The Chediak-Higashi syndrome. Fine structure of giant inclusions in freeze-fractured neutrophils.

The technic of freeze-fracture and etching has been used in the present study to examine the fine structure of giant inclusions in circulating leukocytes from a patient with the Chediak-Higashi syndrome (CHS). The surface granularity of the membranes enclosing the giant inclusions differed slightly from that of normal sized organelles. Two types of giant granules were distinguished in replicas of freeze-fractured CHS neutrophils. The difference in fine structure suggests that one variety is a massively enlarged, but essentially unaltered primary lysosome, while the other develops as a result of continued fusion of small organelles with huge inclusions throughout the stages of polymorphonuclear leukocyte maturation.