Cytobiological and Clinical Aspects of Tissue Mast Cell Leukaemia

S ummary . The authors describe the results of a series of cytochemical, autoradiographic, cytophotometric and immunological investigations carried out in a case of tissue mast cell leukaemia. Leukaemic mast cells showed certain distinctive cytochemical features, amongst which an intense periodic acid-Schiff (PAS) reaction, sensitive to amylase digestion, strong naphthol AS-D chloroacetate esterase (NASDCE), intense lactate dehydrogenase (LD) activity. Proliferative activity, determined autoradiographically with ³H-dT, was considerably low and was mainly confined to the larger cells. Also uridine and leucine incorporation were markedly reduced. Microdensitometry disclosed that the mast cell population was mainly arrested in the G₁ phase. Because of previous attempts to destroy selectively neoplastic tissue mast cells with sheep antihuman IgE serum, a search for surface bound IgE was carried out, but gave a negative result. Possible therapeutic approaches are considered in the light of previous clinical experience and on the basis of the results of the kinetic and metabolic studies.