Chronic eosinophilic pneumonia (CEP) is characterized by chronic or recurrent pulmonary infiltrates with eosinophils, but the precise mechanism of eosinophil accumulation has not been fully elucidated. Eotaxin is one of the CC chemokines that selectively recruits eosinophils and contributes to the pathogenesis of allergic airway disease including asthma, but its roles in pathogenesis of CEP have not been fully elucidated. The authors measured concentrations of eotaxin and other CC chemokines, monocyte chemoattractant protein-1 (MCP-1), regulated on activation, normal T-cell expressed and secreted, macrophage inflammatory protein-1α, and the eosinophil activating Th2 cytokine interleukin (IL)-5 in bronchoalveolar lavage (BAL) fluid from CEP patients (n = 11), and compared these concentrations with those from control subjects (n = 6). The eotaxin (904 ± 203 versus 29 ± 7 pg·mL-1, p = 0.0001), MCP-1 (194 ± 57 versus 15 ± 2 pg·mL-1, p < 0.05), and IL-5 (7.8 ± 2.0 versus 2.7 ± 0.6 pg·mL-1, p < 0.05) levels were significantly higher for cases with CEP in comparison to those serving as controls. Proportions of eosinophil and lymphocyte counts were greater in BAL fluid from CEP patients. Eotaxin and IL-5 levels correlated with the proportion of eosinophils in BAL fluid from CEP patients. MCP-1 correlated with the relative lymphocyte numbers. In short, eotaxin, interleukin-5, and monocyte chemoattractant protein-1 levels were higher in the BAL fluid of CEP patients and these levels may contribute to eosinophil and lymphocyte recruitment and activation in the airways as found with this disorder.
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