Pulmonary Defense Flashcards
What are the immune mechanisms for the upper airways and bronchi?
- Generally innate but some adaptive
- Anatomic barriers
- Angulation
- Cough reflex
- Mucociliary apparatus
- Airway epithelium
- Secretory IgA
- Dendritic cells lymphocytes and neutrophils
What are the immune mechanisms for the alveolar spaces?
- Alveolar macrophages
- Type I/ II/ III alveoalr cells
- Club cells
- Surfactant and opsonins
- Complement
- Neutrophils and eosinophils
What is the sequence of events for the cough reflex?
- Deep inspiration
- Trapping of air by shutting off exit
- Initiation of expiratory effort raising the intrathoracic pressure
- Buildup of pressure
- Sudden release of trapped air at a high pressure
How is the airway epithelium part of defense?
- It acts as a barrier
- It also releases bacteriostatic molecules
- Regulates immune response by containing receptors and producing cytokines
- Supports the microbiome
- Translocates IgA
What defense molecules does the mucus contain?
- IgA
- Lysozyme
- Lactoferrin
- Peroxidases
Describe the mucus blanket and how cilia relates to it.
- Aqueous Sol layer
- Mucus layer
- The cilia move through the sol layer strinking the mucus layer above it and propels it forwards
What conditions can alter the mucociliary clearance?
- Asthma
- Chronic bronchitis
- CF
In the conducting airway spaces what are the active immune responses?
- Intraepithelial and submucosal lymphocytes
- DC
- Cytokines
- Lots of Treg cells
- these produce the largest response
- IL-10 and TGF-B are big players as the environment is immunoregulatory
What is the first line of defense in the alveoli?
- Alveolar macrophages
- Tissue residents and they are long lilved self renewing cells
- Generally an M2 response and they help maintain tolerance
What is the primary cell that goes into the alveolar space?
- Primary responder to threats in the alveolus
- Highly inflammatory but they can get into lumen of airway and deploy NET to trap particles
What are the tissue residents of the alveolar space?
- Alveolar Macrophages
- They are M2 and secrete IL10 and TGF-B for maintenancec of tolerance in the iar space
- They can change their phenotype based on TLR binding and change to M1
What are the surfactant proteins and their significance with immuno?
- SP-A and SP-D act as opsonins
- They bind wide range of pathogens and can suppress microbial growth, as well as damage bacterial membrane and modulate macrophage phagocytosis
What are the immunoglobins found in the alveolar space?
IgA and IgG
what are the non immune opsonins found in the alveolar space?
- Surfactant
- Fibronectin
- MBL
- CRP
- Type II alveolar
- Microbiome
What does the acute inflammatory response require?
- IL-1 and TNF increase adhesion molecules on endothelium
- End result is the slowing down of neutrophils which will follow IL8
What is in the inflammatory exudate?
- Clotting proteins
- Complement
- Kinin cascade
- fibrinolytic protein
Describe the chronic inflammatory response.
- Infiltration of activated T cells and M1
- Mucus gets hypersecreted
- Substantial remodeling of tissues occurs leading to fibrosis
What happens in the early phase acute atopic response?
- Cross linking of the mIgE
- Degranulation of mast cells
- sneezing, pruritis, rinorrhea, congestion
- Preformed mast cell cytokines and inflammatory proteins recruits inflammatory cells to area
Describe the late phase chronic atopic response.
- Influx of eosinophiols, neutrophils, basophils and Th2 cells
- 10 fold increase in mast cell and increased expression of Fce receptors
- Eosinophils are proinflammatory mediators causing local tissue damage
Describe the cells found in chronic asthma related airway remodeling and what they do.
- Leukotrienes C4, D4 and E4 induce bronchospasm, vascular permeability and mucus production
- Prostaglandins D2 E2 and F2 induce bronchospasm and vasodilation
- Recruitment of sm mm cells and fibroblasts occurs leaidng to deposition of collagen in the submucosa
What cell type mediates COPD?
- Th17
- These induce IL-8 secretion from airway epithelial cells
- Recruitment of large population of inflammatory macrophages and neutrophils into the area
What is ventilator associated lung injury?
- Physical damage occurs due to over inflation and mechanical stress
- As well as biodamage due to hyperoxygenation, free radical prouction, influx of neutrophils into tissue to activate endothelium
- neutrophil netosis leading to platelet activation and clot formation
What is vaping associated lung injury?
- Presents with ARDS
- Bilateral CXR infiltrates
- Absence of infection
- Vaping use within last 90 days
- NO OTHER POSSIBLE CAUSE FOR DISTRESS
What causes lipoid pneumonia?
- Caused by inhalation aspiration of lipids
- Usually very rare but increased due to vaping CBD THC bc of the vitamin E acetate
- Essential oils (Chronic)
- vicks, castor oil, olive oil, minereal oil, petroleum jelly,
- Tx: supportive care steroids antimicrobials secondary complication
