Bacterial–viral load and the immune response in stable and exacerbated COPD: significance and therapeutic prospects

Figures & data

Figure 1 Scheme representing the normal airway microbiota and human respiratory pathogens most frequently associated with COPD exacerbations.

Abbreviation: COPD, chronic obstructive pulmonary disease.

Table 1 Breakdown of different bacterial microbiota studies in COPD

Study (reference)	Control subjects	COPD patients	Sampling method	Predominant stage of COPD	Microbes evaluated	Location of study population	Cytokines/biomarkers correlated with bacteria
18	0	143	Sputum	2–3 (stable vs exacerbated)	Hem, Strep, Mor	Out	CRP
19	0	120	Sputum	2–3 (stable vs exacerbated)	Hem, Strep, Mor	Out	IL-1B, IL-8, IL-10, TNF-α
0	0	99	Sputum	2	Hem, Strep, Mor	Out	CXCL8, IL-IB, MPO
21	10	4	BAL fluid	1	Total bacterial community	Out	na
	0	6	tissue	4		In
23	16	8	Tissue	4	Total bacterial community	In	na
24	10	22	BAL fluid	2	Total bacterial community	Out	na
25	10	10	Sputum	na	Strep, Kleb, Pseud	Out	na
26	0	17	Sputum	2–3–4	Total bacterial community	Out	na
27	4	5	Tissue	4	Total bacterial community	In	na
28	0	8	Endotracheal aspirates	4 (exacerbated)	Total bacterial community	ICU	na
29	0	16	Sputum	3–4 (stable vs exacerbated)	Total bacterial community	Out	na
30	0	12	Sputum	2–3 (stable vs exacerbated)	Total bacterial community	Out	na

Abbreviations: BAL, bronchoalveolar lavage; COPD, chronic obstructive pulmonary disease; CRP, C-reactive protein; CXCL8, CXC-chemokine ligand 8; Hem, Haemophilus influenzae; ICU, intensive care unit; IL-1B, interleukin 1B; IL-8, interleukin 8; IL-10, interleukin 10; In, inpatients; Kleb, Klebsiella pneumoniae; Out, outpatients; Mor, Moraxella catarrhalis; MPO, myeloperoxidase; na, not available; Pseud, Pseudomonas aeruginosa; Strep, Streptococcus pneumoniae; TNF-α, tumor necrosis factor α.

Figure 2 Representation of the known mechanisms proposed to explain how influenza virus favors bacterial outgrowth.

Notes: Bronchial epithelial damage is followed by a decrease of neutrophils recruitment, NK activity, and Th17 numbers and activity. Alveolar epithelial damage could be followed by a decrease of alveolar macrophage numbers and activity.
Abbreviation: NK, natural killer.