Increased T-regulatory cells within lymphocyte follicles in moderate COPD

Lymphoid follicles in the lung parenchyma are a characteristic feature of chronic obstructive pulmonary disease (COPD). There are reports of altered CD4 T-regulatory cell numbers in COPD lungs, but the location of these cells within COPD lung tissue specific follicles has not been investigated. The presence of CD4+FOXP3+ T-regulatory cells was assessed in surgically resected lung tissue from 12 COPD patients, 11 smokers with normal lung function and seven nonsmokers by combined immunofluorescence and immunohistochemistry. Organised lymphoid follicles were observed in all three groups of patients, as well as lymphoid clusters lacking organisation. The percentage of CD4 cells that were T-regulatory cells were significantly increased (p=0.02) within COPD (16%) follicles compared with smokers (10%) and nonsmokers (8%). In contrast, there was no change (p>0.05) in the percentage of T-regulatory cells in clusters or the subepithelium between groups. Lymphoid follicles in COPD patients have increased T-regulatory cells. Therefore, T-regulatory activity may be altered within COPD lymphoid follicles. Copyright©ERS Journals Ltd 2009.