RESUMO
Recent studies show that several Siglec receptors, such as Siglec-8 and Siglec-14, may be important therapeutic targets in asthma and COPD. Siglecs are a family of lectins belonging to the immunoglobulin superfamily and recognize sialic acid residues of glycoproteins. Most of Siglecs have intracellular immunoreceptor tyrosine-based inhibitory motifs (ITIM), implicating them in the suppression of immunoreceptor signaling. Siglec-5/14 may be involved in the negative regulation of innate immune responses. The aim of this study was to analyze Siglec-5/14 expression in induced sputum cells of COPD patients in the following treatment combinations: (1) a long-acting beta2-agonist, formoterol; (2) formoterol combined with a long-acting antimuscarinic agent, tiotropium; and (3) formoterol combined with an inhaled corticosteroid or formoterol combined with tiotropium and with an inhaled corticosteroid. Siglec expression was assessed in sputum cells by flow cytometry using a specific monoclonal antibody. Double staining of cells indicated that Siglec-5/14 is expressed in monocyte/macrophages and neutrophils, but not in lymphocytes. Siglec-5/14 expression was significantly higher in patients receiving combined therapy including inhaled corticosteroids compared with patients taking only formoterol or formoterol + tiotropium. Our results suggest that inhaled corticosteroids may exert beneficial or negative effects, depending on the patients' phenotype, through increased immunosuppressive Siglec-5 or immunoactivatory Siglec-14 receptors, respectively.
Assuntos
Corticosteroides/uso terapêutico , Antígenos CD/genética , Antígenos de Diferenciação Mielomonocítica/genética , Broncodilatadores/uso terapêutico , Etanolaminas/uso terapêutico , Lectinas/genética , Doença Pulmonar Obstrutiva Crônica/tratamento farmacológico , Receptores de Superfície Celular/genética , Derivados da Escopolamina/uso terapêutico , Agonistas de Receptores Adrenérgicos beta 2/uso terapêutico , Androstadienos/uso terapêutico , Budesonida/uso terapêutico , Separação Celular , Antagonistas Colinérgicos/uso terapêutico , Quimioterapia Combinada , Fluticasona , Fumarato de Formoterol , Expressão Gênica , Humanos , Imunofenotipagem , Lectinas/agonistas , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Macrófagos/patologia , Neutrófilos/efeitos dos fármacos , Neutrófilos/metabolismo , Neutrófilos/patologia , Doença Pulmonar Obstrutiva Crônica/metabolismo , Doença Pulmonar Obstrutiva Crônica/patologia , Receptores de Superfície Celular/agonistas , Escarro/citologia , Escarro/efeitos dos fármacos , Escarro/metabolismo , Linfócitos T/efeitos dos fármacos , Linfócitos T/metabolismo , Linfócitos T/patologia , Brometo de TiotrópioRESUMO
Immune cells expressing the activation markers HLA-DR and regulatory T cells (Tregs) may be involved in the regulation of chronic inflammation in chronic obstructive pulmonary disease (COPD). In this study we analyzed native and activated cell profiles in sputum of 22 stable COPD patients receiving formoterol (F) or formoterol + tiotropium (F + T) for 3 months. Cells were isolated from induced sputum and were examined on Coulter flow cytometer using fluorescent antibodies specific for CD3, CD4, CD8, CD14, CD19, CD25, CD127, and HLA-DR antigens. Cell profiles and cell activation were assessed by analysis of HLA-DR, CD25, and CD127 co-expression in double-stained samples. Tregs were defined as CD4âºCD25(high) CD127(low) cells. We found that the combined therapy significantly decreased the CD8⺠cell number (p < 0.01). At baseline, HLA-DR was expressed in about 10 % of sputum T or B cells and a higher expression was found on monocytes. The HLA-DR expression on lymphocytes, but not monocytes, was significantly lower (p < 0.01) in patients treated with F + T. Fractions of activated [CD4⺠CD25âº] cells were also significantly lower in the combined therapy group, except for the subpopulation of CD4âºCD25(high) CD127(low) cells which was not altered. We conclude that tiotropium in add-on therapy to formoterol affects Treg cell profiles and decreases HLA-DR expression in airway lymphocytes.