Human CD56+ Cytotoxic Lung Lymphocytes Kill Autologous Lung Cells in Chronic Obstructive Pulmonary Disease

Abstract

CD56+ natural killer (NK) and CD56+ T cells, from sputum or bronchoalveolar lavage of subjects with chronic obstructive pulmonary disease (COPD) are more cytotoxic to highly susceptible NK targets than those from control subjects. Whether the same is true in lung parenchyma, and if NK activity actually contributes to emphysema progression are unknown. To address these questions, we performed two types of experiments on lung tissue from clinically-indicated resections (n = 60). First, we used flow cytometry on fresh single-cell suspension to measure expression of cell-surface molecules (CD56, CD16, CD8, NKG2D and NKp44) on lung lymphocytes and of the 6D4 epitope common to MICA and MICB on lung epithelial (CD326+) cells. Second, we sequentially isolated CD56+, CD8+ and CD4+ lung lymphocytes, co-cultured each with autologous lung target cells, then determined apoptosis of individual target cells using Annexin-V and 7-AAD staining. Lung NK cells (CD56+ CD3−) and CD56+ T cells (CD56+ CD3+) were present in a range of frequencies that did not differ significantly between smokers without COPD and subjects with COPD. Lung NK cells had a predominantly “cytotoxic” CD56+ CD16+ phenotype; their co-expression of CD8 was common, but the percentage expressing CD8 fell as FEV1 % predicted decreased. Greater expression by autologous lung epithelial cells of the NKG2D ligands, MICA/MICB, but not expression by lung CD56+ cells of the activating receptor NKG2D, correlated inversely with FEV1 % predicted. Lung CD56+ lymphocytes, but not CD4+ or CD8+ conventional lung T cells, rapidly killed autologous lung cells without additional stimulation. Such natural cytotoxicity was increased in subjects with severe COPD and was unexplained in multiple regression analysis by age or cancer as indication for surgery. These data show that as spirometry worsens in COPD, CD56+ lung lymphocytes exhibit spontaneous cytotoxicity of autologous structural lung cells, supporting their potential role in emphysema progression.Trial RegistrationClinicalTrials.gov NCT00281229

Dynamics of Immune Cell Types Within the Macaque Corpus Luteum During the Menstrual Cycle: Role of Progesterone1

“…Our findings contrast with several reports using domestic animal models wherein large increases in CD4 + and CD8 + T-lymphocytes occurred in CL at the onset of regression [5,50]. CD3ε antibody was chosen as a marker of T-lymphocytes in the current study because the CD3ε receptor is expressed selectively by all T-lymphocytes, unlike CD8 which is typically co-expressed with CD16 in primate NK cells [51]. Studies in bovine CL focused on a particular subtype of T-cell, CD8 + γδ T-cells.…”

Tissue‐resident innate immunity in the lung

“…104 In humans, lung-associated NK cells respond to influenza A infection by up-regulating degranulation/cytotoxic activation marker CD107a and produce granzyme B and IFN-c, which mediates killing of infected macrophages. 105 Recently, Finch et al 106 showed increased killing of lung epithelial cells by lung NK cells, but not blood NK cells, from patients with COPD was due to DC-NK cell interactions and IL-15a transpriming. CD56 + CD16 + NK cells isolated from the airways of COPD patients have increased natural cytotoxicity in comparison to those from controls, 93 and demonstrate increased killing of autologous lung cells in co-culture experiments.…”

“…CD56 + CD16 + NK cells isolated from the airways of COPD patients have increased natural cytotoxicity in comparison to those from controls, 93 and demonstrate increased killing of autologous lung cells in co-culture experiments. 105 Recently, Finch et al 106 showed increased killing of lung epithelial cells by lung NK cells, but not blood NK cells, from patients with COPD was due to DC-NK cell interactions and IL-15a transpriming. In individuals with asthma, NKs cells in bronchoalveolar lavage fluid are skewed to a cytolytic phenotype and express higher levels of granzyme A.…”

Steroid Resistant CD8+CD28null NKT-Like Pro-inflammatory Cytotoxic Cells in Chronic Obstructive Pulmonary Disease

“…However, further characterization into CD4 + or CD8 + NKT-like cells was not performed in any of these reports. NKT-like cells have also been reported to be increased in induced sputum and bronchoalveolar lavage (BAL) of COPD patients and, importantly, have been shown to be cytotoxic to autologous lung cells (3, 4, 6). …”