CHANGES IN GRANULOPOIESIS DETECTED BY IN VITRO COLONY FORMATION IN ACUTE LYMPHATIC

Summary.-Patients with acute lymphatic leukaemia (ALL) could be divided into two groups at diagnosis-those whose peripheral blood and/or bone marrow exhibited in vitro colony formation and those in whom it did not, but this finding did not appear to correlate with any clinical or haematological parameter, or with prognosis. The colony-forming potential of patients with ALL in their first full remission, early relapse or second remission did not deviate significantly from previously established normal values, but the colony-forming potential of patients in early remission was very significantly reduced. No loss of colony-forming potential of normal marrow cells was noted when they were cultured with cells from patients with ALL. WHILE acute leukaemia in children is usually a disease of lymphatic origin, its nature is such that granulopoiesis is frequently compromised. Since the re-covery and maintenance of granulocyte number and function is central to the achievement and maintenance of remis-sion, the study of granulocyte precursors is relevant in ALL. One method for the assessment of granulocytic potential is the in vitro agar colony-forming cell (CFC) assay, in which colonies of granulocytes and macrophages may be grown from their common precursor cell (the CFC). We have studied a total of 43 patients at various stages of their illness, bone marrow samples being taken only when these were indicated under the appropriate treatment protocol or as part of the general management of the patient. We have attempted to answer two basic questions: (1) Certain prognostic factors are recognized in ALL, such as age, peripheral blood leucocyte count and mediastinal involvement, but they give only a crude guide to prognosis. Could the assessment of colony-forming potential or other features of colony growth help to distinguish patients with good or poor prognosis? (2) What variations may be detected by the in vitro CFC assay during the various stages of the disease