Introduction: The pathobiology of acute respiratory failure in term infants remains poorly defined. Neonatal acute lung disease is associated with an alveolitis characterized by increased levels of cytokines and inflammatory cells in tracheal lavage. Proinflammatory cytokines in airway lavage are significantly elevated above serum levels during acute lung injury and recovery suggesting that these factors are produced locally in the lung. Using RT-PCR we studied cytokine mRNA expression by airway cells (AC), and compared AC number, IL-β, IL-6 and IL-8 levels during acute lung injury and after recovery. Methods: Twenty-five term infants with respiratory failure were lavaged on day 1 of ECMO and 1 day after ECMO. Differential cell counts, ELISA and RT-PCR for IL-1β, IL-6 and IL-8 were performed on lavage samples. Results are expressed as ng/ug secretory IgA(sIgA) or cells/ug sIgA. RT-PCR was standardized with GAPDH.Results: mRNA for IL-1β, IL-6, IL-8 and GAPDH was readily detected in AC on day 1 and after ECMO despite a significant decrease in cell number and cytokine levels. Conclusion: AC actively transcribe IL-1b, IL-6 and IL-8 mRNA and may be the source of these cytokines in lavage fluid. Lung recovery was not associated with loss of cytokine mRNA expression by AC. Table

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