Flow cytochemical patterns of white blood cells in human haematopoietic malignancies. II. Chronic leukaemias.

Peripheral blood samples from 73 patients with chronic leukaemia were measured with the Technicon H-6000 automated haematology analyser to provide flow cytochemical (peroxidase content) and volume (light scatter) discriminated scattergram patterns. For chronic granulocytic leukaemia (CGL), these patterns were so reproducible and distinct that they allowed an immediate diagnosis even without the benefit of microscopic examination. Relative and absolute basophilia was an invariable feature, and remained detected by the H-6000 even when the patient was in haematologic and cytogenetic remission or progressed into blast crisis (BC). Most patients in BC also demonstrated an inordinately high number of large unstained cells (LUC) and high proportions of 'lymphocytes' (small blasts with no peroxidase content by visual inspection). Thus, for patients with CGL, LUC values above 10%, and/or steady increments in the proportion of 'lymphocytes', merit concern as these changes may herald an accelerated phase of disease. The scattergram pattern of untreated chronic lymphocytic leukaemia (CLL) showed a dense accumulation of data points within the lymphocytic 'box' with a small cluster of granulocytic elements. Most patients also had a frankly abnormal proportion of LUC. Sixteen patients with CLL were compared for ratios of LUC to lymphocytes and stage of disease; patients with the most advanced stage (IV) had the highest, statistically significant values, than the patients with more benign disease. Thus, it is possible that follow up with this instrument of patients with CLL will also allow early detection of an impending prolymphocytoid transformation (accelerated phase) of this disease.