RESUMO
The present status of knowledge about the platelet membrane components suggests that glycoproteins (GP) are involved in the intercellular platelet specific reactions, such as adhesion and aggregation. Normal human platelets and platelet membranes solubilized under dissociating conditions produce characteristic polypeptide and GP electrophoretic patterns (PAGE). Platelets and isolated platelet membranes from patients with chronic myeloid leukemia (CML) presented dissimilarities of their glycoconjugates as compared to the normal platelets. The modification of the electrophoretic banding visualized by the periodic acid-Schiff's reagent (PAS) consisted in the decrease of the 155,000 GP L, the presence of two PAS positive bands in the area of the 135,000 normal PAS positive GP LL and a variable decrease of the 100,000 GP LLL (Apparent mol. wt. are indicated). In addition, preliminary data showed an increased catalytic transfer of the labelled galactosyl and N acetygalactosaminyl residues from exogenous nucleotide 14C-sugar precursors onto the CML-platelet endogenous sugar acceptors. These firstly reported data on molecular abnormalities of the platelet membrane GP in CML, suggested their possible relationship with the impaired platelet adhesion and aggregation occurring in this disease or the ability of leukemic platelets to express modified surface membrane components.
