Abnormal Bactericidal, Metabolic, and Lysosomal Functions of Chediak-Higashi Syndrome Leukocytes

Abstract

Phagocytic, antimicrobial, and metabolic functions were studied in leukocytes obtained from three patients with the Chediak-Higashi syndrome (CHS) and compared to normals, individuals, heterozygous for Chediak-Higashi syndrome, and two subjects with chronic granulomatous disease of childhood (CGD). Chediak-Higashi syndrome leukocytes showed normal ingestion of a variety of bacteria, Candida albicans, and polystyrene latex particles. Intracellular destruction was significantly impaired for Staphylococcus aureus, Group D streptococci, and a rough strain of Type II pneumococci over a 2 hr incubation. Killing of Serattia marcescens was consistently delayed at 1 hr whereas that of Escherichia coli and C. albicans appeared normal, unless the incubations were shortened to 20 min. Examination of the rates of killing indicated that the greatest defect occurred in the first 20 min of contact between Chediak-Higashi syndrome cells and bacteria. Separation of Chediak-Higashi syndrome granulocytes from monocytes revealed that the former were most defective in bactericidal activity. After phagocytosis, Chediak-Higashi syndrome granulocytes displayed a normal burst in oxygen consumption and oxidation of glucose-1-(14)C and glucose-6-(14)C and formate-(14)C. Oxidation of glucose-1-(14)C by non-phagocytizing Chediak-Higashi syndrome granulocytes and monocytes averaged 2-3 times normal, whereas glucose-6-(14)C and formate-(14)C oxidation were not significantly increased by resting cells. Iodination of intracellular protein by Chediak-Higashi syndrome leukocytes was significantly increased above normal in both the resting and phagocytizing state. Electron microscopic histochemistry revealed that almost all peroxidase activity was localized to the giant granules in Chediak-Higashi granulocytes, and after bacterial ingestion there was a failure of delivery of peroxidase to many phagosomes. Upon longer incubation more phagosomes acquired peroxidase activity, presumably through a fusion process, although many giant granules remained intact. The contrasting patterns and kinetics of the killing defects and the differing metabolic properties of Chediak-Higashi syndrome and chronic granulomatous disease leukocytes emphasize the pleiomorphic nature of inherited disorders of leukocyte function.