Eotaxin levels in pleural effusions: Comparison with monocyte chemoattractant protein-1 and IL-8

Objective In order to investigate the role of eotaxin in pleural diseases, we measured eotaxin in pleural effusions and studied the relationship betwe en eotaxin levels and recruitment of inflammatory cells, particularly eosin ophils. lnterleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) levels were also measured for comparison. Methods We evaluated 47 pleural effusion samples, 7 transudates and 40 exud ates, The exudates consisted of 19 malignant, 11 tuberculous, and 5 parapne umonic effusions, and 5 effusions of other etiologies. Chemokine levels wer e measured by specific sandwich enzyme-linked immunosorbent assays. Results Eotaxin was detected in all samples examined, but the levels did no t differ significantly among the exudates, There was no significant correla tion between the levels of eotaxin and MCP-1 or IL-8, The level of eotaxin but not the others was significantly higher in eosinophilic effusions (>10% eosinophils among white blood cells in the fluid) than in non-eosinophilic fluids. The number of eosinophils in pleural effusions was significantly c orrelated with the eotaxin levels, but not with the levels of other chemoki nes. The number of neutrophils was significantly correlated with IL-8 but n ot with the others. Conclusions Results suggest that eotaxin contributes to the migration of eo sinophils in pleural inflammation. Taken together with the correlation betw een IL-8 and neutrophils, it appears that the predominant type of pleural i nflammatory infiltrate is controlled, at least in part, by the subgroup of chemokines expressed in the pleural space.