Shifted focus of bronchoalveolar lavage in patients with suspected thoracic malignancy: an analysis of 224 patients

BACKGROUND

Bronchoscopies are extensively adopted for diagnosing and staging thoracic malignancies, but studies are missing as how to keep the process streamlined and more efficient. To evaluate current role of bronchoalveolar lavage (BAL) for cancer and possible infection diagnosis when practicing comprehensive bronchoscopy for patients suspected with thoracic malignancy, and provide foundation for possible practice modification.

METHODS

We retrospectively analyzed a prospectively kept database of immunocompetent patients undergoing bronchoscopy for suspected non-hematologic malignancies. Clinical, radiographic data, bronchoscopic sampling techniques and diagnostic results were recorded. Initially undiagnostic patients were followed up for 2 years for a definitive diagnosis.

RESULTS

Of 224 patients included, 179 (79.9%) were confirmed with active thoracic malignancies. BAL diagnostic yield of cancer based on different radiographic characters of target lesion are as follow: isolated lymphadenopathies 0%, central lesions 45.5%, peripheral masses (diameter ≥3 cm) 21.4%, peripheral large nodules (2≤ diameter <3 cm) 15.8%, and peripheral small nodules (diameter <2 cm) 7.1%, while composite bronchoscopy achieved diagnostic yield of 93.3%, 95.5%, 91.7%, 76.9%, and 66.7% in corresponding lesion types. No cancer was diagnosed solely by BAL-cytology. Proportions of patients with positive BAL culture did not differ significantly between patients with and without pre-test suspicion for infections (P=0.199). In multivariable analysis, infections were associated with age ≥75 (OR 3.0; 95% CI: 1.29-7.06), chronic obstructive pulmonary disease (COPD) (OR 2.7; 95% CI: 1.14-6.26) and diabetes mellitus (DM) (OR 4.5; 95% CI: 1.90-10.44).

CONCLUSIONS

Omitting BAL cytology in settings of comprehensive bronchoscopy may not compromise cancer diagnosis. For patients primarily suspected with thoracic malignancy, performing BAL culture only based on clinical suspicion could miss important infectious etiology.

Uncontrolled asthma and its risk factors in adult Chinese asthma patients

Background:

Asthma affects a large number of patients in China, but relatively little is known about asthma management among Chinese patients. This study aims to estimate asthma control rate among adult Chinese patients and to identify predictors associated with uncontrolled asthma.

Methods:

A total of 4125 asthma patients aged ⩾17 years and representing all regions of mainland China except Tibet were surveyed. Asthma control status was assessed using the Asthma Control Test (ACT) and classified as controlled (ACT score ⩾ 20) and uncontrolled (ACT score ⩽ 19). A multivariate logistic regression model was used to identify predictors associated with uncontrolled asthma from the factors including demographics, rhinitis, allergic rhinitis, and treatment adherence.

Results:

Asthma was controlled in 44.9%, and uncontrolled in 55.1% of the study participants. High rates of uncontrolled asthma were found in patients with treatment nonadherence (77.3%), poor adherence (66.2%), no schooling (64.8%), or obesity (62.9%). The risk of uncontrolled asthma was much higher in the treatment nonadherence group than the complete adherence group [odds ratio (OR) = 4.55 (3.68–5.62), p < 0.001]. Other predictors for uncontrolled asthma included concomitant rhinitis [OR = 1.31 (1.14–1.50), p < 0.001], obesity [OR = 1.31 (1.05–1.64), p = 0.019], asthma duration > 3 years [OR = 1.22 (1.07–1.39), p = 0.004] and age ⩾ 45 years [OR = 1.23 (1.07–1.41), p = 0.004].

Conclusions:

About half of the participants in this study had uncontrolled asthma. Treatment nonadherence is one of the significant predictors, which is very strongly associated with uncontrolled asthma. Efforts should be prioritized to promote patients’ treatment adherence to improve asthma control while attention is needed on rhinitis or obesity.

Decreased CD34+ cell number is correlated with cardiac dysfunction in patients with acute exacerbation of COPD

BACKGROUND AND PURPOSE

Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is associated with a higher risk of cardiovascular disease (CVD). Previous studies have indicated that the reduction of bone marrow-derived multipotent progenitors (CD34+ cells) may lead to reduced vascular repair capacity and may help to identify patients that pose an increased cardiovascular risk. However, the relationship between CD34+cells and CVD risk in AECOPD remains unclear. The aim of the present study was to assess CD34+ cell counts and their relationship with classical adverse cardiac outcome predictors in AECOPD.

METHODS

For our study, 27 patients with AECOPD (GOLD stage III, IV), 26 with stable COPD (GOLD stage III, IV), and 24 healthy controls were enrolled. CD34+ cells were enumerated, and plasma concentrations of N-terminal pro-B-type natriuretic peptide (NT-proBNP), a systemic inflammation marker (high-sensitivity C-reactive protein, hsCRP) and mobilisation marker (matrix metalloproteinase-9, MMP-9), were measured. Echocardiography was performed to evaluate cardiac dysfunction and pulmonary hypertension.

RESULTS

Compared with healthy controls, AECOPD patients had a significantly decreased CD34+ cell count (5.1 ± 2.6 versus 9.4 ± 3.6 × 10³/ml), especially in patients with a prior history of acute exacerbation. For patients with AECOPD, the CD34+ cell count was inversely correlated with NT-proBNP levels, pulmonary artery systolic pressure (PASP) and resting heart rate, and positively correlated with left ventricular ejection fraction (LVEF). In all three groups, CD34+ cell count was negatively correlated with hsCRP.

CONCLUSIONS

The circulating CD34+ cell count was decreased and correlated with cardiac dysfunction in AECOPD patients, and thus may account for the increased cardiovascular risk in this population.

Down-regulation of Aquaporin1 (AQP1) by peptidoglycan via p38 MAPK pathways in primary rat pleural mesothelial cells

BACKGROUND AND OBJECTIVE

This study was designed to investigate the p38 mitogen-activated protein kinase (MAPK) signaling pathway involved in Aquaporin1 (AQP1) expression caused by staphylococcal peptidoglycan (PGN) in cultured rat pleural mesothelial cells (rPMCs) in vitro.

METHODS

RT-PCR and immunoblot analysis were used to determine the relative mRNA and protein levels of AQP1 by PGN in rPMCs. P38 kinase inhibitor SB203580, JNK inhibitor SP600125, and ERK1/2 inhibitor PD98059 were used to determine the effects of PGN-induced AQP1 expression by immunoblot. Activation of p38 by PGN was reflected by detecting the phosphorylation constituent of p38, using immunoblot. The shift of localization after activation of p38 by PGN was investigated by immunofluorescence assay.

RESULTS

AQP1 transcription and protein expression were decreased by PGN in dose-dependent and time-dependent manners in rPMCs. Down-regulation of AQP1 by PGN was blocked only by SB203580, neither by SP600125 nor by PD98059. Furthermore, rPMCs exposed to PGN showed activation of p38 MAPK. Phospho-p38 protein production was increased by PGN stimulation in rPMCs. The localization of phospho-p38 was both in the cytosol and nuclei after PGN treatment, while its normal distribution is mainly in the cytosol in rPMCs.

CONCLUSION

AQP1 expression was decreased by PGN in both dose-dependent and time-dependent manners in rPMCs. This down-regulation by PGN-induced AQP1 in rPMCs may be mediated by the activation of p38 MARK pathway.

The role of the β2 adrenergic receptor on endothelial progenitor cells dysfunction of proliferation and migration in chronic obstructive pulmonary disease patients

BACKGROUND

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in patients with moderate-to-severe chronic obstructive pulmonary disease (COPD), with > 44% of these patients presenting with generalized atherosclerosis at autopsy. It is accepted that endothelial progenitor cells (EPCs) participate in the repair of dysfunctional endothelium, thereby, protecting against atherosclerosis. The β2 adrenergic receptor (β2AR) expressed on mononuclear cells in peripheral blood and CD34(+) cells in bone has been shown to regulate T-cell traffic and proliferation. At present, there have been few systematic studies evaluating β2AR expression on EPCs in the peripheral blood of COPD patients and its role in EPCs migration and proliferation. Therefore, the objective of this study was to determine the role of β2ARs in EPCs function and, if this role is altered, in the COPD population.

METHODS

EPCs from 25 COPD and 16 control patients were isolated by Ficoll density-gradient centrifugation and identified using fluorescence-activated cell sorting. β2AR expression on EPCs was determined by western blotting and real-time PCR. The transwell migration assay was performed to determine the migration capacity of EPCs treated with a β2AR agonist, antagonist and β2AR monoclonal antibody. EPCs proliferation was assayed throughout the cell cycle. Following arterial damage in NOD/SCID mice, the number of EPCs treated with siRNA-β2AR incorporated at the injured vascular site was determined by fluorescence microscopy.

RESULTS

Data showed a significant increase in the total number of β2ARs in addition to an increased expression on early EPCs in COPD patients. COPD EPCs treated with β2AR antagonist (ICI 118551) increased migration to SDF-1α when compared to treatment with the β2AR agonist, norepinephrine. These changes were directly correlated to increase CXCR4 on EPCs. The proliferation of early EPCs treated with β2AR antagonist was improved and was correlated to an intercellular decrease in reactive oxygen species.

CONCLUSION

Changes in β2AR in COPD patients alter EPCs migration and proliferation, contributing to altered EPC repair capacity in this patient population.

Human endothelial progenitor cells isolated from COPD patients are dysfunctional

Cardiovascular disease is the leading cause of morbidity and mortality in patients with moderate-to-severe chronic obstructive pulmonary disease (COPD). More than 44% of these patients present with generalized atherosclerosis at autopsy. It is accepted that endothelial progenitor cells (EPCs) participate in the repair of dysfunctional endothelium and thus protects against atherosclerosis. However, whether COPD affects the repairing capacity of EPCs is unknown. Therefore, the objective of this study was to determine whether and how EPCs are involved in the vascular repair process in patients with COPD. In our study, EPCs from 25 COPD and 16 control patients were isolated by Ficoll density-gradient centrifugation and identified using fluorescence activated cell sorting. Transwell Migratory Assay was performed to determine the number of EPC colony-forming units and the adherent capacity late-EPCs to human umbilical vein endothelial cells. Following arterial damage in NOD/SCID mice, the number of EPCs incorporated at the injured vascular site was determined using a fluorescence microscope. We found that the number of EPC clusters and cell migration, as well as the expression of CXCR4, was significantly decreased in patients with COPD. Additionally, the number of late-EPCs adherent to HUVEC tubules was significantly reduced, and fewer VEGFR2(+)-staining cells were incorporated into the injured site in COPD patients. Our study demonstrates that EPC capacity of repair was affected in COPD patients, which may contribute to altered vascular endothelium in this patient population.

Effects of downregulation of aquaporin1 by peptidoglycan and lipopolysaccharide via MAPK pathways in MeT-5A cells

This study was designed to investigate the signaling pathway involved in aquaporin1 (AQP1) expression caused by peptidoglycan (PGN) from Staphylococcus aureus and lipopolysaccharide (LPS) in human pleural mesothelial cell lines (MeT-5A) in vitro. RT-PCR, immunoblot analysis, and immunofluorescence assay were used to determine the relative mRNA and protein levels of AQP1 caused by PGN and LPS in MeT-5A cells. Activation of MAPKs by PGN and LPS was reflected by detecting the phosphorylation constituents of extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun N-terminal kinase (JNK), and p38 using immunoblot. MAPKs inhibitors were used to determine the effects of PGN- and LPS-induced AQP1 expression by immunoblot. AQP1 transcription and protein expression were decreased by PGN and LPS in dose- and time-dependent manners in MeT-5A cells. Both PGN and LPS activated p38/ERK/JNK pathways in MeT-5A cells. Furthermore, downregulation of AQP1 expression by LPS was blocked by SB203580, SP600125, and PD98059, which are inhibitors of p38, JNK, and ERK1/2, respectively. In contrast, downregulation of AQP1 expression by PGN was blocked only by SB203580, not by SP600125 or PD98059, underlying the importance of p38 MAPK in the downregulation of AQP1 expression by PGN in MeT-5A cells. AQP1 expression was decreased by both PGN and LPS in dose- and time-dependent manners in MeT-5A cells. AQP1 expression was down-regulated by PGN via p38 MAPK pathway, while AQP1 expression was down-regulated by LPS via p38/JNK/ERK pathways.

Potential role of AQP1 and VEGF in the development of malignant pleural effusion in mice

Recent studies have revealed the important role of aquaporin-1 (AQP1) in tumor cell migration and angiogenesis. However, the function of AQP1 in malignant pleural effusion has not been well characterized. We established a mouse model to examine the role of AQP1 and vascular endothelial growth factor (VEGF) in the development of malignant pleural effusion. We showed that elevated expressions of AQP1 mRNA and VEGF protein were associated with increased volume of malignant pleural effusion. These results suggest that AQP1 and VEGF play important roles in the development of malignant pleural effusion in mice, which may help us find new strategies for the prevention and treatment of malignant pleural effusion.

Distinct roles of cholinergic receptors in small cell lung cancer cells

BACKGROUND

Cholinergic receptors are expressed in small cell lung cancer (SCLC); however, the distinct functions of muscarinic cholinergic receptor 3 (mAChR3) and the nicotinic cholinergic receptor (nAChR) in SCLC have not yet been completely elucidated.

MATERIALS AND METHODS

RT-PCR and Western blotting were used to investigate the expression of cholinergic receptors. Flow cytometry was used to detect the integrin expression. Cell proliferation, adhesion and migration assays were carried out in vitro to determine the roles of the cholinergic receptors in SBC3 human SCLC cells.

RESULTS

Both mAChR3 and nAChR were expressed in the SBC3 cells. Acetylcholine iodide (Ach) stimulated SBC3 cell proliferation, adhesion and migration toward fibronectin (Fn). The mAChR3 antagonist, 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP), or the nAChR antagonist, mecamylamine hydrochloride (Meca), inhibited SBC3 cell proliferation in the presence or the absence of exogenous Ach. 4-DAMP abrogated cell adhesion and migration toward Fn induced by Ach, while Meca had no effect. Interestingly, Ach did not alter Fn receptor (alphavbeta1 or alpha5beta1 integrin) expression, while anti-beta1 integrin antibody or anti-alphav and anti-alpha5 integrin antibody completely abrogated cell adhesion to Fn induced by Ach.

CONCLUSION

Both mAChR3 and nAChR are expressed in SCLC. SBC3 cell proliferation is regulated in vitro through both cholinergic receptors. In contrast, SBC3 cell migration and adhesion toward Fn are modulated only by mAChR. Moreover, the stimulatory effects of Ach on cell adhesion and migration through mAChR3 are presumably modulated by functional alteration of alphavbeta1 and alpha5beta1 integrin, but not by any variation in their expression. The mAChR3 antagonist may therefore be a beneficial therapeutic modality for SCLC patients, especially those with chronic obstructive pulmonary disease (COPD) as a comorbidity.

[Effect of leukotriene receptor antagonist on cough variant asthma]

OBJECTIVE

To study the curative effect of leukotriene receptor antagonist on cough variant asthma (CVA).

METHODS

Sixty-four CVA patients received treatment with bricany and montelukas and 68 control patients had bricany treatment for 4 weeks. The recurrence rate was observed in the two groups during the follow-up for 6 months.

RESULTS

The remission time of two groups were 2.5-/+3.6 and 5.3-/+3.8 days in acute phase, respectively, showing a significant difference between them (P<0.05). The recurrence rate of the two groups within 6 months were 20.09% and 40.87%, respectively, showing also significantly differences (P<0.05).

CONCLUSION

Leukotriene receptor antagonist and bricany can effectively control CVA and significantly lower the short-term recurrence rate of CVA.

[Effects of glucocorticoids on tuberculous pleural effusion: experiment with rats]

OBJECTIVE

To explore the effects of systemic glucocorticoid treatment on tuberculous pleural effusion.

METHODS

Ninety Wistar rats were intrapleurally injected with 0.03 mg of standard human Mycobacterium tuberculosis to establish models of tuberculous pleural effusions and then were randomly divided into 2 equal groups both without anti-tuberculosis treatment: glucocorticoids group (GG) undergoing intramuscular injection of 0.3 mg triamcinolone acetonide in the right thigh 24 h after intrapleural injection, and control group (CG) received nothing as control. 8, 24, 32, and 48 hours, and 3, 5, 7, 10, and 15 days after intramuscular injection 5 rats from each group were killed. The thorax was opened, the amount of pleural effusion (PE) was recorded, and the pleural cavity, histopathology of pleura and lung parenchyma were examined. The white blood cell (WBC) count and differential leukocyte count, and levels of total protein (TP), glucose (GLU), and lactic dehydrogenase (LDH) in the PE were determined. Bioassays were used to detect the PE levels of soluble intercellular adhesion molecule-1 (sICAM-1), transforming growth factor beta1 (TGF-beta1), and interferon gamma (IFN-gamma).

RESULTS

The PE volumes of GG 8 - 48 h after the intramuscular injection were significantly lower than those of CG (P < 0.05, P < 0.01), and PE completely disappeared on day 3. The WBC in PE 24 - 48 h after and the percentages of neutrophils 8 - 48 h after the intramuscular injection of GG were all significant lower than those of CG (all P < 0.01). The TP levels 32 and 48 h after the intramuscular injection of GG were both significantly higher than those of CG (both P < 0.01). The LDH level of GG within 24 h after the intramuscular injection was significantly lower than that of CG (P < 0.01). Both the sICAM-1 and TGF-beta1 levels of GG were higher 8 h after the intramuscular injection, but lower 48 h after the intramuscular injection than those of CG (both P < 0.01). The IFN-gamma levels 8 - 48 h after the intramuscular injection of GG were all higher than those of CC (all P < 0.01). The IFN-gamma/TGF-beta1 ratios at different time points of GG were all higher than those of CG, and there were significant differences in those 8 - 48 h after the intramuscular injection between these 2 groups (all P < 0.01). Pathologically, the mean thickness of pleura in GG was significantly less than that in CG. Congestion and edema in subpleural and pulmonary interstitium were less in GG than in CG.

CONCLUSION

Early use of glucocorticoids helps reduce the inflammatory response in pleural cavity in tuberculous pleurisy accelerate the absorption of pleural effusion and decrease the thickness of pleura.

Expression of aquaporin-1 in rat pleural mesothelial cells and its specific inhibition by RNA interference in vitro

BACKGROUND

The discovery of water channel aquaporins (AQPs) has greatly expanded the understanding of the regulation of the water permeability of biological membranes. Aquaporin-1 (AQP1) may be involved in fluid transport in numerous pathological conditions. The objective of the present study was to examine whether AQP1 is present in cultured rat pleural mesothelial cells (PMCs) and to investigate the specific inhibitory effect of RNA interference (RNAi) on AQP1 expression in PMCs, which may provide a new method for the further studies on the relation between expression of AQP1 in PMCs and pleural fluid removal in vivo.

METHODS

PMCs were isolated and cultured from rat pleura. The expression of AQP1 in PMCs was confirmed by immunocytochemical staining and reverse transcriptase-polymerase chain reaction (RT-PCR). Two eukaryotic expression plasmid vectors of short hairpin RNA (shRNA) specific for the AQP1 gene of rat sapien were designed and constructed. The recombinant plasmid vectors were transfected into cultured rat PMCs by cation liposomes. Flow cytometry was used to screen the most effective shRNA at 48 hours after transfection. The expressions of AQP1 mRNA and protein were detected by RT-PCR and Western blotting method at 48 hours after transfection.

RESULTS

RT-PCR and immunostaining revealed that AQP1 mRNA and protein were present in cultured rat PMCs. Two effective eukaryotic expression plasmid vectors of shRNA specific for the AQP1 gene were constructed successfully. The levels of the expression of AQP1 were inhibited by 83.45%, 90.93%, respectively, at mRNA level and 41.24%, 67.60%, respectively at protein level by two recombinant plasmids at 48 hours after transfection. The expression of AQP1 in PMCs transfected with plasmid was significantly lower than that of the cells transfected with the control plasmid HK and that of the untransfected cells (P < 0.01). There was no significant difference in AQP1 expression between the control group and the group transfected with AQP1 nonspecific shRNAs (P < 0.05).

CONCLUSIONS

The expression of AQP1 was present in rat PMCs. The application of shRNA-AQP1 could markedly inhibit the expression of AQP1 in cultured rat PMCs. The use of RNAi is a promising tool for future research into the mechanisms of pleural fluid in vivo.

Increased expression of aquaporin-1 on the pleura of rats with a tuberculous pleural effusion

OBJECTIVE

The purpose of this study was to investigate whether the expression of AQP-1 on the pleura is altered in a rat model with a tuberculous pleural effusion (TPE) and to study its function.

METHODS

A TPE model was established by intrapleural inoculation with 0.03 mg (2 ml) standard tuberculosis bacillus (H(37)Rv). The rats with TPE were sacrificed at different time points (day 1, 3, or 5) after inoculation. The control group received a 2-ml intrapleural injection of saline. The visceral and parietal pleural tissues were harvested and processed for real-time RT-PCR, Western blot, immunohistochemistry, and determination of tissue AQP-1 levels. Recombinant adenovirus Ad-rAQP-1 containing full-length cDNA of AQP-1 was constructed. Six groups of seven Wistar rats were assigned to receive the following treatments: group 1: intrapleural administration of normal saline; group 2: intrapleural administration of tuberculosis bacilli (TB); group 3: intrapleural inoculation with TB at day 7 following intrapleural administration of Ad-rAQP-1 vector; group 4: intrapleural inoculation with 0.03 mg TB at day 7 following intrapleural administration of control Ad-GFP vector; group 5: intrapleural administration of Ad-rAQP-1; group 6: intrapleural administration of control Ad-GFP vector. The expression of AQP-l on the pleural tissue was detected by immunohistochemistry and Western blot analysis. Histopathologic changes of the pleura and the volume of pleural fluid were examined on day 7 following gene intervention or on day 3 following TB inoculation.

RESULTS

Bilateral pleural effusions appeared within 5 days in all rats who received an intrapleural inoculation with TB. The peak amount of pleural fluid occurred on day 3. The AQP-1 expression at protein and mRNA was increased in the early phase of TPE. The expression of AQP-1 was increased in the Ad-rAQP-1 gene transfer group, indicating successful adenovirus gene transfer. The volume of pleural fluid in group 3 (6.1 +/- 0.7 ml) was significantly increased compared with that in group 2 (3.8 +/- 1.0 ml) and group 4 (4.0 +/- 1.1 ml).

CONCLUSION

These findings suggested that AQP-1 was increased in TPE and it may be involved in the formation of TPE.

[Inhibition of the aquaporin-1 gene expression by RNA interference: experiment with cultured rat pleural mesothelial cells]

OBJECTIVE

To investigate the influence of RNA interference (RNAi) on the expression of aquaporin-1 (AQP1) gene and to investigate the feasibility of gene therapy for pleural effusion.

METHODS

Two recombinant plasmids with shRNAs targeting the AQP1 gene, AQP1-1-pGenesil and AQP1-2-pGenesil-1 were constructed. Pleural mesothelial cells were obtained from rats, cultured, and randomly divided into 5 groups: blank control group, Lipofectamine 2000 control group, HK negative control group, AQP1-1-pGenesil-1 transfected group, and AQP1-2-pGenesil-1 transfected group. RT-PCR and Western blotting were used to detect the mRNA and protein expression of AQP1.

RESULTS

The mRNA expression levels of aquaporin-1 of the AQP1-1-pGenesil-1 and AQP1-2-pGenesil-1 transfected groups were inhibited by 83.5% and 90.9% respectively, and the protein expression levels of the AQP1-1-pGenesil-1 and AQP1-2-pGenesil-1 transfected groups were inhibited by 41.2% and 67.6% respectively.

CONCLUSION

RNAi can successfully inhibit the expression of AQP1 and has the feature of sequence correlation of shRNA in the cultured rat pleural mesothelial cells. It may be used as a potential new approach for gene therapy of pleural effusion.

[Study on the relationship between airway bacterial infections and acute exacerbations in patients with chronic obstructive pulmonary disease]

OBJECTIVE

The purpose of this study was to observe the bacterial infections of respiratory tract in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD).

METHODS

130 patients with AECOPD in outpatient department, emergency room or in wards were studied prospectively. Patients were divided into different groups according to both Anthonisen's classification and their lung function status. Sputum were cultured together with bacteria positive rate and types of AECOPD as well as the damage degree of lung function were analyzed.

RESULTS

Of 130 sputum samples, 50 showed positive through culture (38.5%) and 60 strains of pathogens were isolated. Predominant pathogens isolated would include Haemophilus parainfluenzae (20/60), Streptococcus pneumoniae (5/60) and Haemophilus influenzae (10/60). Positive rate of bacterial culture in type 1 AECOPD was 55.0%, higher than those of type 2 (38.3%) and type 3 (18.5%)(P = 0.01) and was increasing with the decrease of lung function of patients with AECOPD (P < 0.02).

CONCLUSION

Positive rate of bacterial culture in patients of type 1 AECOPD was the highest one. Haemophilus parainfluenzae was one of the most important pathogens in AECOPD. There seemed a correlation between positive result of bacterial culture and the severity of COPD.