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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: BACKGROUND, METHODS, RESULTS. Meshes: ATP Binding Cassette Transporter, Subfamily B, Adult, Aged, CD28 Antigens, CD8-Positive T-Lymphocytes, Case-Control Studies, Cellular Senescence, Cytokines, Down-Regulation, Drug Resistance, Female, Flow Cytometry, Glucocorticoids, Humans, Inflammation Mediators, Male, Microscopy, Fluorescence, Middle Aged, Natural Killer T-Cells, Phenotype, Pulmonary Disease, Chronic Obstructive, Receptors, Glucocorticoid.
user
Is lymphocyte senescence in COPD associated with loss of glucocorticoid receptor expression by pro-inflammatory/cytotoxic lymphocytes? Context: Glucocorticoid (GC) resistance is a major barrier in COPD treatment. We have shown increased expression of the drug efflux pump, Pgp1 in cytotoxic/pro-inflammatory lymphocytes in COPD. Loss of lymphocyte co-stimulatory molecule CD28 (lymphocyte senescence) was associated with a further increase in their pro-inflammatory/cytotoxic potential and resistance to GC. We hypothesized that lymphocyte senescence and increased Pgp1 are also associated with down-regulation of the GC receptor (GCR). Blood was collected from 10 COPD and 10 healthy aged-matched controls. Flow cytometry was applied to assess intracellular pro-inflammatory cytokines, CD28, Pgp1, GCR, steroid binding and relative cytoplasm/nuclear GCR by CD28+ and CD28null T, NKT-like cells. GCR localization was confirmed by fluorescent microscopy. COPD was associated with increased numbers of CD28nullCD8+ T and NKT-like cells. Loss of CD28 was associated with an increased percentage of T and NKT-like cells producing IFNγ or TNFα and associated with a loss of GCR and Dex-Fluor staining but unchanged Pgp1. There was a significant loss of GCR in CD8 + CD28null compared with CD8 + CD28+ T and NKT-like cells from both COPD and controls (eg, mean ± SEM 8 ± 3% GCR + CD8 + CD28null T-cells vs 49 ± 5% GCR + CD8 + CD28+ T-cells in COPD). There was a significant negative correlation between GCR expression and IFNγ and TNFα production by T and NKT-like cells(eg, COPD: T-cell IFNγ R = -.615; ) and with FEV1 in COPD (R = -.777).
assistant
COPD is associated with loss of GCR in senescent CD28null and NKT-like cells suggesting alternative treatment options to GC are required to inhibit these pro-inflammatory/cytotoxic cells. Final Decision: yes