Studies of the reticuloendothelial system (RES). II. Changes in the phagocytic capacity of the RES in patients with certain infections.

In our previous communication (1), we have presented data indicating that the phagocytic capacity of the reticuloendothelial system (RES) can be determined by measuring the rate of disappearance of various doses of radioisotopically labeled aggregated albumin particles from the circulation. Since our results followed the mathematical model suggested first by Michaelis and Menten in their studies of enzyme-substrate systems (2), it was possible to postulate that the rate of removal of small amounts of particulate matter from the blood is determined chiefly by the frequency of collision of the particles with RE cells. This concept is also consistent with the known dependence of the clearance rate of trace quantities of particles on the blood flow to the principal RES-containing organs, chiefly the liver and spleen (3). As the number of particles increases, however, the collision frequency is no longer a factor in the reaction velocity, the latter being governed only by the rate of the reaction of the particles with the RE cells. This is evidenced by the fact that progressively larger doses do not increase the rate of removal of the particles to a significant degree. The details of the method and the analytical procedure are discussed in the previous paper (1). The purpose of this communication is to describe the effects of certain infections, namely, pneumococcal pneumonia, typhoid fever, sandfly fever, and tularemia, on the phagocytic capacity of the reticuloendothelial system in man.