Biochemical quantitation of the chemotactic factor inactivator activity in human serum

CFI of whole human serum was measured by a new assay that utilizes chemotactic factor-induced release of a lysosomal enzyme (N-acetyl glucosaminidase) from cytochalasin B-exposed neutrophils as an index of chemotactic activity. The effectiveness of serum as an inactivator of chemotactic factor-induced enzyme release closely correlated with the serum CFI as determined by assay of neutrophil chemotaxis in Boyden chambers. In comparison to serum from healthy persons, there was elevated CFI in the serum from patients with sarcoidosis and Hodgkin's disease by both assay systems. The results indicate that measurement of serum inhibition of chemotactic factor-induced lysosomal enzyme release from neutrophils provides a rapid, reliable, and reproducible assay of serum CFI. (J Lab Clin Med 93:17, 1979.)