[Introductory remarks for symposium on "biological membranes of blood cells"].

Recent progress on studies of structure and functions of biological membranes has been successfully achieved. Various topics on membrane abnormalities in blood cells were selected for this symposium. First of all, in red cell disorders, abnormal red cell morphology is crucial for identification of various kinds of hemolytic anemias. In addition, cytoskeletal protein abnormalities in red cell membrane were reviewed, especially on the pathogenesis of hereditary elliptocytosis and hereditary spherocytosis. Abnormal red cell membrane fluidity was also discussed in relation to insulin receptor on red cell membranes in diabetic patients. A role of growth factors, especially G-CSF and GM-CSF, on granulocytes was described from the standpoint of membrane receptors. Platelets demonstrate various glycoproteins (GP) on their cell membrane surfaces. Abnormalities on these glycoproteins, such as GP IIb-IIIa and GP Ib-IX complex, were observed in thromboasthenia and Bernard-Soullier syndrome. In addition, arachidonic acid cascade is important in platelet functions, especially for signal transduction of extracellular messages through plasma membranes. Finally, a new application of a liposome immune lysis assay was introduced for laboratory determinations of complements, antibodies, and various marker proteins. The symposium will be extremely helpful for further understanding of the structure-function relationship and of the various disorders of blood cell membranes.