LEUKOKINESIS-ENHANCING FACTOR IN HUMAN-SERUM - PARTIAL CHARACTERIZATION AND RELATIONSHIP TO DISORDERS OF LEUKOCYTE MIGRATION

In the presence (as contrasted to the absence) of serum, human polymorphonuclear leukocytes respond with enhanced movement in modified Boyden chambers. This observation is largely related to the presence in serum of a factor which enhances random migration of leukocytes (leukokinesis). This substance, termed the leukokinesis-enhancing factor (LEF), can be fractionated from normal human serum by precipitation with ammonium sulfate. LEF has a sedimentation coefficient of approximately 2.9 S and has an isoelectric point between 4.2 and 5.6. It antagonizes the effects of the cell-directed inhibitor of leukotaxis, thus providing evidence for a complex control of leukocyte movement by serum factors. LEF also has a stimulatory effect on the in vitro movement of human monocytes. A small effect of LEF in phagocytic function of human leukocytes was shown. Three patients with persistent and recurrent bacterial infections have been discussed. In each case, the major in vitro defect of leukotaxis has been a relative deficiency of LEF in their serum. This would appear to represent a previously undescribed defect of leukocyte motility. © 1979.