Polymorphonuclear leukocyte heterogeneity of Fc receptor expression and membrane potential in human neonates

In order to clarify the relationship among polymorphonuclear neutrophil (PMN)-related phenomena, i.e. the Fc receptor expression, the ionic condition of the plasma membrane and chemotactic response, we determined percentage of EA rosette-forming PMN (RFN), membrane potential and PMN chemotaxis in 15 neonates. RFN was assessed by the whole blood method as well as the purified PMN. Membrane potential was examined using the lipophilic fluorescent cyanine dye, 3,3'-dipentyloxacarbocyanine [di-O-C5(3)] and flow cytometry. Both parameters were measured with resting PMN. Numbers of RFN by the two methods have a significant correlation (p less than 0.01, r = 0.881, n = 15). Number of RFN by the whole blood method had a significant correlation with membrane potential (p less than 0.01, r = 0.703, n = 14). Furthermore, number of RFN and membrane potential were significantly correlated with PMN chemotaxis, respectively (p less than 0.01, r = 0.781, n = 14; p less than 0.01, r = 0.695, n = 10). When we examined the effect of beta-adrenergic agents and prostaglandin E1 on number of RFN, membrane potential and PMN chemotaxis, and attempted to confirm the interrelation among these parameters, we observed that PMN chemotaxis was markedly depressed so were both number of RFN and membrane potential. These findings indicate that impaired PMN chemotaxis may in part be related to a decrease in both rosette formation capacity of PMN and membrane potential.