Sputum induction - A useful tool in diagnosis of respiratory diseases

Bacterial load and defective monocyte-derived macrophage bacterial phagocytosis in biomass smoke-related COPD

Lower airway colonisation with species of potentially pathogenic bacteria (PPB) is associated with defective bacterial phagocytosis, in monocyte-derived macrophages (MDMs) and alveolar macrophages, from tobacco smoke-associated chronic obstructive pulmonary disease (S-COPD) subjects. In the developing world, COPD among nonsmokers is largely due to biomass smoke (BMS) exposure; however, little is known about PPB colonisation and its association with impaired innate immunity in these subjects.

We investigated the PPB load (Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis and Pseudomonas aeruginosa) in BMS-exposed COPD (BMS-COPD) subjects compared with S-COPD and spirometrically normal subjects. We also examined the association between PPB load and phagocytic activity of MDMs and lung function. Induced sputum and peripheral venous blood samples were collected from 18 healthy nonsmokers, 15 smokers without COPD, 16 BMS-exposed healthy subjects, 19 S-COPD subjects and 23 BMS-COPD subjects. PPB load in induced sputum and MDM phagocytic activity were determined using quantitative PCR and fluorimetry, respectively.

Higher bacterial loads of S. pneumoniae, H. influenzae and P. aeruginosa were observed in BMS-COPD subjects. Increased PPB load in BMS-exposed subjects was significantly negatively associated with defective phagocytosis in MDMs and spirometric lung function indices (p<0.05).

Increased PPB load in airways of BMS-COPD subjects is inversely associated with defective bacterial phagocytosis and lung function.

Different expression about induced sputum cell sorting in the two main types of chronic obstructive pulmonary disease

BACKGROUND

The difference in expression of sputum cells types between the two main types of chronic obstructive pulmonary disease (COPD) is largely unknown. This study aims to investigate the difference and then wants to depend on sputum cells sorting to direct the treatment of COPD.

METHODS

A total of 218 patients with stable COPD (FEV1 < 80%) were selected. Stable COPD patients (n = 218) were classified as eosinophilic (A phenotype) or noneosinophilic (B phenotype); sometimes, the subjects were separated into cough group (C phenotype) and dyspnea group (D phenotype). Cross-sectional analysis was conducted comparing demographics and clinical characteristics. Receiver-operating characteristic curve was used to assess predictive ability of sputum eosinophils for D phenotype.

RESULTS

The A phenotype showed a higher correlation with the patients complaining of presenting with dyspnea on exertion, the dyspnea group (D phenotype). The B phenotype showed a higher prevalence of those who cough and product sputum, this was cough group (C phenotype). Sputum eosinophil and macrophages counts were significantly higher in patients with dyspnea (n = 95) compared to those with cough (P < .05), and neutrophils were significantly lower in patients with dyspnea (n = 95) compared to those with cough (P < .05). Percentage sputum eosinophil count was predictive of dyspnea (D phenotype) COPD with area under curve (AUC) of 0.831 (95% confidence interval (CI) 0.77-0.89; P ≤ .001). Neutrophils were also predictive of dyspnea (D phenotype) COPD with AUC of 0.276 (95% CI 0.204-0.347; P ≤ .001).

CONCLUSION

These findings suggest that the morphological phenotypes of COPD show several clinical characteristics and different sputum cell sorting.