Background: Chronic obstructive pulmonary disease (COPD) is characterized by airway inflammation and is associated with acute exacerbations. Macrolide antibiotics have been shown to exhibit anti-inflammatory effects in some chronic airway inflammatory diseases. Objective: The aim of this study was to assess the effect of treatment with erythromycin on airway inflammation and health outcome in COPD patients. Methods: We conducted a randomized, placebo-controlled, double-blind trial of erythromycin for a period of 6 months. Thirty-six COPD patients were randomized to treatment with oral erythromycin (125 mg, three times/day) or placebo. The primary outcomes were neutrophil number in sputum and exacerbations. Results: Thirty-one patients completed the study. At the end of treatment, neutrophil counts in the sputum were significantly decreased in the group treated with erythromycin compared with placebo-treated patients (p = 0.005). Total cells in the sputum and neutrophil elastase in sputum supernatant were also significantly decreased in those treated with erythromycin compared with the placebo group (p = 0.021 and p = 0.024, respectively). The mean exacerbation rate was lower in the erythromycin group than in the placebo group (relative risk = 0.554, p = 0.042). Kaplan-Meier survival analysis showed that erythromycin significantly delayed the time to the first COPD exacerbation compared with placebo (p = 0.032). Conclusions: Erythromycin treatment in COPD patients can reduce airway inflammation and decrease exacerbations and may therefore be useful in the management of COPD.

Neutrophil extracellular traps (NETs) may play a critical role in smoking-related chronic airway inflammation. However, the mechanism by which NETs induced by cigarette smoke initiate the adaptive immunity in chronic obstructive pulmonary disease (COPD) is not fully understood. In this study, we explored the effects of NETs induced by cigarette smoke on the myeloid dendritic cells (mDCs) and Th1 and Th17 cells. Additionally, we observed the inhibitory effect of erythromycin on NETs induced by cigarette smoke. We found that elevated NET levels in the sputum of COPD patients were correlated with the circulating Th1 response, mDC activation and airflow limitation. NETs induced by cigarette smoke extract (CSE) could activate monocyte-derived mDCs and promote Th1 and Th17 differentiation in vitro. Erythromycin effectively inhibited NET formation induced by CSE. In vivo, erythromycin decreased NETs in the airway and ameliorated emphysema with Th1 and Th17 cell down-regulation and CD40⁺ and CD86⁺ mDCs suppression in mice chronically exposed to cigarette smoke. These findings provide direct evidence that NETs promote the differentiation of Th1 and Th17 and play a role in the adaptive immunity of smoking-related chronic lung inflammation. Erythromycin is a potential therapeutic strategy for NETs inhibition in COPD.

The incidence of Penicillium marneffei infection has recently increased. This fungus can cause fatal systemic mycosis in both immunocompetent and immunocompromised patients without HIV infection. We retrospectively analysed Penicilliosis patients between January 1, 2003 and August 1, 2014 at the First Affiliated Hospital of Guangxi Medical University. HIV-negative patients with Penicilliosis were divided into two groups: patients with underlying disease (Group D) and patients without underlying disease (Group ND). HIV-positive patients were excluded. The relationships between overall survival and the study variables were assessed using univariate and multivariate analyses. During 11 years, Penicillium marneffei infection was diagnosed in 109 patients. Sixty-six (60.55 %) patients were HIV-positive and excluded from these cases. Forty-three patients were HIV-negative were enrolled. Among these patients, 18 (41.86 %) patients were in Group D, and 25 (58.14 %) were in Group ND. The most common underlying disease was diabetes. There were no statistically significant differences between the two groups in clinical characteristics, except for immune state and prognosis. Group ND had higher lymphocyte cell counts, CD4 cell counts, and CD4 T-cell percentages than Group D (P < 0.05). Patients in Group D had higher recurrence and mortality rates than Group ND (P < 0.05). In the univariate analysis, only underlying disease, CD4 cell percentage, and T lymphocyte cell percentage were significantly associated with overall survival. Penicillium marneffei can infect HIV-negative patients and can cause fatal systemic mycosis. There were no clear differences in clinical manifestations among HIV-negative patients with and without underlying disease. However, Penicillium marneffei in HIV-negative patients in with underlying diseases may cause immune function decline and a deficiency in T-cell-mediated immunity. Underlying disease, CD4 cell percentage, and T lymphocyte cell percentage may be potential risk factors affecting prognosis. Timely, effective, and longer courses of antifungal treatments are important in improving prognoses.

Corticosteroid insensitivity, which is induced by cigarette smoke extract (CSE), is a significant barrier when treating chronic obstructive pulmonary disease (COPD). Erythromycin (EM) has been shown to have an anti-inflammatory role in some chronic airway inflammatory diseases, particularly diffuse panbronchiolitis and cystic fibrosis. Here, we explored whether the combination therapy of EM and dexamethasone (Dex) reverses corticosteroid insensitivity and investigated the molecular mechanism by which this occurs. We demonstrated that the combination of EM and Dex restored corticosteroid sensitivity in peripheral blood mononuclear cells (PBMCs) from COPD patients and U937 cells after CSE exposure. Moreover, pretreatment with 10, 50, or 100 μg/ml EM reversed the HDAC2 protein reduction induced by CSE exposure in a dose-dependent manner. U937 cells exposed to CSE show a reduction in histone deacetylase (HDAC) activity, which was potently reversed by EM or combination treatment. Although 10 and 17.5% CSE increased phosphorylated Akt (PAkt) expression in a concentration-dependent manner, preapplication of EM and the combination treatment in particular blocked this PAkt increase. Total Akt levels were unaffected by CSE or EM treatments. Furthermore, the combination treatment enhanced glucocorticoid receptor (GR)α expression. Our results demonstrate that the combination therapy of EM and Dex can restore corticosteroid sensitivity through inhibition of the PI3K-δ/Akt pathway and enhancing GRα expression.