Background: The appearance and extension of apoptosis phenomenon in lymphocytes originated from the lower airways of patients with pneumoconioses, including silicosis and asbestosis, as well as its relation to the clinical data, remains unclear.
Methods: Bronchoalveolar lavage (BAL) was carried out in 11 patients with silicosis, 8 with asbestosis and in 7 control subjects. L-BAL were a) studied for CD95 and CD95 Ligand expression, b) permeabilized and stained with PI (flow cytometry, ModFit software) for apoptosis/cell cycle analyses and c) stained with Annexin V FITC/PI.
Results: The low number of L-BAL enter apoptosis. No significant changes between studied groups were found in PI determined apoptosis (silicosis: 1.8 +/- 0.7%, asbestosis: 3.1 +/- 0.9%, controls: 1 +/- 0.7%, median +/- SEM). Similar results were obtained, if tested with Annexin V FITC. However, the asbestosis group was characterized by higher CD4/CD8 ratio and increased percent of L-BAL CD95 Ligand expression (21.0 +/- 4.5 vs 13.7 +/- 3.3 in controls). In silicosis L-BAL apoptosis was inversely correlated with FEV1/VC values (r=-0.26, p<0.05). Surprisingly the majority of BAL lymphocytes expressed CD95, the marker of cell susceptibility to apoptotic stimuli; no difference between studied groups was found.
Conclusions: Lower airways lymphocytes seem to be prevented from excessive apoptosis. Tendency to slightly increased percent of apoptotic and/or Fas Ligand cells reflects likely the local immunity alterations in asbestosis patients.