Ultrastructural evaluation of periodate-reactive glycoconjugates in human leukaemia cells

Periodate-reactive glycoconjugates in human leukaemic cells were examined electron microscopically by the periodic acid-thiocarbohydrazide-silver proteinate (PA-TCH-SP) method. Granules in ALL cells were classified into 4 types based on PA-TCH-SP staining features. Abnormal granules containing glycogen were observed only in children with treatment-resistant ALL. Cytoplasmic granules in leukaemic cells of patients with AML and acute monocytic leukaemia exhibited moderate reactivity. The distribution pattern of glycogen in the cytoplasm of leukaemic cells was classified into 3 types, one lacking glycogen, one containing small glycogen particles scattered throughout cytoplasm, and one showing clusters of glycogen particles. Cells with glycogen clusters were observed in ALL cells and in erythroblasts from patients with erythroleukaemia. PA-TCH-SP reactivity was detected in the rough endoplasmic reticulum in acute promyelocytic leukaemia but not in ALL or other types of AML. Megakaryoblasts in megakaryocytic crisis of chronic myelogenous leukaemia exhibited characteristic PA-TCH-SP reactivity similar to that of normal megakaryocytes.