Increased T regulatory cells within lymphocyte follicles in moderate COPD

¹ University of Manchester, Education and Research Centre, South Manchester University Hospitals Trust, Manchester, UK.
² University of Manchester, Education and Research Centre, South Manchester University Hospitals Trust, Manchester, UK.; and Dept of Cardiology and Respiratory Medicine, Hyidovre Hospital, Hyidovre, Denmark

	Abstract

Lymphoid follicles in the lung parenchyma are a characteristic feature of COPD. There are reports of altered CD4 T regulatory cell numbers in COPD lungs, but the location of these cells within COPD lung tissue specifically 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 7 non-smokers by combined immunofluorescence and immunohistochemistry.

Organised lymphoid follicles were observed in all 3 groups of patients, as well as lymphoid clusters lacking organization.. The percentage of CD4 cells that were T regulatory cells are significantly increased (p=0.02) within COPD (16%) follicles compared to smokers (10%) and non-smokers (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. T regulatory activity may therefore be altered within COPD lymphoid follicles.