摘要：

lavage fluids in a group of 16 CF infants that included subjects as young as 4 weeks postpartum (mean age, 1 year). These authors reported increased interleukin-8 (IL-8) and neutrophil levels in CF infants compared with the, control group although the cultures were negative for the usual CF-associated bacte- rial, viral, and fungal pathogens. Interestingly, airway macro- phages from bronchoalveolar lavages of the CF infants were found to contain elevated IL-8 mRNA levels, suggesting that in addition to other cell types such as epithelial cells, the macro- phage may be a contributing source of this neutrophil-recruit- ing chemokine in CF (362). Since CFTR is expressed in mac- rophages, albeit at low levels (486), the possibility that another consequence of a CFTR defect is altered macrophage function, including abnormalities in expression of chemokines such as IL-8, cannot be excluded at present. Regardless of whether the inflammation is initiated by a CFTR defect or provoked by infections with various pathogens, the latter process further aggravates the condition, resulting in the establishment of a vicious circle of chronic respiratory infection and inflamma- tion. As a result, recurring episodes of pulmonary exacerba- tions cause irreversible tissue damage facilitated by protease- antiprotease imbalance (e.g., because of the excess of neutrophil elastase) (28). This leads to typical complications clinically manifested as bronchiolitis, atelectasis, hemoptysis, pneumothorax, fibrosis, and, over the course of many years during which this condition persists, respiratory failure and death (29, 469a).

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