Leukotactic factors in health and disease.

Selected studies of neutrophil chemotaxis have been reviewed. While the multiplicity of chemotactic factors for neutrophils is recognized, it is especially evident that many of these factors are derivatives of the complement system. Also striking is the diversity of enzymes capable of producing chemotactically active fragments from complement proteins. Four conditions are cited in which complement-derived chemotactic factors are found in body fluids or tissue extracts: rheumatoid arthritis, inflammatory nonrheumatoid arthritis, immunologic vasculitis and myocardial infarcts. The interactions of chemotactic factors with neutrophils have been described in terms of the three neutrophil-associated esterases required for chemotactic responsiveness of these cells. Finally, several drugs have been studied, some of which are chemosuppressive in the chemotaxis system. These findings provide some suggestions about the mechanisms of leukocyte chemotaxis and may be relevant to the anti-inflammatory activity of these drugs.