Inflammatory cellular changes in the large airway of asthma COPD overlap (ACO) patients

Abstract

<b>Background:</b> Lack of evidence on the inflammatory cell population in ACO airways has led to their poor prognosis and treatment. <b>Aim:</b> To enumerate inflammatory cell changes in airway wall of ACO and compare them with asthma (AS), COPD current smokers (CS) and ex-smokers (ES), normal lung function smokers (NLFS), and non-smoker controls (HC). <b>Methods:</b> Immunohistochemically stained endobronchial biopsy tissues 12 ACO were enumerated for macrophages (MPs), neutrophils (NLs), CD4+, and CD8+ T cells in epithelium (EPI), reticular basement membrane (RBM) cells/mm, and lamina propria (LP) cells/mm² up to 120 µM deep inside and compared to similar areas in 24 HC, 14 AS, 13&nbsp;COPD-CS, 14 COPD-ES, and 20 NLFS. <b>Results:</b> Compared to asthma and COPD, ACO had higher MPs and lower NLs among the inflammatory cells evaluated. MPs were increased in EPI, RBM, and LP of ACO than HC (p:&lt;0.0001-0001), COPD-CS (p&lt;0.0001, all areas), and -ES (p:&lt;0.0001-0.005). Compared to NLFS, MPs were higher only in ACO RBM (p=0.0003). NLs were decreased in ACO RBM and LP than HC (p&lt;0.0001; p&lt;0.0001), COPD-CS (P&lt;0.05; p&lt;0.05), -ES (p&lt;0.03; p&lt;0.002), and NLFS (p&lt;0.0001; p&lt;0.0001). NLs in epithelium were unchanged except in HC, with higher cells than ACO (p&lt;0.04). While CD8+ cells in EPI and LP were unchanged among groups, it increased in ACO RBM than HC (p&lt;0.03), COPD-ES (p&lt;0.02), and NLFS (P&lt;0.004). Similarly, CD4+ cells were unchanged among groups except with higher cells in ACO RBM than AS (p&lt;0.05), COPD-CS (p&lt;0.02), -ES (p=0.01), and NLFS (p&lt;0.04). <b>Conclusions:</b> To our knowledge this is the first comprehensive assessment of inflammatory cells in ACO. The ACO inflammatory profile were different compared to COPD and asthma patients alone.