Gender differences in the T-cell profiles of the airways in COPD patients associated with clinical phenotypes

Abstract

T lymphocytes are believed to play an important role in the pathogenesis of chronic obstructive pulmonary disease (COPD). How T cells are recruited to the lungs and contribute to the inflammatory process is largely unknown. COPD is a heterogeneous disease, and discriminating disease phenotypes based on distinct molecular and cellular pathways may provide new approaches for individualized diagnosis and therapies. Bronchoalveolar lavage (BAL) and blood samples were obtained from 40 never-smokers, 40 smokers with normal lung function, and 38 COPD patients. T-cell chemokine receptor expression was analyzed with flow cytometry, and soluble BAL cytokines and chemokines were measured using a cytokine multiplex assay. Correlations with gender and clinical characteristics including lung imaging were investigated using multivariate modeling. Th1/Tc1- and Th2/Tc2-associated soluble analytes and T-cell chemokine receptors were analyzed as cumulative Th1/Tc1 and Th2/Tc2 immune responses. A higher expression of chemokine receptor CCR5 on CD8+ T cells in BAL and higher percentage of CXCR3+CD8+ T cells in blood was found in female smokers with COPD compared to those without COPD. CCR5 expression on CD4+ and CD8+ T cells was lower in BAL from male smokers with COPD compared to those without COPD. Among female smokers with COPD, Th1/Tc1 immune response was linked to BAL macrophage numbers and goblet cell density, and Th2/Tc2 response was associated with the measures of emphysema on high-resolution computed tomography. The highly gender-dependent T-cell profile in COPD indicates different links between cellular events and clinical manifestations in females compared to males. Our findings may reveal mechanisms of importance for the difference in clinical course in female COPD patients compared to males.

Keywords: Th1/Th2; bronchoalveolar lavage; chemokines; cytokines.

Conflict of interest statement

The authors report no conflicts of interest in this work.

Figures

Figure 1

Results of univariate analysis. Notes: Percentages of CXCR3+ among (A) CD4+ and (B) CD8+ T cells in BAL. MFI of CCR5 on (C) CD4+ and (D) CD8+ T cells and the MFI of CXCR4 on (E) CD4+ and (F) CD8+ T cells in BAL from healthy never-smokers (NS), smokers with normal lung function (S), smokers with COPD (CS), and ex-smokers with COPD (CE). Horizontal lines represent the median values. **P<0.01. Abbreviations: BAL, bronchoalveolar lavage; COPD, chronic obstructive pulmonary disease; MFI, median fluorescence intensity.

Figure 2

Relative concentrations of (A) IL-13 and (B) CXCL12 in BAL supernatant from healthy never-smokers (NS), smokers with normal lung function (S), smokers with COPD (CS), and ex-smokers with COPD (CE). Notes: Data have been group mean-centered for the removal of batch effects. Horizontal lines represent the median values. *P<0.05; **P<0.01; ***P<0.001. Abbreviations: BAL, bronchoalveolar lavage; IL, interleukin.

Figure 3

Multivariate modeling comparing T-cell subsets and soluble analytes of smokers with normal lung function versus COPD smokers. Notes: (A) OPLS-DA resulted in a significant separation between female smokers and female COPD patients (R2=0.50, Q2=0.41, P=8×10−4). Left panel shows the score plot with the predictive component along the x-axis and the y-axis indicating the numerical order of the subjects. The right panel shows the loadings plot, with primarily eleven variables driving a separation. (B) Among males, the analysis resulted in a significant separation between male smokers and male COPD patients (R2=0.32, Q2=0.25, P=0.016) with primarily eight variables driving a separation. Boxes above zero are markers upregulated and boxes below zero are markers downregulated due to COPD. Black dots: COPD smokers; white dots: smokers with normal lung function. Abbreviations: BAL, bronchoalveolar lavage; COPD, chronic obstructive pulmonary disease; IFN, interferon; IL, interleukin; MFI, median fluorescence intensity; OPLS-DA, orthogonal projections to latent structures discriminate analysis; TGF, transforming growth factor.

Figure 4

Results of univariate analysis on gender-associated factors separate in smokers with normal lung function and COPD smokers. Notes: MFI of CCR5 on CD8+ T cells in (A) blood and (B) BAL. (C) Percentage of CXCR3+ cells among CD8+ T cells in blood, from female smokers and female COPD smokers. MFI of CCR5 on both (D) CD4+ T cells and (E) CD8+ T cells in BAL from male smokers and male COPD smokers. Horizontal lines represent the median values.*P<0.05, **P<0.01. Abbreviations: BAL, bronchoalveolar lavage; COPD, chronic obstructive pulmonary disease; MFI, median fluorescence intensity.

Figure 5

SUS analysis comparing COPD-specific cytokine and T-cell profiles in the male (y-axis) versus female (x-axis) smoking populations. Notes: Variables along the negative diagonal indicate the opposite response to COPD in males and females (variables 1–5), while variables along the outer edges of the y-axis indicate a response to COPD in females, but not males (variable 6). P(corr) [1], the scaled loadings of predictive component for the respective OPLS model. Abbreviations: BAL, bronchoalveolar lavage; COPD, chronic obstructive pulmonary disease; OPLS, orthogonal projections to latent structures; SUS, Shared and Unique Structures.

Figure 6

Associations between pathways and clinical parameters. Notes: Significant associations between pathways and clinical parameters were found among female COPD smokers for the (A) Th2/Tc2 pathway and HRCT attenuation <−950 HU (P=0.002), (B) the Th1/Tc1 pathway and macrophage numbers in BAL (P=0.006) as well as with (C) lung airway goblet cell density (P=0.02). Among male smokers, a significant association was found between the (D) Th2/Tc2 pathway and serum IgG concentrations (P=0.003). Values of r represent PLS inner relation between the respective clinical variables and the respective analytes involved in the respective pathway. Th1/Tc1 pathway: CCR5, CXCR3, CD69 receptors, and BAL mediators TNF-α, IFN-γ, CCL3–5, CXCL9–10. Th2/Tc2 pathway: CXCR4, CD69 receptors and BAL mediators IL-4, IL-13, and CXCL12. u, latent scores variable for the Y-block of PLS; t, latent scores variable for the X-block of PLS. Abbreviations: BAL, bronchoalveolar lavage; COPD, chronic obstructive pulmonary disease; HRCT, high-resolution computed tomography; HU, Hounsfield units; IFN, interferon; IL, interleukin; PLS, partial least squares; TNF, tumor necrosis factor.