Defective Mononuclear Leukocyte Chemotaxis in the Chediak

Chemotaxis of mononuclear leukocytes from humans, mink, and cattle was evaluated in vitro using a morphologic Boyden chamber technique and a new labeled mononuclear radioassay with a double micropore filter system. Significantly decreased mononuclear leukocyte chemotactic responses were noted when human, mink, or cattle Chediak-Higashi cells were tested using autologous serum or endotoxin-activated autologous serum. A similar Chediak-Higashi mononuclear leukocyte defect was noted in humans when kallikrein or dialyzable transfer factor were used as the chemotactic stimulus. Studies using smaller pore filters in the chemotactic chamber exaggerated the chemotactic defect. Serum from ChediakHigashi subjects had normal chemotactic activity. Additional studies on the spontaneous ( random) locomotion of ChediakHigashi mononuclear leukocytes revealed normal results when a capillary tube assay system was used, but abnormal results were obtained when a Boyden chamber micropore filter assay was used, demonstrafing fundamental differences in these two assays of random locomotion. It is clear from these studies that defective mononuclear leukocyte chemotaxis is another feature of the impaired host defenses in the Chediak-Higashi syndrome that may contribute to the marked susceptibility to pyogenic infections se characteristic of this disease.