The active principle in the leukocytosis-promoting factor of exudates.

T HE earlier studies of the writer have demonstrated that the leukocytosis accompanying many inflammatory processes is referable to the liberation at the site of inflammation of a factor closely associated with the pseudoglobulin fraction of ‘ ‘ 2 , 3 The factor per se offers a reasonable explanation for the mechanism of leukocytosis with inflammation. This factor not only induces a discharge ofimmature leukocytes into the circulating blood,’ but it also is capable of producing a hyperplasia of granulocytes and of megakaryocytes in the bone marrow.4 The factor (abbreviated as the LPF) is active on human beings, thus suggesting possible clinical application.5 It has been found to be active on guinea pigs. This animal may well serve as a convenient assay animal.6 In as yet unpublished studies, it has been found that the LPF reinforces the leukocytosis caused by an already existing inflammation. This may be significant in the usage of the material in clinical cases with inflammatory processes. It is quite conceivable that the factor may be utilized as an adjunct to the antibiotics. The leukocytosis-promoting factor has always been recovered in the form of a pseudoglobulin. Recent studies in association with Dr. G. Cooper and Mr. M. L. Dillon at Duke University suggest that the LPF seems to be distributed primarily between the a1 and a2 globulins of exudates. In the present communication evidence is furnished which suggests that the active group in the pseudoglobulin molecule of exudates is a relative simple polypeptide.