A new micropore filtration approach to the analysis of white cell rheology

Transit times of individual polymorphonuclear leukocytes (PMN) through cylindrical micropores with a diameter of 8 microns and a length of 19 microns were measured at pressure gradients of 3 to 10 cm H2O using the Cell Transit Analyzer (CTA); this system employs a conductometric principle and provides a frequency histogram of transit times for greater than 1000 cells within 3 to 4 minutes. Salient results included: 1) linear pressure-flow relations (r greater than or equal to 0.99); 2) mean transit times for PMN on the order of 10-20 milliseconds at a pressure gradient of 4 cm H2O and thus transit times at least 10-fold longer than for RBC under the same conditions; 3) broad distributions with marked skewness toward longer transit times, indicating a wide range of rheologic properties; 4) increased transit times in either hypotonic or hypertonic media; 5) marked increases of transit times following activation with FMLP; 6) considerable differences between the volume distribution and the transit time distribution of PMN. These results suggest the basic usefulness of the CTA for the analysis of rheologic properties of white blood cells in both normal and pathologic states.