EVALUATION OF RETICULOENDOTHELIAL FUNCTION IN MAN.

The CONCEPT of the reticuloendothelial system (RES) as groups of fixed macrophages in various organs which are related functionally and morphologically was developed by Aschoff in 1924. 1 Since that time, experimental studies have amply documented the involvement of the RES in areas of lipid metabolism, tumor growth, antibody production, and general host resistance, 2 but lack of a practical method of measuring RE function in man has hindered an accurate estimation of its clinical significance. In experimental studies, colloidal substances which are known to be phagocytized by RE cells and whose rate of disappearance from the circulation can be measured, such as colloidal gold or carbon, are employed to evaluate RE function. Since these colloids are not metabolized, they cannot be safely administered to human subjects in doses large enough to determine RE phagocytic activity or capacity. Recently, I 131 -labeled aggregated albumin has been developed for the clinical