Leukemia diagnosis

LEUKEMIA DIAGNOSIS Paltrinieri S Department of Veterinary Pathology, Hygiene and Public Health, University of Milan, Italy The diagnosis of leukaemia must be based on the morphology of neoplastic cells and on the identification of aberrant phenotypes by flow cytometry or by molecular methods. These approaches, however, are expensive and/or time-consuming and they should be applied only in selected cases. The laser haematology analyzers classify the cells based on their morphology or structure. Instrumental analysis could thus be a preliminary screening of samples from leukaemic animals. The Cell Dyn 3500 identifies the cells based on their shape, size, complexity and nuclear lobularity: circulating blasts, which are larger than mature cells, can thus be identified, and further classified according to their lineage based on nuclear characteristics. The ADVIA 120 classifies the cells based on their peroxidase content: an increase of large unstained cells (LUCs), usually rare in normal blood, can be consistent with the diagnosis of leukaemia. Moreover, neoplastic cells resist to the lysis induced by the BASO reagent which, in normal blood, lyses all the cells except basophils: the so called “pseudobasophilia” can thus be present in the case of leukaemia. A similar principle for counting basophils is employed also by the Sysmex XT2000iV, which can thus identify lysis-resistant neoplastic cells. In addition, this counter classifies the cells based on their complexity and on their content in nuclei acids, which are stained by a fluorescent dye: blasts cells have a higher content of nucleic acids compared to their normal counterpart, and scattergram specific for acute or chronic leukaemia can be identified. Instrumental screening of leukaemias can thus be performed also in veterinary medicine. Nevertheless, only few reports about the automated analysis of canine or feline leukaemia are available, and the morphological analysis of blood smears is still mandatory.