Introduction:

Diffuse interstitial lung diseases are a hard-to-diagnose heterogeneous group of respiratory diseases. The study of bronchoalveolar lavage through flow cytometry may define typical cell patterns in different diseases and so help confirm the differential diagnosis. The purpose of this study was to retrospectively analyze the clinical utility of cell and lymphocyte subpopulations detected in the bronchoalveolar lavage by flow cytometry in order to define typical cell patterns that allow for making a differential diagnosis of granulomatous lung diseases.

Materials and methods:

The retrospective study included 44 patients. The subjects were diagnosed with sarcoidosis or hypersen sitivity pneumonitis during a period of 3 years. We performed the cellular analysis of bronchoalveolar lavage through flow cytometry and histological and imaging testing (HRCAT, High Resolution Computed Axial Tomography) as part of the diagnosis. The percentages of T cells, B cells, NK cells, CD4, CD8 and CD4/CD8 were analyzed by flow cytometry for the following markers: CD3 +, CD19 + CD4 +, CD8 +, CD3 + CD4-CD8- and CD3 + CD16-CD56-.

Results:

We conclude that the most important parameters were lymphocytosis and especially the CD4/CD8 quotient. This quotient was high for diseases such as sarcoidosis and low for hypersensitivity pneumonitis, in comparison with the values found in the peripheral blood.

Conclusions:

The BAL (Bronchoalveolar Lavage) study is useful for differentiating between granulomatous interstitial lung diseases and other DILDs (diffuse interstitial lung diseases).

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