Migration of neutrophils is dependent on mast cells in nonspecific pleurisy in rats.

To determine the role of mast cells in the recruitment of neutrophils and eosinophils, acute nonspecific pleurisy was induced by injecting isologous serum into normal +/+ and mast cell-deficient Ws/Ws rats. In +/+ rats, neutrophil infiltration peaked 4 h after serum administration, followed by influx of eosinophils after 24-48 h. The levels of neutrophil influx after 4 h as well as the activity of myeloperoxidase (MPO) in pleural lavage-cell extract were significantly lower in Ws/Ws rats than in +/+ rats. In contrast, numbers of eosinophils as well as activity of eosinophil peroxidase (EPO) did not differ significantly between Ws/Ws and +/+ rats. For local reconstitution of mast cells, +/+ rat peritoneal mast cells (PMC) or mesenteric lymph node cells (MLNC) as a control were transferred into the Ws/ Ws pleural cavity. Serum injection into animals with PMC transfer 7 days previously triggered augmented neutrophil influx by approximately 4.7-fold as compared to that in MLNC-transferred animals. Mast cells recovered from the pleural cavity of PMC-transferred rats showed histamine contents equivalent to 20% of that of freshly isolated PMC and retained the reactivity to compound 48/80. These results indicated that dependency of neutrophil recruitment on resident mast cells is greater than that of eosinophils in isologous serum-induced pleurisy.