PURPOSE: The aim of study was to redescribed clinical phenotypes according to sputum inflammatory cell count, and to investigate inflammatory factors in the sputum supernatant and serum in these subgroups.
METHODS: 83 patients with AECOPD and 26 healthy controls were recruited. Sputum induction, sputum processing and cell count were performed. Based on the inflammatory cell proportions in sputum, subjects were categorized into four inflammatory subtypes. Eosinophilic COPD: sputum eosinophils > 2.5%; Neutrophilic COPD: sputum neutrophils > 61%; Low neutrophilic COPD: sputum eosinophils ≤ 2.5% and sputum neutrophils ≤ 61%; Mixed granulocytic COPD: sputum neutrophils > 61% and sputum eosinophils > 2.5%. The inflammatory mediators in sputum supernatant and serum, including serum amyloid-A (SAA), C-reactive protein (CRP), interleukin-6 (IL-6) and matrix metalloproteinase-9 (MMP-9), were measured by using ELISA.
RESULTS: AECOPD patients had increased BODE scores, decreased FEV1, decreased FEV1/predicted %, and decreased FEV1/FVC compared to healthy controls. All the 83 patients were in the Global Initiative for Chronic Obstructive Lung Disease stage II-IV. Among the 83 patients , there were 10(12%)eosinophilic, 36(43%)neutrophilic, 5(6%)mixed and 32(39%)low neutrophilic phenotypes. The level of MMP9,IL-6 and CRP in sputum supernatant was significantly different in four subgroups, among which the mixed cellular COPD was the highest, and the neutrophilic COPD was the second (P<0.05). Similarly, the mixed cellular COPD had the highest level of SAA, IL-6 and CRP in serum, and the neutrophilic COPD was the second (P<0.05).
CONCLUSIONS: Based on the new inflammatory cell phenotypes described above, the expression of inflammatory factors in four subgroups was different. These findings indicate that macrophages are involved in the process of inflammation through different pathophysiological mechanisms in four subgroups.
CLINICAL IMPLICATIONS: The inflammatory phenotype is a useful clinical therapeutic guide for AECOPD assessment and treatment,and can be used as the basis for further research into the pathogenesis of this heterogeneous disorder.
DISCLOSURE: Jie Zhang: Other: Jilin Provincial Science and Technology Departmeng
The following authors have nothing to disclose: Peng Gao, Ke Wang, Xiaoyan He, Yuqiu Hao, Huan Liu, Peter G Gibson
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