Abstract
Increase of monocytes in the peripheral blood of the patients with congenital neutropenia might be a compensatory phenomenon for the lack of neutrophils in defence mechanism.
We attempted to clarify bactericidal and cryptocidal capacity of monocytes, and compared with those of neutrophils. Monocytes were obtained from a patient with cyclic neutropenia, and a patient with severe combined immunodeficiency when neutrophils were absent or greatly reduced with increase in monocytes. Neutrophils were obtained from healthy adults.
Monocyte killing of both Staphy. aureus and Strept. faecalis, and cryptocidal capacity of monocytes were similar to those of neutrophils. The NBT dye reduction capacity of monocytes was not less than of neutrophils.
Myeloperoxidase mediated antimicrobial system provides an especially potent bactericidal activity. Since monocytes do not contain as much peroxidase as neutrophils, peroxidase independent bactericidal system will operate in monocytes more actively than neutrophils.
