Neutrophil chemotaxis under agarose: a statistical analysis and comparison of the chemotactic response of cells from different donors.

Distance of migration and cumulative cell count were determined in parallel to quantitate migration of polymorphonuclear leukocytes (PMNs) of healthy volunteers in the chemotaxis-under-agarose assay. The cumulative percent distributions of the rates of spontaneous migration in the absence of an attractant, of chemokinetic migration in zymosan-activated human serum (ZAS) incorporated in agarose, and of chemotactic migration toward ZAS were approximately normal. Cord blood PMNs are known to respond poorly to ZAS in vitro; this was used to determine whether the chemotactic indices (CI: ratio of migration toward ZAS to spontaneous migration) and the chemotactic differentials (CD: difference between migration toward ZAS and spontaneous migration) correlated with impaired chemotaxis under agarose. Both CI and CD values of cord PMNs were significantly low, indicating a positive correlation. The CI values of healthy volunteers correlated negatively with spontaneous migration, whereas the correlation of the CD values was neither negative nor positive. Since spontaneous migration of PMNS varies, the results support the use of CD values when comparing chemotactic responses of PMNs from different donors; e.g., the CD values were determined to evaluate the responsiveness of HLA-B27-positive PMNs, which we recently found to migrate under agarose toward ZAS more than HLA-B27-negative PMNs. The CD values of HLA-B27-positive PMNs were significantly high, indicating that the cells were high responders.