The European respiratory journal : official journal of the European Society for Clinical Respiratory Physiology
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The phenotype of alveolar macrophages (AMs) is known to be modulated during pathological immune reactions in the lung. In this study, we wanted to determine the relationship between the AM phenotype and changes in the proportions of the various immune cells in bronchoalveolar lavage (BAL). BAL was performed in 76 consecutive patients, including 32 with sarcoidosis, 8 with idiopathic pulmonary fibrosis, 9 with pneumoconiosis, 13 with other respiratory disorders, and 14 controls without evidence of interstitial lung disease. ⋯ Eosinophils in BAL were not associated with a significant increase in AM membrane antigen expression. Prominent changes of the AM phenotype were found in active sarcoidosis showing lymphocytic alveolitis, with more frequent expression of CD54, KiM2, CD71, CD11b and RFD9. In conclusion, this study shows that the phenotype of AMs is related to the type and intensity of the immunopathological reaction in the lung, and correlates with the proportions of bronchoalveolar cells.