Correlation between the Numbers of γδ T Cells and CD4+HLA-DR+ T Cells in Broncho-Alveolar Lavage Fluid from Patients with Diffuse Lung Disease

Abstract

CD4+HLA-DR+ T cells are known to be increasing in broncho-alveolar lavage fluid (BALF) from patients with sarcoidosis, and related to disease activity. Although there are several reports that the number of γδ T cells in peripheral blood from patients with sarcoidosis are increasing, contradictory assertions can be seen about the number of γδ T cells in BALF, and the clinical significance on the presence of γδ T cells in disease site of patients with diffuse lung disease including sarcoidosis. The absolute number of γδ T cells and CD4+HLA-DR+ T cells in BALF were determined by flow cytometry in 107 patients with diffuse lung diseases; 56 with sarcoidosis, 36 with collagen vascular diseases with lung involvement and 15 with idiopathic pulmonary fibrosis. We also measured the number of the transferrin receptor-positive macrophages in BALF. The correlation between γδ T cells and activated (maybe antigen-specific) T cells and macrophages were evaluated. Sarcoidosis patients were also evaluated from the data of the number of γδ T cells in peripheral blood by flow cytometry and clinical backgrounds. A significant correlation between the numbers of these two cell types was detected in each of the three patient groups. The percentage of peripheral γδ T cells was markedly increased in 7 sarcoidosis patients, each of whom also showed affected organs other than lung, however, 5 individuals did not show an increased number of γδ T cells in BALF. The number of γδ T cells in BALf did not correlate with the number of transferrin receptor-positive macrophages in all three patient groups. These results suggest that the increased number of γδ T cells in diffuse lung diseases likely plays a role in immunosurveillance and contributes to the activation of antigen-specific αβ T cell.