Chemokine involvement in tetracycline-induced pleuritis

Sclerosants such as tetracycline (TCN) have often been used in the control of malignant pleural effusions. Although the resultant inflammatory respons e is probably important in the ensuing pleural fibrosis, the signals respon sible for the cellular influx into the pleural space following TCN instilla tion are not well understood. This study, therefore, sought to determine wh ether the chemokines interleukin-8 (IL-8), growth-related protein (Gro), an d monocyte chemotactic protein-1 (MCP-1) were locally elaborated within the first 72 h following intrapleural TCN administration. TCN induced an exudative effusion with high lactate dehydrogenase activity. Although there was no significant change in the pleural fluid total leukoc yte content, the median polymorphonuclear neutrophil concentration decrease d from 1.067 x 10(6) to 2.03 x 10(5) cells.mL(-1) between 24 and 72 h, wher eas the median macrophage concentration increased from 1.44 x 10(5) to 5.98 x 10(5) cells.mL(-1) over the same period. Furthermore, IL-8, Gro and MCP- 1 concentrations decreased between 24 and 72 h. Immunocytochemistry indicat ed expression of IL-8 by pleural mesothelial cells 24 h, but not 72 h, foll owing TCN administration. The data suggest that local elaboration of interleukin-8 and growth-related protein, in part of mesothelial origin, may influence neutrophil recruitme nt in tetracycline-induced pleuritis.