Comparison of lymphocyte immune phenotypes in bronchoalveolar lavage of non-smoking patients with sarcoidosis and other interstitial lung diseases.

Bronchoalveolar lavage (BAL) as complementary method is still used as ancillary tool in diagnosis of interstitial lung diseases. Tobacco smoking has been described to affect the BAL lavage cellular profile. To our knowledge, only few reports have so far investigated CD3⁺CD4⁺ and CD3⁺CD8⁺ lymphocyte subsets in non-smoking sarcoidosis patients additionally stratified according to CXR stage, and compared them to other non-smoking patients with interstitial lung diseases (ILDs).

We compared lymphocytes immune phenotypes, subsets, with CD3⁺, CD3⁺CD4⁺ and CD3⁺CD8⁺ cell markers, in the non-smoking subjects (n=297) including the patients with pulmonary sarcoidosis (S), idiopathic pulmonary fibrosis (IPF) (n=22), hypersensitivity pneumonitis (HP) (n=15), other interstitial idiopathic pneumonias (OIIPs) (n=39). According to prognosis, the patients with S were divided into four groups: 18 patients with Löfgren's syndrome (LS) in chest X-ray (CXR) ≤1 stage, 64 patients without LS in CXR ≤1 stage, 113 patients in CXR 2 stage and 26 patients with advanced CXR ≥3 stage.

After the use of false discovery rate (FDR) correction, relative numbers (%) of CD3⁺, CD3⁺CD4⁺, CD3⁺CD8⁺ and CD3⁺CD4/CD3⁺CD8 ratio showed the most significant differences between the non-smokers with S (both with/without LS) and the non-smokers with other ILDs (IPF, OIIPs, HP). These lymphocytes subsets were further altered in the non-smokers with CXR stage 2 compared to the non-smokers with other ILDs (IPF, OIIPs, HP). We did not observe any differences in these lymphocyte subsets and CD3⁺CD4⁺/CD3⁺CD8⁺ ratio between the non-smokers with advanced sarcoidosis stage (CXR ≥3) and the non-smokers with IPF.

Our data on the non-smokers confirmed the presence of the typical BAL cellular profile in sarcoidosis. The BAL cellular profile was helpful namely for differentiation of less advanced sarcoidosis. Its definite diagnostic utility should be the subject of further clinical studies with large numbers of the well characterized patients taking into consideration other clinical factors influencing BAL cellular profile, such as smoking or treatment.