5 X 10(9) cells/L in peripheral blood, or 20% of cells obtained from bone marrow aspirates. This technique will be a useful adjunct to flow cytometry and other methods when an extensive immunophenotype of leukemia cells is required. An extensive immunophenotype alone may be sufficient for diagnosis of most leukemias.