RT Journal Article SR Electronic T1 Significant increase of CD57+ cells in pulmonary lymphoid follicles of COPD patients JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP erj02015-2009 DO 10.1183/09031936.00201509 A1 J. Olloquequi A1 J.F. Montes A1 A. Prats A1 E. Rodríguez A1 M.A. Montero A1 J. García-Valero A1 J. Ferrer YR 2010 UL http://erj.ersjournals.com/content/early/2010/06/04/09031936.00201509.abstract AB Although the presence of pulmonary lymphoid follicles (LF) has been associated with the progression of chronic obstructive pulmonary disease (COPD), there is no information about the pattern of vascularization, expression of addressins or inflammatory cell densities within these structures in COPD.Histological and immunohistochemical techniques were used to assess the prevalence, structure, localization, vascularization and cell proliferation/apoptosis of LF, as well as the follicular density of B and T lymphocytes, macrophages, dendritic cells and CD57+ cells in lung tissue of 9 non-smokers, 18 smokers without COPD, 16 smokers with moderate COPD and 16 patients with very severe COPD.The density of CD57+ cells within LF of COPD patients was significantly increased compared to non-smokers and smokers without COPD (p<0.05). Moreover, the percentage of LF profiles with cell apoptosis was also significantly higher in COPD patients (p=0.03). By contrast, no significant differences among groups were observed in the follicular densities of other inflammatory cells, nor in the distribution of blood and lymphatic vessels within LF.Since CD57+ cells are important effectors of cytotoxicity and immune regulation, an increase of their follicular density supports the hypothesis of a local immune dysfunction in COPD.