Abstract
T-lymphocytosis was detected in bronchoalveolar lavage fluid of patients with sarcoidosis. To clarify the mechanism of this phenomenon, interleukin-2 receptor (IL-2R) α gene expression of lymphocytes recovered from bronchoalveolar lavage fluid was investigated in 8 patients with sarcoidosis and 5 healthy individuals, using reverse transcription polymerase chain reaction (RT-PCR). Cytoplasmic RNA derived from alveolar lymphocytes was reverse transcribed by RAV-2 reverse transcriptase to cDNA. The cDNA produced by reverse transcription was subjected to PCR. The primers of IL-2R α were utilized and a template derived from IL-2R mRNA was amplified by PCR. Southern blot analysis using 32P labeled cDNA probe for IL-2R α was performed followed by PCR. The intensities of IL-2R mRNA expression in Southern blot analysis were closely correlated to the cell numbers determined in RT-PCR.
All patients with sarcoidosis had higher expression of IL-2R α mRNA transcript in alveolar lymphocytes compared with healthy individuals. Moreover, the expression increased after stimulation by Propionibacterium acnes in 5 of 6 patients with sarcoidosis.
These findings suggest that alveolar T-lymphocytes in the patients with sarcoidosis were activated and played a central role in the pathogenesis of sarcoidosis.
