Advances in the study of myeloid-derived suppressor cells in infectious lung diseases.

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of immature cells capable of inhibiting T-cell responses. MDSCs have a crucial role in the regulation of the immune response of the body to pathogens, especially in inflammatory response and pathogenesis during anti-infection. Pathogens such as bacteria and viruses use MDSCs as their infectious targets, and even some pathogens may exploit the inhibitory activity of MDSCs to enhance pathogen persistence and chronic infection of the host. Recent researches have revealed the pathogenic significance of MDSCs in pathogens such as bacteria and viruses, despite the fact that the majority of studies on MDSCs have focused on tumor immune evasion. With the increased prevalence of viral respiratory infections, the resurgence of classical tuberculosis, and the advent of medication resistance in common bacterial pneumonia, research on MDSCs in these illnesses is intensifying. The purpose of this work is to provide new avenues for treatment approaches to pulmonary infectious disorders by outlining the mechanism of action of MDSCs as a biomarker and therapeutic target in pulmonary infectious diseases.

Body Composition-Specific Asthma Phenotypes: Clinical Implications.

BACKGROUND: Previous studies have indicated the limitations of body mass index for defining disease phenotypes. The description of asthma phenotypes based on body composition (BC) has not been largely reported. OBJECTIVE: To identify and characterize phenotypes based on BC parameters in patients with asthma. METHODS: A study with two prospective observational cohorts analyzing adult patients with stable asthma (n = 541 for training and n = 179 for validation) was conducted. A body composition analysis was performed for the included patients. A cluster analysis was conducted by applying a 2-step process with stepwise discriminant analysis. Logistic regression models were used to evaluate the association between identified phenotypes and asthma exacerbations (AEs). The same algorithm for cluster analysis in the independent validation set was used to perform an external validation. RESULTS: Three clusters had significantly different characteristics associated with asthma outcomes. An external validation identified the similarity of the participants in training and the validation set. In the training set, cluster Training (T) 1 (29.4%) was "patients with undernutrition", cluster T2 (18.9%) was "intermediate level of nutrition with psychological dysfunction", and cluster T3 (51.8%) was "patients with good nutrition". Cluster T3 had a decreased risk of moderate-to-severe and severe AEs in the following year compared with the other two clusters. The most important BC-specific factors contributing to being accurately assigned to one of these three clusters were skeletal muscle mass and visceral fat area. CONCLUSION: We defined three distinct clusters of asthma patients, which had distinct clinical features and asthma outcomes. Our data reinforced the importance of evaluating BC to determining nutritional status in clinical practice.

Increased versus stable dose of inhaled corticosteroids for asthma exacerbations: A systematic review and meta-analysis.

BACKGROUND: Increasing the dose of inhaled corticosteroids (ICS) is commonly used at early signs of loss of asthma control. However, the potential benefits and harms of this strategy remain unclear. We performed a systematic review and meta-analysis to compare increased dose with stable dose of ICS among adults and children with asthma. METHODS: We searched MEDLINE, EMBASE and Cochrane Central Register of Controlled Trials from inception to August 02, 2018. Randomized clinical trials comparing increased doses vs stable doses of ICS for home management of asthma exacerbations in adults or children were included. RESULTS: The analyses included 8 trials totalling 3866 patients. Four trials were judged as low risk of bias, three were unclear risk, and one was ranked as high risk. Increased dose of ICS was associated with a significantly reduced risk of treatment failure compared with stable dose (OR 0.82, 95% CI 0.70-0.97, I2  = 6%; 314 (281 to 351) vs 358 events per 1000 patients; moderate-quality evidence). There was no significant difference in unscheduled physician visits or hospital admission between increased or stable dose of ICS. However, increased dose of ICS increased the risk of non-serious adverse events (OR 3.50, 95% CI 1.93-6.35, I2  = 0%) but not serious adverse events. CONCLUSIONS: Current evidence of moderate quality supports increasing the dose of ICS as part of a self-initiated action plan to reduce risk of requiring a course of systemic corticosteroids in people with an asthma exacerbation. However, we did not find evidence for an impact on hospital admissions or unscheduled physician visits, and increased ICS dose increased risk of non-serious adverse events.