No abstract

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by SARS-CoV-2, a newly discovered coronavirus that exhibits many similarities with the severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) coronaviruses (SARS-CoV and MERS-CoV, respectively). The definite pathogenesis and immunological influences of SARS-CoV-2 have not been fully elucidated. Therefore, we constructed a brief summary comparison of SARS-CoV-2, SARS-CoV, and MERS-CoV infections regarding their immunological changes. In addition, we further investigated the immunological differences between severe and nonsevere COVID-19 cases, and we searched for possible immunological predictors of the patient outcome by reviewing case series studies to date. Possible immunological predictors of a poor outcome are leukocytosis, neutrophilia, lymphopenia (both CD4 and CD8 T cells), an increased neutrophil-to-lymphocyte ratio (NLR), and increased levels of pro-inflammatory cytokines (IL-6 and TNF-α), Th1 cytokines (IL-2 and IFN-γ), regulatory T cell cytokines (IL-10) and Th17 cytokines (IL-17). A more precise immunological map needs to be established, which may assist in diagnosing this disease and facilitate immunological precision medicine treatment.

Asthma is a chronic inflammatory airway disease characterized by variable airflow obstruction, bronchial hyper-responsiveness, and airway inflammation. The chronic inflammation of the airway is mediated by many cell types, cytokines, chemokines, and inflammatory mediators. Research suggests that exposure to air pollution has a negative impact on asthma outcomes in adult and pediatric populations. Air pollution is one of the greatest environmental risks to health, and it impacts the lungs’ innate and adaptive defense systems. A major pollutant in the air is particulate matter (PM), a complex component composed of elemental carbon and heavy metals. According to the WHO, 99% of people live in air pollution where air quality levels are lower than the WHO air quality guidelines. This suggests that the effect of air pollution exposure on asthma is a crucial health issue worldwide. Macrophages are essential in recognizing and processing any inhaled foreign material, such as PM. Alveolar macrophages are one of the predominant cell types that process and remove inhaled PM by secreting proinflammatory mediators from the lung. This review focuses on macrophages and their role in orchestrating the inflammatory responses induced by exposure to air pollutants in asthma.